Aquafeed Magazine Vol 15 Issue 3 2023

MARINE-BASED INGREDIENTS

Health management

Feed processing

HEALTH IS AT THE HEART OF OUR CONCERNS

BOOST YOUR BUSINESS BY OPTIMIZING YOUR HEALTH ADDITIVE STRATEGY

RESTRICT inappropriate use of antibiotics and chemicals

REDUCE losses from subclinical disease and outbreaks

INCREASE economical and ecological sustainability

BOOST feed perfomance and farm productivity

MAINTAINING PERFORMANCE OF SHRIMP FEED DURING FISHMEAL & OIL CRISIS

How nutritional strategies can relieve cost pressure.

PLANT EXTRACTS AGAINST AHPND 30

Plant extracts have shown promising results to limit Vibrio infection in aquaculture.

CHALLENGES AND OPPORTUNITIES FOR EXTRUDED AQUAFEED 51 Challenges to optimize feed costs and opportunities to optimize production and quality control.

CONTACT US

Editor/Publisher: Lucía Barreiro

Consulting Editor: Suzi Dominy

Technical Editors:

Peter Hutchinson, Albert Tacon, Ph.D

Assistant Editor: Marissa Yanaga Conferences and webinars: info@aquafeed.com

Advertising enquiries/request media pack: sales@aquafeed.com

info@aquafeed.com

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INTERVIEW with Chris Stock

Here in the US, we are a leading supplier of aquaculture feeds along the East Coast and into the mid-west region where the market is dominated by warm and coldwater finfish production. There also is an interesting and active segment of RAS fish and shrimp producers in North America that Zeigler has been supporting for many years now.

A lot of our focus is on the shrimp hatchery industry. Zeigler has been involved with shrimp hatcheries since around the time of their commercial inception in the Western hemisphere. Today, Zeigler’s shrimp hatchery diets can be found in every shrimp-farming country in the world with just a few exceptions.

In the early years of the industry, we exported volume grow-out diets around the world. As the need for more locally produced feeds became evident, Zeigler adapted by creating our technology transfer program. This turn-key program has allowed Zeigler’s formulas, technology and brand to continue to contribute to growout production throughout the world. Today, we have five different active technology partners and Zeigler products are currently being produced in North America, South America, Africa and Asia.

AQ: One of the main Zeigler markets is shrimp feeds. How do you see current Asian industry issues and how Zeigler is supporting them?

AQ: Zeigler was founded in 1935 as a livestock feed supplier and moved to aquafeeds in 1967. Where is the company today in terms of size and markets served?

CS: Zeigler’s first aquaculture feeds were produced for trout around 1955, so we are approaching 90 years in business and 70 years in the aquaculture industry. The company transitioned to a specialty feed producer when Dr. Tom Zeigler became the 2nd generation owner and today, we remain a very unique feed company even within the aquaculture industry.

CS: In Asia, we see feed-related challenges at the hatchery level which can exacerbate disease problems on the farm. At the top of the chain, the industry is investing in genetics through high-quality imported broodstock, but things can unravel shortly thereafter. Some hatcheries feed their SPF broodstock contaminated live and fresh feeds, immediately breaching the biosecurity. There are wellmanaged hatcheries that evolved beyond this, but there are still many that have not implemented biosecurity programs that adequately provide protection from the well-documented risks of using locally sourced live and fresh feeds. Pathogen screening programs are important but it is impossible to test every wild polychaete, oyster, etc. for disease. This leaves a gap that allows pathogens through. Once in the hatchery, pathogens like bacteria and microsporidians such as EHP quickly spread. Today, there are very good manufactured broodstock diets and biosecure sources of live feeds

Chris Stock is Global Director –Aquaculture Sales, at Zeigler Bros., Inc.

available as alternatives to risky live and fresh feeds. We need broader adoption of them for the benefit of the entire industry.

At the larval-rearing phase, we see problems emanating from the adoption of cost-cutting tactics in response to stagnant PL prices. It’s problematic that as all other costs have risen, PL prices have not. Unfortunately, a common response to this price crunch is the increased use of low-cost feeds. The low-cost formulations have poor conversion rates and thus water quality becomes more of an issue while animal robustness is simultaneously compromised by decreased nutrient uptake.

All of this occurs against the backdrop of improved growth rates. It is Zeigler’s observation that PL harvest weights have increased by as much as 40-60% over the past 15-20 years. We think this has equated to an increase of 30-50% in total feed used in the hatcheries during that time. What happens when increased feeding rates compound with users adopting lower-quality feeds? One result is more waste to fuel Vibrio proliferation. Current research indicates that Vibrio is associated with outbreaks of disease in hatcheries and farms including white feces disease in ponds. There is a lot of opportunity to mitigate these problems at the beginning of the supply chain.

AQ: One of Zeigler’s shrimp hatchery developments is liquid hatchery feeds. How is the market acceptance?

CS: We’ve been making liquid hatchery diets for just under three decades. We have learned a lot in that time and today they are flagship products for us. In fact, we just launched EZ Artemia Ultra, a 3rd generation product that leveraged all this research and commercial experience to make the best product yet.

Liquid feeds have many advantages including high nutrient availability (digestibility), stability (water quality) and accessibility (buoyancy) which are some of the fundamental benefits over traditional dry diets. Now more than ever, we see liquid diets as excellent vehicles for delivering probiotics directly to the larval gut. Acceptance of liquids remains well behind dry diets but in some markets, you will find widespread adoption. Zeigler has different formulations for different needs so usage depends on the purpose and the market preferences. We do have many who have significantly cut or entirely replaced their Artemia usage. There is no such thing as an Artemia requirement for vannamei larvae. On the other hand, larvae do have requirements for individual nutrients. Our liquid diets meet or exceed larval

nutrient requirements. For example, lipid and fatty acid levels far exceed levels supplied by Artemia nauplii.

AQ: Zeigler also offers feeding systems and services. What markets does Zeigler service and how does Zeigler differentiate itself from other manufacturers?

CS: Zeigler currently deploys technical representatives to all major shrimp hatchery markets. We visit hatcheries worldwide on a daily basis. This provides opportunities to deeply understand challenges and opportunities and share the latest strategies and technologies with our growing list of friends and clients around the world. Information from visits and data from field trials are shared within the company, guiding and directing our R&D efforts. In Florida, we maintain a robust research and development platform where fundamental and applied studies are carried out in highly replicated experimental systems. It is this platform that provides the foundation for our robust product development and improvement efforts which run 24 hours a day, seven days a week.

AQ: How about fish feeds? How do you see the RAS arena?

CS: RAS systems have been here in the US for a long time and we’ve been servicing these operations all along. We do make specialized diets for RAS systems for both fish and shrimp. Zeigler has invested heavily in research on RAS shrimp feeds. Our HI2 diet is a specialty feed designed for these systems where protein conversion efficiencies drive growth at super-intensive densities upon which profitability depends. The diversity of species produced in RAS systems has given us a lot of experience over the years. Of course, there is a lot of talk about the future of RAS in the US and our location is near major metro areas like New York, Philadelphia and Washington DC, which the RAS markets want to serve. Clearly, engaging with RAS producers and collaborators in academic institutions is a priority for us to stay ahead of the curve on RAS industry needs and potential.

AQ: Is Zeigler currently utilizing novel ingredients (insects, SCPs, etc.)? What are Zeigler's sustainability goals in the short and medium term?

CS: Quality ingredients are the key to quality feeds. Our access to quality raw materials from US farmers and our access to a wide array of ingredients enables Zeigler to consistently produce the highest-performing aquafeeds. One of the keys to the sustainability of Zeigler feeds is our

proximity to the highest quality agricultural commodities. In fact, for our RAS shrimp diets, about 60% of total feed ingredients are sourced from within <200 miles of Zeigler’s production site and none of our ingredients are associated with deforestation. Greater than 90% of Zeigler’s diet composition is sourced from ingredients produced in the USA. A hundred percent of our marine ingredients come from MSC-certified fisheries or as byproducts from existing fisheries value chains. A powerful way to reduce aquaculture’s global footprint is to improve feeding efficiencies. Increased feed efficiencies have been and continue to be a key objective for Zeigler. Ultimately stainability has to be a winwin increasing both profitability and environmental responsibility through investment in high-quality feeds and precision feeding systems.

Zeigler is continuously evaluating all types of new ingredients. With our reputation for innovation born from the early development of stable forms of vitamin C, innovators and ingredient suppliers worldwide are represented in our powerful ingredient databases.

We remain on the lookout for both cost effective quality alternatives that reduce demand on marine ingredients and new supplements that responsibly and effectively contribute to improved performance and animal health. At our research laboratories, we continually carry out both internal and contract research on ingredients to generate high-quality data upon which effective formulation decisions depend.

AQ: Zeigler runs an Aquaculture Research Center (ZARC) together with Florida Atlantic University. What does this center add to the company’s capacities? What are the current projects you are working on?

CS: ZARC is our hub for innovation in the areas of shrimp nutrition and health. The facility is designed around several highly replicated systems including larviculture tanks as well as grow-out and broodstock tanks. ZARC’s success centers on both a rigorous management program that allows us to produce powerful statistical analyses on our studies and an amazing team that ensures our trials are run in a highly professional manner. As an example, we’ve been successfully able to measure FCRs in larval stages which are invaluable when designing the next generations of larval diets.

The research done at ZARC is always looking at new things but of course, evaluating our current formulas,

new ingredients and additives as well as potential new formulations and products takes up a lot of the time and space we have available. We have also selectively opened up ZARC for some contract research work as well.

AQ: As mentioned before, Zeigler also offers a technology transfer program. Would you tell us how it works and what are the current partnerships?

CS: Our technology transfer program works with foreign companies to establish highly successful local feed mills. The program begins with engineering, designing or adapting the production facilities of an operation to meet the partners’ goals and local market opportunities. It then focuses on every aspect of running a mill. Zeigler’s nutrition and R&D teams design and manage formulas and new products for the local market, while our QA and operations teams ensure the mill remains efficient and product quality is consistent and up to our high standards. Making good feed is a requirement because the Zeigler name is on every bag made by our local partners and if they are not successful then neither are we.

This program has been a strategically important part of our business and brand for nearly three decades, so we have a very experienced team who oversees it. In that time, we’ve had 11 different partner mills in eight different countries. Today, we have five active partnerships producing shrimp and/or fish feeds in Mexico (2), Ecuador, Egypt and India.

AQ: What are Zeigler’s projections for growth going forward?

CS: I anticipate we’ll focus on continuing to grow sales of shrimp larval and maturation diets and I believe we will leverage these abilities to also bring new products to the fish hatchery market in the future. Much of our growth will likely continue to come from new sales channels and clients overseas, but we support the expansion of the US aquaculture industry and hope to see a greater opportunity for growth in this market as well.

One thing I am most confident about is that Zeigler’s unique company culture which emanates from our size, longevity and continuous family ownership will allow us to continue to differentiate from the competition with not only the products we provide but the way we serve our clients.

NEWS REVIEW

Highlights of recent news from our website Aquafeed.com

CPM acquires IDAH

Engineering specialist CPM acquired IDAH, a move that unites two industry leaders behind a shared mission to sustainably feed, fuel and build a better world. The acquisition of IDAH enables CPM to make inroads in markets where the company has growth ambition. “Specifically, IDAH has great strength and presence in the aquafeed and pet food markets with strong relationships with customers in the Southeast Asia and China markets. IDAH joining CPM is a

Kemin AquaScience unveils feed additive to support shrimp health in Asian countries

The company has launched Pathorol™, a shrimp supplementation product that improves the health of shrimp hepatopancreas, for customers in India, Thailand, Vietnam, Indonesia and Singapore. It is a patent-pending product developed to support a healthy hepatopancreas and digestive system for shrimp and aid in maintaining healthy shrimp throughout their growth cycle. Pathorol is a unique blend of phytogenic compounds that have been shown to enhance the performance and productivity of pond-raised shrimp.

DSM and Firmenich merge to form a nutrition, health,

A-Systems signs partnership to expand to South Asia

Animal feed formulation software supplier, A-Systems, signed an agreement with Dr. Amit Das to distribute A-Systems products to animal feed producers in South Asia. With this partnership, A-Systems aims to strengthen its position in South Asia – India, Bangladesh, Nepal and Sri Lanka.

DSM and Firmenich launched the new company dsm-firmenich that brings together one of the largest innovation and creation communities in nutrition, health, and beauty. dsm-firmenich is organized into four distinct high-performing businesses, rooted in complementary world-class scientific research and manufacturing excellence: Perfumery & Beauty; Taste, Texture & Health; Health, Nutrition & Care; and Animal Nutrition & Health.

Bühler develops new generation of grain cleaners

Bühler unveiled the next generation of its TAS grain cleaning system, the TAS LAAC. The latest model comes with a range of new features, including a remote control for the machine settings and the introduction of ultra-reliable sensors. Its instant compatibility with Bühler Insights allows for advanced trend analysis and much more.

Feed companies updates

New facilities

De Heus Animal Nutrition is building a new aquafeed plant in Njeru, near Jinja, Uganda. This state-of-theart facility will be the first dedicated aquafeed plant in Uganda.

Two fish processing companies, United Fish LLC and Seapride LLC, signed a partnership to establish a USD 20 million aquafeed mill at the Fisheries Zone in Duqm, Oman, with a production capacity of 60,000 tons of shrimp and fish feeds.

Pilmico and Gold Coin, the food and agribusiness subsidiary of the Aboitiz Group, will be allocating PHP 2.83 billion (USD 51 million) in the next 12 months, mainly for its international feed mill expansions in Long An, Vietnam and Yunnan, China.

Bunge and Viterra close deal to merge

Bunge has entered into a definitive agreement to merge with Viterra in a stock and cash transaction. The merger of Bunge and Viterra will create an innovative global agribusiness company well-positioned to meet the demands of increasingly complex markets and better serve farmers and end customers.

Norway approves Aquaterra omega-3 oil for use in aquafeed

The Norwegian Food Safety Authority’s (NFSA) approved Aquaterra® omega-3 canola oil for use in fish feed applications. “Norway has always been a target market for Aquaterra omega-3 oil, and we are excited about the positive contribution to the industry,” said Benita Boettner, global general manager of Nuseed Nutritional.

BioMar Group unveiled the expansion of the marine hatchery trial facilities at their Aquaculture Technology Centre (ATC) Hirtshals in Denmark that will include units dedicated to larval rearing and live feed production to test hatchery feeds for several marine species.

New aquafeeds on the market

Aller Aqua, in partnership with premix specialist VDS, developed a range of aquafeed products that are specifically designed for use in shrimp RAS systems. Skretting introduced a new, innovative feed, Elevia, engineered to offer superior nutrition and water quality in shrimp hatcheries and nurseries. The company also launched Skretting 360+, a complete package of precision-based tools and services, to increase Mediterranean aquaculture’s competitiveness.

ADM launched a functional feed to support fish performance under seasonality variation with hot temperatures, which may cause challenging environmental conditions and disease risks to surge.

Peru cancels first anchovy season

After analyzing the recommendations of the Peruvian Sea Institute (Imarpe), the Peruvian Ministry of Production (Produce), Raúl Pérez Reyes, announced the cancellation of the first anchovy fishing season in the North-Center region. Imarpe concluded that there are no biological conditions for the extractive activities.

Nutrition Technologies signs distribution agreement in Japan

Nutrition Technologies signed an MoU agreement with Sumitomo Corporation that allows the corporation to distribute Nutrition Technologies products into the Japanese market. The company currently ships industrial volumes of material throughout Europe, Asia and South America, from its two-hectare factory in Malaysia.

Adisseo names new CEO

Hao Zhigang, chairman of Adisseo's board of directors for more than five years, was named chief executive officer following the retirement of Jean-Marc Dublanc from his operational duties at Adisseo. This succession ensures a smooth transition to maintain and strengthen Adisseo's strategy and organization.

Wenger.com

The Future Awaits

Built on partnership and innovation, Wenger is providing more opportunities for client success.

For almost a century, Wenger has delivered extrusionbased innovations to our partners. We’ve worked alongside you to develop new processing solutions and better products, providing our industry-leading expertise and ongoing support every step of the way.

We don’t plan on stopping any time soon.

Wenger’s global food processing family is growing, and we look forward to the exciting opportunities that lie ahead. We will continue to deliver even more innovations and technologies to benefit companies that share our vision of tomorrow.

F3 Krill Replacement Challenge

The F3 (Future of Fish Feed) recently launched its fourth contest – the F3 Krill Replacement Challenge – to find substitutes for krill in aquafeed. Krill is a popular ingredient in aquafeed where it is often used as an attractant, palatant and potentially for its nutritional benefits. The F3 judges will select ten registrants with the most commercial promise that meet the challenge rules to compete for the USD 100,000 prize. So far, the following companies have registered – Agri-King Nutrition, Aqua Management Technologies, Bioiberica, Calysseo, dsm-firmenich, eniferBio, Entobel, Guangdong Evergreen Feed Industry Co., Jiangsu Fatide Biotech, Protenga, Revolgene Labs and Sotup, with several looking for industry partners.

A wide variety of marine life depends upon these tiny shrimp-like crustaceans at the base of the marine food chain including whales, penguins, and commercially important wild fisheries such as salmon, rockfish, squid, and sardines. Sharp declines in Antarctic krill densities have occurred in recent years, which are thought to be the result of climate-induced changes in ocean temperature, currents, acidification and regional overfishing.

The commercial krill fishery located in the Antarctic has steadily increased production over the last decade from a high of 200,000 tons in 2010 to 450,000 tons in 2020. The rapidly expanding industrial fishery raises important sustainability concerns, especially due to climate change. Reducing dependence on wild-caught marine ingredients, such as krill, by substituting with more sustainable ingredients can help future-proof seafood supplies meet the global seafood demand and ensure the resiliency of marine ecosystems.

Prior to launching the contest, the F3 Team conducted a preliminary comparative feeding study in Atlantic salmon to evaluate whether a krill replacement challenge could be designed based on the performance of Salmo salar during 90 days of feeding. Two prerequisites were needed to hold the challenge: (1) a plant-based feed with krill (positive control) needed to perform as well as a fishmeal control; and (2) that a plant-based feed without krill did not perform as well as the two

controls above. The results confirmed that there existed a base feed that needed krill to perform as well as a fishmeal control. Using this base feed, the F3 Team could add each of the different challenge entrant’s krill replacements so that each entrant’s feed performance could be compared against each other and against the controls.

Methodology and experimental design

The Challenge Host will be responsible for the proper conduct of the experiments in consultation with the F3 Team, judges, and the scientific review committee. The trial will consist of up to twelve treatments: two controls and up to ten entrant experimental feeds. All treatments will be fed to Atlantic salmon in replicate tanks for 12 weeks. Throughout the trial(s) weight gain, survival and feed conversion ratio will be measured. The treatments have the following labels and compositions:

Control diets

1. Krill Negative Control (KNeg) = F3 plant-based feed* + 0% krill (5% wheat flour added)

2. Krill Positive Control (KPos) = F3 plant-based feed* + 5% krill

Experimental treatment diets

F3 plant-based feed* + up to 5% F3 Krill Replacement from entrants. If <5% inclusion is requested by the entrant, the F3 chief scientific officer will work with the entrant and feed manufacturer to determine how to make up the remaining composition, likely with wheat flour. Table 1 shows the formula for the experimental treatment diets.

All treatments will undergo the same protocols, including feeding regime, water quality monitoring, growth and survival measurements. Protocols and growing conditions for the challenge trial will be similar to those implemented in the preliminary comparative feeding study.

Winner determination

The prize will be awarded to the entrant(s) whose F3 Krill Replacement demonstrates the best “performance”

*The F3 (fish-free feed) plant-based feed includes 6% poultry blood meal as an essential amino acid source. The F3 Team defines “plant-based” as consisting mostly of plant materials, with a small amount of (non-marine) animal protein included.

FEED CHALLENGE

during the challenge trial based on differences that are statistically significant. “Performance” is defined by a combination of weight gain, feed conversion ratio and survival observed during the challenge trial. It will be measured by assessing statistical rather than numerical differences across treatments using the following metrics: Weight Gain: Fish for all treatments will have an initial weight that is not statistically different. Fish weight gain will be expressed in terms of percentage weight gain with respect to the Krill Positive group, e.g. 90% of KPos, 110% of KPos. Weight gain is defined as the percentage increase of the animal’s initial body weight. The experimental treatment that has the greatest increase in fish biomass is likely to win. Any mortality events are factored into this method.

Feed Conversion Ratio & Survival: In the case of a statistical tie in weight gain, the winner will be selected by the Challenge judges factoring in the best (lowest) Feed Conversion Ratio (FCR) and (highest) survival rate.

Table 1. Formula of the experimental diets

for the F3 Krill Replacement Challenge is open until August 31, 2023. For more information on the preliminary comparative feeding study and the F3 Krill Replacement Challenge, visit f3challenge.org or contact the F3 Team at f3krillreplacement@gmail.com

Lysophospholipid-based digestive enhancer to maintain the performance of shrimp feed during fishmeal and fish oil crisis

Waldo. G. Nuez-Ortín, Marleen Dehasque, Martin Guerin, Adisseo SAS

Background: The need for nutritional strategies to relieve cost pressure from high fishmeal and fish oil prices

Global fishmeal and fish oil prices are, to a large extent, linked to the supply situation in South America (Peru and Chile) and demand from Asia (primarily China). Peru is the largest source of fishmeal and fish oil output today and the world’s largest producer and exporter of fishmeal and fish oil. An unsuccessful season in Peru might cause as much as a 20% decrease in global output. Given the quota size and the potential impacts on the stock from this year’s El Niño, Peru has recently canceled the first fishing season for anchovy in the north-central zone, creating new challenges for the global market of fishmeal and fish oil. The cancellation of the Peruvian anchovy season will inevitably increase feed prices, thus aquafeed producers must prepare to use nutritional strategies to reduce the inclusion of fishmeal and fish oil while maintaining the performance of shrimp feeds.

AQUALYSO®, a lyso-phospholipid (LPL) based digestibility enhancer developed for application in fish and shrimp, is proposed as a solution to relieve cost pressure from fishmeal, fish oil and lecithin prices. LPLs are produced by the controlled hydrolysis of phospholipids in soybean lecithin. LPLs have long been recognized for their excellent emulsifying properties, which are due to their mixed lipophilic and hydrophilic characteristics that allow them to interact closely with both water molecules and lipidic molecules. The superior emulsifying properties of LPLs boost the digestion and

absorption process of lipids as a source of energy, as well as of essential lipidic molecules such as poly-unsaturated fatty acids, cholesterol, and fat-soluble vitamins A, D and E. Additionally, LPLs improve the transport and processing of lipidic nutrients in shrimp hepatopancreas. Such metabolic optimization is also key in supporting the reduction of fishmeal, fish oil and lecithin in aquafeeds. A growth trial was conducted to investigate the benefits of LPL-based AQUALYSO in shrimp feed formulated with reduced proportions of fishmeal and fish oil.

Experimental setup: Lyso-phospholipid supplementation to reduce the inclusion of fishmeal and fish oil

Four isoproteic and isolipidic experimental feeds were formulated and are presented in Table 1. Two control feeds containing 1% lecithin were designed with either high or low fishmeal and fish oil inclusions: high fishmeal/fish oil diet (HIGH FM/FO: 20%FM, 3%FO) and low fishmeal/fish oil diet (LOW FM/FO: 7%FM, 1%FO). LPL-based AQUALYSO (AQL) was supplemented at 0.1% into both formulations: HIGH FM/FO +0.1% AQL and LOW FM/FO +0.1% AQL. Cholesterol levels were found at 0.12% and 0.05% in high and low fishmeal/fish oil diets, respectively. Sinking shrimp pellets were produced using a mincer with a 2mm diameter die, dried in an oven at 60°C, and stored at -20°C until use. The four experimental feeds were randomly assigned to 12 tanks (300L, 3 replicates per treatment) in a close recirculation system.

Twenty shrimp (2.39 ± 0.02g) were stocked in each tank. The water temperature of the rearing system was controlled at 28 ± 1°C. The shrimp were fed to 6% of their wet weight 4 times per day at 07:00, 12:00, 17:00 and 22:00. Shrimp were weighed once every 2 weeks and half of the rearing water was exchanged at the same time. Shrimp were fed the experimental diets over 8 weeks. At the end of the feeding trial, the shrimp were bulk weighed to calculate growth performance. Data were assessed for normality and variance homogeneity using the Kolmogorov-Smirnov test and Bartlett’s test, respectively. The results were analyzed by a one-way analysis of variance (ANOVA). When the ANOVA identified differences among the groups, multiple comparisons were made among the means using Duncan’s multiple range test. Statistical significance was determined by setting the aggregate type I error to p<0.05.

Results: Lyso-phospholipid supplementation improves the performance of shrimp feeds with reduced levels of fishmeal and fish oil Supplementation of the lyso-phospholipid-based AQUALYSO supported feed intake and growth performance of shrimp fed high as well as low levels of cholesterol in the feed (Fig. 1). Feed intake significantly

improved by 13 and 21% with supplementation in the high and low fishmeal/fish oil feeds, respectively. The best growth effects were found in the high fishmeal/ fish oil feed supplemented with the additive, showing significant improvements of 16% and 11% in weight gain and specific growth rate (SGR), respectively. A similar pattern was observed in the low fishmeal/fish oil fed; with supplementation, the numerical improvements were 10% and 8% in weight gain and SGR, respectively. More interestingly, supplementation in the low fishmeal/fish oil feed matched the performance of the high fishmeal/fish oil feed, proving the efficacy of AQUALYSO to reduce formulation costs while maintaining the performance of a high-quality feed. Additive supplementation did not significantly affect feed conversion efficiencies of the diets containing high and low fishmeal/fish oil levels. Neither fishmeal and fish oil levels, nor additive supplementation affected survival, which averaged 76% across all treatments. It has been previously demonstrated that 0.1% AQUALYSO can successfully replace 0.75-1% lecithin of a control feed containing 2% lecithin (Lin et al., 2021). In the present study, an average amount of 1% soy lecithin was added to all diets to satisfy the minimal phospholipid requirement for shrimp (NRC, 2011).

Under such formulation strategy, the similar growth

Table 1. Formulation and composition of the experimental diets

*includes 15% fermented soybean meal, 8% corn starch, 10% alpha-starch, 7% squid liver meal, 1.5% choline chloride, 1% vitamin premix and 2% mineral premix.

MARINE-BASED INGREDIENTS

(Li et al., 2019; Liu et al., 2019). In salmon, a recent publication showed that LPLs accelerate the absorption and transport of nutrients in the intestine as well as the processing of nutrients in the liver (Ibarz et al., 2023).

In summary, we demonstrated in this present study that 0.1% AQUALYSO improves the performance of a shrimp feed formulated with low levels of fishmeal and fish oil (respectively, 7 and 1%), making it comparable with that of a control feed containing 20% fishmeal and 3% fish oil. Given the imminent need to further reduce fishmeal and fish oil inclusions in shrimp feeds, LPL supplementation seems an effective strategy to optimize the feed cost and performance of shrimp feeds.

The Aqua Nutrition Platform by Adisseo continues to combine species-specific research on AQUALYSO application strategies and formulation experience while providing services related to feed formulation and processing.

References available upon request

performance between the high fishmeal/fish oil feed and the LPL-supplemented low fishmeal/fish oil feed can be attributed to the additive effect to improve digestive emulsification and promote a more efficient absorption and utilization of essential nutrients such as cholesterol. Previous studies in fish, such as with turbot and channel catfish, have also reported a positive effect of LPL supplementation that is believed to be linked to better absorption and utilization of essential lipidic nutrients

More information:

Martin Guerin Regional Technical Manager Aquaculture APAC/ISC Adisseo

E: martin.guerin@adisseo.com

Figure 1. Effects of dietary lyso-phospholipid based digestive enhancer (AQUALYSO ®, AQL) on feed intake (A), weight gain (B) and specific growth rate (C) of white shrimp fed diets with high fishmeal/fish oil (HIGH FM/FO) or low fishmeal/fish oil (LOW FM/FO). Bars with different letters indicate significant differences (p<0.05).

How can we contribute to build a sustainable aquaculture model?

Gwénola Jan Lafage, Symrise Aqua Feed

A circular economy model helps address three principles: reduce waste, circulate products, and regenerate nature.

Today, there are various questions to address from how to tackle global challenges, such as climate change, biodiversity loss, resource depletion, water scarcity, waste, and pollution, to how to build a resilient model, good for business, people, and the planet. The circular economy model helps address these stakes by applying three principles: reduce waste, circulate products, and regenerate nature (Ellen Macarthur Foundation).

Circular economy

Symrise Aqua Feed specializes in developing, testing, and manufacturing sustainable ingredients and palatability enhancers that help aquafeed manufacturers produce high-performance diets and feed with a low carbon footprint. The company employs a circular model

to bring marine co-products to their highest value. This helps the industry tackle challenges for more sustainable aquafeed. Here we discuss how their solutions can create value for the aquaculture industry (Fig. 1).

Symrise Aqua Feed’s activity forms part of a virtuous model. It collects organic leftovers from the fish and shrimp processing industry, and circulates valuable products along the aquaculture value chain, participating in nature regeneration. This sustainable life cycle of the products comes with a low carbon footprint (Fig. 1).

100% co-product raw materials

According to the Food and Agriculture Organisation (FAO), about a third of all food produced around the

Figure 1. The circular model at Symrise Aqua Feed helps the industry tackle challenges for more sustainable aquafeed.

globe is lost or wasted. It seems simply unthinkable to continue to lose so many valuable nutrients.

Symrise Aqua Feed collects raw materials such as shrimp heads, tuna viscera, tilapia heads and bones or other marine byproducts, which are not used for human consumption. At the same time, these wastes contain many precious proteins, which may have been previously discarded. The company collects more than 30,000 tonnes of these byproducts annually in its three manufacturing sites in Costa Rica, Ecuador and Thailand. These sites are located next to the plants where fish and shrimp are processed, guaranteeing the freshness of the raw material. The locations also help optimize the logistics and minimize the carbon footprint of the raw material transport.

Symrise Aqua Feed ensures that all suppliers follow the principles of responsible and sustainable sourcing, building on our Supplier Code of Conduct and program of certification. Also, by using byproducts, fewer wild stocks need to be caught, which would otherwise go into the fish feed. Incidentally, it reduces the pressure on marine resources.

The process, optimization of nature

The processing and transformation to increase the functional value of the byproducts is possible thanks to worldwide knowledge acquired over the past two decades. Symrise Aqua Feed masters enzymatic hydrolysis, aiming at highly standardized hydrolysates in

liquid and powder form, with multiple benefits such as nutrition, palatability, and health.

Likewise, the company minimizes the environmental footprint of its industrial activities. To reach carbon neutrality from 2030 onwards (scope 1&2), it mobilizes people, measures energy and water metrics, improves the manufacturing process and defines plans for the coming years. As an example, all Symrise plants have implemented operational optimization for reducing energy and water consumption with defined quick wins and best practices sharing.

Following the objective to value any single fraction of byproducts, it also pays attention to its own organic waste. The waste amount varies from 1-25%, according to the level of the solid fraction in the raw material. There is a valorization of left-over materials in the feed chain as much as possible, with further processing into fish or shrimp meals. When the process into a meal is not the best option, other alternative solutions come into play, such as composting with anaerobic digestion. Doing such valorization, Symrise Aqua Feed reduces as much as possible landfilling or incineration. Overall, it is always seeking to find the highest value of fish and shrimp byproducts.

Combined benefits on palatability, nutrition, and health in aquafeeds

The ingredients used in aquafeeds help substitute fishmeal, enhance feed palatability, standardize fish and

Figure 2. An example of a fish feed formulated with a Symrise Aqua Feed hydrolysate manufactured from shrimp head meal. A hydrolysis process produces a highly palatable product with higher protein quality than the classical meal processing method. This allows for the inclusion of less marine protein in the fish feed while using novel protein sources and growing more fish with the same quantity of marine raw materials.

MARINE-BASED INGREDIENTS

feed performance by reducing deviation, and enhance fish health status and fish resistance to environmental and pathogen challenges. With better digestibility and better absorption, the ingredients help reduce “fish in” while maximizing “fish out” ratios (FIFO)(Fig. 2).

There is also the raising of awareness of the reduction of plastic waste by customers. To do so, an action has been set up to move to large packaging such as bulk for the liquid and big bags for the powder. In this area, Thailand’s site is also partnering with Second Life, a social enterprise that empowers local communities to operate long-term socio-environmental projects. In 2022, 75 tonnes of plastic waste were collected and recycled in Thailand.

Sustainable aquafeed for sustainable farming

The zootechnical performance of Symrise Aqua Feed’s ingredients is proven in Aqualis, performance measurement centers, as well as by scientific partners and in aquaculture farms. While guaranteeing high performance, the ingredients also help reduce the environmental impacts of aquaculture. With high palatability, the company ensures high feed consumption while reducing feed waste. With good nutrition, it improves the whole feed digestibility to reduce the release of non-digested feed in the environment and improve FIFO. With health benefits

thanks to bioactive compounds, it enhances resistance to stressful events, improve gut health, increase survival, and helps reduce synthetic inputs.

Conclusion

Using this circular model, Symrise Aqua Feed produces ingredients with a low carbon footprint and high positive social impact. Societal aspects are likewise crucial for the company. It implements local initiatives to promote health at work. Furthermore, safety is the number one priority in daily operations.

In a nutshell, Symrise Aqua Feed is fully embedded in a circular economy model and committed to reducing its environmental footprint. The company gets the best value from fish and shrimp byproducts and participates in improving the aquaculture supply chain, sustainably.

Reference available on request

More information:

Gwénola Jan Lafage

Quality, Regulatory & Sustainability Manager

Symrise Aqua Feed

E: gwenola.jan-lafage@symrise.com

Effect of krill protein hydrolysates on the appetite and growth of salmon and shrimp

For many years, fishmeal has been the main ingredient in feeds for carnivorous fish species and marine shrimp. The main reason was that the nutritional requirements of these species were not well known, and a fishmeal-based diet would produce good results in growth and survival. However, the total world production of fishmeal has been stagnant for many years, while aquaculture and livestock production has steadily increased, putting strong pressure on marine ingredients. For many years, researchers have investigated the nutritional requirements of each aquacultured species, and the substitution of marine ingredients by other non-marine proteins. We now know the amino acid requirements of most aquatic organisms as well as the ideal protein/energy ratio in their feeds, so in theory, we could now produce

feeds with 100% alternative (non-marine) ingredients that would cover the nutritional requirements of the species. However, in practice, when you substitute 100% of the marine ingredients in the feed, even though you formulate it to have the same amino acid profile and protein/energy ratio, you don’t get the same good results as if you used some marine ingredients in the feed.

One reason is that marine ingredients such as fishmeal contain elements and compounds other than just amino acids (micronutrients, nucleotides, carnitine, and phosphorus, just to mention a few). This can be solved by adding these nutrients in the feed as additives. But then, even if we have now a feed with the same characteristics as a fishmeal feed in terms of nutrition, the lack of flavor/smell of marine

ingredients in the feeds can have a negative impact on the feed acceptance. The feeding behavior of fish and shrimp is usually modulated by the taste, smell and flavor of the feed. Some non-marine ingredients have a taste that is not to the liking of many aquacultured fish and shrimp. Other raw materials have a neutral flavor, so the animals eat some feed, but not as much as they would with a feed made of marine ingredients.

There has been a lot of research to improve feed palatability through the use of taste enhancers. Some of the taste enhancers used before are squid meal, poultry meal, krill meal, shrimp hydrolysates and fish hydrolysates. All these palatants are more or less effective in enhancing the flavor and smell of the feed and increasing feed intake.

In recent years, Rimfrost AS, a Norwegian biotechnology company, has developed a special krill hydrolysate made from fresh krill caught in the pristine Antarctic waters. The fresh krill is gently processed on board the fishing vessel directly after the catch, using a patented process (enzymatic hydrolysis). The resulting krill hydrolysate is naturally low in growthreducing components, such as fluoride and chitin, while naturally rich in components that stimulate the feeding of fish by improved attractiveness and palatability (peptides, amino acids, growth promotion factors and nucleotides). The result is a strong palatability that stimulates higher feed intake and better growth and survival.

Trials in Atlantic salmon

In collaboration with Nofima - The Norwegian Food Research Institute, Rimfrost has performed studies on krill hydrolysate addition to Atlantic salmon feeds. The results demonstrated a significant increase in appetite,

feed intake and growth of salmon smolts fed on diets with levels of 2.5% or 5% krill hydrolysate, compared to a standard control feed. During the first 6 weeks after transfer to seawater, salmon smolt fed on krill hydrolysate coated feed, doubled their weight, from 92 to 185g mean weight (specific growth rate of 1.6), compared to the control group with a final weight of 124g (specific growth rate of 0.7) and a specific growth rate more than double of the control feed.

The fish fed the krill hydrolysate were also more robust, suffering fewer scale losses, fewer wounds, and no hemorrhages. Later trials confirmed these results, showing that the application of krill hydrolysate on the feed coating performed better than in the feed core. Similar results were obtained in freshwater stage trials of smolts, indicating the benefit of the krill hydrolysate to enhance the feed intake and growth in all stages of culture.

Trials in shrimp

In our trials with shrimp (Litopenaeus vannamei), the addition of 2-3% krill hydrolysate in the feed allowed us to reduce the amount of fishmeal by 80% without any decrease in growth and same feed conversion and survival as the control group. The addition of the krill hydrolysate as a topcoat in the feed worked well to replace 80% of the fishmeal.

However, when applied in the feed mix, results were even better than top coating the hydrolysate in the feed. Apparently, the leaching of the hydrolysate components (peptides and amino acids) is fast in these feeds, and the effect of the hydrolysate addition is longer lasting by adding it into the feed rather than a top coating. The replacement of 80% of the fishmeal with vegetable proteins with the addition of 2-3% krill hydrolysate gives a cheaper formula price and reduces

MARINE-BASED INGREDIENTS

the reliance on fishmeal, supporting the sustainable growth of the aquafeed sector, especially when fishmeal becomes scarce and expensive.

Conclusions

Krill hydrolysates in aquaculture feed hold great potential to reduce the true costs of aquaculture production systems by improving several critical sustainability aspects.

Rimfrost krill hydrolysates offer the opportunity to produce more aquafeed of high quality with fewer resources. Through improved utilization of feed, less waste, increased growth rates and higher survival rates, annual production of aquafeeds can be increased, without a corresponding increase in marine ingredients usage.

Several studies have shown that krill hydrolysates can improve animal health, robustness, and welfare and thereby survival rates. Krill hydrolysates can make aquaculture feed less dependent on fishmeal. Fishmeal can be substituted with alternative feed ingredients that do not deplete the ocean fisheries. Rimfrost krill hydrolysate has a low environmental footprint compared to similar protein sources, and it comes from a well-managed and sustainable fishery.

References

Albrektsen S. & Romarheim O.H. OlyPep© krill hydrolysate as a feed intake and growth stimulant in Atlantic salmon smolt feed. Confidential Report K-51/2020, Tromsø, Jul. 2020.

Hou Y., Wu Z., Dai Z., Wang G., Wu G. Protein hydrolysates in animal nutrition: Industrial production, bioactive peptides, and functional significance. Journal of Animal Science and Biotechnology, vol. 8, no. 1.

BioMed Central Ltd., Mar. 07, 2017. doi: 10.1186/ s40104-017-0153-9

Kaur K., Kortner T.M., Benitez-Santana T., Burri L. Effects of Antarctic Krill Products on Feed Intake, Growth Performance, Fillet Quality, and Health in Salmonids. Aquac Nutr, vol. 2022, pp. 1–14, Jan. 2022, doi: 10.1155/2022/3170854

López-Alvarado J. & Kanazawa A. Effect of dietary protein sources in microdiets on feeding behavior and growth of red sea bream, Pagrus major, during weaning and metamorphosis. Journal of Applied Aquaculture, vol. 7, no. 3, pp. 53–66, 1997.

Shimizu C., Ibrahim A., Tokoro T., Shirakawa Y. Feeding stimulation in sea bream, Pagrus major, fed diets supplemented with Antarctic krill meals. Aquaculture, vol. 89, no. 1, pp. 43–53, 1990, doi: https://doi. org/10.1016/0044-8486(90)90232-C

More information:

Karl Erik Slinning

EVP

Rimfrost AS

E: karl.erik.slinning@rimfrostgroup.com

Julio Lopez Alvarado VP Sales Aquaculture

Rimfrost AS

E: julio.lopez.alvarado@rimfrostgroup.com

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Getting strategic in Stirling: How to best use global long-chain omega-3 supplies

Brett Glencross, Véronique Jamin, IFFO – The Marine Ingredients Organisation

globally in food systems. People across the world now eat more protein as well as energy-dense foods than ever before and consumption is set to keep increasing. This is underpinned by a rise in meat as well as seafood consumption in Asia, especially in China, where the middle class is growing. In the meantime, consumption of cereals is decreasing.

A recent workshop organized by IFFO – The Marine Ingredients Organisation and held in Stirling, Scotland, on May 31, 2023, was undertaken to explore the knowledge gaps in the omega-3 story. Fish oil is well known as a natural source of the long-chain omega-3’s eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are essential nutrients for all vertebrates. Up to one-third of fish oil is made up of EPA and DHA. In 2021, aquaculture consumed 74% of fish oil, direct human consumption (supplements) consumed 16% and pet food consumed 10% (IFFO). Demand for fish oil for use in aquafeeds continues to soar as farmed fish are increasingly important in the human diet for the supply of EPA and DHA. However, there is increasing competition for EPA and DHA supplies which is pushing the industry to further consider the best strategic use of this resource.

Richard Newton (University of Stirling) reported on his work showing that some critical changes are happening

According to the Food and Agriculture Organization (FAO), sustainable diets are defined as those that are nutritionally adequate, safe, healthy, economically affordable, culturally acceptable, and impose minimal environmental degradation on the planet. While scientists are starting to combine environmental impact and affordability along with nutritional quality in their works (Banch et al., 2023), adding a nutritional index as an additional impact category to the life cycle assessment methodology would make dietary guidelines more robust, commented Newton.

Where are the existing stocks of EPA and DHA being used now?

In terms of the omega-3 story, a key part of strategic platform was to consider what we have now, where it comes from and where it is being used. A 2020 study by Hamilton et al. found that, at a global level, approximately one-third of all the EPA/DHA available for consumption from wild and farmed fish is being thrown away.

In fisheries, it was suggested that this loss can be reduced by improving the natural supply pathways through fisheries management. However, the greatest potential lies within fish processing of both wild-fish and aquaculture production, which currently see a huge loss of potential byproducts, although gains are being made in terms of nutrition, feed delivery and

Fish oil. Credits: Karen Murray

MARINE-BASED INGREDIENTS

genetics, for some species. Globally, opportunities for byproducts vary greatly with 54% of the global fish oil supply coming from byproducts in 2022 as reported by IFFO’s Enrico Bachis. Based on all known sources of fish and algal oil, it was estimated that current global stocks of EPA+DHA were about 155 to 180 thousand tonnes per annum, Bachis reported. While algal oils are an important emerging resource in the sector with a contribution of about 12 thousand tonnes of EPA+DHA in 2023 anticipated, this was not offsetting the recent cancellation of the first anchovy season in North Central Peru, a country that supplies up to 50 thousand tonnes of global EPA and DHA global production.

What do we know about omega-3 physiology in fish?

Including EPA and DHA in our diets is essential: farmed fish should be as nutritious to human consumers as wild fish is. Salmonids and marine species consume high levels of omega-3 long-chain polyunsaturated fatty acids in their natural diet. When farmed, feeding them with EPA and DHA ensures that EPA and DHA are passed on to the human population. However, these species also have their own needs that must be met through their diets.

As highlighted by Nina Liland (IMR, Norway) during the workshop, farmed fish without EPA/DHA are vulnerable to stress and disease. Fish are affected by both their

environment and water temperature, and too little EPA and DHA in their diet change the fatty acid composition in essential organs. A study by Hundal et al. (2022) showed a close relationship between omega-3 and omega-6. Given their role in impacting cell membrane structure and gut, bone, gill, and skin health, the balanced inclusion of EPA and DHA is vital to improving a fish’s resistance to inflammatory diseases.

Exploring the latest science on omega-3 inclusion in salmon feed at the workshop, Bente Ruyter (NOFIMA) referred to a study (Lutfi et al., 2022) demonstrating that dropping EPA and DHA inclusion in the salmon feed below 1% of the diet leads to reduced survival, fatty liver, intestinal pathology, and deformities of vertebrae.

IFFO’s Brett Glencross reported on the latest science on omega-3 use in feeds for marine fish and shrimp. Here Glencross demonstrated that requirements for EPA and DHA inclusion in feeds for these species was even more critical than those of salmonids, due to an absence of the capacity to utilize short-chain omega3 by marine fish and some shrimp species. Indeed, quantitative estimates for requirements by some marine species appear well above those of salmonids.

What happens to those omega-3 when passed to humans?

However, one of the main points to feeding aquaculture fish omega-3 is their role as a vehicle to supply those

Figure 1. People are eating more protein and more energy dense foods. Source: Richard Newton

nutrients to humans. Once passed on to humans, EPA and DHA provide them with special and unique biological properties, changing the physicality of the membrane and how it works, changing protein and lipid structure and function, to work in a more optimal way. This changes gene expression patterns, altering when proteins are produced, cell responses and activation of important biochemical pathways, Professor Philip Calder (Faculty of Medicine at the University of Southampton, UK) explained during the IFFO Omega-3 workshop. The overall benefit of this is the reduction of inflammation which then benefits different organs throughout the body, including aiding visual function, cognitive function, metabolism, inflammation regulation, immune responses, oxidative stress, blood coagulation, organ function and wound healing. Studies have shown that EPA is typically absorbed faster than DHA, but DHA is biologically more stable, so it is retained in the body for longer periods. Consumption of EPA and DHA appears to be essential during pregnancy and early childhood development, especially with breastfeeding.

Where to next?

It appears the omega-3 gap between supply and demand keeps increasing, despite the fact that new sources are being developed and old resources are being more efficiently used. Going forward, we see a continuing need for gains in the efficiency of whatever

MARINE-BASED INGREDIENTS

we use. It makes the best sense to make sure we use what we have in the most efficient way, in the most efficient sectors. We see that ensuring the sustainability of fisheries underpinning fishmeal and oil, as well as looking for new sources to add to the supply is urgently needed. While algal sources are emerging, GM crop sources are still yet to make an impact on the supply stage. But neither is going to supply another 100 thousand tonnes of EPA+DHA by 2030.

References available on request

More information:

Brett Glencross Technical Director

IFFO – The Marine

Ingredients Organisation

E: bglencross@iffo.com

Figure 2. Estimated global EPA and DHA production. Source Holtermann

Antarctic krill’s role in the future of aquaculture

Aker BioMarine

Why a tiny crustacean from Antarctica has emerged as a powerful and sustainable nutritional supplement for aquafeeds.

The aquaculture industry is at a turning point. To feed generations to come, our planet will increasingly depend on food from the sea. This has put aquaculture sustainability in the spotlight, and consumers and producers alike seek to minimize the environmental impact of our seafood and its production.

At the same time, costs are rising across the industry and aquaculturists must explore alternative feeds that meet rigorous nutritional requirements, all while remaining as sustainable as possible.

Simply put, it's an industry under pressure to produce more, minimize its impact, and keep operations efficient. No small task but Antarctic krill plays a key role.

A sustainable crustacean from Antarctica

Most know krill as a crustacean consumed by penguins and whales. It’s a species native to Antarctica, where it travels the sea in swarms, as part of the largest biomass on Earth. As a bottom-feeding crustacean, krill is rich in key nutrients that fish and shrimp need to grow. It contains high levels of vital macromolecules such as proteins and lipids – including the all-important omega-3 fatty acids. In addition, krill is packed with micronutrients such as vitamins A, D, and E, which are key to combatting stress in the body, as well as phosphatidylcholine, which delivers a boost of choline to support digestion and the transfer of information between neurons.

One of the main differentiators of krill lies in its “phospholipid effect”. Omega-3 fatty acids are crucial to the development of fish and shrimp and must be delivered via feed. In krill, these omega-3s are bound to phospholipids, a natural part of the cell membrane. The

results of this, as documented through research trials, often include greater survival rates, fewer instances of disease, and larger, healthier fish and shrimp that appeal to consumers.

The shift away from fish-based aquafeed ingredients

Increasing cost and availability pressure is forcing aquafarmers to seek alternatives to fishmeal-based ingredients in their feeds, which formerly served as the primary source of nutrition. Plant-based ingredients often meet the strict cost requirements but can fail to perform when it comes to growth and survival of the fish or shrimp. Many of the plant sources used today simply lack the required nutrients to boost overall growth performance.

“Decades of scientific research have proven that the balanced nutritional profile of krill meal, and the feed attractants it offers, makes it an ideal feed additive,” explains Lena Burri, Director R&D, Animal Nutrition and Health, Aker BioMarine. “We have participated in trials with several species of fish, as well as shrimp, concluding that krill meal in the aquafeed can enhance disease resistance, boost immunity, stimulate growth and palatability, as well as give overall better results for the producer.”

Krill meal is a powerful ally for fish farmers Krill, as a supplement for or replacement for fishmeal or other plant-based ingredients, has emerged as a powerful ally for farmers looking to improve production and cope with growing pressures, not to mention increasing demand for seafood products.

Global fish consumption is expected to rise by 30 million tons by 2030, according to FAO. The sea will serve as a key source of the required proteins people need – requirements that are predominantly met by land-based agriculture today – but at a fraction of the carbon footprint. “People are growing more conscious about the sustainability of their food,” adds Burri. “We know that we must make better choices for the future of our planet, which means that we require lower carbon sources of food. Aquaculture is key to our food future, and we see that keeping this industry sustainable also comes down to the food that our food eats. Krill is an aquafeed ingredient that farmers can count on for more sustainable and successful production.”

Phyto Aqua, natural & sustainable products for aquaculture

PROPRIA

Sustainable solutions to support shrimp natural defenses: How plant extracts can be an effective asset against AHPND

AHPND: A global issue in shrimp farming

Marine shrimp aquaculture has become a worldwide industry with farms mostly located in Asia and Latin America, ranging in several latitudes from Mexico to Peru, and from China to Australia. Despite different environments, farming systems and technology, the expansion of shrimp farming came with its diseases, which today are also widespread. Among pathogens involved, bacteria from the Vibrio genus are very common in seawater. Different strains from different species are known for causing pathologies like Early Mortality Disease (EMS), currently known as Acute Hepatopancreatic Necrosis Disease (AHPND) and caused by the species Vibrio parahaemolyticus (Tran et al., 2013). Outbreaks of AHPND naturally occur in the first 30 days after stocking a freshly arranged shrimp pond, and mortality rate can reach 100%. Firstly reported in southern China in 2010 and subsequently in Southeast Asia, this disease is now ubiquitous in shrimp farms worldwide.

Dealing with AHPND requires a multi-layer strategy, which generally involves environment control (although depending on the farming system and limited as Vibrio bacteria are native and ubiquitous in waters), antibiotics, genetics, or probiotics.

Shrimp are fragile animals, that do not possess a proper acquired immunity system and rely on innate immunity with unspecific response to any external agent. Then, besides previously mentioned strategies, solutions are being sought by the shrimp farming industry to stimulate their natural defenses and limit the impact of this disease on ponds.

Plant extracts: A wide range of benefits

Among sustainable candidates, plant extracts have shown promising results to limit Vibrio infection in aquaculture. Most of the active compounds from plants used today are secondary metabolites, which are molecules naturally synthesized by plants to enhance their fitness, for example, when fighting parasites and/

Amine Chaabane, Laboratoires Phodé

Table 1. In vitro assays in different Vibrio species

or predators. Therefore, several antibacterial and antiparasitic compounds are found in plant essential oils, which alter the membrane of microorganisms to limit their pressure (Garcia-Valenzuela et al., 2014; Madhuri et al., 2021). Some other plant extracts, in particular pungent spices, have also shown positive biological activity by strengthening the intestinal barrier or stimulating an immune response (Qi et al., 2021). Consequently, mixing plant extract to potentialize their effect could contribute to important improvements in shrimp's natural defenses. Laboratoires Phodé, experts in functional olfaction and plant extracts, have thus

designed Olpheel Protect, a synergic blend of plant extract to limit the impact of pathogens in shrimp ponds and support shrimp natural defenses. To validate the effect of Olpheel Protect on AHPND, several experiments, including an in vitro assay and an infection challenge, were conducted in Vietnam.

Effect on Vibrio growth

An in vitro assay was first conducted with different Vibrio species and strains isolated from different locations, to evaluate the effect of Olpheel Protect (OP) on inhibiting Vibrio growth.

Figure 1. Survival rate 10 days post-challenge (a,b p<0.05)

Figure 2. Phenoloxidase activity at 3 sampling time points. Different superscripts show significant differences (p<0.05) among the groups (lowercase) and between three sampling time points in each group (uppercase).

HP tissues showed signs of EMS/AHPND after 72 hours of post challenge

Olpheel Protect has displayed antibacterial activity on every strain tested, at different levels (Table 1). For example, among three Vibrio parahaemolyticus strains tested, the Thai isolate displayed a lower resistance to the product than the Ecuadorian and Vietnamese strains. Also, variability between species was clearly evidenced, as Vibrio alginolyitucs and Vibrio rotiferianus

strains, involved in other shrimp diseases (white feces), were more resistant with a higher MIC required to limit their growth.

Effect on AHPND infection

To evaluate the effect of Olpheel Protect on AHPND infection in shrimp, 500 specific pathogen free (SPF)

Figure 3. Histological cuts of shrimp hepatopancreas 72 hours p eatment 1 (T1, Olpheel Protect at 0,1%) and treatment 2 (T2, Olpheel Protect at 0,2%) are displayed respectively.

(A) and (B): the HP tubules showed normal strycture without damage (Red arrow)

(C) and (D): HP tubules lacked the presence of vacuoles in B and R cells (Black arrow) and sloughing HP cells (Blue arrow)

(E) and (F): HP tubules lacked the presence of vacuoles in B and R cells (Black arrow) and sloughing HP cells (Blue arrow)

(G) and (H): the HP tubules showed structure without infection by EMS/AHPND (White arrow)

whiteleg shrimp (Litopenaeus vannamei ), with an average body weight of 1.41 ± 0.14g, were split evenly in 20 tanks filled with 75L of brackish water (20ppt) in a recirculating aquaculture system (RAS). Each tank contained 25 shrimp, with 5 replicates per treatment. Different treatments included a negative control (SPF shrimp with no infection, fed a non-supplemented feed), a positive control (SPF shrimp infected with Vibrio parahaemolyticus, fed a non-supplemented feed) and two test treatments with healthy SPF shrimp fed with a feed containing respectively 0,1% and 0,2% of Olpheel Protect. After being acclimated for 2 days and fed commercial diets for two weeks, a challenge with Vibrio parahaemolyticus was started, where infection dosage was previously established through a separate calibration test. The bacterial strain used for infection was isolated from AHPND-affected

Litopenaeus vannamei on a shrimp farm in Loc An, Vung Tau Province, Vietnam. Different parameters such as survival rate, immune system activity, and histological state were evaluated.

Final survival rates 10 days post-challenge are displayed in Figure 1. Infected shrimp without treatment displayed a 50% mortality rate compared to uninfected shrimp. Both treatments indicated clear improvements in survival rate post-infection, with a significant improvement with Olpheel Protect included at 0.2% with an 83% survival rate compared to 50% in the positive control group.

Regarding immunological parameters, phenoloxidase is often used as a marker for the shrimp immune system as it is mainly involved in response to external pathogens (Luqing Pan et al ., 2019). Phenoloxidase activity was not different among both

control treatments at the three sampling times. For treatment 1, an important and significant increase of phenoloxidase activity was evidenced 72h postchallenge, indicating an immunostimulant activity of Olpheel Protect compared to non-supplemented feeds. To finally observe the effect of Olpheel Protect on tissues, histological cuts allowed us to put in evidence the impact of AHPND on hepatopancreas, with big differences displayed between negative and positive control in Figure 3. The use of Olpheel Protect led to improvements in tissues, with treatment 2 showing a similar pattern in tissues than uninfected shrimp, and treatment 1 showing improvements compared to positive control.

A sustainable and multi-functional solution

All the results in this experiment underlined the positive effect that a synergic plant extract blend, Olpheel Protect, had on AHPND-affected shrimp. Antibacterial

activity was evidenced during in vitro assay, with complementary interesting results for etiologic Vibrio agents of other pathologies. Immunostimulant activity was also underlined, and both effects led to improvements in survival rate and hepatopancreas state. This work allowed us to position Olpheel Protect as a complete tool to prevent and limit AHPND's impact on shrimp farms at a global level.

References available on request

More information:

Amine Chaabane Aquaculture Product & Species Manager

Laboratoires Phodé

E: achaabane@phode.fr

The effects of botanicals on gut integrity for efficient use of aquafeed resources

Fabrizio Caruso, Vetagro Spa

Botanicals are widely used as feed additives to increase the growth performance of healthy fish and shrimps or help manage stressful situations with promising results. This large group of feed additives includes a vast variety of molecules largely differing in terms of structural and functional properties so a unique and general mode of action is unlikely to exist. We have been studying their effect on gut integrity and report our findings here.

Intestinal homeostasis in aquaculture

Fish farmers and aquafeed manufacturers are facing rising production costs, eroding profit margins and posing financial threats all along the aquaculture value chain. In the effort to counteract this negative trend, alternative ingredients are often tested, and, despite the widespread availability of plant ingredients, these protein sources can contain anti-nutritional factors, such as fibers, indigestible sugars, and compounds that lower feed intake, palatability, and nutrient digestibility by directly affecting intestinal homeostasis. Intestinal homeostasis, or the regular functionality of the digestive tract and its biochemical processes, is deeply correlated with intestinal mucosa health. The intestinal mucosa is a single layer of epithelial cells connected to each other through inter-epithelial junctions (Fig. 1), and it is the first functioning site for nutrient absorption as well as physical defense against harmful agents. The maintenance of this barrier contributes to the functionality of digestion, nutrient absorption and growth, and directly impacts the wellness of the animals, since barrier dysfunction plays a significant role in gut inflammation and disease susceptibility. Vegetable ingredients and anti-nutritional factors may induce inflammatory processes at the cellular level, with the potential to elicit enteritis of the intestinal mucosa. This is a common phenomenon, as

reported by a recent survey in Norway, which concluded that Atlantic salmon, in commercial production, suffer a high frequency of symptoms of inflammation, especially in the distal intestine, condition escalated in severity throughout the production cycle.

Addressing gut health is, therefore, a common and urgent matter, and an effective way to prevent “submerged" economic losses is the use of functional feeds enriched with compounds able to directly induce an anti-inflammatory response and strengthen the intestinal cellular layer. Natural molecules and their combinations in synergy have untapped potential in this sense. For this reason, our experts focus daily on cell culture models to screen directly on the intestinal

mucosa for the efficacy of the most promising botanical compounds, testing gut health and functionality.

Improving gut integrity via botanical nutrition

We evaluated the effects of the synergistic thymolbased formula of Aviplus® (Fig. 3) on the integrity of intestinal mucosa by testing the Trans-Epithelial Electrical Resistance (TEER) and gene expression of Tight-Junctions (TJs) zonula occludens-1 and occludin. TEER consists in measuring the electrical resistance across a model cellular layer and is a very sensitive and reliable method to assess the integrity and permeability of the cells by measuring how much of the fixed electrical signal is blocked by the cells, hence quantifying barrier function. (Fig. 2). TJs, instead, are junctional multiprotein complexes that directly modulate the adhesion of adjacent epithelial cells, functioning as the gatekeeper to control the diffusion of solutes, regulating ion transport, blocking infiltration of macromolecules, and bacteria and controlling the selective transport of nutrients.

TEER tests were evaluated during 15 days and, to clarify the effect of botanicals against potential threats to the intestine, inflammatory cytokines and bacterial lipopolysaccharides molecules were applied after a short and a long exposure of the cells to the botanicals to mimic a state of inflammation.

The results (Fig. 4) reported not only significantly better gut health indicators under normal conditions, but also better integrity when inflammation occurred in cells treated with botanicals. The thymol-based botanical blend of Aviplus® enhanced the barrier characteristics of the cells both before and after the inflammation, supporting the cells to better react to the challenge while also allowing for a better recovery after the challenge. Similarly, by using the mean of gene expression technology, we were able to measure also how the genes coding for the tight junctions (OCNL and ZO-1), protein complexes keeping the mucosa together, were activated during the trial and we discovered them to be highly more activated when treated with the botanicals.

Figure 2. Trans-epithelial electrical resistance in vitro test

Figure 3. The microencapsulated beads of Aviplus®Aqua

These findings imply that, by applying the proper molecules, a botanical additive can be used as a preventive and even as an intervention measure, when administered during a potentially stressful or pathogenic event, to improve animal intestinal barrier performance and, indirectly, immune status. The full article by Toschi et al. (2020) is published in the international peerreviewed journal “Molecules”

Delivering molecules where they are most needed

The properties of botanicals are a recent discovery in aquafeeds, and they can help aquaculture species deal with a wide range of challenges, from microbial

threats, as in our experience at Vetagro with Vibrio spp., Photobacterium sp. and Flexibacter sp., to resistance to stressful conditions. This added value of Aviplus® happens by boosting antimicrobial defense and general health in fish and shrimp, as the biological mechanisms behind gut health presented in the previous sections indicate.

However, the in vivo efficacy of botanicals must be carefully evaluated according to the technology in use, as additives might not keep up with expectations when transferred from in vitro to in vivo. Factors such as water leaching or thermal pelleting treatments, quite common in aquaculture feed manufacturing, might

Figure 4. Preventive (over) and ameliorative (under) effect of botanicals against inflammatory challenges (Adapted from Toschi et al . (2020); asterisks indicate significant differences)

HEALTH

damage the molecules, preventing the action of an effective dose on the entirety of the digestive system. That is a crucial issue when fish show severe inflammation happening all along the tract and especially in the distal intestine, the furthest segment of the digestive tract, as reported with salmonid cultures. To face these concerns while protecting the beneficial effects of the patented botanical formula, we developed a lipid microencapsulation technology that allows for a slow and constant release, reaching the whole digestive tract, while also increasing the resistance of the botanicals to processes of inclusion in aquafeeds such as extrusion or vacuum oil coating.

Conclusions

The experiment presented was able to conclude the beneficial effect of the botanicals gathered in the Aviplus® formula on the intestinal mucosa and its integrity. These results give a new perspective on the increased growth performances reported in in vivo studies on trout ( Oncorhynchus mykiss ), seabass (Dicentrarchus labrax), seabream (Sparus aurata) and catfish (Ictalurus sp.) as the ones presented in the previous issue of Aquafeed Magazine and allow us to provide a higher degree of services to support farmers, their fish and shrimp by beneficially modulating gut health and indirectly boosting the performance and resistance to diseases.

References are available upon request. The pictures are property of Vetagro S.p.a. and the infographics were created by Vetagro S.p.A. using Biorender.

More information:

Fabrizio Caruso

Aquaculture Specialist

Vetagro Spa

E: fabrizio.caruso@vetagro.com

Stressing the stressors in aquaculture

Temitope Alex Aloba, Muhammad Umar, Bernhard Eckel, Dr. Eckel Animal Nutrition

A fight-or-flight response to stress: which is more applicable in aquaculture? Either way, stressors profoundly affect fish homeostasis, evoking oxidative stress and impaired immune status. Fighting stress is an everyday concern for aquaculture species because of their antigenic environment. Improving the welfare of farmed aquatic species by reducing stress can result in enhanced productivity.

As one of the fastest-growing food production sectors globally, aquaculture provides high-quality protein and essential nutrients for human consumption. But how can we ensure that aquaculture is sustainable in a changing climate? How can we cope with the multiple stressors that threaten the health and productivity of aquatic farmed species? Minimizing stress and optimizing stress resilience would be the best option to ensure aquaculture sustainability and profitability in the face of multiple stressors.

Stress: A common denominator

Stress is unavoidable in aquaculture, whether in a pond, tank, cage or other farming systems. But it can be managed effectively with proper planning and intervention. By its very nature, the aquatic

environment is highly antigenic, which stimulates stress. Besides, other factors alter the self-regulating process by which biological systems tend to maintain stability while adjusting to conditions optimal for survival in aquaculture species. Fighting against stress is an everyday concern for aquaculture species causing an imbalance in the intestinal ecosystem, a risk factor for pathogen infections. Climate change also exacerbates the impact of stressors depending on the production system’s type, location and intensity. Stressors include sudden changes in the environment (salinity, rising temperature, oxygen depletion), animal interactions (predators, intense competition for food, space, or sexual partners, pathogens, parasites), aquaculture practices (handling, transport, crowding, sorting) and water pollution (low water pH, organic chemicals).

Figure 1. Stress response and the impact on aquaculture

Stress response mechanisms

Stress elicits behavioral and physiological responses, one of the primary and essential mechanisms organisms require to maintain homeostasis. Many factors modulate stress response, such as the stressor’s type, magnitude and frequency (Fig. 1). The individual characteristics of the organism, e.g. age, sex, size, genetic background and previous experience, are another factor. It is a common stance that the current model of integrated stress response in all animals comprises adaptation and a fight-or-flight response to stress. While the adaptive response emphasizes the non-specific nature of the many reactive processes evoked by stressors, the fight or flight response involves activating the neuroendocrine system. Either way, an extension of stress response inhibits growth, reproduction, and immunity and reduces the capacity to tolerate additional stressors. In the event of a fight-or-flight response, catecholamines and corticosteroids are released that increase heart rate, blood pressure, respiration, and reallocation of energy. However, in a closed system like aquaculture, this fightor-flight response to stress will most likely apply to all stressors. In most cases, a combination of stressors has additive, more than additive and antagonistic effects. For instance, high temperatures may increase the toxicity of ammonia or lower the resistance to pathogens that inhibit fish growth. At the same time, fluctuations in temperature and salinity have an antagonistic effect on shrimp growth, and their optimal combination depends on their interaction.

Depending on the type, intensity, duration, and frequency of the stressor, aquaculture organisms may exhibit different responses: fight (e.g. aggression), flight (e.g. escape), freeze (e.g. immobility), or fawn (e.g. submission). The optimal response for aquatic farmed species depends on their species-specific characteristics and environmental conditions. For example, some aquatic species are more aggressive, tolerant or mobile than others. Whether it is a fight-or-flight response to stress, an innovative solution to fight stress in aquaculture is inevitable.

Optimizing stress resilience

Nutrition plays a vital role in modulating the stress response and enhancing the stress resistance of aquaculture species. Therefore, the role of feed additives in achieving this cannot be overemphasized. Anta®Ox Aqua is a phytogenic feed additive that protects aquaculture species against stress and inflammation. Plant flavonoids in the diet can help fish cells adapt to stress, by reducing inflammatory reactions. In accordance with this, the flavonoid-rich feed additive Anta®Ox Aqua enhances anti-oxidative capacity by reducing inflammation in farm animals and helps mitigate the effects of inevitable stress in intensive aquaculture production.

In numerous trials, it has been shown how Anta®Ox Aqua positively influences aquaculture species’ stress resilience by having a beneficial effect on their immune and metabolic systems. One indicator of stress is, for

Figure 2. Anta®Ox Aqua reduces stress and improves sustainability as indicated by the immune response and hepatopancreas health parameters of shrimp (SOD; superoxide dismutase, THC; total hemocyte).

instance, an organism’s immune reaction to pathogens. The better the defense system functions, the greater the resistance to potential infections and pathogenrelated stress. In an experiment with shrimp challenged with Vibrio parahaemolyticus, the animals in the group receiving Anta®Ox Aqua showed a more marked response to the challenge than the control group. The higher the dosage of Anta®Ox Aqua, the more pronounced the immune response to Vibrio-induced stress (Fig. 2). In addition, inflammatory cell necrosis of the hepatopancreas evoked by stress was reduced by 25%. Altogether, more improvement in shrimp performance and protection against stressful conditions was achieved.

This is how Anta®Ox Aqua works to the advantage of animals and producers – with more resilience, fewer infections, better performance and more sustainable production.

References available on request

More information:

Temitope Alex Aloba, PhD

Technical Sales Manager

Dr. Eckel Animal Nutrition

Muhammad Umar

Technical Sales Manager

Dr. Eckel Animal Nutrition

Dr. Bernhard Eckel Vice

President

Dr. Eckel Animal Nutrition

E: produktmanagement@dr-eckel.de

Aquaculture feeding trial facility at Dr. Eckel.

The importance of healthy gut in aquaculture

Presanthi Sithapathi, Veolia

Aquaculture is a fast-growing food industry in response to the rapidly increasing global population, which is expected to reach 10 billion by 2050. Today, over 50% of seafood consumed is supplied from aquaculture (FAO, 2022). Demography and consumer demand will continue to require more farm-raised protein supply. In the context of global warming, the decline of certain resources and tensions on food security, the aquaculture industry is facing challenges to secure sustainable protein sources and ensure overall performance and productivity while using fewer resources (Henriksson et al., 2021).

A promising and stable alternative solution is the use of black soldier fly (BSF, Hermetia illucens) larvae from which high-quality protein products are derived (Muller et al., 2017) by upcycling low-value organic substrates. This unique production model contributes to the development of circular economy supply chains.

Black soldier fly-derived ingredients (insect meal and oil) have been extensively studied over the past few years and have shown to be good quality ingredients for all farmed animals (seafood, livestock and pets). In addition, these products also provide a range of health benefits from improved survival, growth performance, and immune responses in shrimp, and both marine and freshwater fish species (Islam et al., 2020, English et al., 2021, Verstraete et al., 2023).

At the same time, functional ingredients are gaining interest in animal nutrition to ensure good gut integrity of aquatic animals to effectively build disease and stress resistance, and also achieve increased productivity and profitability.

Influencing the gut microbiota

The gut is a complex system of tissues and organs that plays an important role in various functions such as

nutrient digestion, absorption, metabolism, growth, immune responses and defense mechanisms. The composition and diversity of gut microbiota of aquatic animals are highly sensitive and modulated by dietary changes. These changes may impact feed efficiency and overall health (Kokou et al., 2022).

Black soldier fly ingredients have functional properties linked to the presence of a wide variety of bioactive molecules (de Silva Lucas et al., 2020). Particularly, three major components, chitin, antimicrobial peptides and lauric acid, have been proven to strengthen the immune responses and reduce pathogen loads in the gut.

Chitin, a polysaccharide present in the black soldier fly’s exoskeleton, has immunostimulatory effects. At a low dietary quantity, it has been shown to increase pathogen resistance by enhancing the innate immune responses in whiteleg shrimp (Litopenaeus vannamei) (Wang et al., 2005), gilthead seabream (Sparus aurata L.) (Esteban et al., 2000) and common carp (Cyprinus carpio) (Gopalakannan et al., 2006).

Antimicrobial peptides (AMPs) have a wide range of properties (antibacterial, antifungal, etc.) leading to increasing interest in their application as potential therapeutic agents. Black soldier fly is known to synthesize AMPs which explains their ability to survive in harsh environmental conditions (Choi et al., 2018).

Lauric acid is a saturated medium-chain fatty acid naturally found in high concentrations in black soldier fly oil. Besides the nutritional values, lauric acid exhibits antibacterial and antiviral properties (Rodde, 2023) with beneficial effects on the gut microbiome and development of the gastrointestinal tract in Siberian sturgeon (Acipenser baerii) (Rawski et al., 2021).

Veolia has recently carried out two studies demonstrating the beneficial effects of insect meal and oil (Entomeal™ and Entolipid) on the gut health of

shrimp and fish. Entomeal™ contains a minimum of 55% crude protein and has a well-balanced essential amino acids profile. The majority of peptides within Entomeal™ are composed of small peptides with 66% below 5 kDa. Entolipid has a unique fatty acid profile rich in lauric acid (>25%). These products are manufactured under a standardized process ensuring consistency, safety and full traceability.

Improving immune responses

A recent study conducted with the University Kasetsart, Thailand, on juvenile whiteleg shrimp (Litopenaeus vannamei ) demonstrated beneficial effects, such as improved immune response and zootechnical performance, using Entomeal™ and Entolipid, in comparison to a standard commercial shrimp feed at isonutrient inclusion levels ranging from 2-10% (Verstraete et al., 2023).

Key results for assessing an improvement in the shrimp immune system related to hemocyte count. The hemocyte plays an important role in the immune system, and they are involved in the activities of phagocytosis against pathogens. An increase in the total hemocyte count, as well as phagocytosis activity, were observed compared to control, indicating an improved immune response when the shrimp were fed a diet containing Entomeal™ and Entolipid at different inclusion levels when compared to control (Table 1).

To further evaluate the immune capacity, two enzyme activities called phenoloxidase and superoxide dismutase were monitored. Phenoloxidase is an important enzymatic pathway in the insect immune system involving the melanization process to encapsulate invading pathogens, while, superoxide dismutase is an enzyme involved in the fight against oxidative stress caused by pollution, infections, and temperature. Both

Table 1. Parameters related to the immune status of L. vannamei shrimp after 45 days of growth

Figure 1. Histology of the hepatopancreas after 7 days challenge test with V. parahaemolyticus at the dose of LD50.

enzyme activities were increased with a diet containing Entomeal™ and Entolipid at different inclusion rates (Table 1).

In this study, histology of the hepatopancreas cells showed reduced sloughing in shrimp fed with Entomeal™ compared to the control after a seven days challenge test with Vibrio parahaemolyticus (Fig. 1). Overall this study demonstrated that feeding shrimp with diets formulated using Entomeal™ and Entolipid resulted in enhanced immune response and improved survival of L. vannamei shrimp. Another recent study conducted on the development of juvenile gilthead seabream with the Hellenic Centre for Marine Research in Greece reported an increase in the level of serum myeloperoxidase activity and nitric oxide concentration in fish fed with Entomeal™, which suggests a positive effect on the fish immune system (study in preparation; Fig. 2).

Ensuring nutrient absorption

Nutrient digestibility was also tested in both the aforementioned trials on whiteleg shrimp and gilthead

seabream. For gilthead seabream, the apparent protein digestibility increased with increasing Entomeal™ inclusions, indicating that it is a suitable, high-quality ingredient for fish feed (Fig. 3).

Protein digestibility varied from 90% to 94% with the lowest observed in the control group, while lipid digestibility was the highest in fish fed with 10% Entomeal™ (88%) and the lowest for fish fed with 5% Entomeal™ (83%).

In the juvenile whiteleg shrimp (L. vannamei) trial, the best apparent digestibility of nutrients was observed with a diet containing a combination of 2% Entomeal™ and 2% Entolipid after 14 days. Usage of 2% of Entomeal™ in aquafeed can improve protein digestibility.

Conclusion

Insect-based functional ingredients, Entomeal™ and Entolipid, are an innovative and sustainable solution to improve gut health, growth performance, and survival rate for different aquatic species. Besides, the use of Entomeal™ in aquafeed can enable the partial reduction of fishmeal in feeds. Further feeding trials and research must be carried out to find out more about the immune-boosting capabilities of insect meal and oil in aquafeeds.

References available on request

More information:

Presanthi Sithapathi

Senior Sales Manager Bioconversion

Veolia

E: presanthi.sithapathi@veolia.com

Figure 2. Fish fed diets supplemented with 0, 2.5, 5 or 10 % of Entomeal TM for 12 weeks. (A) Serum myeloperoxidase activity. (B) Serum nitric oxide concentration.

Figure 3. Apparent digestibility (%) of diets including varying levels of Entomeal™

Yellow pea inclusion in whiteleg shrimp rations

Peas (Pisum sativum) are a staple human food product, and additionally, they have been utilized as a source of protein and energy in swine, poultry, and cattle rations. Notably, yellow peas are commonly used to feed grower and finisher pigs in Canada and several European countries due to their availability, excellent palatability for swine, and favorable pelleting characteristics. The high lysine content of peas per kg protein is a good complement to canola/oilseed rape products that are commonly used in Canadian and European swine (and poultry) feeds. Canola/oilseed rape is relatively low in lysine and high in sulfur amino acids, the latter of which is limiting in peas.

Limited research has been conducted on the use of peas in aquaculture feeds, particularly in shrimp rations. This fact led Pulse Canada, a non-profit

organization based in Winnipeg, Manitoba that works on behalf of Canadian pulse growers and exporters, to commission a trial in Asia to determine the utility of yellow peas as a partial replacement for soybean meal (SBM) for Pacific whiteleg shrimp (Litopennaeus vannamei). The trial was conducted at the Research Center for Aquafeed Nutrition and Fishery Post-Harvest Technology (APOTEC) in Ho Chi Minh City, Vietnam from November 2022 to February 2023.

Methods

Four iso-nitrogenous (CP=36%) and iso-caloric (DE=14.21MJ/kg) diets, that otherwise met all other nutrient requirements of whiteleg shrimp (L. vannamei) according to the NRC (2011), were employed in this study. The control diet included Peruvian fishmeal,

PLANT-BASED INGREDIENTS

Argentine SBM (46%), wheat flour, poultry byproduct meal, a single-cell protein source, wheat gluten meal, corn starch, fish, squid liver and soybean oils, fish soluble extract, soy lecithin, and other additives typical of whiteleg shrimp diets. The treatment diets included 5, 10 or 15% feed peas (CP=20%) at the expense of SBM, which was included in the control diet at 25%, while fishmeal was held constant in all diets at 15%.

Three thousand (3,000) juvenile Pacific whiteleg shrimp (initial bodyweight of 1.0-2.0g) were obtained from a commercial hatchery in the south of Vietnam, housed in an experimental station in HCMC, and acclimatized in three 1,000 L-fiberglass tanks (salinity=15ppt) before entering the feeding trial (120-L tanks, fed 4 x’s daily). The performance parameters that were assessed during the 8-week trial included growth, feed efficiency, sensory characteristics, histological morphology, and body composition.

Shrimp growth performance and feed efficiency were evaluated at the midway point of the trial (28 days) and then again and the conclusion of the trial (56 days).

Results

By the end of the trial, the group receiving 5% yellow peas did not display any adverse effects on either growth or feed conversion, but 15% yellow peas did compromise these parameters. Ten (10) percent yellow peas did not significantly depress growth or compromise feed conversion, but the actual number values were slightly less than those in the control group and the 5% yellow pea group, which suggests that by the end of the 8-week trial, these parameters may have been adversely affected. Notably, the feed intake and survivability of the shrimp in all four groups were the same.

Dietary yellow pea inclusion had no effect on the body composition (moisture, protein, amino acids, lipid, ash, calcium, phosphorus) of the shrimp, and only nitrogen retention efficiency (but not nitrogen retention per se) was slightly decreased at 15% inclusion compared to the control diet. There was no effect of diet on the sensory parameters of color, odor, taste, or texture. The only morphological parameter that seemed to be affected by yellow pea inclusion was a slight depression in the height of the microvillus at the highest level of yellow pea inclusion.

These results indicate that yellow peas can replace soybean meal in whiteleg shrimp diets at up to 10% without adversely affecting growth, survival, or feed utilization. Feeding yellow peas at up to 15% did not adversely affect the whole-body proximate composition of whiteleg shrimp, nor did the shrimp fed increasing levels of yellow peas show any adverse responses in the sensory value of the cooked product. The histological morphology assessment showed that shrimp fed up to 10% yellow peas did not present with any abnormal signs of intestinal or hepatopancreatic morphologies, and 15% inclusion had only a slight effect on villus height but no other adverse effect on the intestinal mucosa or the hepatopancreas.

The commercially practical safe level of yellow peas that can be included in feed formulations like those used in this research trial is somewhere between 5-15%. The assumption is, of course, that the market price of feed peas would make their inclusion economically advantageous to the feed company and the producer. The price of feed peas is affected by supply and by multiple demands in the marketplace. There is a market for several food uses, including direct consumption as a vegetable and as a confectionary product, a market for peas as a raw ingredient for extrusion into noodles, and the use of peas to fractionate into high protein concentrates, isolates, starches, and flours. The final market is that described here for animal feed. The fractionated products are targeted to the highestvalue markets, which include food, animal feed, and companion animal applications. Continued adequate supplies of peas in producing countries, including Canada, will ensure that sufficient volumes are available to meet the future demand that the aquaculture industry has for alternative sources of protein and energy ingredients.

More information:

William W. Riley, Ph.D.

WWR and Associates, Ltd.

E: wmriley54@yahoo.com

Innovation for the blue transformation

Hadrien Delemazure, Clextral

An essential growing market

Fish is known as a high-value food for humans, with health benefits that include long-chain unsaturated fatty acids, vitamins and minerals and a wellbalanced protein supply. Farming techniques have spread throughout the world and today, aquaculture represents a significant amount of human food consumption. The most recent study from the Food and Agriculture Organization of the United Nations (FAO, 2022) confirms that 56% of the consumed aquatic animals in the world, including finfish, mollusks and crustaceans, come from aquaculture. With a world population of eight billion people, the average fish consumption, including mollusks and crustaceans, was estimated in 2020 to be 20.2 kg/ capita. By 2050, with a world population of 9.7 billion, it is estimated to be 22.3 kg/capita in a business-asusual scenario.

Farmed aquatic animals, on land or marine based, are grown using different farming methods such as Recirculation Aquaculture Systems (RAS), basins, tanks, cages, etc. In those conditions, it is necessary to provide and control the required feed to optimize the culture conditions. The feed has to comply with specific physical and nutritional requirements.

The process of feed manufacturing for fish and shrimp represents a fundamental element for ensuring the delivery of consistently high-quality granulates for these intensive breeding processes. For example, it is estimated that over 60% of the production expenses for farmed salmon come from the feed cost itself. Additionally, we have to face challenges such as limited resources of fishmeal and fish oils worldwide and a temperature increase in the earth’s environment that creates irregular conditions for fish capture, uncertain cereals and pulses harvests on earth

PROCESSING TECHNOLOGY

(used more and more to partially replace fishmeal in recipes), and the risks for offshore aquaculture breeding facilities (waves, winds, storms, currents, pollution, etc.).

Aquafeed twin screw extrusion processing

Twin-screw extrusion brings significant technical and economic advantages to the production of aquafeed pellets, thanks to its process flexibility and reliability (Bouvier & Campanella, 2014). It enables:

• Easy adaptation to any change in raw-material composition: moisture, lipid content, particle size distribution, de-mixing of powdered materials. These are due to various sources of raw materials (for example, soy meal can be purchased in many parts of the world), transport and storage (conditions, grinding process, etc.).

• Flexibility to adjust the sinking/floating ability of the pellets to follow as closely as possible the food habits of each animal family.

• Processing a wide range of recipes to respond to industry demand for feeds with low or high amounts of lipids, vegetable proteins, or various sources of protein to meet the specific nutritional requirements and adapt to rapid environmental change.

• Flexibility to adjust the shear, cooking and shaping conditions in the extruder for better nutrition and digestibility.

• Ensuring a high hygienic standard to avoid any contamination during the feed manufacturing process. Considering those requirements, combined with good manufacturing/breeding practices, scientific education,

and adapted legislation, we can nurture high-quality aquatic animals that offer health benefits to people around the world using local production to ensure low carbon footprints.

Clextral has launched innovations, which offer even greater possibilities to process original recipes and use raw materials such as new pulses proteins, insects, krill meals, seaweeds, etc. while always improving pellets quality.

Preconditioning:

Higher efficiency and improved product texture

One of these innovations refers to the preconditioning process; a key operation in fish feed manufacturing. Preconditioning allows the moistening of the powdered mix and pre-gelatinization of the starch molecules through the addition of water and steam; thereby, increasing the pellets’ water stability, enhancing production capacity and reducing wear on the extruder.

The patented, innovative Pre-conditioner+ improves heat and mass transfer to the product due to the Advanced Filling Control device (AFC). It interacts directly with the material inside the mixing chamber and enables the filling ratio to be adjusted from 45% to 75%. The AFC system uses an exclusive conveying screw inside the tank and adjusts the flow by partial and controlled recycling of the material being processed from the outlet to the entry point, thus intensifying the specific preconditioning functions.

By increasing the filling ratio, we increase the residence time inside the preconditioner. This leads to a better gelatinization of the starches along with other variables

Clextral Evolum+ with preconditioner

such as mixing speed and steam addition to reach maximum pellet digestibility.

Laboratory tests have also proven that the final hardness of fish feed pellets increased between 7-29% using the same recipe and adjusting the bottomscrew speed. This relates to the hardness, brittleness and cohesiveness of the pellet. The fish have to ingest a complete piece. A brittle pellet may disintegrate quickly in water, creating pollution and resulting in low ingestion rates. Water stability may be an issue for many species. For example, shrimp are slow feeders: with ingestion times ranging from minutes up to hours. The feed (granulate state) must be cohesive and its nutrient composition must be preserved until it is ingested.

After manufacturing, aquafeed pellets are put in sacks or big bags, transported, stored, and finally distributed manually or

Clextral Preconditioner Plus – Advanced Filling Control

Figure 1. Preconditioner average filling ratio as a function of AFC speed

Figure 2. Pellets hardness as a function of AFC speed

PROCESSING TECHNOLOGY

through mechanical systems such as pneumatic conveyors and automatic distribution units. The pellets must resist abrasion, attrition and crushing during this process. They should not create fines, which are costly sources of pollution and uneaten feed. Additionally, the pellets have to keep their original composition and avoid any leakage of oil or any other coated substances.

During the shutdown and cleaning procedure of the preconditioner, the bottom-screw rotation is reversed to optimize the shutdown, reduce the percentage of waste and facilitate the emptying and cleaning procedure of the preconditioning chamber.

Density control system

The density of aquafeed pellets has to be adapted to the behavior of the fish to increase the timeframe for them to ingest the feed. Clextral has developed a system for instantly varying the density of the material within the extruder. It is possible, for example (depending on the recipe) to quickly pass from an extruded pellet of 350g/L to 750g/L. This fully automated tool ensures the control of the pellets' density and the ability to produce sinking or floating aquatic feed.

With the DCS, the resulting density of the final product can be adjusted according to customer specifications. By adding steam or through vacuum, the density control system ensures the precise density and proper degree of expansion in the product.

The main advantages of the process are:

• Precise density adjustment and control

• Reduced product moisture levels

• Generate high-density products

• Fines recovery back to preconditioner

• Ideal for aquatic feed production

Hygiene

Finally, today much attention is focused on hygienic extruder design, as food safety is key for the fish feed industries. The stainless steel, hygienic Evolum+ frame structure is designed to avoid water stagnation and all the extruder areas are easily accessible. The internal processing assembly of the twin-screw extruder must be cleaned easily as well. Today, Clextral’s hydraulic barrel opening is a paradigm for the industry. It offers access to the screws and barrels in only a few minutes and is a state-of-the-art solution that simplifies preventive maintenance, wear monitoring and cleaning processes.

More information:

Hadrien Delemazure

Fish Feed Market Manager

Clextral

E : Hadrien.delemazure@clextral.com

Figure 3. Example of a trout feed of 5 mm

Challenges and opportunities for extruded aquafeed manufacturing

Jordan Pennells, Artur Rombenso, Danyang Ying, CSIRO

Background

There is no doubt that feed represents an essential aspect of the overall aquaculture system, especially considering that it can contribute to more than 50% of the overall production cost. Embedded within the price of aquafeed, alongside the raw material costs, is the extensive R&D drive to optimize animal nutrition, productivity, and economic viability of a given farming system. A critical factor in this equation contributing to high feed cost is the challenging operation of the extrusion process, which is the predominant manufacturing method for aquafeed products. The choice of aquafeed type has evolved over recent years, shifting from pelleted to extruded feed due to the property profile and the relative benefits these provide. However, extrusion still faces many challenges that must be overcome to optimize feed cost. Several opportunities hold promise for the future of extruded feed manufacturing, which has the potential to streamline industrial product development and optimize product quality control.

“Feed processing techniques play a vital role in aquaculture since it is important to apply the appropriate processing technique to maximize production efficiency at the lowest cost (Wan et al., 2022).”

Press-pellet technology

Pelleted feed has been the predominant feed type supplying aquaculture systems in the past, in part due to price competitiveness and easy-to-operate processing equipment that generates regular-sized and shaped cylindrical pellets. The pelletization process commonly involves a roller-type press that compresses material through a die plate with consistent-sized

holes to generate a hard and high-density pellet. The relatively mild processing temperature of this procedure limits the degradation of heat-labile components that are important for animal nutrition. However, these compressed pellets do not allow for high oil loading and their relatively weak binding leads to product loss, both during transportation and handling in the form of fines and within the water column in the form of pellet breakup and nutrient leaching. These consequences could be addressed during formulation through the selection of appropriate matrix ingredients or binding components.

Extrusion technology

To counteract these limitations, extrusion has been increasingly utilized over the past few decades as the preferred manufacturing method to generate aquafeed. The benefits of extrusion technology include an enhanced capacity to control the final pellet's bulk density and therefore, the floatability and sinking velocity. Extrusion cooking also enables a product with a higher degree of binding, which has the dual benefit of reducing pellet dust during handling and increasing stability once in the water. A more stable feed within the water column has been found to lower the leaching of nitrogen and phosphorus components from the pellet, which is known to contribute to eutrophication (algal proliferation that degrades water quality) (Aşır & Pulatsü, 2008; Glencross et al., 2008).

The high-temperature conditions applied during the extrusion process are known to inhibit the damaging effects of antinutritional factors (e.g., trypsin inhibitors, protease inhibitors, lectin, myrosinase, amylase inhibitors, and cyanogenic glycosides) (Adamidou et al., 2009; Barrows et al., 2007; Drew et al., 2007; Francis et

Ma

Li

P Higher weight gain (WG)

PHigher specific growth rate (SGR)

PHigher hepatosomatic index (HSI)

PHigher protein efficiency ratio (PER)

PHigher protein retention (PRE)

PHigher lipid retention (LRE)

PHigher energy retention (ERE)

PHigher serum triglyceride (TG)

PHigher apparent digestibility

PLower feed conversion ratio

PHigher weight gain (WG)

PHigher protein retention efficiency (PRE)

PHigher lipid retention efficiency (LRE)

PLower feed conversion ratio (FCR)

No significant difference in feed intake

PHigher body lipid level

PHigher lipid retention

PHigher protein retention Shi

• serum triglycerides

• serum total protein

• total cholesterol

• feed intake

No significant difference in:

• growth performance

• whole body composition

• nutrient retention

PBetter growth performance

PIncreased digestive enzymes activities

PEnhanced richness of gut microbiota

PLower lamina propria thickness

PLow intestinal damage

al., 2001), in addition to enhancing the accessibility and utilization of protein and starch components within the feed (Gaylord et al., 2008; Glencross et al., 2011, 2012), leading to lower feed consumption for an equivalent level of productivity (Glencross et al., 2011, 2012; Hilton et al., 1981). Table 1 outlines additional benefits that have been identified by recent studies for extruded aquafeed compared to pelleted aquafeed in fish performance trials.

Extrusion is a high-temperature, short-time process that applies heat, pressure, and shear force to melt and cook the ingredient to generate a porous product.

Ingredients are fed into a heated barrel in a controlled manner, conveyed by rotating screws – single or twin –along the length of the barrel. In many extrusion systems, the screw consists of many individual elements to form the screw profile, such that the ordering and orientation of the parts can be changed to alter the overall screw profile. Screw sections such as “kneading blocks” and “reverse elements” increase the mixing, shearing, and retention of material within that section, which builds backpressure and further enhances material cooking. At the exit of the extruder barrel is a die block, which introduces a

Table 1. Overview of studies within the past decade comparing the benefits of pelleted vs. extruded feed

narrowing of the flow path of the material as defined by the size and shape of the die orifice and contributes to backpressure development. When the superheated material exits the die into the atmosphere, there is an instantaneous and substantial drop in pressure, leading to moisture vaporization within the melt. This phenomenon drives the development of a porous product structure, as the starch and protein-based material expand through this process and becomes locked in a porous structure as the material cools below its glass transition temperature. The complexity of the extrusion process comes in the form of the various factors that impact the transformation of material from ingredients to expanded products. The ingredient formulation plays a major role in this process – components include protein, starch, fiber, lipids, pigments, vitamins, and moisture content. Not only does the ratio of these components impact the extrusion process, but the botanical origin, growth conditions, and pre-processing of plant-based ingredients can alter the structural organization of components (i.e., starch), which can have a dramatic impact on the outcomes of the extrusion process. Moreover, a series of adjustments can be made to the extrusion processing parameters, including the screw speed, barrel temperature profile, and feeding rate, in addition to adjustments to the extruder setup, including the screw profile and the die shape, as seen in Figure 1. Based on the above, it should be evident why the extrusion process is commonly referred to as a “black box” system, and why extrusion operators refer to operation as more of an art than a science. Digging

deeper into the extrusion process can not only give you an idea of the operating principles but also help you start to understand the mechanisms that underpin the product properties generated. Extending this understanding across the vast number of different ingredient types and their relative composition is the cutting edge of food and feed research relating to extruded products.

However, it is important to note that extrusion is not the preferred feed manufacturing technology in all situations, with this article merely outlining the pros and cons of both processing types. This is especially relevant for small-scale aquaculture operations or farms relying on tight profit margins, where pelleted feed may be the most economical choice.

Challenges and opportunities

Extrusion can be a major challenge for aquafeed manufacturing, since the processing conditions significantly affect the properties of aquafeeds, as well as sensitivity toward ingredient variations. In some aquafeed manufacturing settings, the formulation can change from week to week, depending on ingredient cost and availability. This can lead to out-of-specification products requiring rew ork or disposal, process inefficiency undermining sustainability potential, or unwanted process variation that causes sub-optimal product quality. These impacts then flow onto the farmed animal, with feed quality (i.e., nutritional and physical properties) affecting feed intake, digestibility and growth performance.

Figure 1. Extrusion factors that impact the transformation of material from ingredients to expanded products

To summarize this into a list, the following are the key challenges that remain for extruded aquafeed manufacturing:

• Ensuring nutrition requirements and preferred feeding behaviors are met for diverse species

• Optimizing palatability (i.e., taste and texture) of feed for these different species

• B alancing throughput (i.e., efficiency), process sustainability (i.e., energy/waste) and quality

• C ontrolling quality during process variability to minimize rework quantities and product loss

• Overall energy consumption of the process

• Translation of laboratory-based data into the industrial context

• Capital cost of equipment

• Requirement for experienced operators

However, a handful of opportunities are emerging to counteract one or many of these challenges. Novel protein-rich ingredients are under investigation in considerable numbers to reduce the reliance on aquatic-based ingredients such as fishmeal. Emerging alternative protein sources for aquafeed production include macroalgae (i.e., Rhodophyta (red), Chlorophyta (green) and Phaeophyta (brown)), single-cell proteins (i.e., microalgae, bacterial, fungi), and insects (i.e., mealworm, cricket, black soldier fly). This opportunity marks the continuation of a trend that has been in play since the turn of the century, where the ratio of fish-in to fishout within the aquaculture system was 2.57:1 in 2000 but reached 0.82:1 in 2015 and is continuing to drop (IFFO, 2017).

High moisture extrusion presents the opportunity to develop a product that mimics the firm and elastic texture of natural fish flesh. The higher binding capacity of this material also significantly improves water stability, lowering uneaten feed and the associated negative environmental costs. In addition, extrusion at a higher moisture content is an inherently more stable process due to the lowest absolute shears forces and reduced risk of clogging and burning compared to low moisture extrusion. However, an energy penalty is associated with drying extruded products with higher water content.

Near-infrared spectroscopy (NIRS) characterization of both the raw ingredients and extruded products can

enable a greater understanding of the material entering into the extrusion process, in addition to providing a tool to characterize the “quality” of the final product in a timely, non-destructive, and cheap manner that would be attractive for industry adoption.

AI-driven quality control systems are an emerging opportunity to optimize the quality and efficiency of the aquafeed manufacturing process. An example of this is one company – FAMSUN – who is aiming to develop a self-adjusted AI extruder based on reliable mathematical models to predict extruded product quality or provide recommended operating conditions to achieve a desired product property portfolio/ profile. However, at this stage they do emphasize that comprehensive and true predictive capability is a “big if” and it must be considered that their existing mathematical models/relationships are most applicable to their own extrusion system (from which the empirical data underpinning these relationships was generated) and that there is an open question about their transferability to different extrusion scales and setups.

Final considerations

Considering this overview of the extrusion process as applied to aquafeed manufacturing, here are a few final considerations to keep in mind for this topic:

• Extrusion is still considered an art; it is a complex black box process that is difficult to predict and control.

• Extrusion has many benefits over pelleted feed, but also with many challenges that remain unaddressed and questions that remain unanswered.

• T he variability of plant-based ingredients (e.g. botanical origin, growth conditions, pre-processing conditions) can have a dramatic impact on the outcomes of the extrusion process

• It is very important to consider the impact that novel ingredients have on the quality of extruded feed throughout their development.

• CSIRO Food & CSIRO Aquaculture are collaborating to bring more science into the extrusion process. Industry collaboration is welcome to optimize feed quality and develop new products using extrusion technology.

References available on request

Aquaculture production in 2021

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 2021 from FAO Aquaculture, Capture and Global production databases.

Global aquaculture production reached a new high of 126,035,297 tonnes in 2021 (valued at over USD 296.5 billion), with the sector growing at an average rate of 3.25%/year over the period 2015 to 2021 (Fig. 1). Total global fed-aquaculture species production and estimated compound aquafeed usage from 2015 to 2021 reportedly grew at an average annual rate of 4.23%/year and 4.57%/year from 2015 to 2021, respectively (Fig. 4). Moreover, calculated fed species production was estimated to grow from 54.15 million tonnes in 2021 to 64.14 million tonnes in 2025 and 76.53 million tonnes by 2030, and estimated aquafeed usage to increase from 62.55 million tonnes in 2021 to 75.30 million tonnes in 2025 and 90.71 million tonnes by 2030, respectively (Fig. 5).

Figure 1. Top aquaculture country producers in 2021 (metric tonnes; FishStatJ version 4.03.00, March 2023; FAO, 2023).

Figure 2. Top fed aquaculture species groups in 2021. (FAO FishStatJ version 4.03.00, March 2023).

Figure 3. Global production of major fed-aquatic species: 2000 to 2021 (FAO FishStatJ version 4.03.00, March 2023).

Figure 5. Figure Total global fed-aquaculture species production and estimated commercial aquaculture feed usage from 2000 to 2021, and estimates for 2025 and 2030. Fed-species production calculated from FishStatJ release 4.03.00: FAO, 2023.

Figure 4. Total estimated global compound feed usage by major fed species groups was 62.55 million tonnes in 2021. Values given in million tonnes and as % total.

The advancement of biofloc technology in fish nutrition: A revolutionary approach

M.Menaga, S.Felix, Tamil Nadu Dr.J.Jayalalithaa Fisheries University

In recent years, there has been a significant advancement in aquaculture practices, particularly in the realm of fish nutrition. One such revolutionary approach that has gained tremendous attention is the implementation of biofloc technology. It involves the development of microbial communities, primarily consisting of bacteria, algae, and protozoa, in aquaculture systems. These communities, collectively known as bioflocs, offer numerous benefits to fish health, nutrition, and overall production.

The concept of biofloc technology originated from the need to reduce environmental impact, enhance nutrient utilization, and improve water quality in intensive aquaculture systems. By creating and maintaining high-

density bioflocs, fish farmers can effectively convert organic waste, uneaten feed, and excess nutrients into a valuable protein source. This sustainable practice not only minimizes the discharge of effluents but also provides a nutritious food source for cultured fish.

Biofloc formation and composition

The first step in biofloc technology implementation is the formation of bioflocs within the aquaculture system. This process involves the addition of carbon sources, such as molasses, to stimulate the growth of heterotrophic bacteria. These bacteria, along with autotrophic microorganisms, form the foundation of the biofloc community. The microbial composition of

bioflocs may vary depending on the specific system and management practices employed. Bioflocs are primarily composed of bacteria, algae, fungi, protozoa, and organic matter. Bacteria play a crucial role in organic waste degradation, nitrogen conversion, and overall nutrient cycling. Algae, particularly microalgae, contribute to the production of oxygen through

photosynthesis, while also serving as a natural feed source for fish. Protozoa and fungi aid in the breakdown of complex organic compounds, further enriching the nutritional value of bioflocs. The nutritional composition of biofloc reported by the various authors is highlighted in Table 1.

Environmental sustainability

Biofloc technology offers significant environmental sustainability advantages compared to conventional aquaculture practices. The key environmental benefits include:

Nutrient recycling

Biofloc systems facilitate the recycling of nutrients that would otherwise be lost as effluents. The microbial community converts organic waste into biomass, which can then be utilized as a natural feed source for fish. This reduces the discharge of excess nutrients into the surrounding environment, preventing water pollution and eutrophication.

Water conservation

Biofloc technology promotes water conservation in aquaculture systems. The dense microbial communities help maintain good water quality by consuming excessive nutrients, reducing the frequency and volume of water exchange required. This conservation of water resources is especially crucial in areas facing water scarcity or where water quality is a limiting factor.

Table 1. Proximate analysis of biofloc reported by various authors

FISH FEEDS

Reduced carbon footprint

By minimizing water exchange and the need for external feed sources, biofloc technology reduces the carbon footprint associated with aquaculture operations. The implementation of bioflocs contributes to sustainable intensification by optimizing resource utilization and reducing greenhouse gas emissions.

Integrated farming systems

Biofloc technology can be integrated with other farming systems to enhance resource efficiency. For instance, bioflocs can be utilized in the cultivation of economically valuable crops, such as vegetables or algae, in an aquaponics setup. This integration enables the utilization of nutrients released by the fish and promotes a circular economy approach.

Nutritional benefits of bioflocs

Bioflocs offer a range of nutritional benefits for fish reared in aquaculture systems. As the microbial community develops, it accumulates protein, lipids, vitamins, and minerals from the surrounding environment. These nutrient-rich bioflocs can be consumed directly by the fish or indirectly through water filtration systems. The nutritional advantages of bioflocs include:

Protein-rich diet

Bioflocs contain a significant amount of high-quality protein, offering a valuable dietary source for fish. The protein content in bioflocs can range from 30-60%, depending on the system's management. This proteinaceous diet helps fulfill the protein requirements of fish, promoting growth and development.

Essential amino acids

Bioflocs provide a balanced profile of essential amino acids required for optimal fish growth. Fish species, especially herbivorous and omnivorous ones, can utilize the amino acids present in bioflocs efficiently, reducing the need for external protein sources.

Vitamins and minerals

Bioflocs are rich in vitamins and minerals that are essential for fish health. These micronutrients include vitamins A, B complex, C, and E, as well as minerals like iron, zinc, and selenium. The presence of these nutrients in bioflocs contributes to improved immune function, reproductive performance, and overall vitality of the fish.

Enhanced feed conversion efficiency

Incorporating bioflocs in fish diets have improved feed conversion efficiency (FCE). The bioflocs provide a readily available source of nutrients, allowing fish to optimize nutrient absorption and utilization. This increased FCE reduces the amount of feed required for fish growth, resulting in cost savings for farmers.

The utilization of biofloc as a functional feed ingredient in aquaculture offers several benefits for cultured organisms. These functional advantages include:

Improved feed conversion efficiency (FCE)

The inclusion of biofloc in aquaculture diets has enhanced FCE. The high protein content, balanced amino acid profile, and presence of bioactive compounds in biofloc contribute to better nutrient utilization and absorption. Improved FCE not only leads to faster growth, but also reduces the amount of feed required, minimizing production costs and environmental impact.

Enhanced digestibility

Biofloc contains enzymes, including proteases, lipases, and carbohydrases, which aid in the breakdown of complex nutrients and improve digestibility. The presence of these enzymes in biofloc can supplement the digestive enzymes of fish, especially in species with limited endogenous enzyme production, improving nutrient assimilation and overall feed efficiency.

Immunostimulatory effects

Biofloc-derived bioactive compounds, such as antimicrobial peptides and probiotics, have immunostimulatory properties. These compounds can enhance the immune response, disease resistance, and overall health of aquatic organisms. The presence of beneficial microorganisms in biofloc can also modulate the gut microbiota, promoting a balanced and beneficial microbial community.

Gut health promotion

The inclusion of biofloc in aquaculture diets can contribute to gut health maintenance and improvement. The diverse microbial composition of biofloc provides a source of beneficial bacteria that can colonize the fish intestine, positively influencing gut microbiota composition and function. A healthy gut microbiota enhances nutrient absorption, reduces pathogenic colonization, and improves overall intestinal integrity.

Reduction of fishmeal dependency

Commercial fish feeds often rely on fishmeal, which is derived from wild-caught fish stocks. Biofloc technology reduces the dependency on fishmeal as a feed ingredient by providing an alternative, sustainable, and cost-effective feed source. This contributes to the conservation of wild fish populations and reduces the ecological footprint of aquaculture.

Disease prevention

Bioflocs promote a healthy microbial balance in aquaculture systems, reducing the risk of opportunistic pathogens. The competitive exclusion effect of the biofloc community inhibits the growth of harmful bacteria, thereby minimizing the occurrence of diseases. Additionally, bioflocs can stimulate the fish's immune system, enhancing their resistance to infections.

Nutritional optimization in aquaculture feed

Applying omics approaches in biofloc technology allows for the evaluation and optimization of nutritional aspects. By studying the gene expression patterns and metabolic profiles of cultured organisms in biofloc systems, researchers can identify key genes, enzymes, and metabolic pathways involved in nutrient utilization and absorption. This knowledge aids in formulating biofloc-based diets that meet the specific nutritional requirements of the cultured species, improving feed efficiency and growth performance.

Conclusion

The advancement of biofloc technology in fish nutrition has revolutionized the aquaculture industry, offering a

sustainable and efficient approach to fish production. By harnessing the power of microbial communities, fish farmers can enhance feed utilization, improve water quality, and reduce environmental impact. The nutritional benefits provided by bioflocs contribute to the growth, health, and overall well-being of cultured fish. Furthermore, the environmental sustainability advantages of biofloc technology align with the global goals of responsible and eco-friendly aquaculture practices. As research and practical applications continue to evolve, biofloc technology is poised to play a pivotal role in meeting the increasing global demand for seafood while minimizing the industry's ecological footprint.

More information:

M.Menaga

Tamil Nadu Dr.J.Jayalalithaa

Fisheries University

Chennai, India

E: mena.fishcos@gmail.com

S.Felix

Tamil Nadu Dr.J.Jayalalithaa

Fisheries University

Chennai, India

RESPONSIBLE FARMING

Using nutrition as a welfare indicator for farmed tilapia

Marius Nicolini, FAI Farms

Feed accounts for 50-70% of production costs in most tilapia farms. That is why it is crucial for farmers to carefully consider what, how, when, and how much their fish are eating. Well-fed fish have a better life and as a result, they are healthier, better looking, and they reach a higher market value. Well-fed fish are given feed that contains the essential nutrients in sufficient quantities and proportions to provide a nutritious and balanced diet. It is also important that the farmer uses the appropriate feeding methods, where feed is distributed evenly, offered frequently and at the right times to minimize competition for food and reduce aggression. This article summarizes the main

nutritional requirements and best feeding practices to optimize tilapia welfare using information from the publication Tilapia On-Farm Welfare Assessment Protocol for Semi-intensive Production Systems (Pedrazzani et al., 2020).

The nutrients in aquafeeds

The essential nutrients in fish feed encompass proteins, carbohydrates, fats, minerals, and vitamins. While all these nutrients are vital for fish, proteins often receive particular attention from fish farmers due to their cost and direct impact on fish growth. A diet with a high protein content offers numerous advantages,

such as stimulating feed intake, improving feeding efficiency, and accelerating growth rates. However, it is important to note that a high-protein diet can also result in increased waste production, compromised water quality, and reduced return on investment. As tilapia mature, their protein requirements decrease. Post-larvae typically require feed consisting of 45-60% protein, whereas adults and broodstock only need approximately 28-36% protein in their diets (Table 1).

Lipids serve as an energy source while also playing a crucial role in preserving healthy cell membranes, promoting growth, and supporting reproductive functions in tilapia. To ensure optimal nutrition for tilapia, it is essential to meet the minimum requirement of 0.5% for both omega-3 and omega-6 fatty acids in their feed (Table 1).

Carbohydrates, comprising up to 40% of fish diets, serve as a vital energy source. Tilapia, a warm water, freshwater, and omnivorous fish species, demonstrates a higher capacity to efficiently utilize carbohydrates compared to cold water, marine, and carnivorous fish. This characteristic makes tilapia particularly well-suited for growth on a diet that is rich in carbohydrates. However, it is important to be aware that excessive carbohydrate content can lead to a decrease in feed efficiency. While tilapia can handle a relatively high carbohydrate intake, it is crucial to carefully manage the carbohydrate levels in their diet to maintain optimal feed efficiency and maximize growth potential.

Table 1 offers a comprehensive overview of the dietary requirements in terms of crude protein, carbohydrates, total lipids, and key fatty acids (such as omega-3 and omega-6) for different life stages including post-larvae, fry, juveniles, broodstock, and adults. Generally, carbohydrates and fats are required in similar quantities across various life stages. However, younger fish have a higher demand for proteins compared to older fish.

The correct size of the feed pellet

It is crucial to provide fish with the appropriate pellet size corresponding to their specific growth stages. If a fish is given a pellet that is larger than its mouth opening, it may face difficulties in consuming the pellet and there is a risk of choking. Moreover, larger pellets take more time to break down in the mouth, leading to water-soluble nutrients like vitamin B and ascorbic acid to leak into the water before reaching the fish's digestive system. On the other hand, if a fish is fed with pellets that are too small, it will spend more time searching for and consuming its daily ration, expending additional energy that could have otherwise been utilized for growth. Table 2 outlines the recommended pellet sizes for different life stages, ensuring optimal feeding efficiency.

Feeding the right amount

Ensuring appropriate feeding quantities presents a daily challenge for farmers. Insufficient feed intake can have detrimental effects on the growth and development of the fish. Weaker fish may exhibit lower immune responses and be more susceptible to diseases, resulting in compromised health and welfare. Conversely, overfeeding fish significantly escalates production costs. Excessive feed leads to poor water quality, impairing fish development, growth, health,

overall welfare.

Table 1. Dietary requirements for different life stage of farmed tilapia

Table 2. Recommended pellet sizes for different tilapia sizes/ growth stages

RESPONSIBLE FARMING

In both scenarios, animals experience heightened stress, resulting in weakened immunity and increased disease susceptibility, further impacting their health and welfare. Feeding also becomes problematic during periods of stress when fish may lose their appetite. By closely observing the fish and their environment, farmers can adjust feeding practices according to their specific life phase requirements. To address these challenges effectively, it is highly recommended to seek guidance from professionals and consult with feed suppliers. They can provide valuable insights, offer feeding tables tailored to specific farming conditions,

and assist in determining the optimal quantity and quality of feed required. By seeking expert advice and considering individual farming conditions, farmers can establish appropriate feeding practices that promote the well-being and optimal growth of their fish. Figure 1 is an example of a feeding table that can be used as guidelines.

The different methods of feeding

There are three primary methods of feeding fish: manual feeding, automatic feeding, and on-demand feeding. Manual feeding allows the farmer to have

Figure 1. Tilapia feeding table

direct control over the amount of feed provided, enabling them to avoid overfeeding and closely monitor the feeding behavior and overall health of fish in each pond. Automatic feeding systems are particularly suitable for larger farms, as they can significantly reduce labor requirements by up to 90%. These feeders allow for consistent distribution of feed in small quantities over a specific time period set by the farmer. On-demand feeders have the advantage of continuously

RESPONSIBLE FARMING

offering food to fish until they are satiated. This method simplifies daily management, reduces competition for food among fish, and maintains more consistent oxygen demand and ammonia production throughout the day. However, a potential drawback is that fish may engage in food wastage or play with the feed. Irrespective of the feeding method chosen, it is crucial to ensure that the food is distributed evenly and not limited to a single spot or only at the pond's edge. Otherwise, larger and dominant fish tend to consume a disproportionate amount of food, depriving smaller fish of adequate nourishment. This can result in uneven fish sizes within a population and lead to losses for producers. Additionally, adapting the feeding frequency during the production cycle is an important aspect of sound feeding practices. As tilapia grow larger, the amount and frequency of feeding should gradually decrease to align with their changing nutritional requirements.

Phases

Source: Pedrazzani et al . (2023). Manuscript in preparation. Not included ( ) in each production phase

*When rounding a number from one decimal place to none, if the first number after the decimal point is 5 or greater, add 1 to the number before the decimal point; if it's less than 5, keep the number before the decimal point unchanged.

Table 3. Recommended feeding frequencies for different tilapia fish sizes

Table 4. Nutritional welfare reference values for tilapia nursery (NU) and grow-out (GO) phases and different weights

RESPONSIBLE FARMING

Nutritional welfare indicator

The study conducted by Pedrazzani et al. (2020) has played a crucial role in identifying key nutritional indicators that significantly impact tilapia welfare. Through an extensive analysis of scientific publications on tilapia nutritional requirements, feeding practices, and welfare, the researchers have highlighted five indicators that are particularly influential when assessing fish welfare from a nutritional perspective. These indicators include feed quantity, feeding frequency, food distribution, crude protein content in the feed, and Feed Conversion Ratio. The comprehensive work of Pedrazzani et al. has not only helped in understanding the optimal ranges for these indicators but has also facilitated the development of a three-point scoring system. A score of 1 signifies that the indicator falls within the ideal range, indicating good welfare. A score of 2 indicates some variability outside the ideal range

that the tilapia can tolerate without severe welfare consequences. Finally, a score of 3 suggests that the indicator's level is unacceptable and can have adverse effects on fish health and welfare. The table provided below presents the nutritional indicators used for assessing welfare in tilapia production. This resource has been instrumental in aiding farmers by identifying potential shortcomings in their feeding management practices and guiding them toward measures that can enhance their production performance.

More information:

Marius Nicolini

Aquaculture

FAI Farms

Project Manager

E: marius.nicolini@faifarms.com

Industry Events

2023

JULY

14 – 18: 30th Annual Practical Short Course on Aquaculture Feed web.cvent.com

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