Aquafeed Vol 12 Issue 3 July 2020

Vol 12 Issue 3 July 2020

AQUAFEED Advances in processing & formulation An Aquafeed.com publication

MARINE PROTEINS AND OILS Sustainability in feed processing Fermented feed ingredients and additives Mycotoxins in aquaculture Functional feeds Published by: Aquafeed.com LLC. Kailua, Hawaii 96734, USA www.aquafeed.com info@aquafeed.com

AQUACULTURE

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AQUAFEED

VOL 12 ISSUE 3 2020

Contents

FERMENTED FEED ADDITIVE 33 A new feed additive supports immune strength and digestive health in farmed aquatic species.

SUSTAINABILITY IN AQUAFEED PROCESSING 13 The importance of sustainability and how process technologists can move the industry forward.

MYCOTOXINS IN AQUACULTURE 29

COPING WITH SALINITY STRESS 40

How future trends in aquaculture may affect the exposition of certain species-groups to mycotoxin and how to manage this risk.

Feed manufacturers can help farmers tackle salinity stress ensuring high-quality lipids, calcium and magnesium and using feed additives.

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

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AQUAFEED

VOL 12 ISSUE 3 2020

Contents 6

Interview

9

News Review

13 Leading down the road of sustainability

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23

26

16 Fish protein hydrolysate as a sustainable protein alternative in Atlantic salmon diets

19

Tuna oil, a valuable source of DHA for aquafeeds

23

T he world’s first industrial plant for processing of the marine copepod Calanus finmarchicus

26

rill oil and krill meal processing technology K advantages to feed manufacturers

29

33

37

40

Strengthen against salinity stress

46

F unctional feed to solve blue coloration in indoor shrimp farming system

49

L -selenomethionine: A powerful antioxidant for commercial fish species

53

etabolomics gives simple answers to ease the M exploitation of insect meal for aquafeed

Mycotoxins in aquaculture: The risk of generalization in a sector with 466 species New fermented feed additive improves productivity in fish and shrimp culture New tool for shrimp gain and disease management

Columns

44 Albert Tacon – Aquaculture and aquafeed production in 2018

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37

Calendar of events

To read previous issues in digital format or to order print copies, visit: http://www.aquafeed.com/aquafeed-magazine/

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

Peak Survival DVAQUA™ works naturally with the biology of shrimp and fish to help maintain immune strength.

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A strong immune system promotes: Survivability and yield More efficient production Overall health and well-being Natural immune support for all stages of life!

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António Isidoro is CEO and Chairman of the Executive Board of Soja de Portugal. His career began in banking before he became executive director for all Soja de Portugal subsidiaries.

INTERVIEW AQUAFEED: Would you tell us about your background and how it has led you to the feed industry?

AI: I have a degree in management with a postgraduate degree in advanced management in business internationalization ISEG/CEGE. My professional career of more than 20 years began in the banking sector, during which I performed several duties within the Montepio bank company.

Currently, I’m CEO & chairman of the Executive Board of Soja de Portugal - a more than 75-year-old company operating in agribusiness - and other subsidiaries, including Sorgal (the owner of the compound feeds commercial brands such as Aquasoja – aquaculture compound feed, Sojagado – poultry farming and

with António Isidoro livestock breeding, Sorgal Pet Food – pet food for dogs and cats), Avicasal and Savinor (production, slaughter, butchering and commercialization of poultry meat) and Savinor UTS (collection, treatment and recovery of animal co-products).

I also participate in the Board of Directors of IACA (Portuguese Association of Industrial Feed Compounders), executing the functions of executive director, and also on the Board of FORUM OCEANO (Portuguese Maritime Cluster). I participate in the social bodies of several associations related to blue biotechnology and the economy of the sea. I’m involved in the education sector, collaborating with institutions such as ICBAS - Institute for the Biomedical Sciences Abel Salazar, UTAD - University of Trás-os-Montes and

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

7

Alto Douro, AESE - Business School, and also regional high schools.

AQUAFEED: Aquasoja recently turned 26, but its entry into the aquaculture industry was more recent.

How and when did it all begin?

AI: Aquasoja is a commercial brand of Sorgal.

The beginning of the operation in the aquaculture feed industry was a consequence of a very close relationship with academia, as the business plan and the industrial utility was developed together with ICBAS - the Institute for the Biomedical Sciences Abel Salazar from Porto University.

The agreement in 1989 was aimed at developing and producing compound feeds for aquaculture, and was the foundation of Aquasoja, one of the business areas that today represents the majority of the group’s exports. The collaboration with the University of Porto has strengthened over the years. The relationship with this community allows us to access the best possible skills, which would be extremely difficult to obtain if the innovation processes were not internalized. Therefore, Aquasoja consolidated the innovation system over the years on the basis of building symbiotic relationships with national and international universities and wellknown research institutes.

The Aquasoja products were initially only sold in Portugal, as part of a learning period, but five years from the start of operations we started to export all over the world. And we have been growing exports until now, where almost 90% of what we produce is for export.

AQUAFEED: Aquasoja has been developing a circular economy business model. How did this idea come about?

AI: As a poultry producer with its own slaughterhouse, Soja de Portugal has a large amount of co-products available.

We operate in three distinct sectors: animal nutrition (poultry, livestock, aquaculture and pet food), poultry meat production and the treatment and enhancement of animal co-products. With the primary objective of preserving and increasing natural capital by controlling finite stocks, balancing the flow of renewable resources and circulating products and materials, in the field of animal nutrition, raw materials produced by the

The future is circular. Supported by 77 years of experience in the area of animal nutrition, we design solutions that result in added value for our customers, supported by the circular economy.

co-products recovery units belonging to the group are used. These co-products would normally have other destinations, so they are being used efficiently to produce compound feeds. In this way, Soja de Portugal business areas operate in perfect synergy.

The production of poultry meat is done in an integrated regime, with its own production and with the hiring of producers. The poultry produced are fed with rations produced by us and slaughtered in our slaughterhouses.

The co-products generated in the slaughter and cutting process are immediately processed in our processing units, converted into ingredients for animal feed, namely meal and poultry fat. Additionally, we produce other ingredients of animal origin, co-products of the agri-food industry. These ingredients are intended for animal feed and are used in pet food and aquaculture.

One of our R&D axes is the understanding of all the processes from the collection, protocols of processing and biological value. And, of course, being able to control (both in terms of quality and quantity) the source of your protein is a large advantage nowadays.

I can say that one of the pillars of both our petfood and aquafeed business areas is this circular economy model.

The future is circular. Supported by 77 years of experience in the area of animal nutrition, we design solutions that result in added value for our customers, supported by the circular economy.

AQUAFEED: Agri-food co-products are one of Aquasoja’s alternative sources to replace fishmeal and fish oil. What are the main challenges you are facing in

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

8

producing these alternative ingredients in terms of competitive pricing and scalability?

AI: Being able to understand the sources, control quality upstream, adjust the process to our downstream activities are big advantages. Of course, there are limits to the amounts we can process, but we are comfortable with what we have now.

AQUAFEED: Apart from locally sourced ingredients, what other strategies are you following to improve feed production sustainability?

AI: Sourcing locally means less transport, which ultimately means less carbon footprint. It can be challenging as it is not a trouble-free strategy. Markets are not yet ready to understand that carnivorous fish can transform good quality poultry protein as well as fish protein. And being able to discard fish trimmings that are not fit for processing (even though they came from fish consumed by humans) is also sometimes difficult. But, our focus on process improvement is critical. We are always learning new and better ways to produce, with ultimately nutritional and food safety gains.

AQUAFEED: Aquasoja’s main market is Mediterranean aquaculture. Is that accurate?

What are your future market prospects?

AI: Yes, it is. But we have an eye in other markets outside the Mediterranean where we believe we can match the demand.

AQUAFEED: The Mediterranean market for seabass/ seabream remains weak being one of the many challenges the European aquaculture industry faces.

What do you think must be done to boost the industry in Europe?

AI: There are several issues in Mediterranean aquaculture both technical and commercial. From a technical point of view, we have to understand, and this year sadly proved it, that the Mediterranean sea is not as easy as everybody counted on. We are talking of real offshore operations, and the industry must start to discard exposed sites or operate with more adapted structures. Then, from a biological point of view, we have to better understand how to grow our fish in only 60% of the time available (typically temperatures are not suitable for up to 40% of the time), and to keep them as fit as possible. And not forgetting to get the appropriate price for a luxury product.

AQUAFEED: Portugal is becoming an important European R&D hub and Aquasoja has been strongly supporting it. What are your next R&D priorities?

AI: The main axes of our R&D are process improvement (new ways to do better and more functional products) and functionality that are adapted to every kind of market and client.

One of Aquasoja main strategic vectors is innovation.

The company knows that it is a fundamental dimension to lead the domestic market and obtain a prominent position in international markets. The goal is to create 15.00 [381]

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F085 SHIMPO

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tailor-made solutions for clients through constant dialogue, adapting them to the needs and the situation of each one. We believe that an open innovation policy through our network of clients, suppliers, scientific institutions and other partners is part of Aquasoja.

The scientific and technological community is essential to guarantee that the solutions presented to costumers are developed sustainably and guided by the most stringent R&D standards.

67.28 [1709] 39.00 [991] 101.44 [2577]

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End of Head

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15.88 [404]

24.59 [625]

03 54

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108.28 [2750]

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160

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Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020 102.13 [2594] 111.12 [2822] 195.72 [4971]

52.19 [1325]

48.00 [1219]

57.69 [1465]

2

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1.00 NPT [STEAM]

2.00 NPT [WATER]

53.25 [1353]

66.50 [1689]

9

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

Unibio, Skretting partnership for sustainable production of protein

As a result of participating in the FEED-X program, Unibio partnered with Skretting through a Letter of Intent to begin testing Uniprotein® as a feed ingredient for fish and shrimp feed. The agreement shows Skretting’s willingness to

purchase thousands of tons of Uniprotein® if the testing goes according to expectations.

Unibio and its partners would need to invest millions of dollars to increase the production capacity needed to realize the ambitions

of the potential collaboration, and the potential revenue generation will be counted in hundreds of millions of dollars over the years to come.

Uniprotein® is produced based on the fermentation of a microbial culture using methane. It is an organic product and can be easily produced on a large scale. The ambition is to utilize methane that would otherwise be wasted or used in less efficient processes.

Uniprotein® is high in quality and it can easily replace high-value proteins such as super-prime fishmeal and highly concentrated soy products.

BioMar enters feed partnership with Viet-Uc BioMar and Vietnam’s leading shrimp hatchery, Viet-UC have signed a memorandum of understanding with the intention that BioMar will become co-owner and operational leader in the feed factory currently owned by Viet-UC. “We believe that a feed partnership with Viet-UC in Vietnam will bring important synergies to the feed business as well as the hatchery and grow-out business of Viet-UC. Both companies have a common focus on sustainability, food safety, traceability, quality and performance, which we believe will be strong drivers to strengthen and develop both companies as well as the aquaculture industry in Vietnam. There is no doubt that there will be a growing market for high-quality feed in Vietnam,” explained Carlos Diaz, CEO of BioMar Group.

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

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Calysseo inks deal to build its first commercial-scale production facility in China Following the set-up of Calysseo (a joint-venture between Adisseo and Calysta) in February 2020, aimed at developing a major business supplying aquafeed ingredient, an agreement has been signed with all involved parties allowing to settle the first Calysseo production facility in Chongqing, China.

The project will be the very first commercialized FeedKindÂŽ facility

in the world, with its first phase designed capacity up to 20,000 tons expected to put into operation by 2022. Once the first phase project runs successfully, it will be followed by a second phase investment, adding another 80,000-ton capacity, which will allow a prompt market penetration with a potentially rapid expansion in Asia market to build a profitable and sizable business opportunity for all parties.

Salmon Group to introduce grasshopper meal into salmon feed Salmon Group has entered into an exclusive agreement with the startup Metapod, which ensures salmon and trout farmers of the network a nutritious feed for fish.

Metapod has developed technology to produce insect meal from grasshoppers and crickets that ensure local production of one of the most important and

requested ingredients in food, both for animals and humans.

The production will also refine food waste, seeing this as a valuable resource worth bringing back into the value chain. As such, the industry introduces a new resource and new technology, and Salmon Group further reduces its footprint.

BAP releases new feed mill standard

The Global Aquaculture Alliance released the Issue 3.0 of its Best Aquaculture Practices (BAP) Feed Mill Standard. This standard has

been strengthened to reflect the growing reliance of aquaculture on responsibly produced feed.

Expectations continue to rise for accountability in the sourcing of marine and terrestrial ingredients, and this is reflected in ever stricter sourcing requirements.

The BAP criteria for safe feed production have been enhanced and the social accountability requirements have been expanded to provide even greater assurance

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

against child labor as well as forced and bonded labor. There are also new requirements that relate to the sourcing of certified soy ingredients and palm oil. The new BAP standard bakes in requirements for responsible ingredients such as those certified to the MarinTrust standard and requires a minimum of 75% of marine ingredients to be from certified sources, or FIPs, from 2025, thus raising its current 50% bar.

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Barley protein concentrate to be available in North America and Asia markets in 2021 The U.S.-based Scoular Company has entered into an exclusive licensing agreement with Montana Microbial Products to produce and sell a barley protein concentrate in North America and Asia. Barley protein concentrate (BPC) is a sustainable, plant-based alternative protein used in aquaculture feed and pet food. It is produced from

non-GMO barley without using harsh chemicals or solvents.

BPC will provide a non-GMO, clean-label solution for pet food manufacturers seeking high-protein nutrition for their formulas.

Montana Microbial Products developed its patent-pending technology to create the barley protein concentrate.

DSM to acquire Biomin and Romer Labs Royal DSM reached an agreement to acquire Erber Group for an enterprise value of €980m. The value of the transaction represents an EV/EBITDA multiple of about 14 times the 2020 EBITDA (fiscal year ending September 2020).

The transaction, which excludes two smaller units in the Erber Group, is expected to be earnings enhancing in the first year upon completion.

Erber Group’s specialty animal nutrition and health businesses, Biomin and Romer Labs, specialize primarily in mycotoxin risk management, gut health performance management, and food and feed safety diagnostic solutions, expanding DSM’s range of higher value-add specialty solutions.

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Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020 6/25/20 10:05 AM

NEW ON THE MARKET Skretting’s new range of products to improve water quality for fish and shrimp farms As a key part of its ongoing commitment to improving the sustainability of the industry, Skretting has extended its scope beyond the supply of sophisticated and sustainable feeds by creating a new global product line, AquaCare, specifically focused on providing practical solutions for improving water quality for fish and shrimp farming systems.

The first AquaCare product to reach customers is a sustainable

solution that tackles water quality issues and provides a platform for significant efficiency and productivity gains. The simple-touse probiotic is designed to work preventatively, to load the water in pond farming systems with beneficial bacteria that prevent the same space from being occupied by potentially harmful bacteria. are consumed by the bacteria, giving faster preparation of ponds for the following cycle.

Cargill launches its first shrimp feed in Indonesia Cargill launched Harvestar®, the first shrimp feed offered by the Cargill Aqua Nutrition (CQN) business in Indonesia.

On April 24, 2020, Cargill delivered the first Harvestar feed product from the CQN plant in Serang, Banten to its first customers who are located in Lampung, South Sumatera and West Java.

Harvestar shrimp feed is formulated for vannamei shrimp with premium quality raw materials and an immunostimulant to increase the shrimp survival rate. The product design, which includes formulations for the different shrimp life stages, utilizes Cargill’s global expertise and extrusion technology for better feed performance.

In product trials, Harvestar demonstrated a feed conversion ratio of 1.3, which is better than the 1.4 industry average and the 1.6 resulting from other feeds in the market.

AquaCare’s launch has been particularly timely for the aquaculture industries of Egypt and Vietnam, which are largely based on the production of tilapia and shrimp, respectively.

Aller Aqua introduces new feed for Atlantic salmon in RAS

ALLER FLOW was developed for farming Atlantic salmon in RAS environment. Thoroughly tested and developed at the trial station at Aller Aqua Research in Buesum, Germany, ALLER FLOW was created considering the impact of the feed on the entire production system while maintaining focus on fish health and growth.

Aquasoja's new feed range to improve fillet lipidic profile OMEGA, a new line of fish feed products aiming at work on fish fillet characteristics, namely on HUFA omega-3 levels, was launched

by Aquasoja. OMEGA products contain selected fish oil as the lipid added source, increasing intake of

marine ingredients during fish life cycle, with later effect on fillet lipidic profile. “The need for a better ratio ω3/ω6 in humans’ diet is quite an actual topic that deserves the best of our attention,” the company said.

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

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Leading down the road to sustainability Nigel Lindley, NLC-ECO

Courtesy of Ever Extruder and Dedoussis Control systems.

“You cannot be serious!!!” For many who read this, these words may have little meaning. But for my generation and the one before it, these words spoken in 1981

by Wimbledon’s number one player and world tennis champion John McEnroe make perfect sense. John was challenging the referee’s decision as to whether the ball was on the line or out. Hawk eye or video replay came later! For tennis, as with many sports with professional players earning large amounts of money, these decisions were critical for a win or lose.

So how serious are aquafeed companies when they use the word sustainability? How important is sustainability, and how can we, as process technologists, move the industry forward? Ultimately, there is no choice. Sustainability is here to stay. It is of

unprecedented importance wherever production takes place. Sustainability must be part of the DNA of each aquafeed facility. So yes, we have to be very SERIOUS. Having being involved in the aquafeed industry for over 25 years, I have seen many changes, but today, I still visit plants where poor energy recirculation and outdated technology abound. The purchase price remains the determining factor and long-term energy savings or sustainability are forgotten. I see extrusion systems running on technology of more than 30 years, dryers without recirculation and manual control of high capacity systems where the implementation of new technology could give a return on investment within six months of introduction while reducing costs by up to 35%.

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

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Ever Extruder shaft stabiliser system.

effectiveness of preconditioning. It has been around for many years and is undoubtedly a major processing cost reducer. What is potentially the next most critical attribute associated with maintaining production capacity and quality? The answer, of course, is the stability of the extruder. The possibility of creating the most effective pumping system on single screw systems ensures the required constant die pressure, thus maintaining the production capacity and optimal operating conditions, leading to consistency of product quality.

The centralization of the extruder shaft is a key and critical factor to meet stability and consistency. As any engineer appreciates, extruder shafts loaded with screws has a dip point, where some older technology may be applied. For example, some systems apply a type of stationary shear lock consisting of a spider-type accessory that in turn contains a bronze bushing, acting as a bearing and stabilization control. Of course, from the first day the bushing wears, there are no adjustments and performance drops.

I was fortunate in my career to work with two of the world’s leading extrusion system manufacturers that changed the extrusion process beyond recognition, and within that environment had mentors whom I still respect. Unfortunately, I lived in a cocoon and I didn’t realize it at the time, until starting my own consultancy business six years ago. In my opinion, not all the answers come from Kansas but in many cases, it comes from other industries, other applications and through travel and the internet. Stretching that extra mile is possible.

We are a truly global industry.

So, let us be SERIOUS and look at three main areas in the aquafeed production. There are other important steps such as particle size reduction, but today let’s concentrate on immediate and long-term savings in energy, labor and consistency of product and production leading us down the road of sustainability. I am concentrating on single screw extrusion systems, their being by far the main work horse of production in aquafeed, drying and control systems.

Shaft stabilization Let me introduce you to the retrofit that will change your extruder performance from day one. The adjustable shaft stabilizer and carriage package, utilizing Carbide technology. This package using laser alignment on installation will fully centralize the shaft and barrel as one component on single screw systems. This will have immediate and long-term gains.

The extruder will not only operate under optimal conditions, optimum capacity and reduced wear costs, but also will result in higher standards of quality and, of course, in a more sustainable process.

Extrusion system. Upgrades and updates Of course, no one expects that established systems will simply be discarded and replaced by what may be regarded as the latest trend, which could cost several million dollars today. So what simple potential upgrades are available that give instant results?

Most aquafeed process technologists realize the

Advanced die and cutter technology Let’s take a look at another low-cost update that not only delivers higher quality feeds but that vital requirement, consistency. Which operator appreciates the unenviable task of setting up a cutting system with 16-20 knives and which two operators can set up the knives the same way? The answer to both these

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

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control are paramount to utilize energy consumption with 70% of moisture being extracted from the product in the first two zones. The final moisture of the core can be evaporated in a controlled zonal process, significantly reducing energy consumption.

New generation of hybrid batch dryer utilizing both electricity and gas as the heat mediums. Courtesy of Geelen Counterflow.

questions is none. How can any system still promote throwing away blades as a sustainable option? Multiblade, reversible and resharpenable cutter assemblies, reduce downtime and in combination with a selfadjusting hub assembly, offer ease of installation, one single screw fixing in place, and consistent set up each time by all technicians day and night. The result is less tails, less fines and a cut of the highest quality.

Combining this cutter technology with Carbide die options (lasting 5-10 times longer than standard hardened steel dies) with unique characteristics of diameter maintained throughout the die life, results in no expansion change.

Advances in drying technology Anyone involved in the production process of aquafeeds immediately recognizes the importance of efficient and effective drying technology, arguably the most expensive energy-consuming process in the production flow. Effective drying is no longer like searching for the holy grail.

Early, horizontal dyers were expected to have plusminus 2-3% moisture deviation. This results in overdried feeds and more energy usage to ensure that the final moisture does not exceed 9-10%. This approach is not exactly energy or sustainability effective.

Now we can seriously analyze moisture deviations of plus-minus 0.5%. We are seeing drying technology advanced by leaps and bounds since the introduction of the vertical counterflow dryer, where airflow and zone

The revolution.

Computer control systems I started my introduction in the extrusion technology in 1988 and at that time we were all just beginning to visualize the era of technological advancement.

Little did we know what was to come, changing our lives both from a personal and business perspective.

This tool we call the computer has provided the aquafeed producer an opportunity to revise all process parameters, reduce energy consumption, utilize a wider range of raw materials and analyze a complete and comprehensive range of data.

It’s a teaching tool with remote access to any part of the world that has an internet connection. Instant payback!

Sustainability opportunities at the touch of a key.

Traceability programs that detect any abnormal occurrences that can lead to quality challenges in the field together with vital online analysis to predict these challenges and make real-time, live changes to ensure specifications both nutritionally and physically are optimized. We can share online operations, share potential maintenance issues remotely, trend charts to analyze optimum operation of the process.

This is a very serious tool!

In conclusion, these three areas will bring consistency into your process flow, reduce costs and most importantly assist the operator interface with production and product quality, resulting in energy savings, lowering production costs and sustainability as a bonus. In this day and age, stimulated by a growing environmental concern and awareness with regards to sustainability we all need to be SERIOUS.

More information: Nigel Lindley Director and Independent consultant NLC-ECO, UK E: nigel@nlc-eco.com

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

MARINE OILS AND PROTEINS

Fish protein hydrolysate as a sustainable protein alternative in Atlantic salmon diets Jason Whooley, Snehal Gite, Bio-marine Ingredients Ireland

A fish feed trial has been conducted to assess the impact of feeding an 80% plant protein diet with and without fish protein hydrolysate (FPH) supplementation.

The trial examined the impact on the growth and gut health of Atlantic salmon. The study was conducted collaboratively at Teagasc Food Research Centre Moorepark, Marine Institute Ireland, NUI Galway, Bio-marine Ingredients Ireland Ltd. (BII) and published in the journal Scientific Reports (Egerton et al., 2020).

This study was an attempt to re-formulate aquafeeds with novel and sustainable fish protein hydrolysates which can complement plant proteins in aquafeed to enhance the quality and meet the requirements for optimum growth and wellbeing of Atlantic salmon without impacting cost.

Bio-marine Ingredients Ireland, owners of a marine bio-refinery in Ireland, produced fish protein hydrolysates both soluble (SPH) and partially soluble (PHP). These hydrolysates were used as a protein ingredient to replace 10% of plant protein in a fishmeal diet. Commercially available feed ingredients were used and diets were formulated to meet the dietary requirements of appropriately sized salmon. Variable components of aquafeed formulation of experimental diets and associated experimental findings are summarized in Table 1. All diets were iso-nitrogenous and iso-lipidic in content.

Study design The 12-week feeding trial was carried out at Salmon Springs Ltd. freshwater juvenile salmon rearing facility in Co. Galway, Ireland. Atlantic salmon (Salmo salar) were raised from eggs on site. Before the experiment, fish

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

17

Table 1. Variable components of fishmeal diet formulations.

Diet A

Diet B

Diet C

Diet D

Control diet 80% plant protein diet 80% plant protein diet

fishmeal (FM) with 15% fishmeal (PL) with 5% fishmeal and

10% partly hydrolysed

protein (PHP)

Fishmeal (%) 35 15

80% plant protein diet with 5% fishmeal and 10% soluble protein hydrolysate (SPH)

5

5

PHP (%)

0 0

SPH (%)

0 0

Soymeal concentrate (%)

14.34

40.33

40.16

35.68

Rape seed oil (%)

1.18

3.29

3.14

4.29

Potato starch (%)

13.98

5.88

6.20

9.53

Total (%)

64.5

64.5

64.5

64.5

Crude protein (%)

47.78

47.67

47.73

46.46

Crude lipid (%)

19.22

19.46

19.29

19.97

Diet cost (€/MT)

540.58

432.90

541.56

675.1

10% 0 0 10%

Experimental findings of 12-weeks fish feed trials

Digestibility (%)

80.83 70.77

Feed intake (g/fish)

26.55 ± 1.17

25.44 ± 1.88

24.81 ± 1.03

27.43 ± 0.50

Feed conversion ratio

0.92 ± 0.09

1.04 ± 0.06

0.88 ± 0.07

1.05 ± 0.09

Protein production value

3.34 ± 0.43

2.67 ± 0.19

3.08 ± 0.21

2.52 ± 0.19

Protein efficiency ratio

2.48 ± 0.26

2.21 ± 0.13

2.57 ± 0.13

2.19 ± 0.20

Final weight (g)

38.13 ± 2.84

34.14 ± 3.23

37.03 ± 0.88

35.71 ± 1.77bc

Final length (cm)

14.39 ± 0.34a

13.87 ± 0.37b

13.92 ± 0.03b

14.00 ± 0.35b

Final condition factor

1.23 ± 0.01a

1.24 ± 0.04a

1.32 ± 0.03b

1.26 ± 0.04c

Liver weight (mg)

499.67 ± 17.73ab

425.29 ± 25.57a

561.67 ± 28.11b

484.21 ± 30.29ab

Hepatosomatic index (%)

1.31 ± 0.03ab

1.25 ± 0.12a

1.52 ± 0.08b

1.35 ± 0.05ab

a

b

were fed commercial diets (Skretting UK, Cheshire, UK).

At the start of the experiment, salmon (8.44 ± 0.78 g, F = 1.567, df = 11, p = 0.103) were randomly distributed into 1 m3 fiberglass tanks (at a density of 6.5 kg/m3 in 0.4 m3 of water, n = 3). The triplicate tanks were at an initial density of 16.2 kg/L. Average tank density for all treatment groups reached 20 kg/L by day 40 of the feeding trial and tanks were maintained at this density, by periodic removal of fish, for the remainder of the trial. Triplicate groups of fish were fed one of the four treatment diets via automatic feeders during daylight hours (~1.5% BW) for 12 weeks. Tank weights were measured fortnightly to allow for feed adjustments. Feeding was withheld 24

72.86 80.00

c

hours prior to final morphometric measurements at the end of the trial, to ensure that fish were clear from residue feed.

Salmon successfully grows with PHP Reducing the fishmeal component of feeds, from 35% to 15%, in the place of plant proteins (PL diet), resulted in reduced growth in Atlantic salmon parr. However, partial replacement of fishmeal with partly hydrolysed FPH in a high plant protein diet (PHP diet) allowed similar growth performance compared to fish fed the control diet (FM diet). In this study, we have successfully reduced fishmeal to 6% of dietary protein contribution without negative effects on growth.

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

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Specific growth rate, feed conversion ratio and protein efficiency ratio results followed the trend of highest growth rates in FM and PHP fish. Interestingly, the hepatosomatic index was highest in the fish supplemented with PHP (diet C) and significantly greater than that of fish fed on plant protein diet-B. The hepatosomatic index is the ratio of liver weight to body weight. It provides an indication of the status of energy reserve and protein accretion in the fish (Ruyter et al., 2006; Espe et al., 2007). During smoltification, a period of high energy requirements, whole-body and liver lipid and energy reservoirs become depleted (Woo et al., 1978). Atlantic salmon parr with higher levels of stored lipids may have increased energy for smoltification, which may, in turn, prevent a “protein sparing effect” and result in healthier, larger smolts (Virtanen et al., 1991; Gao et al., 2011). Further testing is needed to determine whether the higher hepatosomatic index in the PHP dietary group could enhance robustness during smoltification, e.g. survival rate, disease susceptibility and meeting energy/lipid depletion demand.

Supplementation of a predominantly plant protein diet, containing only 5% fishmeal, with partlyhydrolysed FPH (PHP supplement) is as effective as a 35% fishmeal diet. Despite consuming similar levels of feed, fish on the PHP diet were significantly heavier and had a better condition factor compared to PL fish and FM fish in terms of final weight.

PHP can be considered an excellent ingredient for aquafeeds due to its nutritional value, amino acids profile, low-molecular-weight peptides and bioactive properties. Branched-chain amino acids play important structural roles and act as an anabolic signal for protein synthesis (NRC, 2011). The blood levels of branchedchain amino acids of fish supplemented with PHP were significantly higher than FM and PL fish and might have facilitated the high growth rates recorded in PHP-supplemented fish diet C as compared with diet A and B.

Healthy gut Gut histological changes were examined in the fish from four experimental groups and no inflammatory or degenerative changes were observed which confirmed that all the formulated diets were safe and showed no symptoms of soy-induced enteritis.

Gut microbiota using metabolomics and shotgun sequencing was done to ascribe digestive roles would be beneficial to gain a greater understanding of the interaction of dietary nutrients and gut microbiota and their effects on host health, development and growth. Fish fed on PL diet B, harbour a diverse community that is dominated by the phylum Deinococcus-Thermus and show low inter-sample variation. After the 12-week dietary treatment Firmicutes became the dominant phylum.

Fish fed on fishmeal diet A had the highest α-diversity, while greater variation in inter-sample diversity and community composition was seen in the fish under the other dietary treatments that had significantly higher plant-protein content.

An economically viable alternative The cheapest feed was the plant protein feed B (€432.90 per MT) and SPH supplemented feed D (€675.19 per MT) was most expensive. However, PHP supplemented feed C (€541.56 per MT) offers a competitive price over fishmeal diet A (€540.58 per MT). Hence PHP produced from blue whiting fish could be a sustainable and cost-effective alternative protein source to terrestrial and plant proteins which can be used in aquafeeds.

Conclusions This study showed that farmed Atlantic salmon parr can grow successfully on an 80% plant protein diet when supplemented with FPH (PHP). PHP-fed fish also had relatively high hepatosomatic indices, possibly indicating higher liver lipid stores that would benefit fish during smoltification. Furthermore, a cost comparison of the different feeds highlighted that diet C formulation could be an economically viable alternative.

References available on request

More information: Jason Whooley CEO Bio-marine Ingredients Ireland Ltd., Ireland E: jason@biomarine.ie

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

MARINE OILS AND PROTEINS

Tuna oil, a valuable source of DHA for aquafeeds Dominique Corlay, Aquaculture Natural Solution and Charles Davy, Marine Biotechnology Products

As the demand for fish oils grows and sustainability concerns drive most decisions, the issue of sourcing valuable n-3 long-chain polyunsaturated fatty acid (LC-PUFA) remains with few alternatives. There is a growing interest in algae oils, but supply is limited with high costs and unknown environmental assessments.

Genetically modified vegetable oils will be barely accepted by most consumers in major markets such as Europe. Therefore, fish oils still represent the best

option to fulfill the nutritional requirements of major farmed species such as salmon and marine species.

Tuna oil extracted from the tuna fishing industry represents a unique and sustainable source of the essential fatty acids.

DHA: the most valuable essential fatty acid The n-3 LC-PUFAs, such as docosahexaenoic and eicosapentaenoic acids (DHA and EPA), are considered

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Table 1. DHA/EPA dietary optimal ratio for growth.

Species

DHA/EPA dietery optimal ratio for growth of juveniles

Source

Gilthead seabream

1.5

Rodriguez et al.,1997

Milkfish

>1

Gapaspin and Duray, 2001 Trushenski et al., 2012

Cobia

>2

Yellow croaker

>2

Zuo et al., 2012

Japanese seabass

>2

Xu et al., 2016

Golden pompano

1.4

Zhang et al., 2019

to be essential fatty acids for marine carnivorous fish.

Unlike some freshwater fish, marine carnivores have a low capability to elongate and desaturate C18 fatty acids, i.e., linoleic acid (18:2n-6, LA) and linolenic acid (18:3n-3, ALA) into C20–22, LCPUFA. In recent trials, the requirements of essential fatty acids (EFA) were reassessed at various sizes for salmon (Salmo salar) in real farming conditions. Thus, 10 g/kg EPA + DHA in the Atlantic salmon diet (or 3.5% of total fatty acids), a level previously regarded as sufficient, was found to be too low to maintain fish health under demanding conditions in sea cages (Bou et al., 2017), setting a safety level of 17 g/kg EPA+DHA (5.7% of fatty acids). Recent studies (Kousoulaki et al., 2020) indicate that a higher DHA level

can also contribute to better salmon pigmentation.

Besides the individual effects of DHA and EPA, several studies have demonstrated that the dietary DHA/EPA ratio (Table 1) could affect the growth performance in marine fish. The suitable dietary DHA/EPA ratio not only can improve the marine fish growth performance but also enhance their immune responses. A high DHA content and a high DHA/EPA ratio may reduce skeletal malformation in larval stages. DHA is also better retained due to the oxidation of DHA for energy being more complex through the involvement of peroxisomes. DHA has also known specific key roles in neural (brain and eye) development and function that EPA does not.

Figure 1. DHA and EPA content of some fish oils.

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Table 2. Oxidative status and fatty acid composition of fish oil (CTL) and tuna oil byproducts.

Fish oil specifications

CTL

Tuna Oil BYP

Evaluation of lipid oxidation

Peroxide value PV, mEq (peroxides/kg total lipid)

2,3 1,2

Conjugated diene (E232)

6,9 3,2

Conjugated trienes (E268)

0,6 0,9

Anisidine value (AV)

7 61

Total carbonyl value (CV)

21 37

Lipid-soluble fluorescent products (LSFP)

6 16

Thiobarbituric acid reactive substances (TBARS, mg/kg) 33 41

Polar lipid (PL, % total lipid)

Fatty acid composition (% of total fatty acids)

EPA

13,4 5,5

DHA

4,9 19,2

Unsaturation index

172 208

7 14

Table 3. Growth performance of rainbow trout juveniles fed experimental diets containing standard fish oil (CTL), tuna oil byproducts.

CTL

Initial weight (g)

Tuna Oil BYP

61±1 61±1

Final body weight (g) 364±8 363±10 Daily growth indexa 3.79±0.06 3.78±0.04 Feed conversion ratioa 0.79±0.01 0.8±0.02 Feed efficiencya

1.26±0.01 1.26±0.02

Hepato-somatic index 1.3±0.2 1.3±0-2 a

Values are means ± SD (n=3 except for hepato-somatic index, n=9).

Within rows, means not sharing a common superscript letter (p<.05) according to one-way ANOVA followed by a Newman-Keuls test. Daily Growth index = 100 x [(final mean body weight)1/3 - (initial mean body weight)1/3]/duration (84 days). Feed conversion ratio = dry feed intake (g)/we weight gain (g). Feed efficiency = wet weight gain (g)/dry feed intake (g). Hepato-somatic index = (wet liver weight, g/weight of fish, g) x 100.

Tuna oil: the highest natural source of DHA Among all wild fish species, tuna is ranked as a major predator at the top of the food chain. Through this food regime, tuna species can synthesize LC-PUFA and contain the highest level of DHA of all fish with a typical 5:20, EPA:DHA ratio (Fig. 1).

Tuna oils are extracted from two major sources of byproducts either fresh, such as heads and guts, or

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Table 4. Fatty acid composition levels in muscle lipid of rainbow trout juveniles fed experimental diets containing fresh fish oil (CTL) and tuna oil byproducts at a constant temperature of 17°C ±1°C for 12 weeks.

3 weeks CTL

12 weeks

Dietary Treatment

Tuna oil byproduct

CTL

Tuna oil byproduct

Dry matter (%)

Total lipid (% wet weight) 5.7±1

FA composition (% total FA)

EPA 4.5±0,6 2.4±0.2

DHA 5±0,9b 7.2±1,2a 4.9±1,2b 8,9±1,7a

Unsaturation index 138±9 137±10 129±10 137±15

24.4±1.1 24.5±0.7 26.2±1,4 25,4±0,7ab a

5.3±0.7

6.9±1,1a 6±0,7b

a

5±0,4a 2,4±0,3b

Values are means ± SD. Within rows and for each sampling time, means not sharing a common superscript letter (a,b) are significantly different (p< .05) according to one-way ANOVA followed by a Newman-Keuls test.

cooked from the cannery process. Their potential higher oxidative status expressed by parameters such as anisidine (AV) and peroxide value (PV) of cooked byproducts has been studied by Fontagne et al., 2018. A 12-week trial was conducted on juvenile rainbow trout (initial weight 62±1 g) up to portion market size, fed with diets (iso-energy, crude protein 48%, crude lipid 23%) supplemented either with 15% standard capelin oil (CTL) or tuna oil from byproducts (BYP) as described in Table 2. At the end of the experimental period, no significant differences in growth performance were recorded between dietary groups as shown in Table 3.

Furthermore, muscle lipid content exhibits significant DHA differences in line with initial fatty acid compositions of tuna oil (Table 4).

Tuna oil sustainability Worldwide, the tuna industry presents a case study in valorization. Tuna byproducts are transformed into fishmeal and fish oil (FMFO) across the world, ensuring that there is 100% utilization of fish that are caught.

It is estimated that over 60% of total worldwide catches of tuna (nearly five million tons a year) are transformed in processing plants and nearly 50% of these tonnages generate byproducts which are in turn processed into tuna FMFO. MarinTrust certification applies to most major suppliers.

The Forage Fish Dependency Ratio (FFDR) for species such as salmon is under scrutiny. It should be underlined that byproducts such as tuna are not taken into account in the FFDR. The last ASC feed salmon standards

requested a FFDR to oil below 2.52 with new requests from some food retailers to go below 1.75. Finally, in terms of safety and contamination from undesirable substances such as heavy metals or dioxins/PCBs, most tuna oils contain levels far below maximum limits set by the actual EU regulations.

Conclusion Fish oils from byproducts of the tuna fishing industry represent highly valuable sources of n-3 LC-PUFA which can help the aquaculture industry maintain its profitability and product nutritional quality in a sustainable strategy.

References available on request

More information: Dominique Corlay Consultant Aquaculture Natural Solutions, France E: ansaqua.dc@gmail.com

Charles Davy Advisor Marine Biotechnology Products, Mauritius E: cdavy@mbp.mu

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

MARINE OILS AND PROTEINS

The world’s first industrial plant for processing of the marine copepod Calanus finmarchicus Isak Bøgwald and Hogne Abrahamsen, Calanus AS

The plant is located above the Arctic circle, in the city of Sortland, Norway.

The Norwegian company Calanus AS is currently building the world’s first full-scale industrial plant for processing of the marine copepod Calanus finmarchicus, located above the Arctic Circle in the city of Sortland in northern Norway. The project was triggered by the decision of the Norwegian government’s Ministry of Trade, Industry and Fisheries to open for commercial harvesting of the species, along with an increasing demand for the company’s products.

This decision provides predictability for further investments and puts the company in a good position to supply an increasing number of customers with our health and nutrition products derived from C. finmarchicus. The plant project has a total investment budget of €18 million, of which €7 million is to be financed with equity, and will have an annual processing capacity of up to 10-12,000 tons of raw material.

Sustainable harvesting Considering that the annual biomass production of Calanus sp. is larger than all fish and mammal species combined in the Norwegian Sea (approx. 300 million tons, Skjoldal, 2004), and the development of new technology to minimize bycatch, harvesting the species is deemed sustainable by both scientists and the government. The annual commercial quota is set at 254,000 tons. This is less than 0.1% of the annual production and a statement to the precautions that are taken to ensure sustainability. Most of the quota is to be harvested outside of the 1,000 m bathymetric contour line (oceanic region), which has incited the company to develop state-of-the-art oceanic harvesting technology for C. finmarchicus. Calanus AS is certified for MarinTrust (previously IFFO RS) for its commitment to responsible practices in the areas of raw material procurement and food and feed safety.

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

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The viewing corridor with CTO Kurt Tande and product manager Alice Marie Pedersen of Calanus AS.

Clean and energy-efficient production process The manufacturing process developed by the company allows for the extraction of both oil and proteins without the use of solvents and additives, thus nothing is removed, and nothing is added to the natural products from the copepods. The raw material is frozen immediately on the vessels after harvesting and stored at Holmen Industrial Area, right next door to the processing plant. With process technology in the plant customized to handle frozen raw material, the results are minimal oxidation and deterioration of the products. Renewable energy generated by wind farms and hydropower plants in the area will power the processing plant, and energy used in the manufacturing process will be recycled and reused, e.g. by using heat exchangers. The plant is designed to collect every component of the copepods during the manufacturing process; unique wax ester oil for human consumption, and protein hydrolysate and a powdered meal containing lipids, protein, and chitin for aquaculture feed. This leaves only the water contained in the copepods as waste, most of which is evaporated in the process and run through treatment systems that collect particles and sludge, securing that almost no organic material is released to the environment.

An eco-friendly location The processing plant will be a part of Holmen Industrial Area, and building it on the shores in northern Norway has several advantages for green and environmentally friendly production; i) The proximity to the harvesting areas, vessels and raw material storage facilities reduces transport and thus the carbon footprint of the whole value chain; ii) The access to seawater reduces the use of freshwater in the manufacturing process. Seawater will account for 75% of the water consumption in the process, which is employed mainly for cooling and purification purposes; iii) The proximity to the aquaculture industry and customers. The processing plant is in a central industry hub containing notable feed producers such as Skretting and Biomar, major salmon farmers and other established biomarine companies.

A continuous process The processing plant is designed to run 24/7 with continuous processing. In addition to the process equipment, control rooms and laboratories, the plant also contains all the necessary elements to function as a â&#x20AC;&#x153;miniature societyâ&#x20AC;? including living quarters, wardrobes and dining rooms. There is even a viewing corridor running through the whole plant where visitors

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and guests can observe the process without the risk of contamination. The building project involves two major parties; Total Bygg og Anlegg AS for the construction of the building itself and Skala is responsible for all the process equipment within the plant. Skala is a process solutions provider with expertise in foodgrade technology in terms of sterile production and maintenance, and as a total supplier they will set up the best possible option for each of the processes involved in the production.

Up and running in Q1 of 2021 According to the schedule, the processing plant will be ready for production in Q1 of 2021. The company will obtain feed and food approvals of the Norwegian Food Safety Authority and the Food and Drug Administration (FDA) for the new plant and will renew its ISO 9001:2018 and MarinTrust certifications.

As Calanus AS will increase its production capacity 12-fold following the completion of the new processing plant, the company is in a position to broaden the customer base and are now in a process of branching

Scientifically Selected Solutions for Aquaculture YANG, a patented 3 yeast extract blend that, modulates the immune system and improves digestive health..

out to several relevant markets for the aquaculture feed ingredients Calanus® Hydrolysate and Calanus® Powder.

References Skjoldal, H. R. (2004) The Norwegian Sea Ecosystem, Tapir Academic Press.

More information: Isak Bøgwald Researcher Animal Health & Nutrition Calanus AS, Norway E: isak.bogwald@calanus.no

Hogne Abrahamsen Head of Sales and Marketing Animal Health & Nutrition Calanus AS, Norway E: hogne.abrahamsen@calanus.no

SPECIFIC FOR YOUR SUCCESS

Bactocell, a probiotic that colonizes the stomach and intestinal tract to improve digestion and animal health.

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Not all products are available in all markets nor all claims allowed in all regions.

SPECIFIC FOR YOUR SUCCESS LALLEMAND ANIMAL NUTRITION www.lallemandanimalnutrition.com

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

MARINE OILS AND PROTEINS

Krill oil and krill meal processing technology advantages to feed manufacturers Dimitri Sclabos, Tharos

Tharosâ&#x20AC;&#x2122; krill oil extraction process, working in the North Atlantic krill fishery, reinforced Tharosâ&#x20AC;&#x2122; technology capability to obtain special human-grade and aquafeed ingredients. Along with Norwegian and Icelandic partners, a new net-free krill fishing method, first-ever fishing region and a plug-and-play processing plant were put together in an onboard factory trawler. It sources special krill meal and high-natural antioxidant-

and phospholipid-enriched krill oils, 100% solventfree extracted targeting the pharma and dietary supplements industry. Special low-fat krill meals target the aquafeed ingredient market.

Krill meal in aquafeeds The advantageous properties of South Antarctic krill meal and krill oil (Euphausia superba, Dana) are known

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

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Figure 1. Tharos krill meal and krill oil extraction model process.

by the aquafeed sector (Sclabos, 2014) and they must come from onboard factory trawlers processing them at sea since manufacturing final products at sea have become krill operators’ primary goal.

As described in one of Tharos’ krill meal reports, South Antarctic krill meal nutritional attributes make it a unique feed ingredient for aquafeeds due to krill meal’s protein quality, strong palatability, natural carotenoid pigment (astaxanthin mainly), excellent lipids where omega-3s mainly bound to phospholipids, minerals profile and its chitin and chitosan constituent.

Krill meals’ negligible heavy metals, dioxins, PCBs and heavy metals help this goal.

In the past few years, many studies have been conducted with different aquaculture species using Antarctic krill meal. Krill meal carotenoids are considered essential for the reproduction of aquatic species. In a study feeding juvenile whiteleg shrimp with krill meal, feed preference and grow response was evaluated using a diet containing 3% fishmeal supplemented with either 3% of krill meal or another marine meal. Results indicated that krill meal acts as a powerful feeding effector and growth enhancer for whiteleg shrimp (Nunes et al., 2019).

High-fat krill meal disadvantages Current high-fat krill meal food-grade processing technologies follow the prevailing market drivers – manufactured at sea onboard factory vessels, containing a (high) fat content around 20-27% and targeting on-land krill oil extraction buyers.

This fat level is achievable in the Antarctic’s high-fat

season (March – June) when raw krill contains >5% lipid. This krill meal contains <56% (low) protein content, preferably used to extract phospholipidsenriched krill oils using solvents (chemical)-extraction models, in on-land factories. The resulting oil goes to the growing omega-3 pharma and dietary supplements market categories. Currently, all krill oil extraction factories are not able to produce any krill oil that avoids the use of solvents, the ones forbidden to use at sea.

As of Q2 2020, this food-grade high-fat krill meal is priced >$2.7 USD per kilo FOB, a price that reflects a matrix composed of high Chinese demand, onboard processing costs, the use of expensive food-grade antioxidants, costly packaging (laminated bags with oxygen barrier, vacuum packed and/or with N2 barred) and expensive frozen storage and transportation on its entire value chain. High-fat krill meals are significantly reactive to auto-combustions and oxidation which negatively impact the final quality.

Factory trawlers that manufacture food-grade highfat krill meals, for the current demanding Chinese krill oil extraction market, for example, set the process to retain as much fat as possible in the resulting meal, ensuring the lipids contained in the raw material emulsify with the protein while phospholipids act as the emulsifying agent. This high-fat krill meal (vs traditional 18% max fat content meal) has some handling disadvantage. For example, during the extrusion stage when manufacturing the feed, handling these meals through transportation screws, storage in silos, through mixers and tanks does not “flow or run”

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

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Figure 2. Phospholipids krill oil extraction method.

well because of its poor flow properties, generating blockages and bridges.

The aquafeed sector needs krill meals with good nutritional quality, proteins >60%, (low) fat content of about 10-18%, good flow for an efficient transportation and stowage capacity, and competitively priced vs vegetable and other low-cost ingredients. The latter, although cheaper, compromise feed quality due to its nutritional properties.

Feed-grade krill meals used for aquafeeds are normally priced <$2.4 USD/kilo FOB. They use feed grade antioxidants, packed in propylene bags with black inner bags, or laminated foil bags with oxygen barrier, vacuum packed and/or N2 barred. Consequently, due to seasonal supply variations, feed manufacturers have only highfat meals, with the inconveniences previously described, and protein <56%.

Tharos technology for low-fat krill meals Tharos patented a krill oil extraction technology that sources low-fat krill meals (<13%). This oil extraction process can be entirely carried out at sea from fresh raw krill or on land from frozen krill. The former operates on-board factory trawlers, 100% solvent-free, extracting two types of krill (enriched in phospholipids and triglycerides) and high protein krill meal (>65%).

It is known that krill meals manufactured following the current high-fat food-grade process contain fat levels up to 28%, unlike fishmeal <13% fat. This is due to krill lipids containing 40-60% of phospholipids (PL) known to be difficult to remove in a normal krill meal process. Such PLs are tightly linked to the protein

matrix due to its emulsifying properties. Tharosâ&#x20AC;&#x2122; patent-protected process extracts a large part of the lipids from raw krill such as PL and triglycerides (TG), and the resulting meal contains as low as 10% fat when raw krill is on its fatty period.

The advantages of this technology for the aquafeed industry are a meal with >65% proteins and <10% lipids.

Other advantages include krill mealâ&#x20AC;&#x2122;s exceptional handling properties at the extrusion phase; easier drainage and screw conveyors transportation; easier silo storage; no bridging; no binding; and improves stowage capacity. This type of meal has valuable components such as astaxanthin, TMAO, palatability, etc.

Tharos has two invention patents (IP1 and IP2) for a process that uses exclusively a physical-mechanical method as shown in Figures 1 and 2. The Tharos process has been successfully operated on a pilot-size plant in Antarctic waters and a commercial-sized process in the North Atlantic krill fishery on-board of a Norwegianflagged trawler. The process obtains a krill oil enriched in phospholipids (PL oil) >35% PL and a krill oil rich in triglycerides and astaxanthin (TG oil) >1,000 ppm, and a krill meal with <13% lipids and >65% proteins.

Tharos and its Norwegian and Icelandic partners decided to scale-up the krill oil extraction process to a larger commercial-sized level, putting the current 300k/ hr plant for sale. The wealth of knowledge brought by our Norwegian partner NITG and Icelandic BRIM owner adds to the first-ever net-free fishing system used on the Arctic krill fishery. A new krill oil quality profile is brought to the market sustained by North Arctic krill species features.

References available on request

More information: Dimitri Sclabos CEO Tharos, Chile E: dimitrisclabos@tharos.biz

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Mycotoxins in aquaculture: The risk of generalization in a sector with 466 species Rui A. Gonçalves, Lucta

Fusarium ear rot in corn caused by the fungus Fusarium verticillioides (which produces fumonisins, among others).

For the 2018 SOFIA report, FAO recorded aquaculture production figures for 466 species-groups. The high number of species produced in aquaculture is a multi-level challenge, in which the topic of mycotoxin management cannot be avoided. Despite the great diversity, production by volume is dominated by a small number of species groups. Finfish farming is the most diverse group, however, 20 species-groups accounts to over 83.4% of total production. Compared with finfish, crustacean species represents an easy challenge, with Litopenaeus vannamei being responsible for 53% of all crustacean production. The four main crustacean species represent 87.2% of total production.

Mycotoxins management in aquaculture is relatively young One of the current limitations of mycotoxin

management in aquaculture, especially compared to livestock production, is the level of knowledge about mycotoxins. Know-how about mycotoxin occurrence in aquafeeds and its negative impact on the produced species is still being accumulated. However, it is not easy to increase the awareness of mycotoxins in a sector that is highly diverse. Furthermore, the extrapolation and/or generalization of the already learned concepts may be incorrect and dangerous as the aquaculture sector may lose trust in the excellent work being done by scientists in this field. This articleâ&#x20AC;&#x2122;s approach is mycotoxin management in aquaculture, not as a whole, but taking into consideration the species specificities (e.g., rearing regions, raw materials used, species-specific sensitivity levels), trying to understand how future trends in the aquaculture sector may increase or decrease the exposition of certain speciesgroups to mycotoxin and how to manage this risk. Risk management steps are exemplified in Figure 1.

Aquaculture trends and their associated mycotoxin risk Future growth and sustainability of the industry depend on the ability of the sector to identify economically viable and environmentally friendly alternatives to marinederived ingredients. The industry has been concentrating efforts on finding alternative sources of protein and oil to substitute (or decrease) fishmeal and fish oil in

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Figure 1. Example of the main steps for a mycotoxin risk management plan.

aquafeeds. Consequently, many new alternatives are available, e.g. insect meal, macro- and micro- algae meal or single-cell protein. Nowadays, high costs and limited availability are still challenging, while plant-based meals are still the most viable solution (in terms of availability, costs and standard nutritional profile).

The important questions that remain to be answered and which could highly improve mycotoxin management efficacy in aquaculture are: (1) What species will continue using plant-based diets and which species will replace fishmeal and plant-based meals by alternative protein sources? and (2) What will be the impact of this new trend in mycotoxin management?

Mycotoxin management framed in three big species-groups Herbivorous species From the identified 20 species accounting to over 83.4% of the total production of finfish, 13 species are herbivorous. The top five include carp (32.8% of finfish production) and Nile tilapia (8.3%). These species are generally (except for tilapia) produced for regional consumption. In terms of feed formulations, there is

a high tendency for using local plant raw materials.

As these are considered lower profitability margin species, feed formulations tend to be highly costsensitive as there is no oversight on the inclusion of novel raw materials in these species. Therefore, herbivorous species are, and will possibly continue to be, the major group of species consuming plant meals with higher exposure risk to mycotoxins.

From mycotoxin impact studies in fish, herbivorous species tend to be the most resistant of all groups.

However, extrapolation and/or generalizations should be avoided as mycotoxin negative effects will depend on factors that are non-species related, such as the type of mycotoxins (exposition duration, level and co-occurrence) and environmental factors. Moreover, the lack and/or difficulty to identify mycotoxin exposure symptoms reinforced by the low-frequency mycotoxin contamination monitoring in aquaculture feedstuffs (especially in these low profitable species), makes mycotoxins, in general, often a neglected topic in this group of species. However, an important factor that should be highlighted is the possibility of carry-over effects (i.e., transfer of mycotoxins from feed to fish tissues). It has been shown in the literature (for more

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details see Gonçalves et al., 2020), that some species (namely tropical species due to its low depuration period) may present considerable high carry-over of mycotoxins. This might be a risk for consumers; especially when offals are also consumed.

Invertebrate species Pacific white leg shrimp production represents 52.9% of all crustaceansâ&#x20AC;&#x2122; production. If we add to this the giant tiger shrimp (Penaeus monodon) production, the

total increases to 60.9%. Factors such as a geographical location associated with raw materials used and rearing conditions will be essential when elaborating on a mycotoxin risk analysis plan. Generally, shrimp diets have a considerable level of fishmeal (12% on average), however, it is highly variable depending on the region.

These species will continue to suffer a decrease in fishmeal inclusion, at the moment plant meals and marine byproducts hydrolyzates being the most common ingredients. As shrimp diets are relatively profitable, there are margins to include novel ingredients, therefore decreasing some of the mycotoxins' risks from using plant meals. Nonetheless, special attention needs to be given to marine byproducts hydrolyzates as its low quality and bad storage may lead to AF and OTA contamination (besides the oxidation risk which ultimately will also impact hepatopancreas, similarly to AF and OTA).

It is well documented that L. vannamei is highly sensitive to DON and AF. Therefore, monitoring raw materials that may contain these mycotoxins, ensuring good storage conditions and having a mycotoxin mitigation program, are key to a successful mycotoxin management plan in shrimp production. So far, the literature available indicates a low risk of mycotoxin carry-over.

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Carnivorous Carnivorous species are highly diverse. This group of species, due to its trophic level, presents the highest fishmeal inclusion level when compared to previous groups. Within this group, Atlantic salmon (Salmo

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32

salar) is the most important species, representing 4.5% of finfish production. Salmon is followed by several catfish, trout and diverse marine species.

It is highly likely that this group of species may be the most impacted by the novel ingredients industry.

It is expected that not only will the fishmeal inclusion level decrease but a part of plant meals may be replaced by novel ingredients such as insect meals, single-cell proteins and algae-based meals among others. There is a high possibility that diets for this group of species become more diverse using ingredients which may work as functional ingredients (e.g., insect meals).

In the context of mycotoxin management, this group of species is challenging but also highly attractive, as you need to combine a deep knowledge of mycotoxin risk management, species knowledge and regional ingredients used as well as its mycotoxin risk contribution. The decrease of plant-based diets may decrease the mycotoxin risk exposure to certain mycotoxins (e.g., Fusarium mycotoxins), however, other novel ingredients may necessitate the study of their mycotoxin risk. In general storage, mycotoxin may always be a concern in both raw materials and finished feeds.

It is important to highlight that besides the contamination level, the multi-mycotoxin exposure may be a growing challenge. Therefore, even if the contamination level may decrease due to the use of a broader range of ingredients, it is important to further understand the synergistic effect of low contamination levels of mycotoxins in carnivorous species’ diets. To the current mycotoxin knowledge, carnivorous species are generally highly sensitive to mycotoxins, however, there is still a lack of scientific knowledge in this group and further research is needed, namely, to better understand possible carry-over effects of mycotoxins.

Conclusions Plant-based ingredients may continue to be the main ingredient for herbivorous feed formulation.

Furthermore, the increase of mycotoxin occurrence associated with climate change exposes this group of species to high risk. Moreover, the lack and/or difficulty to identify mycotoxin clinical signs, reinforced by the low monitoring frequency for mycotoxins in

aquaculture feedstuffs and the economic pressure to use local, cheap (low-quality) ingredients, highlights this group as the most exposed to mycotoxins.

Mycotoxin management solutions offered to this group need to be cost-effective.

The most impacting mycotoxins to L. vannamei are well-identified as well as raw materials typically contaminated by those mycotoxins. Storage conditions will play a key role to control storage mycotoxins in shrimp feeds (proper storage conditions are very wellidentified in literature). The possible increase of novel ingredients used in this species may decrease the risk of mycotoxins in the crustacean group. Monitoring raw materials, having a mycotoxin mitigation plan and controlled storage conditions are key to avoid mycotoxin problems in the shrimp sector.

Carnivorous species are possibly the group of species that will be most impacted by novel ingredients.

There is a high possibility that, in these highly profitable species, a significant part of fishmeal, but also plant meals, are replaced by novel ingredients. This, in general, may reduce the mycotoxin exposure risk.

However, further research is needed to understand upcoming challenges, e.g., synergistic effects of lowlevel mycotoxins.

In general, the aquaculture sector needs to start considering the possibility of carry-over of mycotoxins from feed to animal tissues and consequent impact in human health. So far there is little literature on the topic, however, it is already evident that transfer factors may be very different from livestock (for more information consult Gonçalves et al., 2020). Special attention should be given to tropical species where the depuration period is sometimes very low or nonexistent and on species with offals that are consumed.

References available on request

More information: Rui A. Gonçalves Aquaculture Business Developer Lucta, S.A., Spain E: ralexandr3@gmail.com

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New fermented feed additive improves productivity in fish and shrimp culture Kok Leong Wee, Ning Widjaja, Julie Gasper, Diamond V

Today, disease is the most prevalent problem in intensive aquaculture worldwide. In the 2019 Global Outlook for Aquaculture Leadership (GOAL) survey of critical issues facing the shrimp culture industry, disease problems were listed at number one and have been at the top of the list for many years. The economic cost of lost production from diseases is significant and threatens the sustainability of the culture of selected aquaculture species. Therefore, farmers are constantly on the lookout for solutions that can support optimal

health. Ultimately, this can lead to higher productivity and profitability.

There are a variety of factors that influence diseases.

The prevalence of various viral, bacterial and parasitic diseases could partially be attributed to high levels of stress experienced during the culture period. Stress can suppress the immunity of aquaculture animals and make them more susceptible to attacks by pathogens.

Activation of the immune system requires energy and when aquaculture animals are sick, a significant

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amount of energy is channeled towards preparing them to fight off pathogenic threats. This can adversely affect the animal’s growth. When activation of the immune system is balanced and efficient, utilization of energy for immune response will be optimized, and energy can be channeled to other physiological needs such as growth.

DVAQUA™, a feed additive from Diamond V™, supports immune strength and digestive health in farmed aquatic species. This natural* product is produced through a proprietary, multi-step anaerobic fermentation process using Saccharomyces cerevisiae that has been shown to help balance energy spent on maintenance and recovery from stressors while sparing energy to support growth and production. Research shows that Diamond V products, including DVAQUA, have a dual-action effect, as the bioactive compounds in it support the body’s natural immune system and digestive system. On the Figure 1. Total hemocyte count (a) and phagocytosis (b) in Litopenaeus vannamei immune strength aspect, there will be (Tipsemongkol et al., 2009). abc P < 0.05. better disease protection with more efficient responses and faster recovery.

Table 1. Pond shrimp results with 0.25% DVAQUA in Litopenaeus On the digestive health side, it provides better gut vannamei (Tipsemongkol et al., 2009). Means values within the integrity while maintaining a healthy microbial balance. same row sharing the same superscript are not significantly different at P = 0.05.

Ultimately, a feed that supports immune strength and digestive health helps aquaculture animals optimize

Control DVAQUA Difference their performance, growth, and survivability.

Production (kg/ha) 13,217a 14,251a 7.8%a Mean final weight (g) 18.0a 17.4a

-3.4%

FCR 1.75 1.64 a

-6.3%

a

Survival (%) 73.3% 82.1% a

a

12.0%

Table 2. Tilapia hatchery results with 0.125% DVAQUA in Oreochromis niloticus (field trial, 2015). ab P < 0.01.

Control

DVAQUA

Difference

Final Weight (g) 0.25 0.25

-0.0%

FCR 1.46b 1.34a

-8.2%

Survival (%) 80.1% 89%

11.1%

b

a

Enhancement of immune response Improvements in growth and survival rates are supported by the enhanced immune response in shrimp and fish. In a 2009 shrimp study conducted in Thailand, total hemocyte counts and phagocytosis rates were significantly higher when DVAQUA was included in the diet (Fig. 1 ab). In addition, a dose-response effect was observed. Similar results have been observed in various fish trials. However, while immune parameters are important indicators of a product’s effectiveness, they may not be directly relevant in an aquaculture farm setting.

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Interaction of growth, feed conversion rate, survival rate and production As previously discussed, by supporting efficient and balanced immune function, more energy can be spared for growth. And by supporting digestive health, more feed can be efficiently utilized for growth, too.

While strong growth results are something every farmer wants, these can’t be looked at as standalone markers. Bigger shrimp won’t always result in greater productivity – or profit – if there are significantly fewer surviving shrimp or if more feed is used due to inefficient feed conversion. Each of these factors should be considered to understand the full impact of a feed additive.

Multiple research studies have shown that fish and shrimp fed diets containing DVAQUA consistently demonstrate better growth performance and feed conversion efficiencies. In recent shrimp studies from 2018 and 2019, with the use of DVAQUA, net weight has averaged over 6% improvement versus the control, while feed conversion showed a beneficial decrease of more than 4%.

Laboratory trials versus pond trials It shouldn’t come as a surprise that laboratory trials

don’t always represent real-world conditions in a farm setting. Products with research and results in both a controlled lab setting as well as validation on-farm often can provide more reassurance to farmers about the effectiveness of the product.

In the case of shrimp, laboratory trial results for DVAQUA have been validated in ponds, including at a commercial shrimp farm in the Chantaburi Region of Thailand. For 120 days, two treatments with four replicated ponds (each) were fed either a commercial feed only or the commercial feed plus DVAQUA. Not only was growth improved with DVAQUA, but this was accomplished while also improving feed conversion ratio (FCR) and survival along with a total production increased of over 7% (Table 1).

In fish, similar performance improvements have been observed in commercial settings. For example, in a commercial tilapia hatchery in Sao Paulo, Brazil, post-larvae tilapia (average 14 mg) were fed either a commercial feed or a commercial feed with DVAQUA. The fish were stocked into 8 hapas (700 PL per hapa) and harvested after 27 days of culture. Again, a significant difference in survival (+11%) and a beneficial reduction in feed conversion rates (-8%) were observed for tilapia fed the diet containing DVAQUA (Table 2).

Figure 2. Shrimp survival after WSSV challenge in Litopenaeus vannamei (Kangsen and Zhen, 2006). ab P < 0.05.

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Figure 3. Tilapia hatchery results after Streptococcus challenge in Oreochromis niloticus (field trial, 2015). abc P < 0.01

Disease challenges Finally, any discussion of results must consider the real threat and impact of disease challenges. It is in these challenging conditions that the impact of the right feed additive can be most impactful.

For example, white shrimp (Litopeneaus vannamei) were challenged with white spot syndrome virus (WSSV) after 52 days of feeding either a control diet or a diet containing XPC, a precursor to DVAQUA. The shrimp fed the diet containing XPC had survival rates significantly higher than the control (Fig. 2).

These results are supported by another study conducted with DVAQUA evaluating the impacts of Vibrio harveyi where significant improvements in both immune response and survival were noted.

In a tilapia hatchery study, when fingerlings were challenged with Streptococcus agalactiae, those fed a diet supplemented with DVAQUA showed greater resistance to infection compared to fish fed the control diet (Fig. 3).

Summary Today, many farmed fish and shrimp face disease challenges. However, you can address these challenges head-on by promoting overall health and well-being, while improving feed efficiency and growth. A feed

additive such as DVAQUA can help protect gut health and support immunity. When aquaculture animals are healthier this can lead to better growth and survivability, and ultimately, increased production and profitability.

Diamond V has been in the animal feed additives business for more than 75 years. The natural* immune support products are made from a proprietary fermentation process that helps optimize animal health, animal performance and food safety worldwide.

Numerous trials have demonstrated DVAQUA’s efficacy in fish and shrimp under normal conditions and when challenged with selected pathogens. Research shows DVAQUA works with the biology of a wide range of cultured species to maintain immune strength and support the animals’ natural defenses. *as defined by AAFCO

More information: Kok Leong Wee Senior Consultant – Technical Services Diamond V, USA E: kok_leong_wee@crglthirdparty.com

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

PRODUCT FOCUS

New tool for shrimp gain and disease management Nguyen Duy Hoa and Keith Mertz, Cargill Branded Feed

As global shrimp production continues to expand, intensive rearing processes are evolving to optimize growth and efficiency to improve profitability. Intensive farming practices are not without their challenges.

Solutions to modify or modulate gut microbiota may hold promise, including acidification of the gut.

There is an increasing issue of disease management for the shrimp industry along with the need for new and sustainable protein sources. We theorized that we could reduce the environmental impact on disease and growth by optimizing gut health and improving

enzymatic activity and nutrient uptake of the entire diet by engineering a fermented, bioactive protein.

Cargill Branded Feed Group developed a fermented plant protein, Motivâ&#x201E;˘, that has been beneficial at improving growth and conversion in L. vannamei.

Motivâ&#x201E;˘ is a fermented feed ingredient solution that creates a healthier gut environment in shrimp. As a result, shrimp can better utilize the nutrients of the whole diet, increasing their energy and accelerating their growth, weight gain and resistance to disease, including Early Mortality Syndrome (EMS). Because

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Table 1. Response of juvenile (0.74 g) L. vannamei to test diets over an eight-week growth trial in an indoor culture system.

Different letters indicate significant statistical differences (p<0.05).

Initial biomass

Final biomass

Mean Survival final wt

Gwth/ week

Weight gain

Weight gain (%)

FCR

Control

22.65 190.49 6.96b 91.11 0.89b 6.20b 822.86 1.88b

Motiv

21.84 205.61 8.12a 84.44 1.06a 7.39a 1,015.57 1.57a

Control+OA 21.85 189.04 7.18b 87.78 0.92b 6.45b 889.24 1.80b Control+5xOA 22.12 p-value

192.23 6.87b 93.33 0.88b 6.13b 838.61 1.90b

0.8833 0.5205 0.0044 0.1865 0.0058 0.0058 0.0920 0.0092

Table 2. Effect of different diets on growth and performance of L. vannamei after weight weeks. 1 as percentage of the protein in the diet and 2 as per unit of protein. Different letters indicate significant statistical differences (p<0.05).

Control

Motiv 12%

Motiv 24%

Diet crude protein (%) 39.5 32.7 38.5 FCR1 0.48ab 0.44a 0.57b Biomass2 2.78ab 3.17a 2.57b Final weight2 0.21a 0.22a 0.17b Weight gain2 (%) 109.42b 120.28a 96.29c Growth per week (%) 0.025ab 0.027a 0.021b Motiv is a plant-based ingredient, shrimp farmers can increase their output to meet the growing global demand without the depletion of natural resources.

In this article, two trial results are presented showing improvements in energy intake and gain, feed conversion, and survivability in highly-stressful environments. The trials were conducted at the Claude Peteet Mariculture Center at the University of Auburn.

Effect on L. vannamei performance in comparison to acidified shrimp diets This trial compared Motiv™ to a similar reference diet with five times the amount of organic acid found in Motiv™. The reference diet (34.8% crude protein, 8.5% crude lipid diet) was compared to Motiv™, and control supplemented with lactic acid found at one time and five times the amount found in Motiv™.

Juveniles (initial mean weight 0.74g) were stocked in 12, 652 L tanks (three replicates per treatment), at a density of 30 shrimp per tank. Four dietary treatments

were offered four times per day at 07:00, 11:00, 15:00 and 19:00. Daily feed input was calculated based upon an expected growth of 0.8 g wk–1 and an estimated FCR of 1.8. At the end of the eight-week growth trial, shrimp were counted and weighed. Mean final weight, final biomass, survival and FCR were determined.

Results (Table 1) showed that shrimp fed on the Motiv™ diet had a 19.2% improvement in weight gain and a 16.3% increase in feed conversion (FCR).

Diets acidified with organic acid added did not show an impact on performance different from that of the control, indicating that acidification alone does not provide the benefit established by Motiv™.

Motiv™ included at macro levels provided healthy nutrition by improving the overall diet utilization in shrimp, as evidenced by both gain and feed conversion.

Efficacy at different inclusion levels in L. vannamei Motiv™ is a fermented plant protein technology that, when included in the shrimp diet, has demonstrated improved growth and feed conversion.

The technology improves overall diet utilization through modulation of gastrointestinal pH as well as providing cofactors inherent to the fermentation. To achieve optimal results, recommended inclusions of Motiv™ are essential.

This trial compared L. vannamei performance in diets formulated with Motiv™ fed at 12% or 24% of the ration to a reference diet (35% crude protein, 9% crude lipid diet). Dietary amino acids were balanced for all diets. Juveniles (initial mean weight 0.18 ± 0.01 g) were stocked in 20, 162 L square tanks (four replicates per treatment), at a density of 15 shrimp/ tank. Dietary treatments were offered four times per day at 07:00, 11:00, 15:00 and 19:00. Daily feed input was calculated based upon an expected growth of

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

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0.8 g wk–1 and an estimated FCR of 1.8. At the end of the eight-week growth trial, shrimp were counted and weighed. Final weight, final biomass, survival and FCR were determined.

Results (Table 2) showed that after adjusting for protein content, shrimp fed 12% Motiv™ in the diet content improved performance for gain and feed conversion above the 24% and reference diets (8.3% and 9.9%, respectively). Based on the results from this trial, up to 12% inclusion of Motiv™ may provide beneficial results.

Motiv™ was launched in 2019 by Cargill Starches, Sweeteners, and Texturizers (CSST), specifically by a group within CSST called Branded Feed. This same group created the Empyreal 75 protein concentrate for salmon and marine species.

More information: Nguyen Duy Hoa Global Technical Director Cargill Branded Feed, Vietnam E: DuyHoa_Nguyen@cargill.com

New trials to be released These initial research trials for Motiv helped the team at Cargill Branded Feed understand the value and potential of this new fermented protein that effectively provides a prebiotic effect. This led to a commercial launch in 2019, but there are still commercial trials being conducted to better understand optimum inclusion levels for different environmental scenarios, and these results will be shared as they are made available.

Keith Mertz Principal Scientist Cargill Branded Feed, USA

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Strengthen shrimp against salinity stress Tilman Wilke, Anne MĂśddel, Larissa Kiskel, Dr. Eckel Animal Nutrition

Shrimp are sensitive to rapid changes in water salinity.

Drop in salinity is an acute health risk and stress factor for shrimp. Salinity stress can cause acute mortality, loss of appetite, chronic mortality, cannibalism and susceptibility to infections. Heavy salinity fluctuations constitute a serious animal welfare risk that shrimp farmers have to tackle in the course of their animal health and welfare management.

Drop of water salinity happens when pond water is diluted by floods or heavy rainfall. When the pond water is diluted, the number of ions per liter (e.g. calcium, magnesium) decreases. This also includes water hardness (alkalinity). Water pH is typically not affected by this, because the pH-reducing effect of the slightly acidic rain compensates for the dilution.

But apart from a drop in salinity, heavy rainfall bear further risks to shrimp health and welfare: temperature drop, contamination by toxic substances leaching

in from surrounding areas, destruction of pond embankments, stir-up of toxic hydrogen sulfide, as well as overcrowding when shrimp gather in safe areas at the pond bottom. In Southeast Asia, mortality rates from 2 up to 50% have been reported after heavy rainfall incidents.

Once the salinity of the water drops below a level no longer tolerable for the shrimpâ&#x20AC;&#x2122;s organism, the resulting osmotic pressure leads to water influx into the tissue and, in consequence, to dilution of ion and pH gradients, which causes cell dysfunction and cell death (Xu et al., 2017). Salinity stress may also lead to long-term susceptibility to infections and problems in the molting cycle. Immediately after molting, shrimp have to absorb calcium and magnesium to harden their shells. In highly diluted water (low salinity), this process is hindered and slowed down. This paves the way for cannibalism and infections with bacteria and parasites.

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How shrimp cope with salinity stress By nature, shrimp have mechanisms to cope with changes in water quality (Chen et al., 2015). The gills are one of the most important organs for osmoregulation and adaptation to salinity because they are the main place for the exchange of ions between the body interior and the surrounding water. When shrimp are exposed to salinity stress, they actively try to regulate the ion balance via their gills. However, this is an energy-consuming process. To regulate osmolality, the gills adapt the permeability of their cell membranes to hinder water influx into the cells (Chen et al., 2015).

One of the most important constituents of the gill cell membranes are polyunsaturated fatty acids synthesized by the hepatopancreas. It is interesting to realize that for this reason, hepatopancreas health is linked to osmoregulation via effects on gill tissue composition.

Another natural mechanism to cope with salinity stress is the change of the composition of the hemolymph (“blood”) (Chen et al., 2015). Shrimp can modify the ion concentrations in the hemolymph to adapt to changes in osmolality. This process demands a lot of energy and can lead to side effects in other organs. Most of these mechanisms work well for slow long-term changes in salinity. However, they are easily over-challenged by short-term changes in salinity that may happen within a few hours or even minutes.

How to prevent salinity stress?

Salinity stress can ruin farm profit and animal welfare.

Therefore, shrimp farmers take mostly technical measures to prevent pond flooding or to be prepared

in case of an emergency. Typical recommendations for shrimp farmers are: • Do not build too shallow ponds. The same amount of rain dilutes a shallow pond much more than a deeper pond.

• Design sluice gates to permit draining of excess surface water.

• Build canals to divert rainwater away from the pond.

• Install pumps to be able to exchange water rapidly.

• Stop feeding during heavy rain. When it is over, gradually return to normal feeding.

• After the rainfall, estimate the population weekly to avoid over-feeding of the pond due to undetected mortality.

Apart from these technical measures, surprisingly little is known about a further strategy: how feed manufacturers can help farmers tackle salinity stress.

As recent research work has shown, high amounts of polyunsaturated fatty acids (PUFA) in the diet can help shrimp survive salinity stress (Palacios et al., 2004).

Based on our experiences with Anta®Ox Aqua as a general health-protector and energy safer in shrimp feed (Chuchird et al., 2017, Niyamosatha et al., 2015), we hypothesized that Anta®Ox Aqua can also protect shrimp from salinity stress. To test this hypothesis, a scientific study was conducted by a specialized shrimp aquaculture laboratory (IMAQUA, Belgium). Rapid salinity drop was simulated in a tank environment and survival of shrimp was recorded over time. Before the salinity stress test, shrimp received different diets for 35 days. The control group received no feed additive, the diet of the treatment group contained Dr. Eckel

Figure 1. Salinity drop occurs when heavy rainfall dilutes the pond water.

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42

Figure 2. Survival curve of shrimp during salinity stress test (20 ppt drop). Black squares = Control group without feed additive, Green circles = Treatment group Anta®Ox Aqua.

Anta®Ox Aqua at 800 ppm. Because Anta®Ox Aqua is heat and processing stable, the feed additive was mixed in during the pelleting process. During the feeding phase, shrimp were kept in tanks with 70 individuals per tank and with four replicates (tanks) per treatment group. Feed was offered six times per day.

For the salinity stress test, 40 shrimp per group were transferred to a tank with water with low salinity to simulate a minus 20 ppt salinity drop. The survival of shrimp was recorded every 20 minutes for 360 minutes (six hours).

The results were very promising (Fig. 1). Shrimp which were given Anta®Ox Aqua in their feed survived significantly longer during the salinity stress test than shrimp of the untreated control group.

These latest test results demonstrate that Anta®Ox Aqua is an effective new preventive tool for shrimp feed manufacturers to assist shrimp farmers in their animal health and animal welfare management. The following dietary measure should be taken into consideration to make shrimp more resistant against salinity stress: • Ensure high-quality lipids in the shrimp feed (polyunsaturated fatty acids, PUFA).

• Use high-quality calcium and magnesium salts in the shrimp diet, (high bioavailability, low leaching).

• Support shrimp health by applying specialized feed additives such as Dr. Eckel’s Anta®Ox Aqua.

References available on request

Interesting to know Although it is widely accepted that salinity drop and heavy fluctuations in salinity are a risk for shrimp farms, it is interesting to know that moderate, slow fluctuations (± 5 ppt within 8 days) can have a growth-stimulating effect (Su et al., 2010).

More information: Tilman Wilke Product Developer Dr. Eckel, Germany E: product-development @dr-eckel.de

Anne Möddel Technical Sales Dr. Eckel, Germany

Larissa Kiskel Student Intern Dr. Eckel, Germany

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

COLUMN

Aquaculture and aquafeed production in 2018 Albert G. Tacon, Ph.D. Dr. Albert Tacon is a Technical Editor at Aquafeed.com and an independent aquaculture feed consultant. E: agjtacon@aquahana.com

Updated FAO aquaculture data for 2018 from FAO Aquaculture, Capture and Global production databases.

Top 10 species

Mt

APR

US$ B

Grass carp

5.70

3.68

13.0

Whiteleg shrimp

Top 11-20 species

Mt

APR

US$ B

Striped catfish

2.36 18.4 2.9

4.97 21.3 30.2

Roho labeo

2.02 5.78 3.4

Silver carp

4.79 2.57 10.4

Red swamp crayfish 1.71 35.0 14.4

Nile tilapia

4.52 8.73 8.2

Milkfish

1.33 5.96 2.2

Common carp

4.19 3.12 8.7

Tilapias nei

1.03 11.9 1.8

Bighead carp

3.14 4.48 7.3

Rainbow trout

0.85 3.03 3.9

Catla

3.04 9.41 5.0

Wuchang bream

0.78 3.18 2.4

Carassius sp.

2.77 4.77 5.5

Marine fishes nei

0.77 3.37 2.7

Freshwater f nei

2.54 2.19 4.3

Chinese mitten crab 0.76 7.60 9.6

Atlantic salmon

2.43 5.71 17.1

Giant tiger prawn

0.75 0.97 6.3

Figure 1. Top farmed fish and crustacean species in 2018 (Million metric tons, APR% 2000-2018, US $ billion; FAO, 2020).

Top species (FAO, 2019)

Chinese carp* Tilapia Shrimp Catfishes Marine fish FE crustaceans Salmon Other MFW/D fish Milkfish Trout Eel

Total

Tons (Mt)

APR 2000-2017

14.14 3.84% 6.03 9.4% 6.00 9.6% 5.78 14.20% 3.01 6.44% 2.98 11.38% 2.64 5.41% 2.36 12.40% 1.33 5.96% 0.87 2.99% 0.27 1.32% 45.41 Mt

6.8%

*Excludes 12.99 Mt of silver carp, bighead carp, catla & rohu or 23.9% total fish production in 2018.

Figure 2. Top fed fish and crustacean species production in 2018.

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

$ Billion

Top producer

32.57 11.23 38.48 9.49 12.94 28.36 18.59 11.48 2.19 4.01 2.05

China 89.9% China 26.9% China 34.2% Indonesia 24.3% China 50.1% China 93.8% Norway 48.6% China 67.4% Indonesia 66.0% Iran 20.6% China 86.7%

171.39

45

Top fed species

Tons

% on feeds

EFCR

Feed use T t

Chinese fed carp

14,141 58% 1.7 13,943

Tilapia

6,031

93%

1.7

9,535

Shrimp

6,004

86%

1.6

8,261

Catfishes

5,781

81%

1.3

6,870

Marine fish

3,006 83% 1.6 3,992

Freshwater crustaceans

2,961 58%

Salmon

2,637 100% 1.3 3,428

1.8

3,112

Other misc freshwater FW & D fish 2,358

44%

1.6

1,660

Milkfish

53%

1.7

1,196

1,327

Trout

871 100% 1.3 1,132

Eel

269 98% 1.5 395

Total fed species production Mt

45,406

Total feed estimate

52,741

Figure 3. Top fish and crustaceans fed commercial aquafeeds in 2018 (Thousand tons; FAO, 2020).

Figure 4. Total estimated global compound feed usage by major fed species groups was 52.74 million tons in 2018.

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Functional feed to solve blue coloration in indoor shrimp farming system Li Bing, Liu Rujian, He Zhuliu, Dong Qiufen, Peng Zhidong, Guangdong Nutriera Group

Figure 1. ISFS covered by a transparent roof.

China is known as a traditional shrimp culture country with the largest whiteleg shrimp (Litopenaeus vannamei) production in the world. After more than 20 years of rapid development of shrimp farming, some improved and innovative farming models are available to face the challenges of diseases and environmental protection policies. A novel indoor shrimp farming system (ISFS) is becoming more and more popular in the center and north of China with a highly successful farming rate, high yield and high

efficiency. But a phenomenon called â&#x20AC;&#x153;blue shrimpâ&#x20AC;? is also common there, which is a headache for the farmers. This article describes a functional feed solution to handle this problem.

Indoor shrimp farming system The indoor shrimp farming system in north China is mostly distributed around the Bohai Bay, which belongs to the Shandong, Tianjin, Hebei and Liaoning provinces.

Although different farms differ among each other, the

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

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Table 1. Main details of indoor shrimp farming system.

Stocking

size

Nursery Stocking density Feed period (days) (pcs/m3)

PL5 13-20 500-1,000 Commercial

feeds, artemia, etc.

ISFS has several similar features (Table 1): a) intensive and convenient for management; b) a closed system unaffected by external environmental changes, so it is possible to culture the shrimp the whole year with equipment that maintain temperature; c) better farming performance with higher profits; d) requires good technology and power supply.

Blue shrimp in ISFS Blue shrimp is often observed in ISFS and it has raised a concern that it might be a new vannamei shrimp family trait. Many researchers report that this shrimp coloration happens in ISFS, especially when it is

Culture cycle (days)

Harvest size (g/pc)

70-90

>12.5

Production (kg/m3) 8-12

equipped with an opaque roof and shrimp are fed with common feeds. The phenomenon may not be related to shrimp diseases, but the shrimp is spiritless with softshell. Moreover, the marketing price of the blue shrimp usually is $0.2-0.3/kg lower than the normal color ones, because blue shrimp turn white or pink after being cooked (Fig. 2).

The physical color of crustaceans is showed by the pigment cells. Through the nervous system and hormonal control, the pigment granules of the chromatophore cells can be transported in the shrimp body swiftly by kinesin increasing dark coloration and by cytoplasmic dynein to aggregate, leading to light

Figure 2. Blue shrimp (left) and shrimp after being fed with functional shrimp feed (right).

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Table 2. Water quality in tank A and tank B.

Tank

Total ammonia nitrogen (mg/L)

A

B

Nitrate (mg/L)

pH

DO (mg/L)

0.01

0.10

8.20 4.80

0.05

0.25

7.80

4.50

Table 3. Profit analysis of tank A and tank B.

Tank

Stocking density (pcs/m3)

A

B

Culture cycle (days)

Harvest size (g/pc)

Production FCR (kg/m3)

Price (USD/kg)

Profit (USD/m3)

800

80

20.00 12.50 1.15 16.8 210

800

80

19.50

coloration in microtubules. Astaxanthin is the main pigment influencing the shrimp body color, however, the crustaceans cannot synthesize astaxanthin and they can just obtain astaxanthin from the diet.

Astaxanthin is a kind of ketocarotenoid that is purplish red. It combines with proteins to form a variety of heterodimers and makes different colors such as blue, purple and yellow. Shigeru Okada and his team found there was no significant difference in blue caroteneprotein content between dark-gray and blue-black tiger prawns, but the remaining red carotenoids were about six-fold higher in the dark gray than the blue group.

Our theory was that the occurrence of blue shrimp in ISFS is mainly caused by insufficient astaxanthin content in the shrimp body, together with insufficient light, poor water quality and high stress during farming.

Functional shrimp feeds to solve the blue color Currently, shrimp farmers feed with Artemia or incorporate astaxanthin as a feed additive to supply more astaxanthin and solve the color problem. But both Artemia and astaxanthin are costly and the Artemia supply means a pathology risk.

Nutriera Group has developed one kind of special functional premix 971 for intensive shrimp culture in ISFS. The feed additive adjusts the intestinal health, improves the feed utilization rate and strengthens the absorption and precipitation of astaxanthin. It can be used in feed mills or mixed with shrimp feed in ISFS and it can be added to feed two weeks before shrimp harvest. Handling and environmental conditions such as a suitable light, dark tank background, good water quality and optimal shrimp health also help improve shrimp body color.

12.00

1.20

14.7

176.4

Performance of the functional shrimp feeds A trial was carried out in an ISFS at Huangbi of Hebei Province with a stocking density of 800 shrimp/m3.

Tank A was fed on a feed with premix 971 and tank B was fed on a control diet.

After seven days of culture, the water in tank A turned to light and clean from dark and murky, and the suspended solids, residual feeds and feces were reduced significantly, while the water in tank B remained dark and murky (Table 2).

After three days, 90% of the blue shrimp in tank A turned to normal body color and blue color disappeared after seven days. No change was observed in tank B. After seven days of usage of the functional feed with premix 971, the shrimp body color and water quality were improved significantly. The net profit (Table 3) increased nearly 20% with faster growth, a larger production and higher marketing price.

Acknowledgments The China-ASEAN Fisheries Resources Conservation and Exploitation Fund supported this research project on aquatic functional feeds.

References available on request

More information: Li Bing Researcher Guangdong Nutriera Group, China Contact: Dong Qiufen E: qiufendong@gmail.com

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

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L-selenomethionine: A powerful antioxidant for commercial fish species Marieke Swinkels, Orffa Additives Trials with tilapia in Thailand showed increased performance and high protection against pathogenic pressure.

In intensive animal production, high daily weight gain and high feed efficiency are essential. However, high performance is associated with increased levels of stress. Stress, such as from high stocking density, pathogenic pressure and temperature, is associated with enhanced levels of reactive oxygen species (ROS) and linked to suboptimal antioxidant status. Selenium (Se), in this respect, is a very important essential trace element as it is a vital component of selenoenzymes (e.g. glutathione peroxidase, GPx) which play a role in reducing ROS and maintaining a healthy antioxidant status. A disruption of this steady-state causes tissue

damage due to the interaction of ROS with lipids, proteins and DNA. These negative interactions reduce their metabolic activity.

In order to maintain this steady-state, a continuous as well as optimal selenium supply is essential. However, this can be difficult to achieve when uptake from the diet is impaired when stress is present. At that moment, selenium is in high demand to produce selenoenzymes and combat ROS. Selenium storage inside the animal, in that respect, would be beneficial. This article provides an overview of the scientific literature on the beneficial effects seen with the addition of L-selenomethionine to

Figure 1. The metabolism of L-selenomethionine and other selenium compounds (adapted from Rayman, 2004 and Combs, 2001).

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

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Figure 2. Selenium concentrations in the muscle (mg Se/kg dry weight) of Atlantic salmon fed a fishmeal-based diet supplemented with sodium selenite or selenomethionine at levels of 1 and 2 mg Se/kg feed for 8 weeks (Lorentzen et al., 1993).

the diet focussed on salmon, trout and tilapia.

Results from a recent trial on tilapia conducted in Thailand are discussed.

Maintaining an optimal selenium steady-state: A nutritional solution Selenium can be added to the diet in either inorganic or organic forms (Fig. 1). The advantage of using organic selenium (L-selenomethionine, L-SeMet) over inorganic sources (e.g. sodium selenite or selenate) is its ability to be incorporated directly, without conversion, into general body proteins as a methionine source. L-selenomethionine is the only selenium compound that has this ability. The incorporated selenium, in the form of L-selenomethionine, acts as a storage of selenium in the animal. This stored selenium ensures optimal supply even during stressful periods.

If necessary, the stored selenium gets metabolized to selenide (H2Se) then to de novo selenocysteine (SeCys) and will be incorporated, as the active site, in selenoproteins. Other selenium compounds, such as SeCys and sodium selenite, are not storable but will be metabolized to de novo SeCys. These compounds will be quickly excreted when intake is in excess.

L-selenomethionine will only be metabolized to selenide when there is a need. This form is therefore less prone to excretion and toxicity reactions (Rayman, 2004).

Aquatic protein challenge: A case for L-selenomethionine Traditionally, fishmeal was the preferred protein source in aquatic feeds. Due to limited availability, pressure on wild fish stocks and variable prices, there is an interest in alternative, sustainable protein sources. Plant meals, for example, are suitable alternatives in the growing global aquaculture industry.

However, replacing marine ingredients in fish feed with plant sources changes the nutrient composition of the feed. Selenium concentration of fillets is reported to be highly impacted by high levels of substitution, reducing the added value of fish consumption (Lundebye et al., 2017; Betancor et al., 2016).

Although selenium levels are decreasing within the fish, the demand for selenium to protect against (oxidative) stress remains. Stressors (e.g. environmental, metabolic) are an important issue for the productivity and profitability of fish farms. These stressors may cause increased oxidative damage to lipids, proteins and DNA and increased mineral mobilization from tissues and their subsequent excretion. High stress may, therefore, lead to increased mineral requirements.

L-selenomethionine is a highly available selenium source leading to higher selenium deposition compared to inorganic selenium sources (Fig. 2). It can, therefore, counteract selenium depletion caused by plantbased diets.

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

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Table 1. Growth performance, haematological values and immune parameters of fish fed experimental diets. Note: Values show mean, pooled SEM, n = 90. Values in the same row with different letters differ significantly (p < 0.05). White blood cells (WBC), alanine transaminase (ALT), aspartate transaminase (AST), blood urea nitrogen (BUN), malondialdehyde (MDA), relative percent survival (RPS).

Basal diet

L-SeMet treatments

Sodium selenite

treatments

Pooled

SEM Total mg Se/kg feed 0.68 1.78 3.53 4.90 1.75 3.49 5.00

Weight Gain (g)

40.36 b

53.62 a

47.98 ab

39.34 b

40.51 ab

43.07 ab

39.02 b

2.01

Feed conversion ratio (FCR)

1.77 ab

1.42 a

1.54 ab

1.79 ab

1.75 ab

1.67 ab

1.82 b

0.1

WBC (cells/mm )

2,275.5 ab

2,849.0 a

1,859.8 b

2,109.0 ab

2,109.0 ab

2,026.3 ab

1,887.0 b

108.89

Lymphocytes (%)

39.3 bc

49.7 a

42.6 abc

40.5 abc

48.0 ab

41.5 abc

36.0 c

3.6

ALT (U/L)

22.0 a

17.6 ab

19.67 ab

14.0 ab

16.33 ab

13.4 b

15.0 ab

2.93

AST (U/L)

53.33 a

51.4 ab

50.67 ab

61.67 a

48.6 b

67.5 a

66.2 a

10.3

BUN (mg/dl)

Albumin (g/dl)

Globulin (g/dl)

Total protein (g/dl)

3.33 ab

3.50 a

Cholesterol (mg/dl)

175.67 a

Lysozyme activity (U/mL)

3

2.0 1.0 1.3 1.3 1.7 1.0 1.3 0.27 1.03 ab

1.17 ab

0.93 b

1.00 ab

1.03 ab

1.20 a

1.10 ab

0.07

2.3 2.3 2.1 2.3 2.3 2.3 2.2 0.07 3.03 b

3.27 ab

3.33 ab

3.47 a

3.27 ab

0.15

153.67 ab

125.67 b

159.67 a

157.00 a

161.0 a

152.33 ab

9.31

12.50 d

30.25 a

23.75 b

17.67 c

12.80 d

25.00 b

17.00 c

3.82

Catalase activity (U/mL)

6.67 d

20.00 a

13.13 bc

6.67 d

11.25 c

15.63 b

3.25 d

4.42

Myeloperoxidase (OD at 450)

0.70 d

1.16 a

1.13 ab

1.05 abc

0.83 cd

0.71 d

0.71 d

0.10

Superoxide dismutase (U/mL)

39.19 c

47.81 a

43.65 bc

42.75 bc

42.43 bc

45.66 ab

42.75 bc

2.97

Glutathione peroxidase (mU/mL)

15.13 b

38.91 a

27.23 ab

20.32 b

30.4 a

36.2 a

16.75 b

3.40

MDA (mmol/mg protein)

130.12 a

116.39 a

114.24 a

111.96 a

98.29 a

102.76 a

115.71 a

7.30

RPS (%)

-

84.62 53.85 46.15 30.77 53.85 23.08

Control stress and win!

Dietary selenomethionine supplementation offers a way to reduce performance loss under stress, such as crowding conditions (Küçükbay et al., 2008). A recent study, performed at the Mahasarakham University, Thailand, showed increased performance and high protection against pathogenic pressure. A total of 700 Nile tilapia (initial weight 13.52±0.5g) were fed one of seven experimental diets (in triplicate) in fiberglass tanks for eight weeks. Organic Se (L-selenomethionine, SeMet; Excential Selenium 4000, Orffa Additives BV) and inorganic Se (sodium selenite, Na2SeO3) were each added to the basal diet at 1, 3, and 5mg Se/kg. The basal diet (28% crude protein), without Se supplementation, was used as a control.

The final Se concentration of the basal diet was 0.68mg Se/kg. Organic and inorganic Se supplemented

-

diets contained 1.78, 3.53 and 4.90mg Se/kg and 1.75, 3.49 and 5.30mg Se/kg, respectively.

Fish were fed at 5.0% of their body weight twice a day. Parameters were assessed at the end of the rearing period. After eight weeks, 20 fish from each treatment were challenged with intraperitoneal injection of the virulent Streptococcus agalactiae serotype III at 1x107 CFU/mL. The cumulative mortality was observed for 21 days and the relative percent survival (RPS) was calculated.

Table 1 shows that weight gain (WG) of fish fed SeMet at 1mg Se/kg (total selenium amount: 1.78 mg Se/kg) was significantly higher than that of fish fed a basal diet (p<0.05). Lymphocytes were significantly (p<0.05) higher in fish fed SeMet (1mg Se/kg) compared to fish fed a basal diet. Alanine transaminase (ALT), aspartate transaminase (AST), creatinine, blood urea nitrogen

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

52

(BUN), albumin, globulin and total protein were not significantly influenced by dietary Se supplementation.

Increasing dietary Se level, particularly in the form of SeMet, led to a decrease in serum cholesterol concentrations. Interestingly, the innate immune response (e.g. lysozyme, catalase, myeloperoxidase, superoxide dismutase and glutathione peroxidase) activity was significantly (p<0.05) increased with Se supplementation compared to the basal diet group, especially for fish fed SeMet (1 and 3mg/ Se kg). Malondialdehyde (MDA) in fish serum, on the other hand, was decreased numerically for all supplementation levels. Fish fed SeMet (1mg Se/kg) showed the highest relative percent survival after the challenge with S. agalactiae.

Conclusions L-selenomethionine (Excential Selenium 4000) was tested and validated by independent researchers around the world in peer-reviewed publications (e.g.

Berntssen et al., 2018; Silva et al., 2019) and proven to be effective in increasing the selenium and antioxidant status of fish, even under challenging conditions.

This will result in improved performance and immune function. Very high levels of L-selenomethionine (5 mg Se/kg feed) do not appear to have negative effects on performance nor immune parameters.

L-selenomethionine, therefore, has a good application in fish diets when fish are kept under stressful conditions or in any diets where fishmeal is replaced by plant meals. L-selenomethionine helps to maintain selenium concentration in fish fillets and therefore contributes to the positive healthy image of fish consumption for humans.

References available on request

More information: Marieke Swinkels Central Technical Manager Orffa Additives, The Netherlands E: swinkels@orffa.com

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

53

Metabolomics gives simple answers to ease the exploitation of insect meal for aquafeed Riccardo Melis and Roberto Anedda, Porto Conte Ricerche and Giuseppe Serra, CNR Institute for BioEconomy As the global human population continues to grow, there is an increasing need to provide protein sources to feed the world. In the next decade, aquaculture production is projected to increase to over 30 million tons which means there will be a need for an additional 45 million tons of raw materials for fish feed. To reach these requirements, the aquaculture industry is continuously looking for available alternatives to the conventional marine ingredients (fishmeal and fish oil) used in aquafeed. Currently, most of the fish feed diets are mainly formulated with fishmeal and plantbased feeds, as well as with oils from fish and plants.

However, it is ill-advised to substitute large amounts of fishmeal and fish oil with plant-based material due to its lower palatability, the presence of anti-nutritional components, the high amount of fiber and non-starch polysaccharides and the less suitable fatty acid and amino acid profile (Eurostat, 2016).

Since July 2017 (Regulation N° 2017/893), EU legislation permits feeding processed animal protein (PAP) to farmed fish. In light of this, mass production of edible insect species like the yellow mealworm (Tenebrio molitor L.) is attracting great interest as insect larvae meal can be exploited as a novel animal feed ingredient. Indeed, yellow mealworm larvae have a great nutritional value, mainly due to their high protein and fat content (40-45% and up to 35% on a dry basis, respectively), but also thanks to an amino acid profile that meets human and animals (including fish) requirements and a relevant proportion of dietary fibers, vitamins and minerals (van Huis, 2016).

Another interesting aspect of mealworm rearing is the high sustainability of its production since they can be reared on byproducts and wastes deriving from

the agri-food industrial production. This adds several benefits, including the elimination, or significant reduction, of some problems associated with traditional livestock production (Gahukar, 2016), such as the higher environmental impact and the lower feed conversion efficiency than insect production. However, the variability of the nutritional composition of mealworm larvae is wide and strictly associated to both differences in rearing conditions, as well as in feed substrates and post-harvest processing treatments. Differences in feedstuffs and larval postharvest processing consequently impact the quality of insect meals directed to the aquafeed formulations (Dossey et al., 2016; Melis et al., 2018; Gasco et al., 2019; Melis et al., 2019).

Metabolomics in aquafeeds Recognizing this opportunity, Porto Conte Ricerche (PCR), one of the pivotal players of the Science and Technology Park of Sardinia (Italy), in collaboration with a research group of the Institute for BioEconomy (IBE) (formerly Institute of Ecosystem Study, ISE) of the

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

54

Figure 1. Evaluation of different processing methods (freezing and drying methods) on the molecular quality of yellow mealworm larvae (Melis et al., 2018).

Italian National Research Council (CNR) (Sassari, Italy), undertook dedicated research projects during the last three years on the exploitation of insect meal obtained of yellow mealworm larvae, with a particular focus on their application as aquafeeds.

By collecting and characterizing several potential feedstuffs, among the most promising agri-food byproducts, researchers focus on the optimization of sustainable and profitable mealworm mass rearing.

Moreover, PCR scientists have compared the quality of final meal products, that, when incorporated into fish feeds, would result in better growth performance and high nutritional quality of fish.

PCR researchers have adopted an innovative omic technology named metabolomics which provides qualitative and quantitative characterization of the small molecules (metabolites) within cells, tissues or biofluids. Metabolomic-based investigations have proven to be able to provide important answers to well-known problems of the aquaculture sector (Young & Alfaro, 2016) as well as in the field of applied entomology (Snart et al., 2015).

Results By exploiting a metabolomics approach, scientists have detected relevant differences in one of the most critical operations in insect meal production, i.e. the choice of the post-harvesting processing method (Melis et al., 2018). When subjected to different technological processes of freezing and drying, yellow mealworm larvae evolve into different products

(Fig. 1). It was demonstrated that freezing causes less significant molecular changes.

Whereas, low-temperaturelong time drying processes negatively affect mealworm larvae quality by reducing the amino acid pool and by causing hydrolysis of the triacylglycerols components in the larvae fat. Less severe molecular changes are instead observed in larvae subjected to high-temperature-short time drying treatments.

Overall, both freezing and high-temperature-short time drying were found to have a minimal impact on meal quality, therefore should be preferred to preserve the molecular and nutritional quality of mealworm larvae (Melis et al., 2018).

Within the abovementioned research line, researchers have recently reached another important achievement in the understanding of the best rearing practices of insects. By comparing the dried brewers' spent grains (BSG), the major byproduct generated of the brewing industry (Mussatto et al., 2006), with the more conventional wheat bran (WB), as mealworm larvae feedstuff, they evidenced significantly different feed efficiency and changes in metabolisms of larvae fed the different substrates (Fig. 2).

One facet of this recent study has been the reduced feed conversion ratio (FCR) (weight of ingested feed/ mealworm weight gainedĂ&#x2014;100 expressed on a dry matter basis) and the better efficiency in conversion of ingested food (ECI) (mealworm weight gained/weight of ingested feedĂ&#x2014;100 expressed on a fresh matter basis) of larvae fed BSG than those fed WB. This means that, when using BSG, less feedstuff is needed to produce the same quantity of larvae. Mealworm larvae fed BSG also showed higher protein content and almost half the amount of total fat than those fed WB. Moreover, the fatty acid composition of larvae fed BSG resulted higher in omega-6 and omega-3 polyunsaturated fatty acids (PUFA) and lower in monounsaturated fatty acids (MUFA). This modification introduced by BSG is beneficial for both human and animal feed purposes. Significant differences were also detected

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 3 2020

55

Figure 2. Results of the comparison between BSG and WB as rearing feedstuffs for yellow mealworm larvae.

Asterisks below bars are indicative of the significance level of differentiation among feed efficiency parameters and nutrient levels according to the Studentâ&#x20AC;&#x2122;s t test (* = P value < 0.05; ** P value < 0.01). Diagrams and the flow chart on the right summarize the interrelationship of altered metabolic pathways. For more details see Melis et al., 2019.

in the methylamine, glycerophospholipids and energy/ respiratory metabolic pathways of larvae, indicative of a more efficient body fat mobilization during the growth and easier feedstuff assimilation in the mealworm larvae fed BSG.

Conclusions The new sector of edible insect farming as highvalue food and feed source is rapidly emerging.

The technologies needed to efficiently rear and process insects are still in a starting phase and require dedicated scientific investigations to improve quality and production efficiency. Innovative analytical tools like metabolomics have shown to be able to spot the most relevant physiological responses of yellow mealworm larvae to alternative and high sustainable feedstuffs as well as to discover and highlight the impact of different processing methods on insect meals directed to the aquafeed industry. These results are encouraging and further studies are ongoing both at Porto Conte Ricerche and at the CNR Institute for BioEconomy on the selection and test of more rearing substrates and the characterization of mealworm-mealbased aquafeeds on farmed carnivorous marine fish.

More information: Riccardo Melis Researcher Porto Conte Ricerche Srl, Italy

Giuseppe Serra Researcher CNR Institute for BioEconomy, Italy

Roberto Anedda Researcher Porto Conte Ricerche Srl, Italy E: anedda@portocontericerche.it

References available on request

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