Aquafeed vol 11 issue 2 2019

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VOL 11 ISSUE 2 April 2019

A D VA N C E S I N P R O C E S S I N G & F O R M U L AT I O N An publication

Spray-dried eggs

Developing feeds for mullets Yeast cell walls Good dryer design Replacing fish oil in marine aquafeeds Metal amino acid complexes Macroalgae for organic aquaculture Feeding greater amberjack juveniles

PROCESSING Training Technology Victam preview New! Ask the Expert

Bßhler – gentle processing at its best. From raw material handling, cooking and shaping through extrusion to drying and coating of finished products. With an extensive know-how and a passion for quality we ensure product uniformity, production efficiency, and maximum sanitation and safety.

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Complete solutions from a single source. Aqua Feed.

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20170921_International_Aquafeed_October.indd 1

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3 Volume 11 Issue 2 2019




* Cover story

A quick look at what to expect at the feed industry’s premier processing show, Victam International; upcoming aquafeed production courses, what to look for in a dryer.


INTERVIEW Peter Hutchinson


Introducing the latest member of our team: Pete will be answering your processing questions in his new column.

Replacing fishmeal with brewing industry by-products in diets for mullets.




Recent insights in fatty acid nutrition are making fish oil replacement increasingly feasible in marine aquafeeds.


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COLUMNS GREG LUTZ—TRENDS & DEVELOPMENTS Research-based information: An increasingly scarce resource at the global producer level. ALBERT TACON— Interesting nutrition studies in the Chinese literature. PETER HUTCHINSON— ASK THE EXPERT Your processing questions answered CALENDAR OF EVENTS

To read previous issues in digital format or to order print copies, visit:

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Peter Hutchinson, is an aquaculture nutritionist and processing expert. He has owned and operated a pilot scale extrusion facility in Auckland, New Zealand, since 1997, producing a diverse range of extruded products for international clients. With a focus on aquafeed and pet food, he specializes in hands on equipment operation. Pete has a passion for improving product performance, including formulation optimization, onsite staff training, plant utilization and process engineering. Starting in this issue, we are pleased to welcome Pete as our latest columnist: he looks forward to answering your technical questions. His Q&A column is on page 52.

Interview AQUAFEED: Not too many people have your range of expertise in fish nutrition, feed processing and business development. How did you get to where you are today? PH: A lot of shoveling up the mess, then having another crack! My career in fish food started by studying Aquaculture at the University of

with Peter Hutchinson Tasmania, then after working in various hatcheries and other fishy related roles, I set up an aqua feed extrusion venture as part of a family business in 1997. Due to the small nature of the plant I found myself carving out a niche in the R&D sector, producing a range of extruded products including aquaculture feeds, agricultural feeds, pet food, pharma-

ceuticals, biopolymers, plastics, breakfast cereals, snack foods and food coatings. You name it - if it could be put through an extruder, we ran it! I wound up drifting into the food side, which is where I have ended up with my original extrusion plant, reinvented in a partnership as the largest extruded bread crumb

7 producer in New Zealand. While running my plant and acting as a general consultant to industry, I also ended up taking on an agency for USbased extrusion equipment manufacturer, Wenger in 2011, before working directly for them in aquafeed equipment sales. The lure of hands on work eventually drew me back into independent consulting – helping customers get the most out of their plants.

AQUAFEED: You’ve been involved in the development of some novel feeds, such as tuna feeds and broodstock feeds for kingfish. Would you tell us about some of these? PH: Well, firstly you need to understand these are mainly wild fish which generally aren’t accepting of a standard pellet and even if they were, there are practical aspects to drying such large pellets. To improve palatability, we did a lot of work with utilizing fresh (un-rendered) fish products in the extrusion process, as well as modifying traditional semimoist technology so that we could make a soft but durable, highly palatable shelf stable pellet.

Kingfish (Seriola) were a good fit with this technology immediately, and several hatcheries internationally found it an easy transition with excellent results in improving egg production and quality. Tuna are particularly fussy though, and we quickly learned that even if they are targeting pellets at the surface, they could often swim off some distance before spitting the pellets out. In conjunction with Plentex in Australia and Wenger in US, this led to further development including coatings tailored to trigger a gustatory response and the first truly effective extruded tuna feed. There were other important aspects to the final success, such as shaped pellets with active swimming behavior and the ability to center fill with medicated treatments, which would normally be rejected if incorporated in a feed. The beauty of these extruded diets is that they do not carry the pathogen risk associated with fresh feeds, and where broodstock are concerned, enabled supplementation with a range of products designed to boost egg quality. Obviously convenience in storage and feeding is a big factor as well!

AQUAFEED: What are some of the more interesting extruded products you’ve made, other than fish feeds? PH: Where to begin! Snow for the movie industry is a nice highlight as well as being fun stuff to make, and biopolymer moldings to replace expanded polystyrene was an exciting project. The most rewarding is generating useful products from waste— and not only for the feed sector, which was the basis for so many of the contract R&D projects I was involved with. Manufacture of biopolymer spoons made from kiwifruit skin was pretty neat! Also, having developed a ground-breaking earth quake resistant technical aggregate from co-mingled waste plastic for the concrete industry, it would be fantastic to see this product put an end to the dilemma of waste plastics one day.

AQUAFEED: Do you think we’ll ever be able to entirely replace live feeds with manufactured hatchery feeds?

PH: To be honest this one is outside my area of expertise. I’d have to say generally where it is economic to do so, technology eventually wins through. Given the specific require-


“The most common mistake I see would be misinterpreting the use of water, with its relationship to density and cook, in conjunction with SME (Specific Mechanical Energy). Understanding of these two items is critical for establishing durability, water stability, density, oil absorption and prevention of conditions such as GDAS”.

ments for such a diverse range of species, a one size fits all approach seems unlikely to me at this point in time. From what I gather, utilization of prey enzymes due to limited physiological development remains a roadblock in producing ideal live feed replacement. Delivery of a nutrient rich compound feed which contains all essentials in an available form, doesn’t foul the water and is an appropriate density to continuously present itself as a target over an extended period — that is a hard ask. The hatchery process is assisted by

advancements in extrusion though, which allow pellets as small as 0.4mm to be produced directly from the die at significant capacities, reducing the time to weaning as well as mortalities associated with crumble feeds due to their irregular particles, which can cause choking in juvenile fish.

AQUAFEED: What changes have you seen in aquafeed mills over the years, for better or worse? PH: Definitely for the better, the biggest change by far (and I mean big) is smart automation. A lot of key machinery still resembles decades old tech, but the inline monitoring, associated feedback systems and computer control removes much of the mundane operator input. I liken it to the emergence of autonomous vehicles, with the technology here and now to press start, sit back and have the plant take care of the rest — you just can’t do away with the driver altogether yet... Smart automation through inline sampling and integrated feedback brings multiple benefits, not just limited to significant quality improvements, lowered waste and labor savings. It also dramatically increases data gathering and the ability to interpret that data for future product development, saving on raw material costs whilst improving product performance. It is this divergence of the feed production market based on technology that is seeing those already ahead accelerate away from the competition, with knowledge gains transferring directly into

economic gains. Knowledge is power! I am blown away by the speed at which inline data collection and modelling can generate solutions which took me years of hands on trial and error to figure out. Doing me out of a job!

AQUAFEED: With the quickening pace of novel ingredients to replace fish meal, such as single cell proteins, insect meals and algal products reaching commercialization, what challenges – if any – do you think processors and formulators are going to face? PH: Actually, novel ingredients can bring some advantages, whether it be palatability, binding or even things such as ability to increase endogenous fat. Of course, they can present corresponding challenges and it does depend on the format they are provided in. The dairy space in NZ is one to watch for some new ingredients from waste likely to emerge in coming years with some interesting characteristics. Personally, I have never used insect meals, although keen to try if the opportunity arises. The biggest challenge I see commonly with most new ingredients is volume availability and appropriate price. All too often I see significant work put into products where volume is too limited to be worthwhile or there is some unrealistic value attached to it. For the majority, unless it has some very unique beneficial properties (or a value-added marketing spin), the price will be determined by protein score, making many new comers simply uneconomic.

9 I am a big fan of converting waste into something of value, particularly where it is reducing environmental impact. It is part of an increasing trend in the drive for alternative protein sources and an area I have spent much time on with my years in R&D. Bearing in mind that there needs to be an economic driver for these, in so much as you can’t maintain an environmentally sustainable product without first having a sustainable business. From a least cost/manufacturing perspective, I am wary of excessive use of the “S word” in marketing when the reality is driven by economics — fishmeal is expensive. The truth is that fisheries in the main are a regulated, independent resource with other outlets that would take it up if aquaculture stopped using it.

AQUAFEED: What would you say were the most common avoidable mistakes you see in feed extrusion plants? PH: The most common mistake I see would be misinterpreting the use of water, with its relationship to density and cook, in conjunction with SME (Specific Mechanical Energy). Understanding of these two items is critical for establishing durability, water stability, density, oil absorption and prevention of conditions such as GDAS. All too often I see people limiting water if they have dryer issues for example, without understanding the impact they are having on pellet quality. When I see bags of feed with oil bleeding everywhere, I can almost guarantee that feed will have issues

with durability on feeding, have poor water stability, variable density and potentially lead to oil belching, with the cause likely due to both water and SME being limited during process.

AQUAFEED: So, what is the worst thing you’ve ever had to deal with? PH: Ha! I smell — a lot! Heat, dust, malodorous materials, fires, spills... Something blocking or coming apart at 10 tonne an hour is usually exciting — in a bad way! Although when you have dealt with these things on enough occasions, it becomes just another day in the office. I couldn’t say any particular event was the worst. You eventually build the nerves required to hold it together when wheels start to fall off. In the end it’s all just nuts and bolts. You might need a few parts, maybe a bit of machining and a few spots of weld, but you’ll be up and running again.

AQUAFEED: Crystal ball gazing: what changes do you think we’ll see in aquaculture feed processing and diet design in the future? PH: Legislation and public resistance notwithstanding, I feel that GM will lead major change from a raw material perspective. The pace of development in this field in terms of aquafeed critical nutrients such as DHA and EPA will lead to dramatic supply chain shifts, more so than alternatives such as those from algae which remain supply and cost limiting. GM will have a greater single impact than any other in the race to reduce reliance on marine resources I believe.

Greater levels of pre-processed raw materials are also likely, with hydrolyzing as an example used to improve the stock material and to stabilize it in the same process, often increasing utilization of novel or waste materials. On the process side, as mentioned earlier, ongoing developments with automation, particularly in conjunction with AI, will lead the way in improving product performance and through natural association, business metrics. On a more grass roots machinery level, preconditioning is one item which is still evolving and translating into real results. The importance of this is often underestimated, especially where sinking feeds are concerned. The ability to maximize cook in conditioning allows for increased freedom in manipulation of the extrusion process itself. Particularly with the increased use of novel ingredients, some of which can be in a slurry or sticky and hydroscopic, the ability of well-designed conditioners to keep product moving and friable whilst achieving a high level of cook is critical to further process.


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NEWS REVIEW Highlights of recent news from Sign up at for our free weekly newsletter for up-to-the-minute industry news

Study questions sustainability of plant ingredients Feed companies are increasingly substituting fishmeal with plant-based ingredients which is recognized to be a more sustainable practice. A multidisciplinary team of researchers studied the trade-offs between marine and terrestrial resources in shrimp feeds. They found that the substitution of fishmeal moved pressure to land-based production systems with environmental repercussions. The study modeled incremental fishmeal substitution, from 20-30 percent to zero, by plant ingredients such as soybean meal concentrate, rapeseed meal concentrate, pea protein concentrate and corn gluten meal, which are typically included in modern feeds for the two main

shrimp species produced globally, whiteleg shrimp (Litopenaeus vannamei) and black tiger shrimp (Penaeus monodon). The team then assessed the impact that this could have on marine and terrestrial resources, such as fish, land, freshwater, nitrogen and phosphorus. Researchers found that complete substitution of 20-30 percent of fishmeal totals, depending on the species, could lead to an increasing demand for freshwater of up to 63 percent, land of up to 81 percent and phosphorus of up to 83 percent. Wesley Malcorps from the University of Stirling’s Institute of Aquaculture said that substituting fishmeal for plant ingredients would shift resource

demand from the oceans onto the land, potentially adding pressure to the land-based food production systems, which are already under pressure to meet global demand for food, feed, biofuels, and bio-based materials. In turn, this would affect the environment and biodiversity, as well as the availability and prices of crops. Malcorps suggested that finding an optimal balance between marine and terrestrial resources in aquafeed, strategically including high quality fishmeal, improving the use of fish byproducts and food waste in feeds and investigating the potential for novel ingredients such as microbial biomass, algae and insect meals should be explored.

iFishIENCi, new European fish feeding project A new four year EU Horizon 2020 project, iFishIENCi, is bringing together multiple partners in a trans-disciplinary effort towards making improvements to fish farming worldwide. The project’s full title is “Intelligent fish feeding through integration of enabling technologies and circular principles.” Aller Aqua Research, AquaBioTech Group, Norwegian Research Centre and Helenic Centre for Marine Research are some of the iFishIENCi’s partners.

Using advanced digital information technology, iFishiENCi will develop a Biology Online Steering System (iBOSS) which will monitor fish and their environment for healthy sustainable farmed fish. The iFishIENCi project will also develop novel feeds based on more sustainable ingredients. New feed formulations will help to maintain quality fish growth using ingredients made from recycled and organic resources, reducing dependency on protein from wild-caught fish.


BioMar Group to gain full ownership of APSA, Chile

Subject to approval by authorities, BioMar will acquire the 50% remaining shares in the Chilean factory APSA. Ending 10 years of successful collaboration with AquaChile, this will immediately release capacity for BioMar in Chile. Back in 2007, when BioMar acquired Provimi Aqua, the joint venture in the APSA factory was part of the package. Since then BioMar Chile has been producing feed to AquaChile and to various other customers from the JV. The acquisition, representing a value of US$17 million, follows the acquisition last summer of AquaChile by Agrosuper. Beyond this operation BioMar Chile continues the commercial relationship

with Agrosuper and AquaChile: “Looking forward we expect to continue delivering feed to AquaChile. We are cooperating in a very positive way and we are determined to maintain a fruitful commercial relationship”, explained Carlos Diaz, CEO, BioMar Group. Currently, BioMar operates 14 feedmills and is currently constructing another two. The company has production facilities in Norway, Chile, Denmark, Scotland, Spain, France, Greece, Turkey, China, Costa Rica, Ecuador and very soon also in Australia. Worldwide, BioMar supplies feed to around 80 countries and for more than 45 different fish species. BioMar is wholly owned by the Danish industrial group Schouw & Co.

ADM completes acquisition of Neovia Archer Daniels Midland Company has successfully completed its €1.544 billion acquisition of Neovia, creating a global leader in value-added products and solutions for both production and companion animals. ADM has made a series of expansions and investments

in recent years, including Protexin, a provider of probiotic supplements for aquaculture. With the addition of Neovia, ADM Animal Nutrition has a global presence, offering premixes, complete feed, ingredients, additives and amino acids.

Aller Aqua joins Ghana tilapia seed project A 3-year program titled “Accelerating aquaculture development in Ghana through sustainable Nile Tilapia seed production and dissemination,” TiSeed will address issues related to tilapia seed and improve productivity and profitability of tilapia cage and pond farming in Ghana, with particular focus on women and youth small-scale fish farmers. Over the past decade, Ghana’s tilapia farming has experienced tremendous growth in production, contributing to improved incomes for the industry and animal protein for consumers. But loses of over 100 tons of cage-farmed fish in the Lake Volta region in recent months highlight the challenges that Ghana faces to keep growing. The program covers research, effectiveness analysis, and process and impact evaluation about specific innovations in broodstock development and management, seed distribution, seed quality monitoring, certification system and extension services. Aller Aqua Feed Ghana Ltd. joins a consortium of international and local research institutes, led by IFPRI, supported by the Water Research Institute of the Council for Scientific and Industrial Research (CSIR) in Ghana, KIT Royal Tropical Institute in the Netherlands and WorldFish.


Algal oils and proteins gain acceptance in Norwegian salmon feed Norwegian salmon producer, Lingalaks, has been feeding 50% of their salmon production on a diet produced by Skretting since October 2018; it includes omega-3 EPA + DHA algal oil produced by Veramaris, a joint venture of DSM and Evonik. “Omega-3 EPA + DHA from natural marine algae allows us to produce healthier and better salmon. It also gives us the unique opportunity to differentiate our company within a competitive market", Erlend Haugarvoll, Lingalaks owner, said. German retail chain Kaufland is the first to put the new salmon on the shelf. “It’s not as simple as just substitution, and many years of research have allowed this breakthrough,” Mads Martinsen, Director Product Development, Skretting Norway, commented. Meanwhile, more than 350,000 tons of BioMar fish feed with Corbion's AlgaPrime™ DHA has been delivered to Norwegian salmon farmers since 2016. AlgaPrime™ DHA is a native algae ingredient that contains approximately three times the level of DHA of fish oil. AlgaPrime™ DHA is a clean and sustainably produced ingredient through fermentation-based cultivation with non-GM cane sugar as a feedstock. It allows incorporation at high levels without concerns of PCB and dioxin accumulation that can be an issue for some forage fish and fish oil. Since 2016, Corbion has been producing AlgaPrime™ DHA at large industrial scale.

“Through our partnership with BioMar, we’ve seen strong adoption of AlgaPrime™ DHA and have shown our ability to make a significant impact on the aquaculture industry over a short period of time,” said Marc den Hartog, Executive Vice President of Innovation Platforms at Corbion. “AlgaPrime™ DHA is helping to provide consumers with options that are better for their families and the environment and meeting retailer and consumer demand for healthy and more nutritious seafood.” “At BioMar, we’ve seen an increased global demand for feed formulated with alternative ingredients such as AlgaPrime™ DHA, due to their nutritional performance and sustain

ability excellence,” Vidar Gundersen, Global Sustainability Director at BioMar, said. “Our aquaculture feeds with AlgaPrime™ DHA continue to be adopted and trusted by salmon farmers, as they look to improve the omega-3 content and sustainability profile of their salmon.” Salmon brands that include AlgaPrime™ DHA are now available in US, UK and EU markets offering consumers farm raised salmon with an improved sustainability and nutritional profile. In addition, AlgaPrime™ DHA-fed salmon have been included in ready-to-eat and meal kit delivery services, providing consumers with algae-fed salmon through multiple retail touch points.


Developments in aquafeeds Updated meagre feed from Aquasoja Commercial diets for sea bream have been used for meagre (Argyrosomus regius) with low success and specific commercial diets differ widely among feed companies, and in general have conservative formulas. Since the optimization of protein:fat ratio is an essential condition for a well-balanced diet, AQUASOJA updated its meagre feed. REGIUS is based on high levels of high-quality animal protein, to provide meagre the best responses in terms of growth and feed conversion. Two versions are available: Orange for use with land-animal proteins and fat inclusions and Blue, for without.

Aller Aqua RAS feed Aller Aqua lauched PowerRAS to meet the high demands of Recirculating Aquaculture Systems (RAS) in terms of feed efficiency, optimal water quality and subsequent fish growth. Fish produced in RAS represent a steadily growing volume of total aquaculture production. The accurate optimization between water parameters and fish biomass requires external factors to seamlessly integrate into the equilibrium. The company said that feed is the most influential external factor in RAS. Therefore, feeds for RAS need to fulfil the requirements of this highly sophisticated and complex production technology

Skretting introduces a raft of new feeds Skretting has introduced a soft extruded feed for bluefin tuna, available in Japan, that has been created using patented production technology. The company has been working for 20 years to establish a viable alternative to baitfish feeding protocols. During that time, Skretting evaluated several feed types – from wet mashes to a wide variety of sausage formats. The new diet’s texture is softer than pellets for other farmed species and has lower water content than baitfish, offering higher conversion rate. Skretting Egypt launched Nutra for the domestic tilapia market. The range consists of high-performance starter diets supporting first-feeding fry by providing the specific nutrients and right particle size for each life stage, from egg to fingerling. Nutra is already on its way to Kenya, Uganda, Cote d'Ivoire and Mali.

The introduction of Nutra was recently followed by Protec for tilapia, a new functional diet designed to help support tilapia and enhance their ability to cope during challenging situations, including the hot summer seasons. Protec helps to support the natural defenses of the fish: it supports the immune system and it optimizes the balance between fish, microbes and environment. Skretting has also upgraded its SHIELD diet to increase the support to farmers producing gilthead sea bream (Sparus aurata). In 2017 the company launched a functional diet that specifically supports intestinal challenges for Mediterranean species. The new SHIELD diet also offers the same level of support for fish exposed to parasites targeting the gills. Intestinal and gill parasite challenges are, by far, the most widespread health problems facing sea bream producers today. SHIELD helps maintain the structural integrity of the intestines and the gills.


Applications open for Hawai’i-based 2019 cohort of HATCH aquaculture accelerator program Hawaii Strategic Development Corporation (HSDC) and the University of Hawaii’s UH Ventures, LLC (UHV). HATCH, a sustainable aquaculture accelerator program that seeks to find, develop and scale disruptive aquaculture startups, has begun taking applications for its 2019 cohort. The program will be based at the Natural Energy Laboratory of Hawaii Authority (NELHA)’s Hawaii Ocean Science and Technology Park with extensive visits and network in Bergen and Singapore. The new accelerator and its associated investment fund were established by NELHA, the

The accelerator will initially be fully funded for three years and is expected to nurture three cohorts of 10-12 globally relevant aquaculture technology startups per year. The program offers €100,000 per team, €50,000 in cash and €50,000 in kind contributions. The program looks for teams with innovative and scalable solutions that solve significant problems in the aquaculture industry in order to enable its long-term sustainability.

Bühler and Alfa Laval insect processing solutions Bühler Insect Technology Solutions (BITS), a pioneering provider of integrated solutions for insect rearing and processing, and Alfa Laval, a world leader in heat transfer, separation, and fluid handling, have been cooperating since early 2018 with the objective of combining their strengths to provide efficient and integrated production plants.

up production as demands increase. The products will be offered exclusively through Bühler Insect Technology Solutions. The two companies will also cooperate on further research and development, marketing and after-sales services.

"We are convinced that insects will play an important role in making our food system more sustainable. With the The two companies have jointly construction of the first industrial-scale developed tailored solutions for heat insect plant in Europe nearing completransfer, solid and lipid separation, and tion, we will soon have an operating fluid transfer that can be integrated proof point of the viability of our insect seamlessly into modular insect plant process technology in an industrial solutions. Thanks to their joint setting,”President of the Global Sales expertise, these highly flexible solutions and Service Organization at Bühler allow insect producers to easily ramp Group, Dieter Voegtli said.


Atle Kvist has been appointed Managing Director Mowi Feed . He will report to Ben Hadfield, COO Mowi Feed. Kvist will be active in bringing the new Kyleakin feed plant in Scotland up to its full production capacity and maintaining and enhancing the good manufacturing performance of the Bjugnplant. Kvist was previously Managing Director of EWOS Norway and has a long career in salmon feed production.

David Whyte

BioMar has appointed David Whyte as the Managing Director of their new fish feed manufacturing plant in Tasmania. The plant, currently in its construction phase will be ready for commissioning in early 2020.


Cracking the code Recent insights into fatty acid nutrition are making fish oil replacement increasingly feasible in marine aquafeeds By Artur N. Rombenso, Ph.D., Bruno C. AraĂşjo, Ph.D., MarĂ­a T. Viana, Dr. Sc., Jesse T. Trushenski, Ph.D.

Long-chain polyunsaturated fatty acids (LC-PUFAs) are physiologically necessary molecules serving a number of structural and biochemical roles in vertebrates, including fishes. These fatty acids are present in significant quantity in marine-origin ingredients like fish oil that are commonly used in the manufacturing of industrially compounded aquafeeds. However, reliance on fish oil as a raw material is considered a limiting factor for growth of the aquaculture sector. The limited availability and variable, but generally high cost of fish oil continue to incentivize efforts to spare or completely replace fish oil in aquafeeds with vegetable oils and terrestrial animal fats. Replacing fish oil in feeds for marine finfish has proven uniquely challenging, but recent insights (e.g., the role of individual LC-PUFAs, the influence of alternative lipid composition on fish oil sparing success, the LC-PUFA sparing effect, and others) indicate that it is increasingly possible to satisfy the fatty acid requirements of these species without impairing

growth or the nutritional quality of farmed fish.

Fatty acid essentiality in marine finfish Most marine finfish have limited capacity for de novo synthesis of LCPUFAs such as eicosapentaenoic acid (20:5n-3, EPA), docosahexaenoic acid (22:6n-3, DHA) and arachidonic acid (20:4n-6, ARA) from their C18 polyunsaturated fatty acid (C18 PUFA) precursors alpha-linolenic acid (18:3n3, ALA) and linoleic acid (18:2n-6, LA). Regardless of whether a species can transform C18 PUFAs into LC-PUFAs, it is important to recognize the clear distinction between these two classes of fatty acids and the unique functional properties that only LCPUFA possess (Trushenski and Bowzer 2013). Our research to better understand fatty acid essentiality in marine finfish has revealed two additional principles: not all LC-PUFAs are equally important in terms of satisfying dietary requirements, and

the fatty acid composition of the lipid source influences LC-PUFA bioavailability and degree of tissue fatty acid modification associated with fish oil sparing. DHA and EPA support normal development and growth of marine finfish species in a number of ways. Recent research has suggested that DHA is more critically needed in marine fish feeds than EPA. In experiments with cobia Rachycentron canadum (Trushenski et al., 2012), California yellowtail Seriola dorsalis (Rombenso et al., 2016) and white seabass Atractoscion nobilis (Trushenski et al., 2013; Rombenso et al., 2015), it was observed that fish oil could be completely replaced by soybean oil without impairing growth or fillet DHA content by supplementing the diet with DHA alone. Additional experiments performed with Florida pompano Trachinotus carolinus and totoaba Totoaba macdonaldi showed that fish oil could be completely replaced by beef tallow without affecting growth perfor-

18 mance, though LC-PUFA supplementation was needed to maintain fillet fatty acid profiles (Rombenso et al., 2017; Mata-Sotres et al., 2018). Although LC-PUFAs, including EPA, exhibit important functions mainly related to immunity, reproduction and other essential processes in marine finfish, a number of studies have shown that dietary supplementation with EPA is relatively unimportant, so long as the diets contain adequate amounts of DHA and, in some cases, ARA (figures 1 and 2) (Trushenski et al., 2012; Emery et al., 2016; Rombenso et al., 2016).

Fig.1. Weight gain (%) and FCR (feed conversion ratio) of juvenile California Yellowtail fed diets containing different levels of n-3 and n-6 long-chain polyunsaturated fatty acids (LC-PUFAs).

Fig.2. Dietary and fillet fatty acid profile of juvenile California Yellowtail fed diets containing different levels of n-3 and n-6 long-chain polyunsaturated fatty acids (LC-PUFAs).

Indeed, ARA may be particularly relevant, despite limited research on its importance in marine finfish feeds. Although it is typically present in very low levels, dietary supplementation with ARA warrants careful attention because this nutrients biochemical potency and many physiological roles. Our study performed with California yellowtail indicated ARA was as important as DHA in satisfying the essential fatty acid requirements of this species. This fatty acid is also highly relevant in terms of human health, dietary formulation should consider maintaining adequate levels in the edible tissues of fish as a prime metric of success. As with all investigations of the nutrient requirements, attempts to define the fatty acid requirements of marine finfish should consider survival and growth, as well as other factors such as temperature, salinity and life stage.


Saturated and monounsaturated fatty acid-rich lipids Researchers investigating the use of finishing feeds in hybrid striped bass Morone chrysops × M. saxatilis culture observed that consumed saturated fatty acids (SFAs) did not accumulate in the tissues according to the simple dilution model commonly used to describe tissue fatty acid profile change in fishes (Lane et al., 2006). Rather, tissue levels were consistently lower than the dilution model’s predictions. This seemingly minor, but unexpected, finding ultimately led to a series of studies (see Trushenski et al., 2008a, 2008b, 2011a, 2011b, 2011c, 2015) that changed the way nutritionists think of fish oil sparing and fatty

acid requirements of freshwater and marine species. Over the past decade, researchers have affirmed that dietary SFAs are generally not proportionally reflected in the tissues of finfish. Unlike C18 PUFA, which readily accumulate in fish tissues, SFAs are not proportionately deposited in fillet or other tissue types. Replacing dietary fish oil with alternative lipids rich in SFAs and, to a lesser extent, monounsaturated fatty acids (MUFAs) typically does not result in substantial enrichment of these fatty acids in the tissues. What’s more, SFA- and MUFArich feeds do not induce the same degree of long-chain polyunsaturated fatty acid (LC-PUFA) loss that is usually associated with fish oil sparing. This so -called “omega-3 sparing effect” (Turchini et al., 2011) has been documented in numerous finfish (see

Replacing dietary fish oil with alternative lipids rich in SFAs and, to a lesser extent, monounsaturated fatty acids (MUFAs) typically does not result in substantial enrichment of these fatty acids in the tissues.


Fig.3. Weight gain (%) and FCR (feed conversion ratio) of juvenile white seabass fed diets containing standard (C18 PUFA-rich) and hydrogenated (SFA-rich) soybean oil with or without DHA supplementation.

Trushenski and Bowzer 2013; Alhazzaa et al., 2018), including a variety of marine finfish such as cobia, Atlantic salmon Salmo salar, white seabass, Florida pompano (Trushenski et al., 2013a, 2013b; Woitel et al., 2014a, 2014b; Rombenso et al., 2015, 2016, 2017). In addition to reducing the effects of fish oil sparing on tissue fatty acid profiles, SFA- and MUFA-rich lipids appear to increase the efficiency of LC-PUFA metabolism, effectively reducing the LC-PUFA requirements of finfish. Fish oil can be replaced in feeds intended for species with LCPUFA requirements so long as the diet is supplemented with another source of these nutrients. However, the amount of LC-PUFA supplementation needed is considerably lower when the alternative lipid used in lieu of fish oil is rich in SFAs and/or MUFAs (figures 3 and 4). The apparent LCPUFA requirements of Atlantic salmon, Florida pompano, California yellowtail, white seabass, totoaba (Emery et al., 2016; Rombenso et al., 2017, 2018; Mata-Sotres et al., 2018) have been effectively reduced by feeding SFA- and MUFA-rich alternative lipids (figure 5).

Ongoing trials and perspectives

Fig.4. Dietary and fillet fatty acid profile of juvenile White Seabass fed diets containing standard (C18 PUFA-rich) and hydrogenated (SFA-rich) soybean oil with or without DHA supplementation.

Ongoing trials with cobia and California yellowtail evaluating dietary SFA/MUFA and ARA/DHA ratios have been carried out in Brazil and Mexico aiming to further understand the aforementioned findings. Research conducted at Southern Illinois University in recent years has also

21 attempted to reassess the fatty acid requirements of various finfish in terms of trophic levels. As most studies, if not all, described in this article are short-term research feeding trials, longer-term validation trials from juvenile to market size fish are needed. In this context, a growout trial using fish-free feeds (i.e. no fish meal and oil) with totoaba is currently underway in Mexico.

ACKNOWLEDGMENTS We would like to thank the São Paulo Research Foundation for the postdoctoral fellowship of Bruno Araujo (project number: 2018/13000-2). We also would like to thank CONACYT (PN_2016-2293) and PRODEP (UABC-PTC-679).

References available on request. Fig.5. Differences in DHA and EPA content across dietary treatments and weight gain (%) and FCR (feed conversion ratio) of juvenile Floripa Pompano fed diets rich in SFA and MUFA lipids supplemented with different levels of DHA, EPA and DHA +EPA.

Artur N. Rombenso Research Scientist CSIRO, Australia E:

Bruno C. Araújo Post-doctoral fellow Universidade de Mogi das Cruzes, Brazil E:

María T. Viana Senior Research Scientist Universidad Autónoma de Baja California, Mexico E:


Jesse T. Trushenski Director of Science Spring Salmon LLC, USA E:



Trends and Developments By C. Greg Lutz, PhD.

Research-based information: An increasingly scarce resource at the global producer level.

Dr. Greg Lutz is a Professor with Louisiana State University Agricultural Center. He is also an author and consultant, and serves as the Editor in Chief of Aquaculture Magazine. E: The concept of extension education in agriculture can be traced back almost 4,000 years. In places like Mesopotamia and Egypt, government officials disseminated advice on crop production and avoiding losses from flooding and pests like rats and insects. The motivation was fairly simple: more crop production meant more tax revenue for the governing kingdoms. More formal written “factsheets� appeared in the times of the ancient Greeks and Phoenicians, and as was the case with so many things from these civilizations, the Romans later adapted them for their own purposes. In China, the communication of agricultural production recommendations across

the countryside had already been established by 200 AD, once again to improve the cash flows of landowners and generate more tax revenues. Modern extension education got its start in England in the 1850s and 1860s. Scholars from historic universities like Cambridge and Oxford began considering offering lectures on literary and social topics to the rapidly growing urban population. Shortly thereafter, these initiatives were extended to rural areas and the focus shifted to agronomic topics. These activities eventually became the inspiration for similar efforts in the U.S. and elsewhere. Agricultural extension in the U.S. has not only served to disseminate research-based

information to producers for many decades (agricultural producers in the Land Grant system, fisher-folk in the Sea Grant system, and aquaculture producers in both), but also to present university researchers with real-world problems prioritized by stakeholders. However, as the historically targeted audience for extension outreach has declined significantly in the U.S., these organizations have reached out to new audiences and stakeholder groups in an effort to remain relevant. The fragmented nature of the U.S.

23 aquaculture industry, combined with a relative lack of political clout, has left many producers with no direct technical support from any government agency. Another phenomenon has also begun to undercut the value of the traditional extension model in U.S. aquaculture: the privatization of research. Many large companies have reached a point where a significant portion of their research needs can be addressed in-house. And, many of the smaller aquaculture operations currently in business have no nearby university or government professionals to collaborate with. As a result, these businesses have also chosen to embark on in-house R&D, often with limited resources. In many countries, extension support for aquaculture development has never really been available, and so similar situations prevail. There is little incentive to share results generated from privately funded work, so the role of Extension becomes somewhat constrained in these situations. Some government funded grant programs in the U.S. also result in technologies or methods that are not freely available to the public. Fortunately, many government programs in the U.S. and E.U. now require funded researchers to include specific outreach goals and information-sharing deliverables. In much of the world, however, the rank-and-file producers of aquaculture species have less and less access to timely research -based production recommendations. Throughout the world, specialized producers (including many aquaculture producers) who may not have direct access to Extension professio-

nals with the appropriate expertise are increasingly seeking information from other sources. In the age of the internet and in spite of the lack of Extension technical support, tools still exist for publicly funded aquaculture research to reach industry stakeholders, digitally and objectively. But in most of the world research-based

information is becoming more difficult for producers to access, especially when generated with private, inhouse funding. In the coming decade aquaculture producers and those who provide their inputs will need to expend more effort to connect the dots and translate R&D results for widespread application. AFâ„Ś


Spray-dried eggs: an economical and sustainable high-quality source of nutrition for aquaculture feeds By Ingmar Middelbos, Senior Technical Services Manager, IsoNova Technologies LLC, USA

Spray-dried chicken egg product (Gallus domesticus) has a long history of use in human food, pet food, and terrestrial livestock feeds, primarily because of its high-quality protein. The essential amino acid profile of egg is considered ideal for nearly every species. Therefore, egg protein is used as the benchmark for in vivo evaluation of protein quality in feedstuffs (Donadelli et al., 2019). Despite its success in livestock feeds and pet food and the apparent knowledge in the aquaculture industry about the high nutritional value of eggs (Hertrampf and PiedadPascual, 2000), adoption in aquaculture feeds remains limited. Likely, historical assumptions about availability and/or cost of egg products are key factors, but these outdated assumptions should be challenged.

Fig. 1. Feed-grade spray-dried eggs as powder (left) and micro-granule (right).

The nutritional package of eggs make it uniquely suited for aquaculture, and when evaluated on a cost-in-use basis, eggs are exceedingly cost effective vs. current alternate ingredients. In addition, dried egg product can enhance the sustainability profile of aquaculture feeds while also providing end consumers with a recognizable and easy to understand “feed my food eats� narrative.

Spray-dried eggs processing and composition Dried, feed-grade eggs are made by processing (100% USA-origin) eggs and separating the egg liquid from shell. The liquid is spray-dried into a powder, which may be microgranulated to improve handling (Fig. 1). The process includes a pasteurization step to minimize biosecurity risks, but the eggs are not cooked at high temperatures. This low-temperature processing ensures that heat-sensitive amino acids such as lysine remain intact and available. A high-quality dry egg product analyzes well above 90% available lysine and above 95% in pepsin digestibility. Additionally, the

25 coproduct nature (from the human food industry) of feed-grade eggs make it a sustainable source of nutrients. As a feed ingredient, eggs are a rich source of the more expensive components in feeds, protein and energy. The overall nutrient composition of eggs is somewhat different from other more traditional aquaculture feed ingredients (Table 1). Eggs deliver total protein comparable to soybean meal (47% vs. 48%), a highquality amino acid profile that rivals or exceeds fishmeal, up to 80% less ash compared to fish meal and poultry byproduct meal, and 50-75% more (calculated) metabolizable energy than the comparative ingredients in Table 1. Additionally, eggs are naturally rich in phospholipids (12% total, 75% of which is phosphatidylcholine) and very high in cholesterol (approximately 16,000 mg/kg) – both phospholipids and cholesterol have unique nutritional value to several aquaculture species.

Benefits of eggs as an aquafeed source Based on information derived from National Research Council publications (NRC, 2006; 2011), the amino acid profile of egg protein better meets the needs of many fish and shrimp species than most staple ingredients used in aquaculture feeds today (Table 2). Egg protein is particularly rich in sulfur amino acids (methionine and cysteine), which can become limiting with current industry trends that aim to replace fishmeal

Table 1. Macronutrients in spray-dried eggs in comparison to common aquaculture feed ingredients.

Component, %, as-is

Spray-dried Menhaden eggs Fishmeal

Poultry Soybean byproduct meal (48%) meal






Fat Ash

41.1 3.6

9.6 19.0

13.6 14.5

0.9 5.8

ME (calculated, kcal/g)










Total phospholipids





*Estimated values **Unknown

Table 2. Essential amino acid profile of egg protein in comparison to common aquaculture feed ingredients. Sources for Tables 1 and 2: NRC 2006, NRC 2011, AEB 2006. Spray-dried eggs

Menhaden Fishmeal

Poultry byproduct meal

Soybean meal (48%)































Methionine + Cysteine

























Amino acid, g/100g protein

with soybean meal. This can make eggs a useful tool to further spare fishmeal without the risk of compromising the required dietary essential amino acid profile. In practice, the most suitable place for eggs are in diets for species that have either a high combined protein and energy demand (e.g., salmon, trout) or have unique dietary needs, like shrimp (cholesterol and phospholipids).

In those shrimp feeds that rely on supplementation of dietary cholesterol, phospholipids, or both, eggs provide multiple benefits. Every kilogram of egg added per metric ton of feed can spare approximately 0.75 kg of fishmeal (as a protein source), 0.02 kg synthetic cholesterol and 0.12 kg of supplemental phospholipids. Adding up the cost of sourcing these three components separately makes a compelling economic case to evaluate eggs as an “all-in-one” package.

26 The dietary lipid content should be monitored when formulating with eggs. Dried eggs contain approximately 40% total lipids including 13% saturated lipids (33% of total lipids in dry eggs are saturated). To maintain total dietary lipids and saturated lipids in acceptable ranges for shrimp, maximum egg formulation rates are estimated in the 6-8% range. Nevertheless, using 60 kg/metric ton (6%) eggs as an example, approximately 45 kg fishmeal, 1 kg cholesterol, and 7 kg phospholipids can potentially be spared. In feeds for salmon and trout, which require high dietary protein and energy levels, eggs are a natural fit. The amino acid profile fits well with dietary needs, eggs are a net protein contributor (47% vs. 38-40% dietary targets), and eggs are dense in metabolizable energy. In contrast to shrimp feeds, the saturated fat in eggs may be a benefit in fish diets, where it can help satisfy the low but statutory saturated fat needs of these species, which cannot be met with fish oil and plant-based oils. Most of the success of eggs in terrestrial livestock feeds is seen in

specialty or specific life-stage feeds, where high animal performance early in life strongly correlates with economic performance at go-tomarket time. The clearest example of this is in early pig nursery diets, where eggs can help spare expensive blood plasma, fishmeal or a combination of both (Nessmith et al., 1995; Schmidt et al., 2003; Song et al., 2012). Eggs could play a similar role in larval feeds for aquaculture species. However, the highly proprietary nature of larval feed formulations complicates pinpointing exact value-added applications and use rates. Despite the nutrient benefits that eggs can bring to aquaculture diets, to date, adoption remains limited. In addition to outdated availability and cost assumptions, another likely reason is a paucity of research data evaluating its performance in the relevant species. Trialing is needed to demonstrate that the high analytical nutrient value of egg translates into accelerated performance, savings in diet formulations, or, ideally, both. Studies in a variety of terrestrial species demonstrate amino acid digestibility of dried eggs is universally

Ingmar Middelbos, Senior Technical Services Manager IsoNova Technologies LLC, USA E:

high (Murray et al., 1997; Norberg et al., 2004). In summary, dried eggs are well-positioned to become a staple nutrient source in aquaculture diets, but research and field testing is needed to verify its real-world contribution.

References available on request



Not every yeast cell wall is created equal By Dina Krßger, New Product Development Managerand MariÍt van der Werf, Global Growth Platform Director, Ohly GmbH, Hamburg, Germany Intensive aquaculture as well as increased bacterial resistance due to the common use of prophylactic antibiotics has led to serious problems with diseases and pathogen infections. Therefore, there is an increased interest in functional feed ingredients that can be used instead of antibiotics. Recently, there has been growing evidence on the beneficial health and growth promoting effects of yeast cell walls in various aquaculture species. Yeast cell walls, commonly referred to as MOS, are rich in two functional polysaccharides with known health improving properties: mannan oligosaccharides (MOS) and β-glucans. Around 1,000 scientific papers have shown the benefits of yeast cell walls in animal husbandry and aquaculture and have demonstrated that their dietary supplementation improves animal health and performance. However, despite the well-accepted benefits of yeast cell walls and all the scientific evidence, there are an increasing number of reports from farmers that their performance under farming conditions is not consistent. This is because yeast cell walls from different sources are highly different in composition.

Benefits of yeast cell walls in aquaculture Supplementation of marine animal diets with yeast cell walls improves their general health and immune system and increases their survival rate and resistance against infections. For instance, the mortality rate in rainbow trout was reduced by half (Minguez et al., 2016), while survival rates in Pacific white shrimps following Vibrio harveyi infection increased from 68% to 92% (Widanarni et al., 2018). In salmon, sea lice attachment and the number of fish infected by sea lice were

reduced by 37% and 25% respectively (Dimitrolgou et al., 2011).

Other benefits of including yeast cell walls in aquaculture include improved growth performance and body composition. In shrimps, this had led to 125% weight gain and subsequently higher final body weight (Genc & Ebeoglu, 2013). In beluga sturgeons, body weight gain increased 125% with a final body weight 54 g heavier than control group (Taati et al., 2012). In salmon, yeast cell wall inclusion contributed to an 8% faster growth and 11% higher protein retention (Refstie et al., 2010).

28 Yeast cell wall treatments also improve gut health and morphology in aquaculture species. In salmon this resulted in a decrease in diarrhea thereby eliminating soybean mealinduced enteritis (Refstie et al., 2010).

the liquid yeast cell wall by-product streams from different producers. They dried the yeast cell walls, substantially increasing their shelf life,

What are yeast cell walls? Traditionally, yeast cell walls are a byproduct from the yeast extract production industry. Entire yeast cells are lysed followed by the separation of the soluble intracellular fraction, the yeast extract, and the insoluble yeast cell wall fraction (Fig. 1). The liquid yeast cell walls were initially sold to farmers close to the manufacturing plant. With the increasing demand of yeast cell walls, many companies emerged collecting

Fig. 1. Production of yeast cell walls.

allowing their global distribution. Upon an even further growth in demand and/or because of cost reasons, more recently spent brewer’s

29 or biofuel yeast collected from different breweries or bioethanol production plants, is being used as the raw material for yeast cell wall production.

Yeast cell wall composition is highly variable It was long thought, that yeast cell walls have a relatively consistent composition. However, in the last decades it has become clear that the opposite is the case and yeast cell walls are highly variable in composition as well as in structure (Klis FM et al., 2002; Orlean P, 2012). The fermentation conditions and yeast strain are known to have a great effect on the yeast cell wall composition (Aguilar-Uscanga & Franรงois, 2002). Consequently, the source of the yeast (Fig. 2) used for yeast cell wall production is the key that determines product consistency.

Yeast extract, beer and bioethanol producers all use their own yeast strains and fermentation conditions that create large differences in their cell wall composition. Especially when yeast cell walls are produced from spent yeast, the batch-to-batch variation will be higher as yeast from many different production sites is used.

Impact of yeast cell wall production processes on product composition The production process has also a large effect on the composition of the yeast cell walls. Although it is commonly thought that all yeast cell walls are produced by autolysis, in fact more and more yeast cell walls are produced by hydrolysis. In the hydrolysis process, the addition of exogenous proteases not only

Fig. 2 . Yeast raw material sources for the production of yeast cell walls.

... the source of the yeast used for yeast cell wall production is the key that determines product consistency.

30 In order to ensure a robust improvement in animal health and performance by yeast cell walls, Ohly has now introduced two different yeast cell wall products of high consistency onto the market based on primary cultivated baker’s yeast (Saccharomyces cerevisiae). Ohly-GO® MOS is a yeast cell wall product produced by autolysis, containing MOS on the outside of the yeast cell walls. Ohly-GO® Wall is a yeast cell wall product produced by hydrolysis, containing a mixture of MOS and βglucans on its outside.

References available on request.


Fig. 3. Difference between autolyzed versus hydrolyzed yeast cell walls.

results in the lysis of the yeast, it also results in the hydrolysis of the mannoproteins that are present outside of the yeast cell. As hydrolyzed mannoproteins are soluble, they no longer end up in the insoluble yeast cell wall fraction after centrifugation (see also Fig. 1). Therefore, the MOS content of hydrolyzed yeast cell walls is some 50% lower than that of autolyzed yeast cell walls.

Moreover, yeast cell walls are spheres (Fig. 3) and therefore the functional carbohydrates present on the shell determine its functionality. Autolyzed yeast cell walls contain MOS, while

hydrolyzed yeast cell walls contain a mixture of MOS and β-glucans (Fig. 3). MOS and β-glucans have different modes of action underlying their health benefits (Kwiatkowski & Kwiatkowski, 2012; Spring, P et al., 2015). MOS binds to gut pathogens, thereby limiting their colonization of the intestinal tract. In contrast, β-glucan is a modulator of the innate immune response, activating phagocytic cells subsequently increasing their ability to fight pathogens. Moreover, yeast β-glucans bind mycotoxins.

Mariët van der Werf Global Growth Platform Director Ohly GMBH, Germany. E:

HatcheryFeed A division of ~ uniting the aquafeed industry since 1998 ~

The only media platform dedicated to nutrition, feed and feed management for early life stage and broodstock farmed aquatic species

Photo © Valentin Thépot




Evaluation of different feeding frequencies in the growth of greater amberjack juveniles By Salvador Jerez Herrera, Centro Oceanográfico de Canarias, Instituto Español de Oceanografía, Tenerife, Islas Canarias, Spain.

Feeding the right way is fundamental to improve the growth performance and condition of reared greater amberjack, reduce the feed cost and prevent environmental deterioration.

Greater amberjack (Seriola dumerili) has recently attracted much attention and has been recognized as one of the more promising candidates to help diversify finfish aquaculture production. It is expected to increase in future production based on the successful progress achieved in recent

years and due to the relevant results obtained in the recently concluded DIVERSIFY project. The use of appropriate feed management strategies results in higher growth rates, improved feed efficiency and less feed wasted with the consequent economic and

environmental advantages. There are a few previous studies on frequency and ration effects on greater amberjack growth performance (De la Gandara et al., 2004; Jerez, 2013), but the information is scarce. The results obtained during the project DIVERSIFY related to parameters that affect the

33 use of feed on the farm (temperature, feeding rates, stocking densities) are of great importance for the industrial production of this species (Mylonas et al., 2019). The present study was conducted in the frame of the project DIVERSIFY to investigate the effects of different feeding frequencies in larger greater amberjack juveniles (> 250 g). During the trial, fish growth performance and feed efficiency were evaluated.

Fig. 1. Facilities of IEO in Tenerife, Canary Islands (COC).

Fig. 2. Greater amberjack hand-fed.

Growth trial One hundred and eighty greater amberjack juveniles (~250 g and 23.0 cm, initial body weight and length, respectively) produced in the facilities of the Centro Oceanográfico de Canarias (Instituto Español de Oceanografía) in Tenerife, Spain, were divided into 12 homogeneous groups and reared with a constant water exchange and aeration and under natural photoperiod, salinity and temperature during four months.

Triplicate fish groups were fed daily ad libitum with a commercial turbot diet (3-5 mm diameter; Skretting Ltd, Norway; 52 % crude protein and 20% crude fat) at a feeding frequency of 1 (08:00 h), 2 (08:00 and 18:30 h), 3 (08:00, 13:30 and 18:30 h) and 7 (08:00, 10:00, 12:00, 13:30, 15:00, 17:00 and 18:30 h) meals day-1. The daily feed intake was calculated (FI). Fish were sampled and weight gain (WG, g), percentage of weight gain (%

WG, %), coefficient of variation for weight (CV, %, standard deviation by mean weight), feed conversion ratio (FCR, feed consumed by biomass produced) and condition factor (K, g cm-3, body weight by cubic length) were estimated. Five fish at the beginning and six fish per treatment at the end of the trial (120 days) were slaughtered and hepatosomatic (HSI, %) and viscerosomatic index (VSI, %) were used as production performance indices.


Results During the experiment, average DO was 92.4 ± 4.8 % (7.1 ± 0.4 mg O2 l-1), and temperature decreased from 19.4 ºC to 18.1 ºC throughout the experiment (mean ± S.D. temperature of 18.8 ± 0.4 ºC).

In this study, greater amberjack juveniles fed 1 meal day-1 showed a lower final body weight (by 392 g) than the other three feeding strategies (2, 3 and 7 meals day-1). However, the different feeding frequencies did not affect body weight variations of fish (P > 0.05), although fish fed 1 and 7 meals day-1 showed the higher coefficient of variation (CV) (Table 1). The WG of fish fed 1 meal day-1 was lower (by 117 g) than the one shown by fish fed 2, 3 and 7 meals day-1, which presented a percentage of weight gain of 53.3, 57.6 and 60.7 %, respectively, values between 10 and 17% higher than showed by fish fed 1 meal day-1 (by 43 %) (Table 1).

Table 1. Initial and final body weight (g), and coefficient of variation (CV, %) of body weight of greater amberjack juveniles fed at 1, 2, 3 and 7 meals day-1 after 120 days. The data presented are mean ± S.D. of the 3 replicates.


Initial Body Weight (g)

Final Body Weight (g)

1 meal day-1










2 meal day-1










3 meal day-1










7 meal day-1










CV (%)

Table 2. Condition factor index (K; g cm-3), hepatosomatic (HSI; %) and viscerosomatic index (VSI; %) and percentage of decrease with respect to the initial value of greater amberjack juveniles fed 1, 2, 3 and 7 meals day -1 after 120 days. The data presented are means of the three replicates. Different letters indicate significant differences (P < 0.05).



Change vs. initial


Change vs. initial


Change vs. initial

(g cm-3)






1 meal day










2 meal day










3 meal day










7 meal day










Fish fed 1 meal day-1 showed a significantly lower condition factor (K) compared to 7 meals day-1 (P < 0.05) at the end (120 days). Also, hepatosomatic index (HSI) was lower in 1 meal day-1 respect to 3 meals day-1 (P < 0.05) (Table 2). Furthermore, fish fed 1 meal day-1 showed a marked decrease of K (13.7 %) and HSI (61.2 %) respect to the initial indices (2.12 ± 0.09 and 1.27 ± 0.14, for K and HSI, respectively). However, viscerosomatic index (VSI) was similar regardless of the feeding strategy and decreasing between 46.8 and 43.2 % respect to the initial value

Fig. 4. Feed intake (FI) and feed conversion rate (FCR) of greater amberjack juveniles fed 1, 2, 3 and 7 meals day-1 after 120 days. The data presented are means of the three replicates. Different letters indicate significant differences (P < 0.05).

35 (5.89 ± 0.79). Fish fed 1 meal day-1 showed the higher feed intake (FI), about 37% more feed compared to fish fed 7 meals day-1 (Fig. 2). Furthermore, they showed the worst food efficiency, resulting in reduced FCR (by 2.5 %). For larger greater amberjack juveniles (> 250 g), the better results in growth performance and feed conversion rates were obtained when fish were fed from 2 to 7 meals day-1. The findings of the current study have practical significance for establishing greater amberjack rearing practice. Furthermore, a technical “production manual” for greater amberjack has been also released by the project and is freely available in the project’s website. It can be used by the industry to continue the study of the potential of greater amberjack as an alternative marine

species for European warm-water aquaculture. References available on request.

Acknowledgments The project DIVERSIFY was funded by the European Union’s Seventh Framework Program for research, technological development and demonstration (KBBE2013-07 single stage, GA 603121, DIVERSIFY). Exploring the biological and socio-economic potential of new/emerging candidate fish species for expansion of the European aquaculture industry, six new/ emerging finfish species were identified with a great potential for the expansion of EU aquaculture. This EU funded project, which started in 2013, achieved all its objectives in the greater amberjack research. The knowledge achieved let greater amberjack to be considered as a feasible farmed species for the aquaculture industry.

Salvador Jerez Herrera Senior Researcher IEO, Centro Oceanográfico de Canarias, Spain E:




Recent publications By Albert G. Tacon, Ph.D.

Aloha. Continuing the theme from the last issue, I have collected some of the most recent publications in 2019 that I think will be of interest.

Effect of dietary inclusion of cottonseed meal on growth performance and physiological and immune responses in juvenile grass carp, Ctenopharyngodon idellus. Liu, Haokun; Quangen Yan; Han, Dong; Jin, Junyan; Zhu, Xiaoming; et al. (2019). Aquaculture Nutrition, 25(2):414-426. An 8‐week feeding trial was conducted to evaluate the effect of replacement of dietary fishmeal with cottonseed meal (CSM) on the growth performance and health status of juvenile grass carp, Ctenopharyngodon idellus (6.67 g). Six isonitrogenous and isoenergetic diets were formulated with different CSM levels (0, 121, 241, 362, 482 and 603 g/kg diet). The first limiting amino acid was methionine, which decreased with an increase in dietary CSM from 361 to 538 g/kg. When the dietary CSM content was lower than 241 g/kg, the limiting amino acid was histidine. Thermal growth coefficient (TGC) and feed efficiency first increased and then decreased (p < 0.05), which was consistent with the change in the limiting amino acid. The feeding rate increased with a rise in the dietary CSM level (p < 0.05).

The activity of digestive enzymes except trypsin decreased significantly (p < 0.05), serum aminotransferase activity and triglycerides increased, serum cholesterol decreased (p < 0.05). When dietary CSM was raised to 362 g/kg, intestinal villi and hepato-pancreas tissue were injured. When the dietary CSM was 603 g/kg, alternative complement pathway haemolytic activity was inhibited (p < 0.05). The gossypol level in dorsal muscles from each treatment was below the detection limit. Based on the quadratic regression analysis of the TGC, the optimal dietary CSM level was 175.9 g/kg, and the maximum could be up to 351.8 g/kg and still result in the same TGC as that of control group.

The effects of dietary Eucommia ulmoides Oliver on growth, feed utilization, antioxidant activity and immune responses of turbot (Scophthalmus maximus L.). Zhang, Beili; Li, Chaoqun; Wang, Xuan; Zhou, Huihui; Kangsen Mai; et al. (2019). Aquaculture Nutrition, 25(2):367-376.

Dr. Albert Tacon is a Technical Editor at and an independent aquaculture feed consultant. E:

The present study was conducted to evaluate the effects of dietary Eucommia ulmoides (EU) on growth, feed utilization, antioxidant activity and immune responses of turbot fed a basal diet (CON) or EU‐supplemented diets with 5.0 g/kg (EU1), 10.0 g/kg (EU2) and 20.0 g/kg (EU3) EU leaf powder. After 70‐day trial, EU supplementation did not affect nutrient utilization, but reduced feed intake (FI) and specific growth rate (SGR) of fish at doses above 5.0 g/kg. Superoxide dismutase (SOD), catalase (CAT) and total antioxidant capacity (T‐AOC) activities in the EU‐supplemented groups were significantly higher than those in the

37 control group at a dose of 20.0 g/kg. Significantly reduced malondialdehyde (MDA) contents were observed in EU‐supplemented groups at doses over 5.0 g/kg. Furthermore, fish fed 20.0 g/kg EU showed the highest lysozyme (LZM) activity among groups. The EU‐supplemented diets with doses above 5.0 g/kg significantly enhanced the mRNA expressions of cytokines. The expression level of major histocompatibility complex II alpha (MHC IIα) was significantly upregulated compared to that of the control fish when the supplemental level was at 20.0 g/kg. Taken together, the present study indicated that the EU could remarkably enhance the antioxidant activity, non‐specific immunity and maintain an active immune response in turbot.

hydrolysate (KH) to replace fishmeal, respectively. Triplicate groups of 30 fish were fed for 10 weeks to apparent satiation twice daily. At the end of the feeding trial, the mRNA expressions of insulin‐like growth factor (IGF‐1) gene in liver, peptide transporters (PepT1) gene in pyloric caeca and proximal intestine and neuropeptide Y (NPY) gene in brain in all groups were determined. IGF‐1, PepT1 and NPY expression levels in HKH group were significantly increased compared with those of LKH and control (p < 0.05), which was consistent with the SGR, feed efficiency, PER and PPV. These results indicated that dietary 100 g/kg krill hydrolysate could improve growth performance and upregulate the mRNA expression of IGF‐1, PepT1 and NPY genes in juvenile turbot.

Dietary krill hydrolysates affect the expression of growth‐related genes in juvenile turbot (Scophthalmus maximus L.). Zhang, Lili; Guo, Bin; Liang, Mengqing; Xu, Houguo; Wei, Yuliang. (2019). Aquaculture Nutrition, 25(2):406-413.

Effect of variation in the dietary ratio of linseed oil to fish oil on growth, body composition, tissues fatty acid composition, flesh nutritional value and immune indices in Manchurian trout, Brachymystax lenok. Yu, Jianhua; Li, Shuguo; Chang, Jie; Niu, Huaxin; Hu, Zongfu; et al. (2019). Aquaculture Nutrition, 25(2):377-387.

A 10‐week feeding experiment in indoor flow‐through seawater system was conducted to investigate the effects of dietary krill hydrolysate on the expression of growth‐related genes in juvenile turbot (Scophthalmus maximus L.; initial body weight 9.45 ± 0.01 g). Three isonitrogenous and isolipidic experimental diets containing high plant protein were formulated to contain 0 (control), 50 g/kg (LKH) and 100 g/kg (HKH) krill protein

In order to study the effects of linseed oil substitution on the growth, body composition, tissue fatty acid composition, flesh nutritional value and immune indices of juvenile Manchurian trout, five feed types containing different levels of linseed oil (LO) mixed with fish oil (FO) were prepared: 0 (0 LO); 250 g/kg (25 LO); 500 g/kg (50 LO); 750 g/kg (75 LO); and 1000 g/kg (100 LO); and fed to

juvenile Manchurian trout (initial weight 6.43 ± 0.02 g) for 9 weeks. The results showed that substitution of FO with 750 g/kg LO did not affect the growth of juvenile trout, with protein content in the dorsal muscle, and lipid content in the liver not showing any significant difference (p > 0.05). The highest lipid content found in muscle samples occurred for the 25 LO diet. The fatty acid composition found in the dorsal muscle and the liver of the Manchurian trout reflects the fatty acid composition in the diet, where the relative amount of linolenic acid (ALA), linoleic acid (LA) and docosahexaenoic acid (DHA) found in these organs has a positive linear correlation with their relative composition in the diet (p < 0.05). As the amount of LO in the diet was increased, the composition of ALA found in the sampled organs increased, while the composition of DHA and eicosapentaenoic acid (EPA) decreased. At the same time, the index of atherogenicity (IA) and thrombogenicity (IT) of the muscle samples from the 75 LO and 100 LO diets was significantly lower than for the 0 LO and 25 LO diets (p < 0.05), while the flesh lipid quality (FLQ) in the 100 LO diet was significantly lower than for the other diets (p < 0.05). The aspartate transaminase (AST) activity decreased initially, and then increased, as the level of LO replacement for FO was increased, with the 25 LO diet being significantly lower than for other groups (p < 0.05). The alanine aminotransferase (ALT) activity in serum samples from the 100 LO diet was higher than that from other diets. The lysozyme (LZM)

38 activity in both serum and liver tissue first increased to a peak for the 25 LO and 50 LO diets, respectively, and then decreased as the level of LO was further increased. There was no significant change in the alkaline phosphatase (AKP) activity in the liver samples; however, the acid phosphatase (ACP) activity decreased significantly from the highest value for 0 LO feed group. In conclusion, the composition of fatty acids in the dorsal muscle and the liver was found to be modified by the diets, and with the diet containing less than 750 g/kg LO, being both beneficial for growth, and improved immunity, while maintaining the nutritional value of the lipid content in the dorsal muscle during the 9‐week period.

Effects of xylan and cottonseed meal on growth performance, digestion, intestinal morphology and the expression of two peritrophin genes of Chinese mitten crab, Eriocheir sinensis. E Ren, Shengjie; Zhu, Jianming; Cai, Chunfang; Wang, Zhi; Chen, Wen; et al. (2019). Aquaculture Nutrition, 25(2):529-539. Xylan is one of the main non‐starch polysaccharides (NSPs) in cottonseed meal. This study aimed to evaluate the anti‐nutrition effect of xylan and to better understand cottonseed meal as a feed ingredient for the Chinese mitten crab, Eriocheir sinensis. A diet containing 280 g/kg fishmeal without cottonseed meal or xylan was formulated as a control (FM diet). A second diet (XYL diet) was supplemented with 53.3 g/kg xylan according to its amount in the third

diet, the cottonseed meal diet (CSM diet), which was formulated to include 400 g/kg cottonseed meal. The last diet (CSM + XYLase diet) included 400 g/kg xylanase hydrolysed cottonseed meal, in which most xylan was hydrolysed. Diets were isonitrogenous (370 g/kg crude protein) and isoenergetic (17.58 KJ/g) and were randomly fed to 12 tanks of crabs for 8 weeks. Results showed that no difference was detected among groups in growth performance, serum biochemical index, or digestive and metabolism enzyme activity (p > 0.05). The apparent digestibility coefficient (ADC) of dry matter was FM > XYL > CSM + XYLase > CSM (p < 0.05). The ADC of protein in crab fed diet FM and XYL was significantly higher than CSM and CSM + XYLase (p < 0.05). Cottonseed meal decreased the fold height of the hindgut, upregulated the expression of peritrophin genes of Es‐PL44 and Es‐PP1 (p < 0.05), while xylan decreased the fold height of the hindgut and upregulated the expression of Es‐PP1 (p < 0.05). These results indicated that the negative effect of cottonseed meal and xylan on digestibility partly compensated by enhanced absorption of the hindgut innerly and by supplementation of xylanase externally, and cottonseed meal is an attractive alternative protein source in general for Chinese mitten crab.

Hypoxia‐induced changes in survival, immune response and antioxidant status of the Pacific white shrimp (Litopenaeus vannamei) fed with

graded levels of dietary myo‐inositol. Chen, Shijun; Xie, Shiwei; Chen, Ming; Zhengshi Mi; He, Qian; et al. (2019). Aquaculture Nutrition, 25(2):518-528. A 3‐hr experiment was conducted to investigate the effects of dietary myo‐inositol (MI) supplementation on survival, immune response and antioxidant abilities in Litopenaeus vannamei under acute hypoxia stress. Six practical diets were formulated with supplementation of graded levels (control group 0, 0.1, 0.2, 0.4, 0.8 and 1.6 g/kg dry diet) of MI and were randomly assigned to triplicate groups of L. vannamei (mean weight 0.40 ± 0.00 g) for 8 weeks. Ten healthy shrimp (final mean weight approximately 11–14 g) randomly selected from each tank were exposed to hypoxia stress after feeding trial. After 3‐hr acute hypoxia stress, survival of shrimp fed MI‐supplemented diets (except 0.1 and 0.4 g/kg diets) was significantly increased compared with the control group. Shrimp fed control diet had lower activities of alkaline phosphatase (AKP), acid phosphatase (ACP), total antioxidant capacity (T‐AOC) and glutathione peroxidase (GPX), and higher malondialdehyde (MDA) and protein carbonyl (PC) contents in hepatopancreas than those fed the MI‐supplemented diets. In addition, mRNA expression levels of heat shock protein 70 (Hsp70), catalase (CAT) and penaeidin were significantly differentially regulated in hepatopancreas. In summary, dietary MI supplementation may have a positive effect on improving resistance to acute hypoxia stress of L. vannamei.

39 Taurine alone or in combination with fish protein hydrolysate affects growth performance, taurine transport and metabolism in juvenile turbot (Scophthalmus maximus L.). Wei, Yuliang; Liang, Mengqing; Xu, Houguo; Zheng, Keke. (2019). Aquaculture Nutrition, 25(2):396-405.

The study was conducted to investigate the effects of taurine (Tau) alone or in combination with fish protein hydrolysate (FPH) on growth performance, the expression of Tau transporter (TauT) and metabolic profile in juvenile turbot. FM, FPH0, FPH0+T, FPH10 and FPH10+T diets, respectively, contained 300, 150, 150, 80, and 80 g/kg fishmeal. FPH10 and FPH10+T diets contained 62 g/kg FPH. FPH0+T and FPH10+T diets were, respectively, prepared by supplementing the FPH0 and FPH10 diet formulations with 8 g/kg Tau. Specific growth rate was the highest in FM group and the lowest in FPH10 group. TauT mRNA levels in fish fed Tau supplemented diets were

significantly lower than that in Tau unsupplemented diets. NMR‐based metabolomics analysis showed that Tau contents in liver of FPH0+T and FPH10+T were significantly higher than that of FM, FPH0 and FPH10. In muscle, Tau contents were significantly decreased in the FPH10+T versus FPH0 and the FPH10+T versus FPH10 comparisons. In conclusion, 62 g/kg FPH to replace fishmeal may not affect Tau synthesis, transport and metabolism. However, Tau supplemented alone or in combination with a certain level of FPH could reduce the requirement for Tau synthesis and transport and increased Tau levels in muscle and liver.

Regulations on glucose metabolism affected by dietary carbohydrate in different strains of juvenile gibel carp (Carassius gibelio). Song, Xuerong; Han, Dong; Liu, Haokun; Yang, Yunxia; Jin, Junyan; et al. (2019). Aquaculture Research, 50(4):1075-1086.

This experiment was conducted to study the effects of dietary carbohydrate on glucose metabolism in gibel carp (Carassius gibelio) as well to investigate if different clones had different responses to carbohydrate intake. Unselected Dongting strain (DT strain), selected gibel carp “CAS III” (A strain) and gibel carp “CAS V” (F strain) were fed with no corn starch diet (0C), 30% corn starch diet (30C) and 45% corn starch diet (45C) for 8 weeks. The results showed that selected F strain showed higher growth performance. F strain and A strain showed better control on postprandial glucose regulation by increasing plasma triglyceride, plasma cholesterol, liver and muscle glycogen contents and also enhancing glycolysis and restraining gluconeogenesis. DT strain had higher body lipid and lipid utilization. In conclusion, gibel carp could tolerate 45% dietary carbohydrate and F strain showed better growth by increasing glycolysis while decreasing glycogenesis. AFΩ

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Metal amino acid complexes and their benefits to shrimp health By Mihai Sun, Ph.D., Aquaculture Nutritionist, Zinpro Corporation.

Global shrimp aquaculture production has continually increased over the last 30 years, reaching 5.1 million metric tons in 2016 (Tacon, 2018). Despite this growth, the shrimp industry has been severely challenged by diseases, caused by viruses and bacteria. White spot and early mortality syndrome have been a significant cause of shrimp loss during the last 25 years. To maintain shrimp health status when faced with these challenges, improvements in biosecurity and farm management and the need for complete dietary nutrition have been widely discussed. This article focuses on how complex trace mineral nutrition benefits shrimp’s immune system and helps to improve shrimp health status.

The shrimp immune system is relatively primitive compared to vertebrates. Vertebrates can generate both innate and adaptive immune responses against invading organisms. However, as a crustacean, shrimp have no adaptive immunity memory cells to produce immunoglobulins – they only have generic and nonspecific immune response when challenged by pathogens. Hence, shrimp mainly rely on an innate immune response against environmental challenges. As a result, the key to improve overall shrimp health status is to enhance innate immunity. For shrimp, there are several

important immune parameters that are necessary to evaluate health status as well as potential disease resistance. Those parameters include total hemocyte count, phenol oxidase activity, superoxide dismutase activity, glutathione peroxidase activity and so on.

Shrimp health status indicators One common indicator of shrimp health status is the total number of hemocytes in the hemolymph (Fotedar et al., 2001). Loss and

42 damage of hemocytes will decrease shrimp immunity, increase the susceptibility against pathogens and even cause mortality (Yeh et al., 2004). For penaeid shrimp, hemocytes are phagocytes and they have the same biological properties and functions as vertebrate macrophages, granulocytes and natural killer cells (Van de Braak, 2002). The hemocytes are required for clotting, encapsulation and phagocytosis function and to initiate a pro-phenol oxidase cascade as an immune response.

Fig. 1. Neutralization of reactive oxygen species (ROS).

Typically, the focus for providing dietary trace minerals has been to maximize shrimp growth performance. However, improved immunity is an additional area of benefit that has often been overlooked by both academics and industry.

Another common indicator of shrimp health status is phenol oxidase, which is a key enzyme for shrimp immune system function. This enzyme is responsible for the activation of melanogenesis in invertebrates (Wyatt, 1961). Furthermore, research has shown that phenol oxidase is an important enzyme to protect against

several pathogens (Cerenius & SÜderhäll, 2004). For shrimp, superoxide dismutase and glutathione peroxidase are very important antioxidant enzymes, which catalyze reactive oxygen species into water by two steps (Fig. 1). Most of the important enzymes for shrimp health are metalloenzymes, which require a metal cofactor for their activity. For instance, phenol oxidase is an enzyme that contains Cu. Cu and Zn are integral parts of Cu/Zn superoxide dismutase enzymes (Cu/Zn SOD). In addition, Se is important to incorporate into selenoproteins, such as glutathione peroxidase. Hence, trace minerals and their associated metalloenzymes, are critical to enhance shrimp immunity and health status. Dietary trace mineral supplementation is essential to provide complete nutrition for shrimp aquaculture, especially for intensive production. Typically, the focus for providing

dietary trace minerals has been to maximize shrimp growth performance. However, improved immunity is an additional area of benefit that has often been overlooked by both academics and industry. Another often overlooked area is that trace mineral supplementation is available on the market with different forms that vary in their animal performance benefits. Among the forms most often shown by peer-reviewed research to be superior in providing improved animal performance is the complex form, which has been chelated with an amino acid ligand. The complex form uses an amino acid transporter rather than a metal transporter to provide essential minerals to the animal’s organs, tissues and enzymes to improve animal performance. Inorganic and most other organic trace mineral forms rely solely on metal transporters that are less effective in mineral uptake and absorption.


Benefits from the complex trace mineral form To this point, a study (Jintasataporn et al., 2015) compared a zinc, manganese, copper, iron and selenium treatment in either an inorganic form (inorganic treatment), a combination of inorganic and complex forms (combination treatment) and solely as a complex form (complex treatment) containing half the mineral dosage as the other two treatments (Table 1). After an 8-week trial period, the results show that the survival rate increased for shrimp fed either on combination or complex treatments compared to shrimp fed with an inorganic treatment (Fig. 2). As for immunity parameters, results for the total hemocyte numbers (Fig. 3) show that the combination treatment resulted in the highest hemocyte count. The complex treatment had the next highest count, but not significantly different than the inorganic treatment. In addition, the phenol oxidase activity results show that shrimp fed with the complex treatment expressed the highest activity compared to combination and inorganic treatments (Fig. 4). All immunity parameters indicate that shrimp immunity is boosted by the treatments supplemented with a metal amino acid complex. After this 8-week feeding trail, a challenge trial was conducted to further evaluate shrimp immunity. Shrimp were challenged with Vibrio harveyi by subcutaneous injection and the mortality rate was recorded from day 1 to 7. As Figure 5 shows, shrimp mortality rates increased from day 2

Table 1. Dietary treatments.

Fig. 2. Total survival rate after the 8-week trial.

Fig. 3. Total hemocyte count after the 8-week feeding trial.

44 estimated. Determining optimal trace mineral supplementation for both growth performance and immunity is very relevant for today’s shrimp industry. For commercial feed manufacturers, a review of current trace mineral supplementation dosage and form will be the first step to improve shrimp immunity and overall health status. References available on request. AFℌ

Fig. 4. Phenol oxidase activity after the 8-week study.

Fig. 5. Mortality rate of white shrimp after challenge with Vibrio harveyi.

to 7 for all treatments. However, on day 7, shrimp fed with combination and complex treatments had significantly (p<0.05) lower mortality rates compared with shrimp fed the inorganic treatment. The cumulative 7 -day mortality rate results are consistent with the total hemocyte count and phenol oxidase activity results, which indicate that shrimp fed either combination or complex treatments had boosted immunity parameters that increased their disease resistance.

Today, the shrimp aquaculture industry is facing multiple challenges among which there is a lack of acquired immunity that makes vaccine prevention for viruses or specific pathogens impossible for shrimp. In other words, the industry must rely highly on biosecurity, management practices and complete nutrition to maintain shrimp health status. Trace minerals are essential for shrimp growth performance. However, the benefits of trace mineral on shrimp immunity has often been under-

Mihai Sun Aquaculture Nutritionist Zinpro Corporation E:


Mullets, a family for aquaculture diversification By Juan Miguel Mancera, Luciano Vílchez-Gómez, Juan Antonio Calderón, Isabel Pujante, Francisco Javier Moyano, María Angeles Esteban, MUGILDIET Proyect, Spain.

Why thick-lipped grey mullet?

Fish are conventionally classified as carnivores, omnivores and herbivores based on their food preferences. This is linked to the adaptation of their digestive physiology, which is designed to obtain the highest nutritional value from the available food. In the case of cultured fish, successful rearing relies, to a great extent, on a detailed knowledge about the feeding habits, nutritional requirements and digestive capabilities of the different species. Therefore, the study of digestive physiology is a key issue to obtain valuable information on factors that affect the

net efficiency of food transformation. Within this context, one of the most important issues is the evaluation of types and functional features of digestive enzymes involved in the hydrolysis of the main nutrients. For this reason, a great number of recent studies have been oriented to the evaluation of different aspects of the digestive biochemistry in cultured fish species. Most of these descriptive studies are focused into the proteases, while information on other enzymes like carbohydrases or lipases is scarce.

The thick-lipped grey mullet (Chelon labrosus), a commercially valuable species in many local markets in different Mediterranean countries and with a long tradition of being cultured under extensive systems, is currently considered a potential candidate for intensive aquaculture as an alternative to the production of sea bream and sea bass. It presents high growth rates and tolerance to great variations in salinity and temperature as well as in food availability. Mullets have been described as omnivorous during their early stages with a tendency to become herbivorous with age. This change in feeding habits has been described also in C. labrosus, which are zooplanktophagus during the early stages and phytobentonic in adult stages. However, it is unclear to what extent this variation in feeding habits is linked to changes in the digestive biochemistry of the species. Our work focused on assessing several aspects of the digestive biochemistry of C. labrosus, including functional characterization of the main digestive enzymes (proteases, amylase and lipase) as well as changes in their total

46 activity at different developmental stages. Results showed that optimal temperature and pH for the different enzymes were greatly coincident to those reported in other species. Also, important changes in the relative contribution of the enzymes at different ages were evidenced (Figure 1), most of them linked to the reported variations in feeding habits along development from a partly carnivorous diet during early life stages, to plant rich diet in later stages. Hence, a decrease in pepsin activity and an increase in alkaline protease activities were observed when comparing juveniles of two sizes Fig. 1. Activity profile of digestive enzymes in C. labrosus specimens of different weight. (45 and 180 g average weight). Such decrease in pepsin activity provided functional evidence of a progressive at any age are consistent with the composed by an inner reaction decrease of the role of chemical lipase profile of a functional herbivochamber, formed by a cellulose stomach digestion with age, being the rous. dialysis membrane with 1,000 Da function of this latter gizzard-like molecular cut off. This inner reaction Due to the good euryhaline capacity organ more oriented to the mechanichamber is surrounded by an outer of this species, the effect of different cal breakage of food. Also, the chamber, where a continuous flow of environmental salinities (from 0 to 40 observed increase in trypsin activity buffer allows the constant removal of ppt) on the gene expression of these may be related to an increase in plant digestive products, which is maindigestive enzymes and their total protein content in diets of older fish tained by a high precision multichanbiochemical activity was determined. (more than 300 g). This indicated an nel peristaltic pump (Figure 2). So, in Several gene sequences of the adaptation to a better digestive use of vitro assays simulating the digestion enzymes pepsinogen 2 (pga2), these food items. In addition, no of C. labrosus were carried out in trypsinogen 2 (try2), chymochanges in the activity of lipase with order to test the potential effect that trypsinogen (ctr) and pancreatic alpha age were observed. The relatively high variable amounts of salts in the amylase (amy2a) were cloned for the alpha-amylase in relation to low digestion, as a result of regular water first time. It was found that the trypsin activity supported the intake taking place in different water expression of these genes was hypotheses that older fish fully environments, may exert on protein influenced by the salt contents of the developed as functional herbivores, hydrolysis. Assays performed in the water on which the fish were should exhibit high carbohydrase and range of 0 to 40 ppt showed a more maintained. low protease profiles. Therefore, the efficient hydrolysis of protein at We have the capacity to assess high level of alpha-amylase activity in salinities under 12 ppt. This suggests intestinal proteases functionality of these larger fish indicated the that in fish living at higher salinities, fish using a gastrointestinal model increased importance of this enzyme some compensatory mechanisms (GIM) aimed to simulate gut protein as fish becomes herbivorous. The very should exist (i.e. a higher enzyme hydrolysis under controlled condilow values of lipase measured in fish secretion or a longer gut retention tions. The GIM is a small bioreactor

47 time) to ensure that the net efficiency of the digestive process is maintained. Results confirm that thick-lipped grey mullet is a strongly euryhaline species but its acclimatization to extreme salinities involves an extra expenditure of energy and, probably, negatively affects growth.

Alternative diets and immunology Our team was working on the design and validation of a diet suitable for mullets (Chelon labrosus, Liza aurata and Liza ramada) which replaces fishmeal with by-products of the brewing sector. During the last year,

some foods were evaluated with different levels of fish meal and oil replacement. Biothesan, a company finalist of Fishtech Awards, Qingdao 2018, produced the experimental feeds and were able to replace the seventy-five percent of the diet by brewing by-products. We are still working on a complete replacement of the fish meal and oil, and the results that we obtained are encouraging. After the trials, fish fed with commercial diets (control) and Biothesan’s feeds had a similar immune status and nutritional development. These feeds were made with a high amount of brewer spent yeast (65 % of weight) and a small amount of brewer spent grain. Solving

the bottleneck of the use of small pelagic fish for fish meal production is the primary objective of these diets. We hope these new feeds will soon be on the market because they break two aquaculture gaps, the high cost of the feed for farmers and the environmental problem with fish meal trap.

With the aim of evaluating the possible effects of the experimental diets on fish immunity we developed different trials. No significant effects were recorded when mullets were fed 60 days with commercial diets or experimental diets (40 % or 70 % of yeast replacement) on the main immune parameters determined in skin mucus and serum. The only

Fig. 2. Diagram of the bioreactor used to simulate in vitro, under different conditions, the digestive hydrolysis of protein by enzymes of C. labrosus.


Figure 3A-Figure 3B. Experimental facilities of Servicios Centrales de Investigación de Cultivos Marinos (SC-ICM) (CASEM, University of Cádiz, Puerto Real, Cádiz, Spain; Operational Code REGA ES11028000312), where experiments were carried out.

significant difference was detected on the seric protease which was increased in fish fed on the 70 % yeast replacement diet, respect to the values recorded on fish fed commercial diets. Furthermore, no significant differences were detected on the humoral immunity of mullets fed diets with different amount of proteins (47 % or 32 %). These results corroborate that this fish species can be fed with different diets without suffering any negative impact on its immune system.

Conclusion In recent years, there has been a tendency to try to produce herbivorous species or species capable of feeding on high vegetable protein content feed. In this sense, mullets, including the thick-lipped grey mullet

(Chelon labrosus), are species that combine the requirements for efficient production and a reduction of feed costs. The objective of our research was to increase the knowledge about the physiology and digestive biochemistry of this species in order to establish specific feeding guidelines. Finally, the sustainability of aquatic foods is related to many factors, but one of the main ones is the availability of enough raw materials at a reasonable cost. Brewing spent grains and yeast may be a different option to consider for the design and production of future diets for aquaculture and they contribute directly to the circular economy. References available on request.


Juan Miguel Mancera Professor of Zoology Universidad de Cádiz, Spain E:


Organic Aquaculture Challenges, hopes and macroalgae By Alexandre Veille, Asia Aquaculture Manager, Olmix.

Domestication of animals presumably started by simply recognizing mutual benefits. The animal receiving food and protection, and humans benefited from its valuable meat, bones and skins and later on for milk, wool, motion power, etc. (Reed, 1984). Starting 11,000 and 2,000 years ago with sheep (Benecke, 1994) and carp (Colin, 2011) respectively, cohabitation lasted until the Industrial revolution in the 18th century. Mechanization allowed the introduction of crop rotation system and it’s scaling up. Starting in England (Seidl, 1995), this system resulted in more efficient land use and opened the way for fodder production which made it possible to intensify livestock production. While aquaculture arose in Asia (Australia and China), modern aquaculture would emerge in Europe and America from the industrial era.

From modern farming… The difference between traditional animal farming and so called “modern” farming lies in intensification and specialization (Hartung, 2000). The first referring to less

mechanized, in/outdoor and family owned systems. The second refers to monoculture, with animals specially bred for the purpose, and kept in specialized buildings. Consumers

rarely recognize this production system, as farming is often associated with the traditional concept of a farm with several animal species. The catchword “animal factories” then

50 spread quickly and complaints were voiced that animals are considered as “animal machines” (Harrison, 1964). In general terms, “intensive animal husbandry” is often interpreted as “mass animal farming” with all its negative connotations. However, it allows affordable meat and the debate has since moved from food supply, to food safety and animal welfare.

To Organic farming… Soon, this new agro-industry faced recurring issues in crop production, such as erosion, soil depletion, decline of crop variety (GMOs concerns) and quickly extend to animal production through various scandals: BSE (Bovine Spongiform encephalopathy, commonly known as Mad Cow disease), horse-gate, GMO salmon etc. To reverse this trend, farmers in Europe and America developed another way of farming called “Organic”: “a production system that sustains the health of soils, ecosystems and people. It relies on ecological processes, biodiversity and cycles adapted to local conditions, rather than the use of inputs with adverse effects. “Organic Agriculture combines tradition, innovation and science to benefit the shared environment and promote fair relationships and a good quality of life for all involved." ̶ the International Federation of Organic Agriculture Movements (IFOAM), 2005. This label connotes better standards, higher prices and a verifiable claim for the production processes and

practices as well as consumer expectation for food quality, safety, traceability and sustainability. Although, practices and standards developed for terrestrial species aren’t easily applicable to aquaculture species, some main principles are widely accepted, such prohibition of antibiotics, GMOs and use of wild fishmeal (IFOAM & (EC) N° 710/2009). The increasing market share of organic foods, increasing consumption of fish, declining fishery harvests and environmental concerns, placed more focus on "organic aquaculture." This market has grown from 53,000 MT in 2009 to 400,000 MT in 2016, where Asia leads with China (77%) followed by Europe (22%). Segmentation can only be accurately assessed for some 20% of the market, but salmon, mussels, carp and shrimp are the main organically produced species. Although this remains a niche market, it is worthy of attention and one that could solve some recent aquaculture challenges. With increasing production volume, world prices keep declining and for some species to below production cost. Irish salmon couldn’t compete with its UK and Norwegian neighbors, so by converting to organic farming, higher prices could be supported. Similarly, in Vietnam organic pangasius filet (dory fillet,…) provided a way out from the “catfish price war” (Tu Van Binh 2006). However, consumers value product origin and traceability, inviting an overlap of concepts such as sustainable, biological, fair trade and environmentally-friendly aquaculture, that can mislead the consumer towards

organic labeling; therefore operators should not consider “organic” as selfsufficient (EUMOFA 2017). Unfortunately, while antibiotic-free aquaculture should already be the norm, recurrent refusals in Europe or in the USA due to antibiotic residue prove otherwise. To support the conversion to “organic”, farmers first need access to environmentally friendly products. New products such as natural antibacterials, immunomodulators and water management additives need to be available otherwise production will be at the mercy of existing diseases (Vibrios, Streptococcus and Aeromonas, virus, etc). Going “organic” is not a way back to ancient times, but a combination of traditional methods with current science and technology.

Thanks to seaweeds… Many years of research with seaweeds and the development of a complete biorefinery process (from collection of macroalgae to final extracts) has lead Olmix to create various innovative solutions to improve the general health in aquaculture, making animals more resilient to challenges, both environmental and pathogenic. Sulphated polysaccharides extracted from seaweeds are at the base of innovative solutions when used either as functional supplements due to their biological activities or using their structural properties to modify the layered structure of montmorillonite clay.


Fig. 1. Improved survival after challenge when treated with ALGIMUN® containing MSP®IMMUNITY. Biohelis research center - Mexico.

the lines of defense when facing environmental and pathogenic pressure. Use of these products are in line with the current trends of reduced antibiotics use, organic farming, sustainable production, traceability and environmentally friendly farming, all concepts that consumers are considering more and more important, and also have been proven to give a better and more consistent price for the farmer. AFΩ

Fig. 2. Improved survival after challenge when treated with MFEED based on copper grafted interspaced montmorillonite clay. Can-Tho University – Vietnam.

Depending of the algae and the structure (sulphation degree, type of sugars, length of osidic chains…), the sulphated polysaccharides (OLMIX MSP®) have specific biological activities. For example, MSP®IMMUNITY extracted from green algae has an immune-modulatory effect in fish and shrimp, enhancing their general health. Healthier animals become more resistant to environmental and pathogenic challenges (figure 1.).

Structural seaweed polysaccharides are used to modify clay (Olmix patented process) into for example interspaced montmorillonite with copper grafted in it which will preferentially target pathogenic bacteria, resulting in a more beneficial gut microflora and leading to bigger and stronger animals (figure 2.). Versatility of these seaweed polysaccharides allow for application at both farm and feed mill, to optimize

Alexandre Veille Asia Aquaculture Manager E:



Ask the Expert Your aquafeed processing questions answered Welcome to my first column. The aim is to help you tackle the real world challenges you’re facing in producing quality aquafeeds. Send your questions to


The factory is producing only floating feed. The factory has no experience in sinking feed and I am asking for help to make it. For floating feed for warmwater fish, the factory uses only 2-3% of fish oil, and all for coating. The factory does not have vacuum coating. For trout feed, fat is up to 25%. How do you mix and add the oil during operation? What percent of oil should we use for adding to the raw materials and what percent for coating?

There are several parts to this question and you will face some significant challenges without modifications to plant. I will start by breaking into two parts, firstly the sinking/density and then considerations on fat. There are also formulation considerations, but I will focus on process today. It is quite possible you could make a low to moderate fat sinking diet with the equipment you have on hand, although from your description, the type of extruder used often has a shorter barrel than would be ideally

suited to sinking feeds and the screw profile will often be set to continuously increase shear rates from beginning to end, designed for the purpose of making floating feeds.

Producing sinking feeds favors a longer barrel (longer length to diameter) and a screw profile where work is developed further back in mid barrel. This allows time for more cooling and low shear dwell towards the die when required. Provided die open area is appropriate (greater open area is required for sinking feeds), then this type of screw profile will make production of sinking feeds easier. It is important to note that this “sinking” type screw profile can also be used to make floating feeds, provided appropriate pre-die restriction (back-up dies) and die open area is used. There are other factors such as utilization of process water and steam inputs used to regulate density, with increased cook in the conditioning phase an advantage for producing sinking feeds, as it allows more process freedom in the extruder itself. Crucially, the use of water follows an

Peter Hutchinson is a Technical Editor at, the owner— director of ENH Ltd., New Zealand, and an aquaculture feed consultant. E:

expansion curve determined by the level added, which needs to be understood. Die design is an important factor with sinking feeds. Not only does the open area need to be appropriate, but just increasing open area can create issues with uniformity, so hole arrangement is crucial and dies tend to have longer land length with longer tapered lead in than floating feeds. With regard to process fat addition, this would commonly be in a range of 1-4% and injected into the extruder

53 barrel (rather than in mixer with mash as you are probably doing now). Added process fat will increase density, however this can come at a cost of reducing SME below appropriate levels, which can impact cook, water stability, pellet structure and ability to absorb coated fat. Lack of SME and poor water stability can also lead to a condition in some species called GDAS. The remaining fat required to reach finish product target will need to be coated. Now here is where things get more complicated. The sort of high fat feed you are describing actually requires a floating feed off the extruder die at a specific density to match the level of fat coated. The fat fills the air voids within the pellets, enabling the feed to sink. To obtain 25% fat in the finished pellet, this will require 1520% of the fat to be coated (depending on endogenous fat in raw materials and fat added in process). If you over expand the feed it will still float post coating. Not enough expansion and the feed won’t be able to absorb and hold the fat. Atmospheric coaters are unable to force the fat deep into the pellet core and are therefore limited to around 810% of fat addition at a maximum, with level achieved dependent on SME and overall expansion rate. By now you have probably already established that your atmospheric coater is not going to be up to the job and you will require a vacuum coater to produce a feed at 25% fat which is of appropriate quality. Vacuum coaters function by first drawing a vacuum in the coating chamber,

spraying in the oil and then releasing the vacuum, the resulting increase in pressure causing the fat to be forced deep into the pellet’s core.


We are now suddenly getting too much expansion and pellets are floating. Is this issue with formulation or extruder operation? Assuming your formulation hasn’t changed I am picking there is a process issue here. If you have significantly increased functional starch, then you may need to take a look at formulation as a possibility. I have listed below here items which I think you should consider: 1) Die blockage. This will obviously depend on your die hole size and milling and screening equipment. If you are running smaller diameter feeds, check you don’t have a hole in a screen somewhere, or a source of large particles from something breaking down in the system. If your feeds are larger diameter, this is unlikely to be an issue unless you are facing problems with mineral deposit build up on the screws and die. 2) Die open area is too low. If you have changed dies, check your die open area is appropriate to feed rate. 3) Excess steam in barrel. Also check for leaking valves and ensure that you are not delivering more steam into barrel than you think. 4) Check water addition is in the correct range. Remember that water

addition runs along a density curve, so establish where you are on the curve. If you can get there without feed becoming too sticky, higher water will generally produce a better product than lower water. Water requirement is very much formulation dependent. 5) Oil added too early in process. Injecting oil in barrel is more effective than adding to mash in blender when trying to increase density. Also check that your oil addition has not changed and that it is delivering as expected (i.e. pump working, lines and injection points not blocked.). 6) Check feed rate is appropriate to the die open area. 7) Increase cook in the preconditioner if you can and try significant cooling on the extruder at the same time. Try a die spacer with cooling on it as well if available. 8) If you are using a restriction plate or valve behind the die, check it is not too restrictive.

9) Extruder wear. Excessive extruder wear will reduce the effective pumping ability, leading to increased shear and expansion. 10)

Change screw speed.

11) Screw profile. I assume this hasn’t changed, but depending on what arrangement you have, you may like to try dragging some of the work back down the screw and easing up towards the die. Hope this helps and I look forward to hearing how you get on. AFΩ


Conference and feed show offer unique experience for Aquafeed Horizons delegates

There’s a reason Aquafeed Horizons is held along side Victam International. There is nowhere else in the world where delegates have the opportunity to get their hands on so much key feed processing equipment as at the world’s oldest and largest feed and grain show. Of course ancillary equipment as well as ingredient companies are also represented, but it is the extruders, pellet mills, coolers, dryers and mixers, that makes a visit to Victam International unique.

Essential information WHEN:

June 12—14, 2019

WHERE: Hall 6, Koelnmesse, Cologne, Germany REGISTRATION: Free of charge if you register online. On site: t €60,- (excl. VAT) (A separate fee will be charged for the conferences) Register here: HOURS: Registration and badge pick-up: 08:00 Monday – Friday Conferences & technical seminars: 09:00 – 17:00 Monday - Friday Exhibition: 10:00 – 18:00 Mon, 10:00 – 16:00 Wednesday Network reception: 18:00 – 19:30 Monday TRAVEL, VISAS, ACCOMODATION:

55 A quick look at a small sample of what’s on show for aquafeed production. Clextral answers feed markets with high capacity extruders and with small and medium flexible lines dedicated to high added-value products. Value added pet food products, such as treats, bi-colored, co-extruded, moist and semi-moist, premium and super premium, nutritional, functional and so on, can be extruded in Clextral lines ranging from 300 to 1000kg/h. High capacities can be achieved with high flexibility and consistent product characteristics: quality nutritional Extrusion-Link has been supplying twin screw machinery into the aquafeed, cereal, petfood and snack industries for over 20 years. The company has chosen to exhibit at Victam for the first time this year following an increase in activity in the aquafeed industry and the development of its new EL range of twin screw extruders. Extrusion-Link are known for rebuilding twin screw food extruders and they are now also proud to offer the new EL twin screw extruder range at a comparable price to a rebuilt extruder. Whichever option is chosen, the customer is guaranteed a quality machine at a reasonable cost. Extrusion-Link offers full training and process commissioning with all their machines as well as post installation back up, servicing and ongoing support. Extrusion-Link have also installed many complete lines and are happy to discuss your project whatever the size.

Stand D078

value, higher starch gelatinization for increased digestibility, large variety of raw materials. High capacity lines for pet food are now standardized for “standard“ pet food (10 to more than 16T/h output). Clextral has developed an expertise in fish feed production at high capacities up to 30 T/h final fish feed which is the highest capacity ever reached on this type of production. This process skill has been transferred to the production of pellets with diameters over 35 mm, and as small as 0.5 mm diameter.

Stand E051

Good solutions require experience and innovation. Tietjen Verfahrenstechnik GmbH, based in Hemdingen near Hamburg, is a medium-sized company in the mechanical and plant engineering sector. The team of around 50 employees has been building hammer mills and individual grinding systems since 1959. years since the company was founded, more than 2,000 systems have Customers use these systems for dry been delivered worldwide. and wet milling in the feed sector, for pet food and fish feed, as well as for Stand B041 biogas plants or in recycling. In the 60


Since 1986, Setrem has been designing and marketing single-screw extruders and their peripheral equipment all over the world. Originally specialized in the dry process (manufacturing of extruded soybeans, feed for livestock ...), the company has considerably extended its skills to meet all production requirements. Customized solutions for all industries thanks to the flexibility of its extruders, SETREM has followed and anticipated market developments by offering custommade equipment. Its extruders are well adapted to the dry process as well as the moist process and make it

possible to manufacture both sinking and floating fish feeds. We offer complete lines, with capacities from 40 kg / h to 10 tons / h. The main advantages of our equipment are:

· · · ·

Softness and robustness of use, Low operating cost, Quality of extruded products. Multipurpose equipment.

Stand E053

AQUAFEED INNOVATION AWARD 2019 For contribution to the advancement of aquafeeds is proud once again to honor the achievements and contribution of the allied industries to the advancement of aquafeed development with the Aquafeed Innovation Award. The Technology and Ingredient category winners of this year’s Award will be announced during the evening reception at Victam International on June 12, 2019.


Amandus Kahl will reveal a completely new designed Extruder to meet the increasing requirements of the fish feed and pet food markets. The new extrusion product family comes with four different machine sizes covering the whole range of performance from lab-scale up to 10 t/h industrial largescale applications. All machines are available as machine-only or as turnkey extrusion lines comprising all required process steps .

The new Extruder comes with the proven Amandus Kahl stop bolt technology for perfect mixing and venting in the first barrel section. Dedicated process zones for compaction, cooking and pumping assure high flexibility and various adjustment options. Exchangeable screw elements ensure perfect adaption to changing formulations and quality parameters. These features are complemented by fine-control measures such as screw speed adjustment, steam/water addition to the extruder barrel and individually controllable heating/cooling jackets - all adjustable during operation for direct product quality response. The combination of individually adjustable screw elements and the fine-control measures enable customers’ requirements to be met in the vast majority of cases. Complex and expensive additional equipment to influence expansion behavior is not required, allowing customers to save investment as well as operational costs.

During the design process, the main focus of the company’s engineers was to create an operator-friendly machine. This is achieved by a doublehinge head connection, ensuring fast die changes and fast knife replacement. The frame-mounted touchscreen based operator panel complements the user-friendly design and gives access to all relevant operational data, settings and options during start up and operation.

Extensive prototype testing in the test center in Reinbek showed very good results in terms of product quality, capacity and process stability for the production of sinking as well as floating fish feed. The first series machines were sold to the upcoming countries in northern Africa; commissioning is expected to be finished in early 2020.

Stand D011

grinder-lines, hammer mills, cooler, crumblers and other main components, as well as high-quality accessories and spare parts for pellet mills. Innovation is driven by customer demand and achieved by a very well-educated and trained team able to offer excellent and customized products that meet the usual high German quality standards. In cooperation with their global partners, With more than 40 years of experience, Münch-Edelstahl is a leading company the family owned business MÜNCHin the pelleting sector, offering state-of Edelstahl GmbH in Hilden, Germany, -the-art products and technology. ranks among the leading worldwide Stand: C041 exporting manufacturers of pellet presses, complete pellet mill- and


The vacuum coating process, invented by Dinnissen more than 25 years ago, was an evolution of the PegasusÂŽ Paddle Mixer. In this double-axle mixer product is raised in a fluidized zone, giving a gentle, fast and efficient mixing process. In experiments carried out in a special mixer under vacuum conditions high concentrations of liquid were sprayed onto feed pellets. Upon removal of the vacuum the liquid was drawn deeply into the coated pellets. This technology can increase fat content of pellets up to 42%, increase product flow out of the silo, prevent pollution and reduce contamination at farms. Dinnissen has perfected vacuum coating over the past years and made it suitable for many other applications. Present-day systems can accurately spray different fluids in low to high doses on the product, as well as apply multiple layers of liquids and powders onto granules and extruded products.

PegasusÂŽ Vacuum coating by Dinnessen.

mills; mixers; bucket elevators; belt and drag/chain conveyors; sieves / pre -cleaners; crumblers and slide gates and diverters. The company is focused on customer's needs and so offer their customers a global service, starting from the first design until installation and commissioning of all the machines and installations.

Stand: F059

Stand B031

Rosal Instalaciones Agroindustriales, S.A. are experts in design and manufacture of machinery and construction of complete facilities for processing and producing all types of animal feed: Turn key feedmills, including aquafeed plants; premix plants; micro -dosing stations; pellet mills; countercurrent coolers; hammer mills; roller

Franz Ludwig GmbH / Mainz will show their mobile unit FL-ProfiCheckADVANCED for measurement of moisture and temperature of bulk materi-

als of all kinds. It is very user-friendly due to its ease of operation and the integration of wireless technology connection to PC/Laptop. It has applications in almost every process situation and allows convenient evaluation, quality control and monitoring during every phase of processing - from evaluating the condition of materials to be processed to the finished product. Measured value displaying and parameter setting via mobile devices with ANDROID operating system by free download app. The operation via APP on mobile devices enables the separation of the measuring instrument and the control unit. The high computing power of the PROFI CHECK ADVANCED is thus fully available for measuring signal processing, which allows the precise execution of complex measuring procedures. Through free software updates the user benefits from continuous further development.

Stand A047


Future-proof aquafeed production starts with co-creating the perfect fit. The challenge with aquafeed production is to achieve the right density and to produce floating, slow sinking or sinking pellets, while water stability is ensured. As a result of an increase of prices for animal protein

and the call for sustainability feed, producers look at alternative ingredients which leads to the processing of an increased number of raw materials and ingredients. Depending on which machinery is used, different challenges can be met.

-how and co-creation are essential in finding the perfect fit. Whether you are looking to modernize or expand your aqua feed production, want to replace aging machinery with futureproof innovations, or need advice in the planning and setup of a completely new aqua feed mill, Van Aarsen is the knowledge partner for you.

Stand C011

Van Aarsen believes that sharing know

The staff of looks forward to welcoming you to Stand A003 at Victam International 2019



Aquafeed Horizons 2019 The 12th Aquafeed Horizons international conference for aquaculture feed professionals returns once again to Cologne, alongside Victam International on June 12, 2019. Join your colleagues from around the world for a packed day of expert presentations. Optimal design and processing of aquafeed Robert Strathman, President, Famsun-USA Design and Engineering Ensuring a high level of line performance with minimal quality defects requires a keen understanding of how technical features, such as buoyancy and water stability are affected by formulation, ingredient selection, and the production process. Several critical aquafeed design features, and their interactions will be discussed.

Process optimization in aquafeed, a challenge with fluctuation in raw material qualities and formulations Daniel Stoffner, Product Manager, BĂźhler AG One of the challenges in aquafeed production is the fluctuation in processing parameters due to fluctuations in raw materials and least cost formulations. The question to be answered is, how can we optimize the process and the production planning to improve the overall performance in daily operations? Extruded aquafeed quality management; relationship between technology and extruded aquafeed quality Thomas Ellegard Mohr, Sales Director, ANDRITZ Feed & Biofuel A key to successful fish farming lies in correctly adapted feed formulas, high quality ingredients, controlled homogenous content and optimum physical feed pellet properties. Increased feed demand impacts the availability of "classic" raw materials, bringing new challenges to extrusion technologies and process control to adapt.

Practical realities associated with micro pellet production Dana Nelson, Aquafeed Specialist, Extru-Tech, Inc. The focus of this talk will be the practical presentation and discussion regarding the use of extrusion equipment to produce micro pellet aquatic feeds. Specific details and experiences will be presented with an emphasis on critical issues.

61 Insects as a substitute for fishmeal: Influence on the extrusion process and the product properties of carp feed Julian M. Foerster, Application Technician, Brabender GmbH & Co. KG In order to bring black soldier fly larvae meal into greater practical use, knowledge is needed about how it influences the production process and the product. Experiments in a master thesis to achieve an acceptable carp feed master thesis addresses this topic.

Key leading indicator best practices in the extrusion/drying process Charles Engrem, Director of Aquafeed Process, Wenger Manufacturing The Extruder and Dryer are a key part of most aquafeed ventures, and they can easily consume the profits of a company without having a systematic approach to control the profit leaks. This presentation will present key essential best practices.

IoP: Leveraging people, process, and platforms to maximize aquafeed production

Paul D. McKeithan, Head of Digital Services, Bühler Aeroglide Digital services and the industrial internet of things (IIoT) are transforming processing operations with intuitive and intelligent analytical capabilities. Many aquafeed manufacturers already have the data, sensors and controls. But why do they need the noise of IoT?

Modelling tools to evaluate aquafeeds Luís E.C. Conceição1, Tomé S. Silva1, Filipe Soares1, Ivar Rønnestad2 1

SPAROS Lda, Portugal, 2 University of Bergen, Norway

The replacement of fish meal and fish oil often affects protein digestibility, nutrient retention, and has major impact on nitrogen and phosphorus waste. What modelling tools are there to make quantitative assessment of the effects of these changes in feed formulations on fish performance, feed costs, consumer-value, and environmental impact? The importance of producing high-quality fry in order to obtain well performing juveniles up to farmgate Tania De Wolf1, Geert Rombaut2 and Alessandro Moretti2 1

Maricoltura di Rosignano Solvay srl, 2INVE Technologies

Nutrition, microbial management and immuno-stimulation during the early stages results in new concepts, that are applicable in aquaculture production and health management practices of farmed fish in the Mediterranean area, to produce high quality fry, which will further develop into well performing juveniles up to the farm gate.

62 Controlling Phosphorus Discharge in Aquaculture John Mollison, Prairie AquaTech This presentation will describe the process and mechanism used by Prairie AquaTech in developing dietary formulations as well as measurement matrix and challenges/ opportunities within production environments needing to reduce P discharge.

Optimization of the use of lipids in aquaculture diets Nicola Tallarico, Regional Director EMENA - Kemin AquaScience Guidelines to prevent lipid oxidation processes, highlighting the attention to the features to look for when selecting antioxidants for different substrates. The author focuses on the importance of synergism between molecules, and how different antioxidants respond differently depending on the composition and origin of fats to stabilize.

A microalgal oil containing EPA+DHA as a source of omega 3 in aquaculture species

Ester Santigosa, Senior Scientist Aquaculture, DSM Nutritional Products France Research conducted by Veramaris has demonstrated that an algal oil rich in EPA and DHA can be used in fish oil-free or marine ingredient-free aquafeeds obtaining growth rates, fatty acid digestibility values and fillet fatty acid profiles comparable to those of fish fed with standard commercial diets without compromising animal's health.

Sponsored by:

Pre-registration required! Places are limited—Register now to avoid disappointment.

HOW TO REGISTER: Complete your Victam International registration (free) and continue to the conferences registration page:


Aquafeed production courses Upcoming training opportunities in aquafeed production Aquafeed extrusion training - Technical with a practical focus

In each location, the courses are held in cooperation with an institution with an extruder in their pilot plant. “This way we can provide a practical demonstration that the theory works!” An additional bonus is that these institutions – like FôrTek (Centre for Feed Technology) in Norway and the Fish Nutrition and Physiology Laboratory at the Catholic University of Temuco in Chile – are a source of supplementary expertise in areas like fish nutrition. Access to their pilot plants is also available to companies for R&D trials. They also provide more in-depth specialist programs in areas like Extruder Die Design and Extrusion Scale-Up & Process Transfer.

Experienced engineers and course presenters, Dennis Forte and Gordon Young, have been working together, offering extrusion training to industry for almost twenty-five years. But training is not their main business – most of the time they work with companies to help them establish and improve their processes. So they bring this practical focus and experience to the courses that they present. They now offer three-day courses relevant to aquafeed extrusion on four continents: Specialist Aquafeed Extrusion Technology courses in Norway and Chile, and more generalized Food & Feed Extrusion

courses in Thailand and Australia. Each course typically attracts attendees from a range of surrounding countries. The courses start from the basics - so no previous knowledge/experience is necessary. But the program quickly progresses to quite advanced technical concepts. “We see experienced participants nodding their heads as they start to understand the reasons behind the “odd” things they have observed in their factories. So different people take learning at different levels, depending on where they started from.”

The courses are presented in English, but simultaneous translation into Spanish will be provided in Chile in 2019. Training is also provided to companies on-site. The 2019 Norway program was offered in April, but next year will be presented later in the year. Dates for other relevant courses are: July 22 – 24: Applied Food & Feed Extrusion, Bangkok, Thailand. August 5 – 7: Food & Feed Extrusion Technology, Werribee, Australia. November 4 – 6: Aquafeed extrusion Technology, Temuco, Chile.

65 November 7 – 8: Food & Feed Drying Technology, Temuco, Chile. February 13 – 14, 2020: The Design of Food Extrusion Dies, Sion, Switzerland.

September 30 – October 2, 2020: Aquafeed Extrusion Technology, Ås, Norway. October 1-2, 2020: Extrusion Scale-Up & Process Transfer, Ås, Norway

More information:

26th Annual Practical Short Course Aquaculture Feed Extrusion, Nutrition & Feed Management

The Process Engineering R&D Center (formally Food Protein R&D Center) of Texas A&M University has been conducting their short course and education training for more than 35 years. In 1994, they started the Aqua Feed Extrusion, Nutrition and Feed Management short course in collaboration with the Wildlife and Fisheries department of Texas A&M University. In the beginning years of this program, the course was two weeks long. The first week being focused on nutrition and field trips to

different fish and shrimp farms and feed mills. The second week’s focus was on feed extrusion and other related topics. After 5 years, this course was consolidated into one week based on feedback from the industry since it was not easy for the industry personnel to be away from work for two weeks. The main objectives of this course are to train production personnel in principles and characteristics of extruders and support systems for effective selection and operation;

review current practices for preparation of aquaculture feeds; demonstrate equipment in operation and familiarize attendees with practical aspects of feeds extrusion and review aquaculture nutrition and feed management practices. This one-week course begins on Sunday with an introduction and reception and continues through Friday afternoon with tours of the Texas A&M University fish farm and research facility. The course begins on Monday with the introduction and principles of extrusion; the global aquatic market and the various species of fish, shrimp, etc. and where they are produced in the world; principles of dry extrusion and its application in aquatic feed; plant dust collection and weighing / feeding; dry extrusion of full fat soy and partially defatted soybean meal; protein concentrate for aqua feed; bulk material handling in extrusion processes and other commercial applications of dry extrusion. After these talks participants leave for the PERDC pilot plant for demonstrations such as full fat soy using whole soybeans with a dry extruder, full fat soy using dehulled soybeans with a dry extruder and fisheries by-products recycling with a dry extruder. Tuesday’s course starts with principles of aquaculture nutrition: Part 1; optimizing aqua feed quality: oxidation control; microbial growth control and palatability; continuous spray and coating systems; solutions to common grinding problems; commercial vitamin product forms,

66 vitamin premixes and their performance in aquatic feed; ultra-fine grinding for aquatic feed; characteristics and applications of interrupted flight expanders and processing of full fat soy products, aquaculture feeds. Participants leave for the pilot plant for demonstrations of full fat soy using interrupted flight expander, aquatic feed using interrupted flight expander, surface coating systems for aquatic feed and pulverizing of ingredients. Wednesday’s course starts with ingredients and recipe considerations; preconditioning technology; single and twin screw extruders and their applications in aquatic feed; high fat extrusion and product densification; product analysis and laboratory techniques; NIR analyzer on ingredients and aqua feed; drying and cooling systems for aquaculture feed.

Pilot plant demonstration will be of salmon feed for vacuum infusion using a single screw extruder, ultra-fine fish feed using twin screw extruder and NIR analyzer on ingredients and aquafeed.

Friday starts with odor control in an aquafeed plant; shrimp feed management and deed physical characteristics; least cost feed formulation and optional tour of Texas A&M University's aquaculture facilities.

Thursday’s course starts with automated control of extrusion systems; principles of aquaculture nutrition: Part 2; extrusion die technology; vacuum infusion coating principles for aquatic feed; extrusion processing technologies; microaquatic feeds; troubleshooting: ensuring a smooth running extrusion operation. Participants leave for the PERDC pilot plant for multiple demonstrations of floating catfish feed using single screw extruder, high fat yellow tail feed using a twin screw extruder and vacuum infusion for aquatic feed.

Participants receive their completion certificate during the graduation lunch on Thursday.

Dates: August 25-30 Location: Process Engineering R&D Center; Texas A&M University System Contact: Dr. Mian N. Riaz, More information:


Progressus’ Aqua Feed Milling AgriSchool

AgriSchools are courses designed and developed by Progressus® that aim to unify and enhance industry knowledge of agriculture and aquaculture production and management systems. AgriSchools are residential, university based, 5-day short courses that deliver independent unbiased information in a classroom style format and encourages a high level of participant-facilitator interaction and information exchange. In AgriSchools 5th year, Progressus® runs six AgriSchools courses, two of which are

certificate in Aqua Feed Milling and certificate in Aqua Nutrition.

Progressus’ Aqua Feed Milling AgriSchool is a comprehensive course covering all aspects of aqua feed production from receiving, storing, and processing raw material to finished feeds packing and warehousing. It covers the production of fresh water and marine fish feeds, as well as shrimp feeds. A big part of the program is developed at a commercial aqua feed mill which produces both pelleted and extruded feeds.

The course is facilitated by some of the most experienced milling professionals in the industry and it is highly recommended for industry professionals that would like to upskill and/or update their knowledge. All the AgriSchool course material has been created in conjunction with industry and university experts and is constantly reviewed and updated to ensure AgriSchools’ participants receive the latest industry knowledge, best practices and standards as applies to the Asian conditions and practices. The course is delivered in English. Translation in Vietnamese and Thai are available upon request. Certificates are awarded jointly by Kasetsart University and Progressus.

Dates: September 23-27 Location: Kasetsart University, Kamphaeng Saen Campus, Nakhon Pathom, Thailand Contact: More information:

Kansas State University’ IGP Institute educates globally on feed industry topics Training feed providers on the best practices for feed handling is the focus of the IGP-KSU Feed Manufacturing Course offered at Kansas State University in Manhattan, Kansas, June 18-21, 2019. “This course covers receiving, grain quality, grinding, mixing, extrusion and

storage. All of these principles apply to aquaculture,” says Carlos Campabadal, IGP Institute feed manufacturing and grain quality management outreach specialist. Along with the classroom training, participants also experience hands on learning in the O.H. Kruse Feed Technology Innovation Center where they have training on the opera-

tion of the pellet mill as well Bioprocessing and Industrial Value Added Products Innovation Center (BIVAP) where they observe the extrusion process in making feed. Another educational opportunity that is of benefit to the aquaculture industry professionals is the IGP-KSU Risk

68 Management Course planned for August 5-9, 2019 in Manhattan, Kansas. “This training really focuses on the principles of risk management and commodity price control,” Campabadal says. “A lot of the course content focuses around the concepts of hedging and related strategies for maximizing profits.” This offering is led by Guy H. Allen, senior agricultural economist with the IGP Institute. Allen recently joined the IGP Institute bringing with him more than 25 years work experience in global grain trading. This training is divided into two sections with the basic class held August 5-7 focused on futures trading and hedging, and the advanced offering planned for August 8-9 covering risk management through the use of options and OTC markets. Participants can attend one section or the full training depending on their needs. Also, August 13-16 the IGP Institute will be hosting the IGP–KSU Extrusion Processing: Technology and Commercialization course led by Sajid Alavi, professor and extrusion specialist. It focuses around technology, equipment and product development as it relates to extrusion processing. “This course has an aquafeed and pet food processing component to it and includes a hands-on session on the science and practice of sensory evalu-

ation of foods as well as a look at consumer acceptance of new products,” Campabadal says. Along with these courses, the IGP Institute also conducts customized trainings for companies and organizations. One of the main aquafeed partners is WISHH (World Initiative for Soy in Human Health).

are installing a new mill that will produce feed for aquaculture,” Campabadal says. “I was able to show them important aspects of equipment operation and facility design that will allow them to have an efficient manufacturing facility in alignment with good manufacturing practices.

“We are always looking for educational ways to support the aquafeed industry,” Campabadal says. In addition to courses, the industry is served through technical visits where grain science and industry faculty focus on ways to grow and store grains used in aquafeed processing. “I recently returned from Cambodia where I met with professionals that

Dates: IGP-KSU Feed Manufacturing Course - June 18-21 IGP-KSU Risk Management Course - August 5-9 IGP–KSU Extrusion Processing: Technology and Commercialization - August 13-16 Location: Kansas State University, Manhattan, Kansas, USA. Contact: Lisa Moser, More information:



Good dryer design for high quality aquafeed By Jammy Ho, R&D Supervisor, IDAH Co. Ltd. In today’s fiercely competitive market environment, every miller uses similar processes and ingredients; therefore product quality and manufacturing cost become the crux of competition. Overviewing the process, dryer performance plays a critical role in this game. Two main issues need to be considered to select a suitable dryer. First is the average moisture control of the dried product and second is energy efficiency. Both are related to water! Moisture uniformity is one of the critical factors for evaluating dryer performance. In the feed production process, moisture uniformity is not only related to product quality and energy efficiency, but also directly impacts profit. Because products are sold by weight, a narrow moisture tolerance will improve product quality and avoid raw material loss. As shown in Figure 1, the black curve indicates the traditional dryer and the red curve the more advantageous dryer, such as a carousel dryer. A narrow range of moisture tolerance allows the moisture set point to be higher without the risk of exceeding the maximum moisture limit. Profit is

Fig. 1. Moisture uniformity comparison of carousel dryer with traditional dryer. (IDAH, Taiwan)


… The amount of profit that can be gained due to moisture uniformity, in combination with accurate moisture control, can be surprising.

shown as a green zone. Assuming the maximum moisture content of the final product is 10%, in a carousel dryer the moisture control set point will be 9.5%, as opposed to 8% in the traditional dryer. The result is 1.5% more product while at the same time saving drying energy. The amount of profit that can be gained due to moisture uniformity, in combination with accurate moisture control, can be surprising. For instance, imagine a feedmill that produces 100,000 tons of extruded aquafeed per year with a maximum moisture content of 10%. Products cost $200 per ton. If we compare a dryer with ±0.5% and another with ± 2.0%, there is 1.5% more product to be sold with the same amount of raw ingredients. It is easy to calculate that if you use a carousel dryer savings can be estimated at $300,000 a year (100,000*1.5%*$200). In addition to the sales profit, a narrow moisture tolerance also avoids energy waste from over-drying. For example, for a 10 ton/hour capacity extrusion line, 1.5% less moisture evaporation will save 200 kg/hour steam consumption.

In short, with the carousel dryer the product is handled with a more stable moisture control over time and less over-drying (avoiding product loss) and it has a higher average moisture content.

Design requirements What are the design requirements to achieve a dryer with ± 0.5% moisture tolerance? · The product layer height needs to be lower (normally less than 20 cm). A high layer will cause uneven drying, because the bottom product is drier, as air enters, than the product on the top, where air leaves. · Round shape design optimizes air flow distribution. Since it has no dead spots inside the dryer, it also improves the air distribution and hygiene. · A counter-flow air stream optimizes the heat transfer that goes through the perforated circular trays and product. Product moves in circles in a cross-counter air flow. · The product in the dryer is rotating and discharging into a lower deck and tumbled for mixing. This is done in each deck before the product leaves the dryer, resulting in very uniform moisture as all the product gets the same treatment by passing different air volume and temperatures. · The product flow is first-in, first-out (FIFO). Every pellet gets the same retention time and during production, the operator can easily check the quality of the batch and correct it immediately if necessary.

Energy efficiency Another indicator of dryer performance is energy efficiency, as drying is a high energy-consuming operation. When the extrudate is discharged, its moisture content can be 20-30%. The dryer energy is easily more than 50% of the plant’s energy consumption. Thus, it is a very challenging task to optimize the drying process efficiency without compromising the quality. The ultimate goal is energy saving and product quality improvement. Several studies in the literature show how the drying inlet/outlet parameters impact energy efficiency. It can be concluded that the inlet, outlet process air temperature and air volume are the three major factors that determine the amount of water evaporation. Basically, the value of air volume to drying surfaces multiplied by air velocity. The drying surface is fixed by specific design, the velocity is limited by the size and density of pellets, therefore only the delta T is the flexible parameter for energy efficiency. The rule of thumb for delta T is as follows: · The air flow temperature that leaves the dryer need to be lower: the lower the outlet air flow temperature, the more air energy is used for water evaporation. · The air flow temperature that enters the heater need to be higher: the higher inlet air temperature means the air flow needs less heater energy to approach the set point temperature. Therefore, a good air system, like a carousel dryer, has the following

71 retention time parameters all impact dryer performance, it is necessary to set simple protocols that are easy for the operator to follow, as shown in Figure 3. In the carousel dryer design, the operator only needs to verify the product outlet moisture, then adjust the inlet air flow temperature until approaching the target moisture. In practice, one percent moisture drop requires a 3oC temperature raise.


Fig. 2. The characteristics of a carousel dryer design. (IDAH, Taiwan)

characteristics, (as shown in Figure 2): · Uses the recirculation air system: Uses the cooler air or dryer exhaust air as the make up air. · Independent heating zone: The desired air volume and delta T can be set in each specific zone.

Fig. 3. A sample of individual heating section with independent control. The benefit is low exhaust air temperature and less steam consumption. (IDAH, Taiwan)

· Counter-flow design: the definition of counter-flow in the dryer design is that material drops from top down and the air flow motion is bottom up; as shown in certain literature, the counter-flow design will be more than 10% more efficient than a cross-flow dryer, like a belt or horizontal dryer. · Easy control: Since the delta temperature, air volume and

Jammy Ho R&D Supervisor IDAH Co. Ltd E:


EVENTS April 28 – May 3: 23rd International Seaweed Symposium

For details of industry events: visit the Calendar

Submit your event details to:

26 – 28: Aqua Fisheries Myanmar Yangon, Myanmar

Jeju, Korea


7 – 10: Aquaculture Europe 2019 29 – 30: 13th World Congress on Aquaculture & Fisheries

Berlin, Germany

Seoul, Korea


12 : 12th Aquafeed Horizons

21 – 24: GOAL Conference 2019

Cologne, Germany

Chennai, India

18 – 20: Asian Pacific Aquaculture

31 – Nov 2: Aquaculture Taiwan Expo & Forum 2019

13 – 14: RASTECH 2019 Washington, USA

14 – 16: AFIA Purchasing and Ingredient Suppliers Conference Florida, USA

15 – 16: US Microalgae Industry Summit

Chennai, India

July 15 – 17: Applied Food & Feed Extrusion Thailand Bangkok, Thailand

Taipei, Taiwan

November 4 – 6: Aquafeed Extrusion Technology Course Temuco, Chile

Florida, USA

August 14 – 15: TARS 2019

7 – 8: Food and Feed Drying Technology Course

29: Aquaculture Awards 2019

Bali, Indonesia

Temuco, Chile

Edinburgh, UK

20 – 23: Aqua Nor


Trondheim, Norway

13 – 15: International Symposium on Aquaculture Nutrition

12 – 14: VICTAM International

Yucatán, Mexico

Cologne, Germany


17 – 18: Aqua Fisheries Cambodia

10 – 11: Aquaculture Innovation Europe

19 – 22: Latin American and Caribbean Aquaculture 2019

Phnom Penh, Cambodia

London, UK

San Jose, Costa Rica

73 Volume 11 Issue 2 2019

CONTACT US Editorial: Executive Editor/Publisher: Suzi Dominy Associate Editor: Lucía Barrera

Advertising enquiries/request media pack: Technical feed consulting:

Technical editors: Peter Hutchinson Albert Tacon, Ph.D. Warren Dominy, Ph.D.

Senior Technical Consultant: Warren Dominy, Ph.D. Accounts & All other enquiries:


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