Aquafeed Vol 12 Issue 2 2020

Vol 12 Issue 2 April 2020

AQUAFEED Advances in processing & formulation An Aquafeed.com publication

ENZYME ADDITIVES IN PLANT-BASED DIETS COVID-19 impact on aquafeeds New extrusion processing technology Trace minerals Prebiotics against fish diseases

Published by: Aquafeed.com LLC. Kailua, Hawaii 96734, USA www.aquafeed.com info@aquafeed.com

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AQUAFEED

VOL 12 ISSUE 2 2020

Contents

HOW THE AQUAFEED INDUSTRY IS COPING WITH CORONAVIRUS 14 As part of the global food supply chain, the aquafeed industry has not escaped the impacts of these unprecedented times.

VACUUM COATER 19 Improving feed production capacity and saving energy in feed mills through a new series of vacuum coaters.

ENZYMES IN PLANT-BASED INGREDIENTS 40 The supplementation of enzymes improves the digestion of natural and supplemented feed, thereby improving the feed efficiency and performance.

PREBIOTIC TREATMENTS 51 Protective effect of prebiotics against bacterial diseases in striped catfish and a new infectivity model using immersion bath.

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AQUAFEED

VOL 12 ISSUE 2 2020

Contents 6

Interview - Pilar Cruz

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News Review

14 Weathering the pandemic

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19 Vacuum coater on trials: Capacity up for aquafeed production?

A new way of drying shrimp feed

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New extruder for the growing demands of fish feed production

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exhibitors Biosurfactants: A new nutritional concept in aquaculture

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Natural feed additive improves health conditions in the aquaculture business Application of enzymes in fish feed for profitable fish farming

100+

Enzyme pretreatment of plant ingredients used in diets for mullet

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hy trace minerals levels and source must be adjusted W speakers in aquaculture diets

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ietary potassium-diformate affects growth performance D and survival rates of vannamei-shrimp in hatchery and grow-out in worldwide aquaculture

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prebiotic treatment of edwardsiellosis in striped catfish A (Pangasianodon hypophthalmus)

Columns

27 Peter Hutchinson – Ask the expert

43 Albert Tacon – Mycotoxin publications

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400

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54 Greg Lutz – Trends & developments

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Calendar of events

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

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 2 2020

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Pilar Cruz is president and group leader for Cargill Aqua Nutrition business. Her background spans 18 years in leadership roles with Cargill and includes running the company’s strategy and business development group, leading teams in Cargill’s animal nutrition and animal protein businesses, and managing teams in Latin American, Europe, Canada and the United States.

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

PC: First and foremost, thank you for taking the time to get to know me, and for your interest in learning more about Cargill’s Aqua nutrition business. I have worked in the animal nutrition and animal protein industries for more than 15 years – in different places of the world, and have a good perspective of these industries globally.

Certainly, aquaculture was part of the landscape for my previous work and I have always stayed close to the aqua business because I find this industry very relevant to fulfill Cargill’s mission of nourishing the world safely, responsibly and sustainably. Aquaculture is also a fascinating industry with a lot of opportunities

with Pilar Cruz for growth. I’m super excited to bring my previous experience to aquaculture and dig into the opportunities that we see in this industry, including finding new sources of sustainable ingredients, developing functional feeds and nutritional solutions that will help our customers be more productive, and partnering with our communities to raise their standards. I am excited about being part of a company that wants to make a difference through food, agriculture and aqua nutrition.

I also know that my experience in leading Cargill’s global strategy and business development function, which will help me propel our strategy and our aqua business forward. We are confident this is a growth business with plenty of opportunities to help our customers thrive!

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AQUAFEED: Cargill spans the supply chain from field to table; how do these businesses work together?

PC: As an integrated operating company that operates in over 70 countries, we’re successful because we put our customers and our purpose – nourishing the world in a safe, responsible and sustainable way – at the center of everything we do. This gives us agility and stronger integration to make the connections that enable success.

Cargill has been in business for over 150 years, and if you look back at our history, our company has always moved food from where it is produced to where it is needed. Today, we are working to implement sustainable practices and develop healthy, delicious products that consumers want.

Our role as a global, integrated food company gives us a unique perspective on where we’ve come from – and where we’re going – as an aquaculture industry.

A couple key areas of opportunity we see are efficient and sustainable value chains, characterized by a consistent, quality product, on-time delivery, supply availability, pricing predictability, traceability, and sustainability; variety in product mix and packaging, including unique flavor profiles, easily prepared items, and convenient and sustainable packaging; and new routes to market where consumers eat is changing.

There are blurred lines between snacking - home and away - and fragmented channels.

AQUAFEED: Would you tell us about Cargill's aquafeed business? What is the production volume and your geographic coverage?

PC: As a thought leader within the global aqua nutrition industry, Cargill’s strategy is to focus on getting as close to our customers as possible in order to enable their success. To facilitate this closeness, our global teams are located in different regions around the world. We operate 40 facilities – 20 fully dedicated to aqua nutrition – around the globe, including aqua-focused Cargill Innovation Centers in Chile, Norway and the United States that drive our research, development and innovation of products and services. We are recognized as a leader in innovative nutrition and technology and our brands support customers across regional businesses in Chile, the North Sea, North America, northern Latin America and Asia.

While it is possible to make a series of diets for the lifecycle of salmon that entirely replace fishmeal using other ingredient sources, we do not feel that it is necessary as we have our focus on sourcing sustainable sources of fishmeal.

AQUAFEED: Beyond the "commodity" species you feed - salmon, shrimp and tilapia, what other species do you see coming up as a growing market?

PC: From a species standpoint, our top priorities are shrimp and salmon. We also work with strategic customers on numerous regional species such as tilapia, eel and others. Our marine fish feeds are tailored to meet the needs of a wide range of marine fish around the world.

AQUAFEED: The USDA deregulated Cargill’s proprietary canola for cultivation in the U.S. What is the expected impact of this new source in terms of fishmeal consumption?

PC: Salmon feeds have fallen from using up to 70% marine ingredients in the 1990s to between 10-20% according to customer requirements today. While it is possible to make a series of diets for the lifecycle of salmon that entirely replace fishmeal using other ingredient sources, we do not feel that it is necessary as we have our focus on sourcing sustainable sources of fishmeal. We are also seeing increasing evidence from farmers that fishmeal is important to the long-term health of the fish, probably due to the micronutrients in it which are not supplied by plant-based ingredients.

Our preference is to continue to use relatively small amounts of sustainably sourced fishmeal from whole fish or trimmings, complemented with other sources of protein from sustainable supply chains. Our aim is not to focus on particular ingredients, but rather be able to get the nutrients we need to deliver nutritious feeds from a wide range of sustainable supply chains. To this end, we work with our suppliers to demonstrate their sustainability credentials and where required, improve

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them. In June 2018, we started a global initiative with WWF to learn more about the sustainability of the wild fish stocks we source from and how they are managed. The initiative includes a review of our global 2017 sourcing of fishmeal and oil against our public commitment to sourcing more sustainable marine ingredients. The initiative showed that in Scotland and Norway combined, we are already sourcing 65% of our total marine ingredients from MSC (Marine Stewardship Council)-certified fisheries, according to figures from 2017 and 2018. Globally, we are at 43%. Our 2025 goal is that all marine ingredients should come from MSC-certified fisheries, and we hope to continue our collaboration with WWF in pursuit of this goal.

We understand that the planet has finite resources and believe that it is our job to find innovative feed options for our customers that will protect the planet while supporting sustainable protein production.

AQUAFEED: Cargill recently partnered with Innovafeed and White Dog Labs for sustainable alternatives to fishmeal. Apart from this, what other strategies are you following to improve feed production sustainability?

PC: Feed has a major influence on the sustainability of aquaculture. Raw materials need to come from sustainable supply chains, reducing competition for resources with other food production systems.

Aquafeed must be formulated to meet the needs of the fish in the environment where they are farmed.

But feed can also affect the health and welfare of the fish, improving overall efficiencies and also delivering the nutrients that human consumers will eat.

Our wide range of health feeds reflects our commitment to working alongside customers to understand the issues they face and help solve them.

One example is EWOS Dermic, a revolutionary solution we launched in 2018. Cargill’s research team drew on 15 years of trial results to develop a dietary package that supports skin health and integrity through nutrition. With EWOS Dermic, customers are seeing rapid repair of skin damage and fewer downgraded fish at harvest. Trials indicate that the fish recover their appetites faster after handling, returning to their healthy growth patterns. Our health feeds, as part of integrated health management programs, have already played a major part in almost eliminating the use of antibiotics in salmon farming in Norway and Scotland.

AQUAFEED: Cargill is making a significant investment in human and animal health business. Are there any solutions in the future portfolio that will apply in the aqua industry?

PC: You’re correct – Cargill is making a significant investment to build a leading digestive and immune health business for both animal and human application, which emphasizes the growing importance of health among both farmers and consumers and demonstrates our commitment to growing this business into a leading player in the industry.

By applying science, technology and research, Cargill Health Technologies is developing new categories of products that strengthen the immune system, drive better overall health and unlock the full potential of the bodies we’re feeding – both animal and human.

Through our work in understanding and influencing the microbiome, we’re creating solutions that improve digestive and immune health at all stages of life to help nourish the world in a safe, responsible and sustainable way. We have started to apply solutions from our Health Technologies business to aqua applications.

Today we’re able to significantly improve the health of shrimp and tilapia with our DVAQUA product, which supports animals during challenging conditions like early mortality syndrome (EMS). We also have several projects in process to combat some of the most difficult health challenges in aquaculture, such as sea lice in salmonids. Providing solutions to large health challenges like these are critical to improving the welfare of aquatic animals, and financial support to farmers.

AQUAFEED: In terms of aquafeed research and innovation, what can we expect to see in the near future?

PC: I see two big areas of opportunity that will see significant development in the next few years.

The first is digital. Accurate and available data will continue to drive better insights, farm management and ultimately success for our industry. We developed a platform called myEWOS, which is a flexible digital platform that enables us to build and deploy data or digital services, helps customers better plan their production strategy, monitor and compare farm performance, and assess fish quality. Customer data is stored in our SeaCloud database, which allows accurate analyses and feed recommendations based on big data from the production of over 1.5 billion salmon.

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The myEWOS platform and SeaCloud are also key in developing new green solutions such as the ongoing work to deliver feed with a lower carbon footprint due to sensor and machine-based optimizations of the supply chain.

The second area is in feed ingredients. A range of “novel” ingredients are achieving scales that enable them to be introduced to the salmon feed market.

As I mentioned in regard to InnovaFeed and White Dog Labs, protein sources are arising from bacterial origins, capturing nitrogen and creating the amino acids and some other micro-nutrients needed for feed.

Supplying new sources of EPA and DHA which are not related to fish oils, traditionally the only source available at scale, also bring exciting developments.

AQUAFEED: Where would you like to see the aquaculture feed business in 10 years?

PC: Aquaculture production needs to more than double between 2010 and 2050 to meet the projected fish demand according to the World

Resource Institute (WRI 2018). And while aquaculture provides relatively efficient means of supplying animal-based protein as well as a range of essential micro-nutrients, it also brings a range of environmental and social sustainability challenges that must be addressed to enable the sustainable growth of the industry.

This is the challenge – but I believe, also a great opportunity for our industry. We are growing, expanding and investing in our aqua nutrition business because we see great opportunities in line with our customers' growth – and in order to be able to nourish a growing population. Cargill research shows that protein demand will grow by more than 70% over the next 30 years. Seafood will be the largest part of this growth, contributing to 37% of this demand growth in the next six years. Cargill wants to be there to support the increased demand from consumers as well as our customers growth aspirations. This is an exciting time to be in the aqua business and to be a part of the Cargill Aqua Nutrition business.

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

Sustainably-fed trout and salmon now available in French and German markets

Skretting, Veramaris and Innovafeed has supported the launch of sustainably raised salmon and trout fed in some European markets.

Trout produced by Truite Service, fed with a Skretting diet that incorporates an algal oil developed

by Veramaris, arrived on retail shelves in France in February. In

2019, they made waves when salmon raised on a similar diet were first made available to French consumers by retailer Supermarché Match. In Germany, Kaufland has become the first retailer in the country to introduce salmon rich in omega-3 fatty acids EPA and DHA. The salmon, which is available

Nutreco invests in Kingfish Zeeland Nutreco invested in Dutch company Kingfish Zeeland, which aims to bring supplies of yellowtail kingfish to the U.S. and European markets through

a proprietary recirculating aquaculture system (RAS).

In addition to the investment, the companies will also cooperate on further development of RAS feeds.

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 2 2020

under Kaufland’s own brand K-Blue Bay, has been fed a diet containing natural marine algal oil

by Veramaris. French retail group Auchan is also introducing a trout raised on a novel feed by Skretting enriched with algal oil from Veramaris and insect meal from InnovaFeed.

For the first time the entire value chain came together to create a unique consumer proposition, combining farming, feed efficiency and alternative ingredients. In addition to meeting consumer expectations for responsibly produced food, this proven new approach to aquaculture diets is also responsible for generating increased sales, with Supermarché Match recently reporting a 12% growth in its salmon category following the launch of salmon from Norwegian farmer Lingalaks, fed Skretting’s aforementioned salmon diet.

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Aquasoja’s new functional feeds to boost fish health

Aquasoja launched two functional feeds, Ygeia Derma and Ativia.

YGEIA DERMA is reinforced in zinc and vitamin C to enhance epithelial regeneration in immune response promoters and includes extracts of flavonoid-rich plants with anti-inflammatory and anti-stress effects. A decrease in the incidence of skin rash, loss of body weight and mortality and a regeneration in the skin of fish is achieved in seabass and seabream when fed

with the correct feeding rate. YGEIA DERMA is the second product of the YGEIA range, a line of functional feeds composed of 100% natural ingredients to prevent or solve certain issues in farming conditions.

The company also launched ATIVIA, a new line of feeds that aims at protecting saltwater and freshwater fish above 50 g from endo and ectoparasites and pathogenic bacteria. In order to mitigate and/ or prevent the negative effects of

parasites and pathogenic bacteria in fish, the new diet aims to reduce health risks (secondary infections), morbidity and the risk of horizontal contaminations, and improve immunocompetence and increase survival rates. ATIVIA contains 100% natural-based functional ingredients that act synergistically and through multiple mechanisms on external and internal barriers like skin, gills and gastrointestinal tract.

Adisseo and Calysta establish a joint venture to commercialize FeedKind® Adisseo and Calysta signed an agreement to establish a joint venture named Calysseo to develop FeedKind®, an innovative feed solution for aquaculture, and to provide exclusive supply for Asian markets.

The strategic partnership will also see the construction of

the world’s first commercial FeedKind® production facility in China with the first phase expected to start operating in 2022, delivering 20,000 tons of FeedKind® protein per year. The second phase of the partnership will add a further 80,000 tons of capacity to the site, allowing for

extended market penetration leading to further development to follow customer demand.

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New functional feeds to outcompete pathogenic bacteria

PEOPLE IN THE NEWS Trond Williksen Benchmark appointed Trond Williksen as chief executive officer. Trond, a seafood veteran that has held senior executive positions in the sector for over 20 years, will officially join Benchmark on June 1, 2020.

Wee Kok Leong Aller Aqua developed a new functional feed concept, Aller Aqua Support. The concept includes a series of aquafeeds based on a blend of functional ingredients that promote growth and survival in fish, as well as disease resistance and prevention.

These new diets balance the microbial community in the fish gut, preserving beneficial bacteria to outcompete pathogenic ones. The diets protect the fish and do not cause side effects or exhaustion, boosting long-term effectiveness. No prescription or withdrawal time is required.

The Support concept is currently available for trout, catfish, carp, tilapia, sturgeon, sea bass and sea bream and is applied to Aller Aqua’s fry and selected grower feeds.

Nuseed partners with ADM for omega-3 canola processing in the U.S. Nuseed entered into an agreement with ADM for crushing and processing Nuseed’s proprietary omega3 canola in the U.S. The first scaled crush of the grain harvested by Montana and North Dakota contract growers is anticipated in the second quarter of 2020.

Nuseed Omega-3 Canola, the world’s first plant-based source of long-chain omega-3 fatty acids, has been developed in collaboration with CSIRO and the Grains Research and Development Corporation (GRDC).

Cargill’s Diamond V® business hired Wee Kok Leong as senior consultant – technical services, Aqua. Wee brings with him over 37 years of extensive academic and commercial experience.

Siddharth Jain Ridley Corporation Limited appointed Siddharth Jain as chief executive officer-Novacq™ to advise the completion of the land and feed mill acquisition in Thailand. “With the investments

by Ridley Corporation (RIC) in Australia and Thailand, we have a great opportunity to commercialize Novacq™ globally for the benefit of the global aquaculture industry,” said Sid.

Leo Xie-Lei Kemin Industries appointed Leo Xie-Lei as president of Kemin AquaScience™, the company’s global business unit that serves the aquaculture industry. Xie-Lei is succeeding Kemin AquaScience’s™ first president, KP Philip, who will continue to lead strategic projects for Kemin Industries.

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Weathering the pandemic Aquafeed.com staff

COVID-19 is affecting us all. As part of the global food supply chain, the aquafeed industry has not escaped the impacts of these unprecedented times.

Patrick Charlton, CEO of Alltech Coppens, summed up the situation: “As with all food sectors, the impact varies from region to region and country to country.

Markets primarily dependent on export have been the first to see declines in demand and are responding accordingly. Producers are adapting by managing their stocks to prevent an oversupply,” he told Aquafeed.com.

“Many of the fish species farmed globally are dependent on demand from the restaurant and catering trade, and the effective closure of these markets during lockdown is going to impact demand at the local level.”

“We see that aquaculture is highly affected in all high-value export species, such as salmon, shrimp and marine fish,” Peter Coutteau, Business Unit Director

Aquaculture at Adisseo confirmed. “Dominant markets for these items are in lockdown. Restaurants, tourism, reduced access to supermarkets … it all minimizes the consumption of high-value seafood. Locally, mostly freshwater fish production is less affected, similar to the poultry sector, since it continues to be on the local menu.”

“For our clients, business is not as bad as expected: big farmers have found new ways to sell their fish and the small ones are selling in short food supply chain since the French market is buying French now, a measure that has been very helpful,” French feed manufacturer, Le Gouessant Aquaculture said. “But it is really difficult for many small and medium fish farmers.” The company reported that it was doing its best to deliver on time to its customers, but the transportation and logistics could be complicated in Europe.

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The largest global feed companies are of course in the strongest position to withstand the immediate pressures imposed by the pandemic. “We’re working very hard to monitor the situation, and so far, we don’t see immediate consequences for feed production at our factories,” one of the largest, Skretting, told us. “We have a good overview of the status of all ingredients so that we know if and where we could potentially face challenges.

While feed production is not impacted for now, a number of our clients are experiencing the collapse of markets. This will no doubt affect us in the weeks and months to come.”

Pilar Cruz, Group Leader and President of Cargill’s aqua nutrition business said: “We have seen increases in demand as our customers respond to the uncertainty in front of them. In response to this, we are working very hard at running our plants to be able to meet our customers’ needs. Currently, we’ve been able to successfully manage our raw material supply chains to meet higher customer demand and feed supply logistics.”

Asked about the impact of COVID-19 on Cargill’s customers, she noted that “in the U.S. and Europe we’ve seen a drop in overall [seafood] demand in the short term as consumers purchase more in retail channels rather than via food service. As a result, many salmon farmers are opting to reduce harvest and keep fish in the sea longer. We expect long-term demand for salmon to continue to increase.”

“In the shrimp supply chain, the COVID-19 outbreak is leading to disruptions due to reduced customer demand in destination markets and canceled orders.

This is leading to significant price drops at origination markets as farmers and processors deal with the realities of an oversupply situation, resulting in panic harvests and diminished stocking of shrimp for the new season.”

Regional impacts Every country and region share the same challenges, but the impacts have been different.

CHINA Nowhere has the effect on exports been more pronounced than in China, the Ground Zero of the pandemic. Exports to Korea have stopped, and exports to the country's other main seafood markets of Japan, the EU and the U.S. have slowed dramatically.

Sustainable aqua farmers who produce specifically for these overseas customers have been particularly hard hit. There are however cautious signs of a potential recovery in the country as it emerges from lockdown, although the effect will be slowed by a backlog of shrimp and fish stocks from prior months.

Most of the feed mills have been running at normal production. Although the price of some feed ingredients was initially higher, as logistics improve the ingredient supply has become more stable and prices are going down, Nutriera Group told us.

With low confidence in the economy and aquatic product consumption, harvesting has been slow.

There are a lot of fish still stocked in the ponds, resulting in higher feed volume compared with last year. As to shrimp, the prices are still good and the domestic supply is not enough to meet local market demand. Annually, China needs to import more than

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Main culture area

January - March 2020

South (Guangdong, Guangxi, Hainan, Fujian)

Stable or a little decrease

Center (Hubei, Hunan, Anhui, Henan, Jiangxi)

Decrease about 20%

Yangtze river delta (Jiangsu, Zhejiang, Shanghai)

Stable or a little increase

Southwest (Sichuan, Yunnan, Guizhou, Chongqing)

Stable or a little decrease

North (Tianjin, Hebei, Beijing, Heilongjiang, Jilin, Shandong, Shanxi)

Decrease about 20%

Table 1. Aquafeed market expectations in China by Nutriera Group.

900,000 tons of shrimp from India, Ecuador, Vietnam and other countries. But these countries are deeply impacted by the COVID-19, and import and export was blocked and slower recently. This makes the shrimp price strong and may be higher in the coming weeks.

SPAIN Spain has suffered badly from the pandemic, topping the EU incidence charts as we go to press.

However, the production of fish feed continues at its normal pace, although with staff limitations, Javier Ojeda, General Manager, Business Association of Marine Aquaculture Producers of Spain (APROMAR) said. The daily supply of feed to Spanish aquaculture farms is not being hindered. Work on aquaculture farms is also considered an essential activity and keeps pace, albeit with the complications of the precautionary measures imposed, he said.

Fresh fish sales in Spain have fallen, on average, by 55%, however, frozen and canned fish has increased.

While aquaculture farmers are dealing with less financial liquidity due to lower harvests, they see fish stocks (live biomass) increase beyond what was anticipated.

The uncertainty makes it hard to plan. “Farms are reducing their maximum feeding rates to try to limit the damage in case the crisis lasts longer, but feed consumption continues to grow,” Ojeda explained.

“This creates two problems: higher feed consumption in the coming quarters, and greater difficulty for farmers to cope with feed payments.”

Besides, hatcheries have stopped their activity due to the lack of rotation of fish in the on-growing farms. In the EU, the vulnerability of aquaculture has been recognized

and will attract specific financial support programs by the EC; Ojeda says these will not be enough, however.

“Spanish aquaculture companies expect direct support measures to materialize. We are waiting for direct help to compensate for the loss of liquidity and to allow some form of temporary storage of fish out of the water (filleted and frozen),” he said.

INDIA India imposed a three-week lockdown from March 24 to April 20 which may well be extended in view of the large size of India and its huge population. All activities and operations, other than those classified as essential have not been allowed to operate.

“The lockdown initially crippled the transportation of fries and fingerlings, feed, fish and shrimp and movement of labor for the farms, harvest and feedmills,” Yeo Keng Joon, Chairman of fish and prawn feed manufacturer, Bharat Luxindo Agrifeeds Pvt Ltd, India said.

“Some shrimp hatcheries were forced to drain out 5-10 million seeds due to lack of demand, labor and transport, because of movement restrictions. Several feed companies announced shutdown until the end of March.

Scaled down startup has since been affected, with most factories reporting lower production rates.”

Several shrimp processors reported that they would close operations due to a shortage of labor and logistical problems. Aquaculture related organizations took up the issue with respective state governments, and shrimp and fish have now been classified as essential, allowing their transportation. “This allows aquaculture-related industries to operate as usual during the lockdown.

Hence we do not foresee any further disruption in raw

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material supply, feed production an feed supply to farmers,” Yeo said.

At ground level, problems persist due to locked down workers not able - or unwilling to risk COVID-19 infection - to go to hatcheries, farms or plants.

Most shrimp and fish farms have re-stocked cautiously given the lower demand and uncertainties. Some states and regions reported as low as 40% stocking compared to last summer. However, annual Indian shrimp production and feed demand will not be significantly affected by the COVID-19 lockdown, Yeo predicted.

“Greater impact from lower international shrimp prices can be expected; fish production, which is mainly for domestic consumption, will be significantly affected by the expected impact of COVID-19 on the domestic economy causing lower demand for fish,” he added.

Feed ingredients and the feed supply chain A huge volume of commodity raw materials and additives on which aquafeed mills depend originate in the United States. As of now, the demand, price and availability of ingredients seems to be stable.

John Stewart, Director, Membership and Stakeholder Engagement at the American Feed Industry Association and the AFIA staff representative on the Aquaculture Committee, said ingredient manufacturers are still working to get those ingredients to their end-users.

“So far we have not heard of any major disruptions,” he said. A key piece of this success was AFIA’s advocacy to have the animal food, including aquaculture feed,

supply chain deemed “essential” by state and federal governments keeping them operating.

In Europe, the whole EU feed chain, including aquafeed, came under intense pressure at the early stages of the COVID crisis, before and during the first days of the ‘Green Lane’ agreement, due to cross-border trade problems, leading to very long downtimes at certain border posts, unclear quarantine measures and lack of PPE for drivers, Alexander Döring, Secretary General of The European Feed Manufacturer's Federation (FEFAC) told Aquafeed.com. “These issues have now been resolved and the supply chain for feed and aquafeed products is operating relatively well given the difficult circumstances. However, issues remain with supplies of certain micro-ingredients and expected lower availability of EU produced vegetable proteins (non-GM) due to the downturn of activities of the EU biofuels sector.”

Specialty markets including farmed fish were immediately affected by the loss of the food services market, and consumers currently prefer prepacked foods, which hurts fresh products like farmed fish.

"The EU feed sector will see the main economic impact of the COVID crisis in the farmed fish sector in Q3/Q4 as we expect farmers to lower their replacement numbers due to downturn in consumer demand," Döring said.

He said FEFAC welcomed the inclusion of the feed sector as an essential economic activity and noted that there has been an overall improvement in cross-border feed transport, and that livestock farmers are receiving their feed in adequate quality and quantity. “The main

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concern that the European Commission and the Member States need to share is more precise guidance on how to ensure the flexibility to allow sufficient workforce at feed plants, while applying COVID social distance rules, including regular access to personal protective equipment (PPE) for drivers and other staff.”

Logistic problems due to disruption of international and local transport has certainly made it difficult for some companies who operate on a global scale.

However, the demand for fishmeal and fish oil remains robust worldwide. “Fishing and reduction operations have continued to be carried out almost everywhere,” Enrico Bachis, Market Research Director at IFFO said.

“This has been possible thanks to the fact that the reduction industry has been associated with the essential food supply chain through the feed sector. However, the reorganization of shifts and work patterns to minimize staff interactions and satisfy new governmental guidelines have obviously delayed the supply chain of fishmeal and fish oil. A special dispensation from the limitations of workers’ free movement was granted to the sector’s companies, which are currently busy implementing maintenance work to plants and vessels in view of the forthcoming fishing season."

He noted that “Peru is still under a fishing ban in its more productive area, the North-Centre, as it usually happens between the end of March and mid- April.”

As we go to press, the Peruvian government had not announced a new quota yet but a new research cruise to evaluate the status of the anchovy biomass was underway.

Feed additive and ingredient suppliers we spoke to said they were able to maintain supply for now.

Evonik’s business as a feed additive manufacturer has not been affected to a high degree these past few months. “How long this will last we don’t know but some impact is expected in Q2. We can report that production and supply chains are stable,” Torben Madsen, Head of Product Line Sustainable Healthy Nutrition, Evonik Animal Nutrition told us.

Adisseo has activated a continuity plan in the face of near lockdown in France. “Our European manufacturing units are benefiting from the good practices established in our Chinese plant, which allowed us to successfully keep running production since the beginning of the Coronavirus crisis in China,” Peter Coutteau said. “Therefore, as we speak, European and Chinese plants are still producing at standard levels and we have taken additional measures to mitigate impacts in our production schedules.”

So far, Coutteau said their aqua business has not been affected, possibly due to a balanced distribution of business in terms of regions and species which allowed them to spread the risk. “Seeing the governments planning to gradually release lockdowns in major consumer markets, starting with China, we expect that the outlook for the aquaculture industry will improve in the coming months.”

Industry leaders we spoke to were confident in the long view, echoing the predictions of Patrick Charlton: “Before coronavirus began to spread, we saw an increase in aquaculture feed production globally - a 4% increase, according to data from the Alltech Global Feed Survey.

Just as other sectors will stabilize as the crisis subsides, we expect fish to continue to play a significant role in feeding the world, and for market growth to reemerge.”

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 2 2020

19

Vacuum coater on trials: Capacity up for aquafeed production?

Lu Mingshang, FAMSUN Field trials using several PTZL5000 vacuum coaters have proven their effectiveness and have shown many product quality benefits in large-scale high-end aquafeed production.

Coating is an industrial process that uniformly applies either a liquid or a powder on to the surface of a product of any possible shape or size to create new functional properties. The introduction of vacuum coating systems into the aquafeed industry provided greater flexibility for feed manufacturers to overcome product quality challenges that a typical ambient coating system could not do, such as achieving homogenous coverage at low-fat inclusion levels, maximizing fat inclusion levels and ensuring sufficient fat penetration that avoids leaching of oils into the ponds.

Vacuum coating technology creates a subatmospheric pressure within a mixing chamber.

An atomized or even a molecular condensable vapor is injected into the chamber to encapsulate each pellet with a thin film. Vacuum coating allows the application of oil, fat, pigments, flavors, attractants, vitamins and other liquid ingredients in this manner. After a short mix cycle, the chamber pressure is brought back up to ambient levels. When applicable, the dry ingredients can then be introduced. This is an important sequence, as the oily film is often the adhesive that holds the dry powders into feed pellets. Vacuum coating brings improved coverage, palatability and functionality to most feed products.

FAMSUN vacuum coaters While making continuous improvements, FAMSUN has developed a series of vacuum coaters with the latest innovations to meet the demanding requirements of

Figure 1. FAMSUN PTZL5000 vacuum coater.

the fast-growing aquafeed market. The PTZL vacuum coater (Table 1), with excellent sealing performance, creates and maintains a strong vacuum at a range from -950 mbar to 0 mbar and can achieve liquid addition levels up to 36%.

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 2 2020

20

to pellets when mixing, and minimum residues when discharging. An ABB controller ensures excellent liquid addition performance in terms of accuracy, speed and cycle-time. The FAMSUN PTZL vacuum coater is a flexible tool for the production of a wide variety of highquality products within a single production line.

The recent addition of the PTZL5000 vacuum coater into the product portfolio allows FAMSUN to provide a whole range of coating performance from 4 t/h up to 15t/h.

Figure 2. Aquafeed after coating.

The vertical screw and the efficient spraying system work together to uniformly expose the feed pellets to the atomized liquids. Also, the smooth surface of feed contact parts and tight tolerances of the screw rotor and vessel chamber, assure minimal wear or damage

Field trials prove greater capacity With a designed volume of 5,000L, the PTZL 5000 vacuum coater is the perfect model for large-scale aquafeed producers. Several successful field trials were completed in aquafeed mills by FAMSUN experts to confirm its performance. These experts optimized the batch cycle times and other parameters of each machine and were able to achieve excellent results for customers in terms of product quality, capacity and process stability.

Table 1.

Item / Model Capacity (t/h)

PTZL2000

PTZL3000

PTZL4000

PTZL5000

4-8

8-12 10-13 12-15

Power (kW)

15+22 22+22 22+22 37+22

Effective volume (L) 2,000 3,400 4,000 5,000

Batching time (min) 6

6

6 6

Working vacuum (mbar) 200

200

200

200

Limited vacuum (mbar) 40

40

40

40

Pellet size (mm)

Pellet flow accuracy (%) 0.8

0.8

0.8

0.8

Liquid adding range (%) 1-36

1-36

1-36

1-36

Liquid adding accuracy (%) 1

1

1

1

2-15 2-15 2-15 2-15

Table 2.

Item / Feed for Marine tilapia Pompano Die hole dia. (mm) 3 3

Pompano 3

Bulk density (g/l) 360 370 370

Vacuum degree (mbar) 1,000 800

700

Feed weight per batch (kg) 1,000

1,200

1,200

Liquid addition ratio (%) 6.4

9.3

9.3

Coating time per batch (s) 222

273

250

Capacity (t/h)

16.2 15.7 17.2

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 2 2020

21

Products tested were marine tilapia and pompano in two separate feed mills in Guangzhou Province of China. For both plants, feed pellets were extruded from 3mm die and coated with liquid in a PTZL5000 coater after drying. The difference between the two applications was the required liquid addition level, which was 9.3% for pompano and 6.4% for the tilapia feed.

For tilapia feed, the low liquid addition level did not require a vacuum, thus enabling a short total cycle time of 222s for each batch of the coating process.

The production capacity reached was 16.2 t/h.

Production trials on pompano feed were conducted in an aquafeed mill in Zhaoqing, Guangdong Province of China. The new feed mill included six FAMSUN PTZL5000 vacuum coaters for liquid application after drying. During initial production tests, a vacuum of 700-800mbar and a total cycle time of 273s were the target parameters to coat a 1,200kg batch of feed.

The initial capacity reached was 15.7 t/h. After some optimization, the coating time per batch was shortened

to 250s and a sustained capacity of 17.28 t/h was achieved (Table 2).

The pellets from these trials were of uniform color, illustrating excellent coverage (Fig. 2).

By reaching the target fat addition levels, a product with proper nutrition and functionality was also achieved. Due to the PTZL5000 coater's advanced capacity, feed producers can save energy and improve production capacity. In both field trials, the PTZL5000 outperformed expectations for efficient feed production.

More information: Lu Mingshang Mechanical structural designer FAMSUN R&D E: lms@famsungroup.com

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Aquafeed: Advances in Processing & Formulation Vol 12 Issue 2 2020

22

New way of drying shrimp feed Jammy Ho, IDAH In a modern shrimp feed pelleting process, more liquids are added into the mash feed. This, in combination with long term steam conditioning, is increasing gelatinization and water stability for a better endproduct quality. Recipe cost optimization can be limited if there are drying capacity restrictions. In a lot of situations, moisture removal with only cooling is not enough and an extra drying step is required.

Moisture control becomes more and more crucial for quality and cost price reasons.

In traditional shrimp feed processing, there are separate machines for drying and cooling. The products are dropped from the pellet mill/post-conditioner into the dryer for moisture removal, then into the cooler to cool down the product with ambient air. Moisture control is done by checking product after the dryer and corrections are made according to finished product moistures. The process is as shown in Figure 1.

Integrating drying and cooler in one solution New to the market is the carousel dryer and cooler combination, a unique solution for both energy efficiency and precise moisture control.

Optimizing moisture control is a lot easier if the retention time is short and the dryer and cooler applies a first in, first out (FIFO) principle. Plus the moisture can be controlled directly after the cooler so the impact of more or less water evaporation in the cooler is already taken care of in the total moisture control cycle. Therefore, an integration of the dryer and cooler into one compact machine with a FIFO discharge principle like the carousel dryer will give an outstanding control performance (Fig. 2).

The carousel working principle The complete unit consists of an upper drying zone and a lower cooling zone. The product comes in through a rotary valve and then around in the dryer. After nearly one revolution, the product is gently discharged and mixed into the next lower tray. This process is repeated

Figure 1. Traditional dryer and cooler flow chart.

Figure 2. Dryer and cooler combination flow chart.

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 2 2020

23

Figure 3. Dryer cooler combination product and air flow scheme.

Ambient air cools the product and after filtered and heated it is used as drying air for the upper section.

Due to the multiple tumbling and optimal air use in the round dryer, the drying process is extremely efficient resulting in a low exhaust air temperature. This carousel dryer – cooler combination model has some beneficial features when compared to the traditional equipment.

Figure 4. Moisture uniformity comparison between the carousel dryer and traditional dryer.

until the product is discharged from the drying zone into the cooling zone and the product drops from the last tray into the outlet where a rotary valve prevents air leakage (Fig. 3).

Improving product moisture control Managing the temperature and moisture content of the finished product is the main task for the drying and cooling process. However, when the feed is overdried, it causes material loss as well as extra energy consumption. When the feed is too wet, the product will have a higher risk of quality degradation and mold growth.

A carousel dryer is working according to the first in first out (FIFO) principle. Having the product circling around in a steady and controlled airflow, all the products will get the same heat treatment and retention time. Combine this with a unique and easy control system and its real-time monitoring and modification of the drying parameters such as drying air temperature air volume and retention time.

Because the carousel dryer is giving a uniform and constant moisture level, the target average moisture can save energy and raw materials (Fig. 4).

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 2 2020

24

Improving energy efficiency The drying and cooling process accounts for a significant part of the overall energy consumption. Rising energy costs and sustainability awareness regarding energy consumption have driven feed manufacturers to request further support to improve their drying and cooling functions. To maximize energy efficiency, we have to look into: • Maximizing the use of warm product energy.

• Minimizing the amount of water evaporation.

• Minimizing energy loss with the exhaust air.

By using the cooling air as makeup air into the dryer, product energy can be reused and the amount of exhaust air is limited.

Due to the high drying efficiency, the exhaust air temperature also reduces the loss of energy by the already low exhaust air volume. Low exhaust air volumes will also reduce the cost of odor treatment if required.

Reducing the space required While upgrading the production capacity of a feed mill or improving the production process, the introduction of new equipment into the facility is required and space limitations may arise.

The carousel dryer is already more compact than a normal used dryer. The dryer - cooler combined design has even more space requirement advantages (Fig. 5).

In the limited available space, the cooler was positioned high in the building. The carousel dryer-cooler positioned under the post-conditioner avoids the hot product transport and a lot of air ducting.

Figure 5. Dryer and cooler combination layout.

Potential savings For example, using cooling air as makeup air for the dryer. If you assume that the temperature differential between the ambient and cooler exhaust air is 25°C, you save up to 30 kg/t steam.

At the same time, you will reduce the amount of exhaust air by 50%, reducing odor treatment cost significantly if required.

Getting better moisture control, for example 0.5%, is saving not only about 10 kg/t steam consumption in the dryer but, even more important, saving 0.5% raw materials cost and having a 0.5% higher output capacity.

More information: Jammy Ho R&D Supervisor IDAH Co. Ltd., Taiwan E: jammy.ho@idah.com

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 2 2020

PRODUCT FOCUS

New extruder for the growing demands of fish feed production The extruder OEE NG from Amandus Kahl GmbH & Co. KG set to capture the market for the production of pet food and fish feed of the highest quality.

The German machine manufacturer Amandus Kahl has been manufacturing a new extruder for the production of fish feed and pet food since 2019. The extruder OEE 25 NG (New Generation) was introduced into the market with a screw diameter of 250 mm and a resulting capacity of up to 10 t/h. The 2020 series will be expanded by two extruders with screw diameters of 200 mm and 150 mm for smaller production volumes.

The new equipment and technology level of the Kahl extruder OEE NG After more than 20 years of experience with extrusion machines, customers now receive a completely new extruder to meet the growing demands in the production of fish feed. During the design phase, the focus was on producing a user-friendly machine with new performance standards.

A double-jointed connection enables a fast tool and knife change. The design was also a focal point - the extruder OEE NG is manufactured with a framemounted touch screen to control all relevant operating

data, settings and options even during operation.

The machine also features the proven Kahl stop bolt technology for successful mixing and venting in the first cylinder section. Special process zones for compaction, cooking and kneading ensure high flexibility and a wide range of adjustment options.

The Kahl extruder can also be ideally adapted to changing the formula.

Fine control measures, such as the possibility of adjusting the screw speed, adding steam or water to the extruder barrel or individually adjusting the heating and cooling jackets have also been taken into account in the design. A comparison of the screw diameters of both Kahl extruders clearly shows an increase in throughput. Thus, a capacity range of 10 t/h is achieved in large industrial applications.

The advantages and options of Kahl machines at a glance The already mentioned fast knife and die change provides high efficiency. Furthermore, the possibility

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 2 2020

26

to change the distance between knife and die during operation allows a flexible definition of the desired extrudate size. Amandus Kahl produces the requested machine as a single unit or turnkey extrusion line.

In both cases, no expensive additional equipment is required to influence the expansion behavior.

This saves not only investment costs, but also operating costs. The company defines the specific project together with the customer and finds the most suitable solution for a successful production.

Apart from the actual extrusion, turnkey extrusion lines include all process steps such as grinding and mixing of the components.

Steam conditioning, drying, coating, cooling and packaging are also performed by machines from Amandus Kahl.

Quality made in Germany successful for 140 years Founded in 1876, the company has been successfully manufacturing machines and plants for conditioning and pelleting of various raw components and product mixtures for more than 140 years. Ever since the company was founded, the pelleting press has been at the center of production. Thanks to its flat die, it has established itself as a unique selling point on the commercial market in countless industrial sectors.

The high quality is also reflected in every other machine and plant "made in Germany." In addition to pan grinder mills for energyefficient wood crushing, cooling and drying plants or expanders in various designs, Amandus Kahl customers can obtain extruders for various industrial sectors such as the food or animal feed sector for different production capacities.

More information: info@akahl.de

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 2 2020

Q&A

Ask the Expert Your aquafeed processing questions answered

Q: Did you see pictures of screw profile? Is this ok? I don’t think there is much wear.

Ah, maintenance! Screw and barrel sleeve wear can catch you unaware and will inevitably cause more grief on those products which are trickier to run, such as low-fat small diameter sinking feeds, with some raw materials more sensitive to the reduced pumping and increased shear caused by wear.

As a rule of thumb on new parts for a nominal 10 t/h single screw, a gap of no more than 2 mm between head and screw would be appropriate (the gap being proportional to extruder size) and by the time that gap has hit 4 mm, you could be expecting some issues to pop up, such as surging, excess heat and general lack of pellet uniformity.

When wear is more than this, you may start to experience some back feeding as well, particularly on smaller machines. Refined starches and low wheat formulations are likely to show up any wear related problems earlier. But don’t hang your hat on a fixed wear diameter measurement – read on.

Using a shaft support bush is always preferable, as without it deviation caused by radial load will create excessive forging wear (metal on metal contact), particularly on the final head and screw, not to mention reducing life of the main thrust bearing, as well as reduced bearing seal life, leading

to oil leakage from the bearing housing. If your shaft support is worn to the point it is allowing screw on head clash, then this is a priority fix – a replacement bush is going to set you back a lot less than replacing screws!

Clearly, the shaft needs to be aligned correctly in the first place, using a clock/dial indicator to ensure minimal runout (deviation from center). Don’t overtighten nuts when pulling up a shaft, or your bearing will run hot with excessive load. This will require experience to perform, using supplier specification. Perform regular checks on the shaft locking mechanism. If a locking ring with retaining ring/tab washer is used, ensure the tab washer is intact and tabs are in place. Lock nuts can loosen and tabs move/break over time, resulting in excessive shaft play and premature wear.

There is little point in my providing a fixed tolerance for bearing endplay or shaft runout, as this will depend on specification from the equipment provider and length of the extruder shaft.

Tolerance in the shaft support bush and head support should take into account the amount of runout in order to avoid undue stress on the shaft from moment load in the shaft alignment.

If you have a twin screw and notice what appears to be forging wear marks running down the face of

Peter Hutchinson is a Technical Editor at Aquafeed.com, the owner – director of ENH Ltd., New Zealand, and an aquaculture feed consultant.

Send your questions to: pete@aquafeed.com

the flight, act immediately to check for shaft timing, thrust bearings or damaged/twisted shafts.

Pinning a time frame on expected life for screws is not practical either, so I’m not going to attempt to provide a guide here. It depends on the type and hardening process of steel used, raw materials processed and operating conditions. I’ve come across screws flogged out in a couple of months by incorrect operation or utilizing sand loaded fishmeals for example, whereas the same screws may have lasted years under ideal conditions.

The difficulty in providing a fixed measurement limit for screw and head wear is that it is so much

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 2 2020

28

dependent on finished product specification, raw material and the types of screw profile used as to the impact it will have. Simply measuring diameters may not be enough to indicate how the wear is impacting performance. Abrasion wear will often round off the leading edge of the flight tip without necessarily impacting overall diameter greatly, and I have seen problems arise with performance well before significant loss of screw diameter, due to the impact this type of wear can have on effective pumping action and subsequent increase in shear.

So, a word to the wise on screws if all your raw material and process changes just aren’t getting you back to where you should be - when in doubt, swap them out!

if you can manage it. Placing holes too close to retaining plate structures behind the die will disrupt flow, leading to short or wedged pellets from these holes.

• Shorter land lengths produce more radial expansion and are generally utilized for floating feeds. Longer land lengths produce more axial expansion and higher overall density, being generally used for sinking feeds.

There can be some cross over here and floating feeds can still be produced from longer land length dies under the correct conditions, with longer land length tending to produce more uniform looking pellets.

• Excessive land length can create too much surface drag. If extralong land length is required, then using PTFE or various other low friction compounds as inserts is an option.

• If you are looking to use steel inserts to save money on die plates, it may seem like a good idea, however, is rarely effective.

The reason being, insert holder plates and inserts wear at differing rates as they are swapped around. They continuously require resurfacing to match in order

Q: In relation to dies, do you have any hints to offer?

Sure do. Easiest to list off a few key items, so here we go.

• Ensure uniform flow distribution to die holes. This entails uniform placement of the holes over the die plate and flow distribution leading from final screw to plate.

One ring of holes is preferable with larger diameter die holes

MAX.

393.31 [9990] 391.31 [9939]

15.00 [381]

MIN.

Ă12.00 [305]

F085 SHIMPO

36.91 [937]

to avoid blades catching proud inserts and breaking, or poor cut quality on recessed inserts.

• Avoid excessive open area.

A common trap for newcomers is the mindset that more holes equals increased capacity.

Unfortunately, this is at odds with the fundamentals of extrusion process, leading to surging, potential lack of cook and poor pellet quality.

• Understanding total open area requirements for control of density is essential. As mentioned in previous articles, whilst expansion is impacted significantly by formulation (particularly starch content), total die open area provides ultimate regulation over pellet density. As an approximate guide 150mm/t/h open area for floating feeds and 300-450mm/t/h for sinking. Bearing in mind high-fat diets will float before fat coating is applied and will require open area somewhere in between. As the die hole diameter falls below 2.5mm you will need to increase total open area to account for the extra restriction caused by drag from increased surface to volume in the die.

MAX.

31.19 [792]

MIN.

29.19 [741]

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

30.38 [772]

ALL FROM A SINGLE SYSTEM

BIN Inlet

P.O. Box 8 100 Airport Road Sabetha, KS 66534, USA Phone: 785-284-2153 Fax: 785-284-3143

30.00 [762]

19.16 [487]

64.83 [1647]

108.59 [2759] DCC Inlet

End of Head

CYL. Disch.

15.00 [381]

With Extru-Tech’s ADT (Advanced Densification Technology), the possibilities are far reaching. ADT technology gives you the option to produce sinking feeds with excellent consistency and density. That same ADT technology can produce floating

FROM SINKING TO FLOATING

feeds with high protein characteristics … all from a single extrusion system.

269.88

In the aquafeed business, you either sink [6855] or swim.

Contact Extru-Tech today at 785-284-2153 or visit us online at www.extru-techinc.com

284.00 [7214]

278.03 [7062] 1.93 [49]

extru-techinc@extru-techinc.com www.extru-techinc.com

199.38 [5064]

18.00 [457]

1.00 NPT

P.O. Box 8 • 100 Airport Road • Sabetha, KS 66534, USA Phone: 785-284-2153 • Fax: 785-284-3143

12.56 [319]

51

06

0

15.88 [404]

24.59 [625]

03 54

256T

108.28 [2750]

2.00 NPT [STEAM]

3/4 NPT

2.00 NPT

12/13/18 12:00 PM

80 NORGREN

0

88.00 [2236]

160

MAXUM SIZE 10

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 2 2020 102.13 [2594] 111.12 [2822] 195.72 [4971]

52.19 [1325]

48.00 [1219]

57.69 [1465]

2

ET-296i.indd 1

1.00 NPT [STEAM]

2.00 NPT [WATER]

53.25 [1353]

66.50 [1689]

29

Biosurfactants: A new nutritional concept in aquaculture Carlos Rodriguez, Ă lvaro RodrĂ­guez, Ewa Sujka, Liptosa

Lipids are a group of natural organic compounds comprised of fats, oils, phospholipids and sterols.

Dietary lipids are utilized in aquafeeds as a major source to spare protein. They also influence flavors and texture, are a highly digestible concentrated source of energy that supplies 8-9 Kcal/g and provide fatty acids needed for the proper functioning of many physiological processes (Nantes, 2015). Moreover, it is important to consider that fish oil is an expensive raw material in aquafeed production and nutritionists must optimize the inclusion and digestion of dietary lipids.

Reduction of FISH IN : FISH OUT (FIFO) ratio using vegetable-sourced oil instead of fish oil is a current trend in the aquaculture industry to meet sustainable performance requirements. Therefore, boosting the digestion process is an important issue.

Emulsifiers to increase lipid digestibility Depending on the type of added oil, digestibility will vary. Unsaturated fats are much more digestible than saturated fats. Emulsifiers show more efficiency when the fatty acid profile of the added fat is more saturated, although they are also able to increase the digestibility

of the unsaturated fraction of vegetable oils, as in the case of soybean and rapeseed oils.

In order to supply a product to cover the requirements and needs of lipid digestion, LIPTOSA has designed and manufactured Digest Fast, an outstanding biosurfactant made up of a combination of botanicals with emulsifying substances.

The emulsifiers used in animal nutrition are aimed at increasing the digestibility of the feed added lipids that are also effective tools in the optimization of the formulation costs, as increased digestibility allows reduced inclusion of added oils. Emulsifiers increase the active surface of lipids, allowing a higher action of the lipases and favoring the formation of micelles.

Its positive effect is more pronounced with lower digestibility of dietary lipids.

Herbal extracts play an important role in the maintenance of good health of the liver and/or hepatopancreas. It is considered of big importance to avoid possible liver disorders such as hepatic steatosis, a process responsible for the loss of liver functionality.

Lipid infiltration in hepatocytes during periods where fish are subjected to intensive feeding leads to the

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 2 2020

30

of expected growth. The mobilization of liver fat, thanks to the botanicals included in Digest Fast, favors the functionality of hepatocytes during the whole productive cycle.

Digest Fast has also shown beneficial effects in the prevention and resolution of degenerative liver conditions of different etiological issues due to the presence of toxic or infectious agents, allowing hepatic cell regeneration, reversing the process and contributing to the recovery of function.

Figure 1. Feed Conversion Ratio (FDR; a) and Protein Efficiency Ratio (PER; b) on seabass feed on diets with different levels of Digest Fast (DF). Trial run by Sparos.

Figure 2. Fat retention (a) and energy retention (b) on seabass feed on diets with different levels of Digest Fast (DF). Trial run by Sparos.

partial loss of liver functionality and consequently reduction of zootechnical performance.

Some of the fish species, such as salmonids, sea bream, seabass and meagre, tend to accumulate visceral fat at liver level, which leads to the reduction

Biosurfactants trials in European seabass Digest Fast was tested in several laboratory tests as well as field trials. In this paper, we would like to share the summary of trials on European seabass (Dicentrarchus labrax) run by Sparos Research Center (Portugal) and at Aydin Adnan Menderes University (Turkey).

In the trial conducted by Sparos Research Center (Portugal), two different levels of Digest Fast were included in a control diet replacing a percentage of the added soybean oil (DF (Digest Fast) 0,1% = Ctrl 1% soybean oil + 0,1% Digest Fast; DF 0,2% = Ctrl - 2% soybean oil + 0.2% Digest Fast).

Results showed a significant zootechnical improvement in both Digest Fast diets when compared with the control diet, showing the effectiveness of Digest Fast as a substitute for soybean oil, reducing the cost of feed with the subsequent lower production cost.

An increase in terms of energy retention, protein efficiency ratio (PER) and fat retention was obtained in fish fed with Digest Fast which opens the possibility of improvements in the performance of eviscerated and filleting, which provides a competitive economic advantage of maximum interest for farmers.

After the 63-day feeding trial, DF 0.2% showed a significantly higher final body weight (FBW) and specific growth rate (SGR) than control and DF 0.1%.

DF 0.2% showed a significantly lower feed conversion ratio (FCR) than DF 0.1% diet. Digest Fast supplemented diets showed a slightly higher digestibility of fat and energy. This higher digestibility could explain the significant beneficial effects on the overall growth performance criteria.

The 4-month trial carried out at Aydin Adnan Menderes University (Agriculture Faculty, Department of Aquaculture and Fisheries) also showed the best results with feed that included the nutraceutical Digest

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 2 2020

31

Fast when compared with a control diet.

It might be helpful to note the outstanding hepatic state considering the area of infiltration of hepatocytes, somatic hepatic index and liver weight of the fish feed on the diets with different commercial emulsifier levels.

Conclusions Digest Fast is a very useful tool for aquaculture nutritionists. Its inclusion in the feed formulation will guarantee optimal liver health and functionality resulting in a significant enhancement in the zootechnical performance. Digest Fast is much more than an emulsifier thanks to the synergy achieved between its botanical and emulsifying ingredients.

Feeding cost is the biggest part of overall production costs in aquaculture, so all efforts toward nutritional and handling improvements will have a positive impact on farm profitability. Digest Fast can help optimize this concern, reducing the percentage of inclusion of fat in diets, enhancing the absorption of fat-soluble nutrients such as vitamins and pigments, and with the possibility of boosting the digestibility of unsaturated fatty acid fraction in aquafeed and the digestibility of saturated fats.

More information: Carlos Rodríguez Aquaculture Technical Support Liptosa, Spain E: carlos.rodriguez@liptosa.com

Ewa Sujka Commercial director Liptosa, Spain E: esujka@liptosa.com

Álvaro Rodríguez Aquaculture Area Responsible Liptosa, Spain E: ara@liptosa.com

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 2 2020

32

Natural feed additive improves health conditions in the aquaculture business Juan M. Alfaro, Felipe Almendras, Enrique Guillamón, Alberto Baños, DOMCA SAU, Greenvolution, DMC Research Center

Aquaculture has recently become one of the fastest-growing segments of the livestock industry in response to the decline in the number of animals caught by traditional fishing. However, while this sector continues to prosper and grow, fish farmers and feed manufacturers today face complex challenges in aquaculture.

The intensive culture of fish generates a stressful physiological environment leading to the suppression of the immune system and susceptibility to infectious diseases. Moreover, the presence of xenobiotics in aquatic environments has been considered an inducer of different diseases and undesirable effects in aquatic life. Diseases are now a primary constraint to the culture of many fish species, impeding both economic and social development in many countries.

For decades, chemotherapeutic agents, such as antibiotics, antiparasitics and disinfectants were

used to prevent and control fish diseases. However, today consumers demand farmed fish raised under welfare conditions and have increasingly stressed high food quality and safety standards in the absence of concomitant pollutants, antibiotics and carcinogens. Traditional use of antibiotics and other chemotherapeutics in fish culture has been criticized because of their potential development of antibioticresistant bacteria, environmental pollution and the accumulation of residues in fish tissues.

Feed additives as substitutes of antibiotics Since the European Union ratified a ban in 2006 on the use of all subtherapeutic antibiotics (Regulation 1831⁄2003⁄EC), scientists and industry have intensified efforts to identify and develop safe dietary supplements and feed additives that enhance the health and immune system of farmed fish. In this

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Target microorganisms tested

AQUAgarlicTM Active ingredients (µg/ml)

Yersinia ruckeri 10 Lactococcus garvieae 100 Aeromonas salmonicida 5 Flavobacterium onchorhynchi 50 Photobacterium damselae 10 Vibrio anguillarum 30 Lactococcus piscium 100 Vagococcus salmoninarum 1,5 Aeromonas piscicola 5 Piscirickettsia salmonis 30 Saprolegnia parasitica 50 Table 1. Minimum Bactericidal Concentration (MBC).

Figure 1. Growth inhibition halo of AQUAgarlic™ against Vibrio anguillarum.

sense, probiotics, prebiotics, plant-derived natural compounds (phytogenics) or bacteriophages have been shown as potential substitutes for the use of antibiotics in aquaculture.

Phytogenic feed additives, known as PFAs, are substances of plant origin added to animal diets known to have a range of bioactive properties. Herbs, spices, essential oils and plant extracts all serve as source for bioactive compounds. Among them, organosulfur compounds from Allium spp. have been reported to promote health status, with a positive influence on the microbiota, intestinal health and immune system.

These compounds have also shown beneficial effects as

growth promoters and appetite stimulants, as well as antimicrobial properties in fish culture, enhancing fish health, food safety and quality while conserving the aquatic environment.

In recent years, the R&D department of the Spanish company DOMCA SAU, has been working on the development of natural origin additives to help fish farmers and feed producers improve the quality and performance of their products. This work shows the in vitro antimicrobial effectiveness of organosulfur compounds derived from Alliaceae plants (included in the product AQUAgarlic™, DOMCA SAU) against pathogens of interest in aquaculture, and also the in vivo efficacy after the addition of these compounds to the diet in the form of feed supplement.

Material and methods To evaluate the antimicrobial activity in vitro, the Minimum Bactericidal Concentration (MBC) by broth microdilution method was used as recommended by the National Committee for Clinical Laboratory Standards (CLSI, 2012). Decreasing concentrations of AQUAgarlic™ were prepared, in dilutions 1:2, and inoculated with the different bacterial strains at final concentration of approximately 105 CFU/ ml. Target microorganisms tested were; Yersinia ruckeri, Lactococcus garvieae, Aeromonas salmonicida supbsp. salmonicida, Flavobacterium onchorhynchi, Photobacterium damselae subsp. damselae, Vibrio anguillarum, Lactococcus piscium, Vagococcus salmoninarum, Aeromonas piscicola, Vibrio algynoliticus, Streptococcus agalactiae, Piscirickettsia salmonis and Saprolegnia parasitica obtained from several Culture Collection (ATTC, CECT, DSMZ).

All assays were made in duplicate.

The evaluation of the effectiveness of AQUAgarlic™ in vivo was carried out with infection challenges measuring the percentage of survival against Aeromonas salmonicida, Lactococcus garvieae and Yersinia ruckeri in rainbow trout (Oncorhynchus mykiss).

After ten days of acclimation, fish were fed with diets including AQUAgarlic™ for 15 days, after which they were infected intraperitoneally using a dose of 105 CFU/ ml. Non-infected groups were inoculated with sterile saline to simulate management stress conditions in the control fish. After infection, mortality was counted daily in each experimental group during the duration

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of the trial (12-20 days post-infection). Rainbow trouts, weighing an average of 20 g, were distributed using a two by two design generating four experimental groups for each challenge: - Group 1. Non-infected trout with standard diet.

- Group 2. Non-infected trout supplemented with 0.5 Kg/Tn AQUAgarlic™, in feed.

- Group 3. Infected trout with standard diet.

- Group 4. Infected trout and supplemented with 0.5 Kg/Tn AQUAgarlic™, in feed.

Results MBC was established between 5 and 100 µg/ml for all pathogenic microorganisms tested (Table 1).

The results showed a significant antimicrobial activity against all the tested strains, with growth inhibitions ranging from 10 to 90 mm in the halo diameter (Fig. 1).

The in vivo trials (Fig. 2) showed an increase in survival of the animals infected and fed with a supplemented diet including AQUAgarlic™, having survival rates of 60.5%, 96.0% and 99.3% for the infected groups that received the treatment against Y. ruckeri (Figure 2a), A. salmonicida subsp. salmonicida (Figure 2b) and L. garvieae (Figure 2c).

In comparison, the untreated infected groups showed survival rates of, accordingly, 11.1%, 51.0% and 33.3% for each of the above pathogens. The RPS (Relative Percent of Survival) of AQUAgarlic™ supplemented groups were 55,57%; 91,84% and 98,95% respectively.

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Aquafeed: Advances in Processing & Formulation Vol 12 Issue 2 2020

Discussion Diseases caused by aquatic organisms are a great challenge in aquaculture systems.

Bacterial diseases are usually controlled using vaccines or antibiotics. However, consumers demand a minimum or zero use of antibiotics for farmed fish and the World Health Organization (WHO) also requests a rational use of these substances in the livestock industry to decrease the resistance to antibiotics in humans. The aquaculture industry is actively seeking to decrease the use of antibiotics and PFAs are a great option that complements and boosts the effects of vaccines.

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The results obtained reveal the potential benefits in the use of AQUAgarlic™ to improve fish health and survival through its inclusion in the feed. The functionality of its active ingredients, based on organosulfur compounds from garlic and onion, has been extensively reported by different scientific studies.

The broad-spectrum antimicrobial activity of these natural compounds against grampositive and gram-negative bacteria, fungi and yeasts, is particularly remarkable.

Furthermore, these metabolites from Allium plants have also demonstrated excellent modulating properties of the immune response and intestinal microbiome, improving the animal physiological status and preventing the outbreak of infectious processes.

Piscirickettsia salmonis is a relevant disease agent in the salmon industry in Chile, which explains the large majority of the use of antibiotics in this industry. Vaccines help partially, but alternative therapies from natural compounds that may replace the use of antibiotics are required. Furthermore, fungal diseases in fish are also a common cause of using bath treatments with formalin, salt or other chemotherapeutants to prevent or treat fungal infections caused by agents of the Saprolegnia family. Environmental restrictions are limiting the use of these bath treatments, so the use of natural products through feed seems to be a promising alternative that may help protect the fish and the environment.

Our results show that some important challenges of the aquaculture industry, like the high mortality rates associated to Piscirickettsia salmonis and Saprolegnia parasitica, can be reduced using bioactive compounds from Allium plants. Therefore, the product AQUAgarlic™, which includes these compounds, could be used as a natural alternative in fish feed for the prevention and treatment of infectious diseases in aquaculture. However, it is necessary to encourage doing more in vivo trials to validate the use of their compounds as green alternatives to improve fish health while taking care of the environment.

Figure 2. In vivo survival against Y. ruckeri (a), A. salmonicida subsp. salmonicida (b) and L. garvieae (c). u Control (non-infected fish); Control diet (infected fish); l Diet supplemented with 0.5 kg/Tn of AQUAgarlic™ (infected fish).

More information: Juan M. Alfaro Senior Technical-Commercial Manager DOMCA SAU, Spain E: juan.alfaro@domca.com

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Application of enzymes in fish feed for profitable fish farming Vidya, A., Harikumar, S., Satish K., M. Rajalekshmi, Kemin AquaScienceTM

Improving the efficiency of feed utilization is essential as feed accounts for the largest cost in fish farming.

However, certain nutrient-rich ingredients in the feed cannot be fully digested and metabolized by the animal resulting in partial or incomplete absorption of such nutrients, which results in a negative impact on the overall performance and growth of the animals.

Application of specific enzymes in fish feed can help in eliminating the effects of anti-nutritional factors and improve the utilization of dietary energy and amino acids, resulting in enhanced performance of fish.

Raw materials in fish feed Most of the raw materials used in the fish feed industry are plant-based such as corn, corn gluten meal, rice bran, wheat bran, sunflower seed meal, groundnut meal, cottonseed meal, linseed meal, copra meal and

DORB (de-oiled rice bran). All these raw materials have high fiber, which is the undigested part of the feed, not digested by the innate enzymes naturally found in the fish gut. The non-digestible fiber includes high levels of non-starch polysaccharides made of cellulose, hemicellulose and lignin. Evidence reports an increase in the viscosity of the digested feed due to the presence of non-starch polysaccharides, which leads to a decrease in the available nutrients in the feed.

Innate enzymes in fish The most common enzymes reported in carps are lipase, trypsin, chymotrypsin, amylase, maltase and cellulase-exogenous (microbial).

Most feed ingredients of plant origin also contain anti-nutritional factors such as protease inhibitors (Kunitz trypsin inhibitors, Bowman-Brik Inhibitors),

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Trial I Area of culture

Control 15 acres

Treatment 10 acres

Rohu: 25,000. Catla: 2,000

Rohu: 35,000. Catla: 3,000

Diet

Commercial fish feed without supplementation of enzymes

Control feed + ZyvantaTM Aqua 100 DR @ 1g/kg

Trial II Area of culture

Control 10 acres

Treatment 8 acres

Rohu: 21,000. Catla: 2,000

Rohu: 17,000. Catla: 3,000

Commercial fish feed without supplementation of enzymes

Control feed + ZyvantaTM Aqua 100 DR @ 1g/kg

Stocking density

Stocking density

Diet

Table 1. Farms trials details.

lectins, saponins and phytic acids. Unlike other antinutritional factors, phytic acid is not degraded by heat treatment during pelleting. Phytic acid is known to interfere in the absorption of minerals like calcium, magnesium and potassium and harm the growth and development of fish.

Exogenous enzyme supplementation Supplementation of exogenous NSPases (non-starch polysaccharides degrading enzymes) and phytases is known to improve digestion of natural and supplemented feed, thereby improving the feed efficiency and performance. The addition of NSPases

and phytases is a smart solution for improving the profitability in aquaculture. It not only helps in the digestion of raw materials containing high fiber but also helps in reducing the usage of minerals like MCP and DCP (mono and dicalcium phosphate).

Kemin AquaScience research team has formulated an enzyme product with the combination of NSPases and phytase based on the raw materials used in fish feed and the feeding behavior.

ZyvantaTM Aqua 100 DR is a multi-substrate enzyme powder containing NSP (Non-Starch Polysaccharide) enzymes and phytase and was developed to improve the nutrient quality of fish feed.

Figure 1. Effect of ZyvantaTM Aqua DR (enzyme) without and with fish intestinal extract (FIE) on sugar release from DORB. Each experimental data represents the mean of the values Âą standard error (n = 3), p<0.05.

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The application of the product is at farm level where it is mixed with the feed right before consumption by the animals.

This paper summarizes the application and benefits of ZyvantaTM Aqua 100 DR through digestibility and growth trials conducted at Kemin AquaScience Research Laboratory and subsequent commercial trials done in India. It also reports the application of the liquid form of ZyvantaTM Aqua 100 LQ developed to apply at feed mills using Post Pellet Liquid Application Technology (PPLA).

In vitro digestibility studies In vitro sugar released by ZyvantaTM Aqua 100 DR in combination with fish intestinal extract (FIE) was prepared by mincing the whole intestine extracted from Rohu fingerlings using a phosphate buffer (7.4) in ice cold conditions. De-starched, de-oiled rice bran was studied at pH 7.4 and 37°C using the Nelson-Somogyi method. Significant improvement in digestibility (p â&#x2030;¤0.05) was observed when the enzyme powder was used alone and in combination with FIE (fish intestinal extract). Studies indicated a synergy between endogenous enzymes and supplemented enzymes (Fig. 1).

In vivo growth studies Two in vivo trials were conducted in commercial farms at Bhimavaram, Andhra Pradesh to demonstrate the benefits of ZyvantaTM Aqua 100 DR. The farms had a mixed culture of Indian major carp Rohu and Catla.

ZyvantaTM Aqua 100 DR was coated on top of the feed with a gel binder prior to feeding, at a dosage of 1 g/kg and control pond fish were fed with feed without product supplementation. The fish were fed once a day for

90 days. The effect of enzyme supplementation on weight gain was recorded by netting approximately 100 fish, thrice from sides of the pond and the average weight was calculated and recorded once in 30 days.

The details of farm Trials I and II are on Table 1.

Farm trial results Commercial Trial I showed an increase in weight gain in the treated groups (Fig. 2) with the treatment group Rohu weighing 50 grams more and Catla weighing 40 grams more than the control group.

In Trial II, the control group of Catla was 20 grams less than the treatment group, and the same group gained 190 grams more than control group at the end of the trial (Fig. 3). Similarly, Rohu in treatment ponds gained 30 grams more than the control group at the end of the trial.

Skin pigmentation In both trials, a better utilization of phytoplankton and algae resulted in enhanced carotenoid bioavailability.

Supplementation of ZyvantaTM Aqua 100 DR showed an increase in the pigmentation of carp. This was observed by visual examination during the trials and was consistently reported by farmers.

Application of liquid enzymes in fish feed mills using post-pellet liquid application (PPLA) The inclusion of additives in the feed can be done in two ways, in-process addition and post-process addition. The temperature of the feed during extrusion usually rises to the range of 70-800 at preconditioning and 120-1400 before extruder. Application of heatsensitive supplements such as enzymes and probiotics is not possible through in-process technique.

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Figure 2. Body weight increase in Trial I. Rohu (left) and Catla (right).

Figure 3. Body weight increase in Trial II Rohu (left) and Catla (right).

Application in the form of liquid additives after pelleting is a good alternative. It is a common practice in feed mills to coat the feed pellets with oil after extrusion. The level of oil used is often as high as 1 - 3%, making the coating process easier. On the other hand, enzymes are required in lesser quantities (0.1 %), which requires high accuracy and precision in the coating process.

Post-pellet liquid application (PPLA) technology The most critical factor in post-pelleting application is the precision of the dose given and co-efficient of variance (CV) of additive in feed sample. The maximum CV percentage in daily ration portion of target animal diet is 10%. It is also vital that the enzyme coated on the feed must have good binding with the feed matrix to prevent the leaching of enzymes into water.

Kemin AquaScience has developed a tailor-made liquid application system called SMART BOX â&#x20AC;&#x201C; PPLA System.

The equipment sprays liquid enzymes on the surface of the finished pelleted feed right before the bagging step. The system contains a PLC (Programmable Logic Controller) for automation, gravimetric batch controller, feedback sensor, precision dosing pumps, air atomized spray nozzles, high pressure dosing pumps, impact weigher and spray chamber.

The unit also consists of a weighing tank, rotary feeder, baffle type dispenser, carrying conveyor and spray nozzles. The three-baffle design ensures uniform spraying of the product on the entire pellet.

For accurate dosing of the enzyme, measurement of feed flowing into the spray chamber is critical. The six air atomized spray nozzles in the SMART BOX â&#x20AC;&#x201C; PPLA System ensures that the feed is evenly distributed with liquid enzymes.

Conclusion Post pellet application of enzymes for fish feed is an attractive way of solving the indigestibility of the fiber on feed raw materials. Not only does it improve the fish performance, but it also decreases the eutrophication of pond water caused due to the release of undigested feed and phosphorus, thus helping farmers to maintain water quality and animal health.

More information: Vidya Arumugam Regional Technical Manager Kemin AquaScience, India E: vidya.a@kemin.com

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Enzyme pretreatment of plant ingredients used in diets for mullet F. Javier Moyano, Francisca P. MartĂ­nez, Waldo G. Nuez-OrtĂ­n, University of AlmerĂ­a and Adisseo

Mugilidae (mullets) are a group of fish showing an increasing interest for aquaculture due to their rapid growth, resistance to a wide range of environmental conditions and omnivorous profile. Over the past few years, the culture of these species, particularly of the grey mullet (Mugil cephalus), is considered a priority within the current strategies of European aquaculture. Besides specific research aimed to complete its reproduction in captivity, the culture of grey mullet requires the development of suitable species-specific diets. In this sense, several studies have demonstrated the possibility of using high amounts of plant by-products with a limited nutritive value in its feeds, even during the early stages of development.

This represents important advantages, like a higher diversity of offer and availability, as well as positive environmental and economical features.

Enzyme additives in plant-based diets From a nutritional point of view, plant by-products also present limitations, linked both to their amino acid imbalances and to the presence of a wide variety of antinutritional compounds like alkaloids, lectins, digestive enzyme inhibitors, indigestible carbohydrates (mainly non-starch polysaccharides; NSPs) and phytate.

The use of enzyme additives may be a powerful tool to counteract the potential negative effects derived from the presence of phytate and NSP, and thus increase the nutritional value of plant ingredients. The addition of carbohydrases capable of totally or partially hydrolyze NSPs has shown positive effects on the nutritive use of feeds since in many cases these compounds form a matrix that hinders the access of digestive enzymes to the protein and starch present in cereal and leguminous seeds. Similarly, the use of phytase has shown positive

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INGREDIENT (in g/100 g d.w.)

FEED

Fishmeal 67/10

10.00

Soybean meal 47

18.83

Defatted rice bran

10.00

Brewer’s spent grain

20.00

Soybean protein concentrate

8.00

Corn gluten meal 60

8.00

Guar meal (Korma)

11.16

Fish oil

3.25

Sunflower oil

2.60

Soy lecithin

0.65

Squid hydrolysate

1.50

Vitamin/mineral premix

0.05

Taurin

0.30

Yeast

3.00

PROXIMATE COMPOSITION (in g/100 g) Crude protein

38.00

Crude fat

3.49

Digestible carbohydrates (starch + oligosaccharides)

10.56

NSP

27.73

Ash

6.21

Phosphorus

0.85

Phytate P

0.35

Table 1. Ingredients and proximate composition of the diets used in the experiment.

effects on diets for different fish species due to its ability to improve the whole nutritional use of different ingredients and to reduce phosphorus discharge into the environment.

Almost all the published works dealing with the use of enzyme additives in fish feeds have tested their inclusion in the feeds using some protected forms or applied post-extrusion via oil top coating or spraying, resulting, in most cases, in a limited effectiveness and somewhat contradictory results.

We present some results obtained within a project aimed to develop feeds for the grey mullet, Mugil cephalus, formulated with very high contents of plant ingredients. Such ingredients were pre-treated by

solid-state hydrolysis (SSH) with an enzyme mixture before the preparation of the feed pellets to reduce the contents in NSPs and phytate. SSH operates with a percentage of solid substrate greater than 15%, so little or no free water is present. However, the hydrolysis is performed under optimal conditions for the enzymes, so their activity is not affected either by the high temperatures reached during feed preparation or by the biochemical conditions present in the gut of the fish.

Use of enzymes prior to pelleting The diets were designed to include a low amount of fishmeal (10-15 g/100 g) but a high amount of plantbased ingredients (>70% in weight) including 300 g/kg of by-products like brewer’s spent grain and rice bran (Table 1).

SSH of the mixture of plant ingredients was carried out after milling them to a mesh size of 0.5 mm, being after mixed with citrate buffer (pH 5.0, 0.1 M; 1:2 w/v) to obtain a moist mass providing the optimal conditions for the action of the multienzyme complex. The product used was Rovabio®, a mixture of xylanases, glucanases, arabinofuranosidases, as well as phytase, provided by Adisseo. It was added to the mixture by spraying four hours prior to mixing in with the rest of the ingredients used in the feed.

Two feeds (enzyme-treated and control without enzyme pre-treatment) were prepared and tested on triplicate groups of juvenile mullets of 12 g initial weight, maintained in the facilities of CTAQUA (Cadiz, Spain), that were fed during six weeks on the experimental diets. The effect of the multienzyme complex on the chemical profile of the mixture of plant ingredients was evaluated by measuring reducing sugars, pentoses and phytate present prior to and after the treatment.

As indicated in Figure 1, the amounts of potentially bioavailable reducing sugars and pentoses were significantly increased (by 35% and 25%, respectively) while the amount of phytate was reduced by 36%.

These increases in the potential bioavailability of nutrients were reflected in the growth and feed efficiency measured in the fish.

Enzyme pretreatment increases nutritional value of feeds Due to the high contents in plant by-products, values of FCR and SGR in the control diet were quite unfavorable,

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Figure 1. Differences in nutrient content of experimental feeds (g/100 d.m). Statistical comparisons between feeds (3 samples per feed) with or without enzyme treatment are detailed in asterisk. Values showing the asterisk differ significantly with p <0.05.

Parameter

Control diet

Enzyme treated diet

Initial weight (g/fish)

11.89 ± 0.55a

12.38 ± 0.16a

Final weight (g/fish)

13.21± 0.49a

15.36 ± 0.04b

Increase (g/fish)

1.33 ± 0.28a

2.98 ± 0.15b

Feed consumption (g/fish) 8.65 ± 0.45a

9.23 ± 0.17b

FCR (g feed/g fish)

5.89 ±1.48a

3.11 ± 0.19b

SGR (g/100 g fish/day)

0.25 ± 0.05

0.50 ± 0.03

a

b

Table 2. Zootechnical indicators obtained in the nutritional assay performed on mullet juveniles.

but the use of the enzyme mixture significantly improved it by nearly 50%. Such results could be explained considering several positive effects associated to the use of the enzymes under optimal operative conditions such as: a) the partial hydrolysis of NSP could enhance the bioaccessibility of the fish digestive enzymes to fractions of nutrients that otherwise could be hardly digested (the so called “cage effect”); b) the reduction in the amount of phytate also had very positive effects, not only through increased availability of phosphorus but also of some fractions of protein and minerals that form complexes with phytate; and c) the use of citrate buffer at pH 5.0 to develop the SSH also could enhance solubilization of some minerals, like Fe or Mn. Also, from a practical point of view, the use of enzyme pre-treatment by SSH adapts the more suitable operative conditions (dose, reaction time, etc) to the specific features of different plant ingredients. Since the enzyme mixture is used prior to pelleting, inactivation due to thermal processing should eliminate any further undesired effect.

Conclusions The results obtained suggest the utility of the enzyme pre-treatment of ingredients in diets for M. cephalus and may help in the future development of commercial feeds based on the use of high amounts of by-products for this species.

Acknowledgements The present work was funded by CEIMAR (II Call for Projects of Bussines Innovation) and by Pesquerías Isla Mayor S.L. (PIMSL). Brewer’s spent grains were gently provided by “Origen” brewery (Almería, Spain).

More information: Fco. Javier Moyano Professor University of Almería, Spain E: fjmoyano@ual.es

Francisca P. Martínez MsC in Biotechnology University of Almería, Spain

Waldo G. Nuez-Ortín Lead scientist aquaculture Adisseo, Belgium

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COLUMN

Mycotoxins publications Albert G. Tacon, Ph.D.

Mycotoxins and compound aquaculture feeds Mycotoxins in aquafeeds is a topic that continues to gain attention especially due to the replacement of fishmeal with plant-based ingredients. Many scientific publications have recently reported on the effect in fish and shrimp. Some of the more recent publications are featured in this column.

For those interested in the full list, please don’t hesitate to contact us.

Gonçalves, RA; Schatzmayr, D; Albalat, A; Mackenzie, S. (2020).

Mycotoxins in aquaculture: feed and food. Reviews in Aquaculture, 12(1):145-175.

Nunes, EMCG; Pereira, MMG; Costa, APR; Araripe, MNBA; Calvet, RM; et al. (2019). Effects of aflatoxin B1 on performance and health of tambaqui fingerlings (Colossoma macropomum). International Aquatic Research, 11(1):73-83.

Gonçalves, RA; Menanteau‐ Ledouble, S; Schöller, M; Eder, A; Schmidt‐Posthaus, H; et al. (2019).

Effects of deoxynivalenol exposure time and contamination levels on rainbow trout. Journal of the World Aquaculture Society, 50(1):137-154.

Nácher‐Mestre, J; Ballester‐ Lozano, GF; Borja, G; Portolés, T; Calduch‐Giner, J; et al. (2018).

Comprehensive overview of feed‐to‐fillet transfer of new and traditional contaminants in Atlantic

salmon and gilthead sea bream fed plant‐based diets. Aquaculture Nutrition, 24(6):1782-1795.

Gonçalves, RA; Naehrer, K; Santos, GA (2018). Occurrence of mycotoxins in commercial aquafeeds in Asia and Europe: a real risk to aquaculture? Reviews in Aquaculture, 10(2):263-280.

Gonçalves, RA; Tu DC; Nguyen, NT; Santos, GA; Encarnação, P; et al. (2018). Aflatoxin B1 (AFB1) reduces growth performance, physiological response, and disease resistance in Tra catfish (Pangasius hypophthalmus). Aquaculture International, 26(3):921-936.

Modra, H; Sisperova, E; Blahova, J; Enevova, V; Fictum, P; et al. (2018).

Elevated concentrations of T‐2 toxin cause oxidative stress in the rainbow trout (Oncorhynchus mykiss). Aquaculture Nutrition, 24(2):842-849.

Dr. Albert Tacon is a Technical Editor at Aquafeed.com and an independent aquaculture feed consultant.

E: agjtacon@aquahana.com

Huang, Q; Tan, Beiping; Dong, X; Zhang, S; Yang, Q; et al. (2018).

Effect of chitosan oligosaccharide and mycotoxin adsorbents on intestinal mucosa structure and gut flora of Litopenaeus vannamei.

Zhongguo Shui Chan ke xue; Beijing, 2:373-383.

Matejova, I; Svobodova, Z; Vakula, J; Mares, J; Modra, H. (2017). Impact of mycotoxins on aquaculture fish species: A review. Journal of the World Aquaculture Society, 48(2):186-200.

Qiu, M; Wang, Y; Wang, X; Sun, L; Ye, Riying; et al. (2016). Effects of T-2 toxin on growth, immune function and hepatopancreas microstructure of shrimp (Litopenaeus vannamei).

Aquaculture, 462:35-39.

Goncalves, R. (2016). Aflatoxins: a threat to yellow catfish production.

World Aquaculture, 47(1):56-57.

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Anater, A; Manyes, L; Meca, G; Ferrer, E; Luciano, F; Bittencourt; et al. (2016). Mycotoxins and their consequences in aquaculture: A review. Aquaculture, 451:1–10.

Sealey, WM; Hooley, CG; Rosentrater, KA; Gaylord, TG; Barrows, FT. (2015). The effect of a mycotoxin deactivation product on growth of juvenile rainbow trout fed distillers dried grains. North American Journal of Aquaculture, 77(4):429-436.

Nacher-Mestre, J; Serrano, R., Beltran, E; Perez-Sanchez; Silva, J; et al. (2015). Occurrence and potential transfer of mycotoxins in gilthead sea bream and Atlantic salmon by use of novel alternative feed ingredients. Chemosphere, 128:314-320.

Greco, M; Pardo, A; Pose, G (2015).

Mycotoxigenic fungi and natural co-occurrence of mycotoxins in Rainbow trout (Oncorhynchus mykiss) feeds. Toxins, 7(11): 4595-4609.

Tola, S; Bureau, DP; Hooft, JM; Beamish, FWH; Sulyok, M; et al. (2015). Effects of wheat naturally contaminated with Fusarium mycotoxins on growth performance and selected health indices of Red Tilapia (Oreochromis niloticus O. mossambicus). Toxins, 7(6):1929-1944.

García-Morales, M-H; PérezVelázquez, M; González-Felix, ML; Burgos-Hernández, A; CortezRocha, M-O.; et al. (2015). Effects of fumonisin-containing feed on the

muscle proteins and ice-storage life of White shrimp (Litopenaeus vannamei). Journal of Aquatic Food Product Technology, 24(4):340.

histopathological alteration in Fenneropenaeus indicus. Iranian Journal of Fisheries Sciences, 12(4):813-826.

Hauptman, BS; Barrows, FT; Block, SS; Gaylord, TG; Paterson, JA; et al.

(2014). Potential for a mycotoxin deactivator to improve growth and performance of Rainbow trout fed high levels of an ethanol industry co-product, grain distiller's dried yeast. North American Journal of Aquaculture, 76(4):297-304.

Pietsch, C; Bucheli, TD; Wettstein, FE; Burkhardt-Holm, P. (2011).

Frequent biphasic cellular responses of permanent fish cell cultures to deoxynivalenol (DON). Toxicology and Applied Pharmacology, 256(1):24-34.

Sheikh-Ali, SI; Ahmad, A; MohdSetapar, S-H; Zakaria, ZA; AbdulTalib, N; et al. (2014). The potential hazards of Aspergillus sp. in foods and feeds, and the role of biological treatment: A review.

Journal of Microbiology, 52(10): 807-818.

Wozny, M; Obremski, K; Jakimiuk, E; Gusiatin, M; Brzuzan, P. (2013).

Zearalenone contamination in rainbow trout farms in NorthEastern Poland. Aquaculture, 416-417:209.

Barbosa, TS; Pereyra, CM; Soleiro, CA; Dias, EO; Oliveira, AA; et al.

(2013). Mycobiota and mycotoxins present in finished fish feeds from farms in the Rio de Janeiro State, Brazil. International Aquatic Research, 5(1):1-9.

Ghaednia, B; Bayat, M; Sohrabi Haghdoost, I; Motallebi, A A; Sepahdari, A. (2013). Effects of aflatoxin B sub(1) on growth performance, health indices, phagocytic activity and

Hooft, JM; Elmor, A-H; Encarnacao, P; Bureau, DP (2011). Rainbow trout (Oncorhynchus mykiss) is extremely sensitive to the feed-borne Fusarium mycotoxin deoxynivalenol (DON). Aquaculture, 311(1-4):224-232.

Holland, P (ed.); McNabb, P (ed.); Lawrence, J (ed.); Loreal, H (ed.); Toyofuku, H (ed.); et al. (2011).

Marker compounds and relative response factors - issues for screening natural toxins in food.

Discussion document for the Joint FAO/IOC/WHO ad hoc Expert Consultation on marine biotoxins in molluscan shellfish. FAO fisheries and aquaculture technical paper.

283-289. FAO, Rome (Italy), Gbore, FA; Adewole, AM; Oginni, O; Oguntolu, MF; Bada, AM. et al. (2010). Growth performance, haematology and serum biochemistry of African catfish (Clarias gariepinus) fingerlings fed graded levels of dietary fumonisin B sub(1). Mycotoxin Research, 26(4):221-227.

A full review of the recent bibliography will be presented at the Biomin World nutrition Forum that will be held in October 28-30, 2020 in Cancún, Mexico.

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Why trace mineral levels and sources must be adjusted in aquaculture diets ClĂĄudia Figueiredo-Silva, Zinpro Animal Nutrition Your trace mineral content and source may be limiting performance.

Farmed fish and shrimp nutrition levels have changed over the years due to ingredient availability, price, regulatory and environmental constraints and consumer demands. While these changes helped meet cost and sustainable aquaculture requirements, they left the fish and shrimp industry looking for ways to meet nutritional requirements while maintaining high growth and production rates. Currently, a major challenge is developing more efficient production and feeding concepts that meet the worldâ&#x20AC;&#x2122;s growing nutritional and health needs. Moving to precision nutrition requires additional effort to understand and re-evaluate nutritional needs of fish and shrimp fed diets with new and alternative ingredients. The nutritional value of feed is affected by the ingredients

used and the balance of added micronutrients to include, availability of amino acids (AA), fatty acids, vitamins, and minerals, which impact feed efficiency, growth, health and quality of the final product presented to the consumer.

Reductions in fish meal (FM), as well as other marine ingredients of high nutritional value, require the adjustment of both level and source of trace minerals (TM) in aquaculture nutritional programs. Furthermore, due to regulations on TM supplementation and total dietary concentration, the aquaculture industry must look for alternative TM sources that meet both animal and regulatory needs. For example, the European Union set a complete feed zinc limit of 180 mg/kg for salmonids and 150 mg/kg for other fish. According

Figure 1. Trace mineral content of selected ingredients relative to fishmeal.

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Figure 2. Trace mineral functions in fish and shrimp.

to the European Food Safety Authority, the 2016 regulatory limits could reduce the amount of zinc in feces, with a potential environmental impact of ~20%, ensuring consumer safety, animal health and welfare without affecting animal productivity. This requires aquafeed producers to establish ways to be more efficient with TM supplementation.

Replacement of fishmeal with plant and/ or land-animal by-product proteins significantly reduces TM level in aquaculture diets Nutrient recommendations, such as those from the NRC (2011), need to be reviewed, given a progressive reduction of FM and increased use of plant-based ingredients in fish and shrimp diets. Through the ARRAINA project, the European Academy and the feed industry have joined efforts to re-evaluate nutrient recommendations for fish-fed practical diets with reduced or complete elimination of FM. Experiments in Atlantic salmon showed a clear difference between zinc supplementation required in plant-based diets and zinc required in semi-purified or purified diets. Zinc levels were recommended well above 37 to 65 mg/kg diet recommended by the NRC (2011), and very close, or even above, the EUâ&#x20AC;&#x2122;s 180-ppm upper allowable limit. Differences in the TM profile

of marine vs plant ingredients and bioavailability of TM sources used may help explain results. Comparisons of TM profile of different protein sources to that of FM, expose significant limitations in zinc, selenium, and iron, among others.

Figure 1 illustrates the varying levels of TMs in common fish and shrimp feed ingredients relative to standard 60% crude protein FM. Relative to FM, plant proteins and land animal by-product proteins can be limiting in zinc and selenium content by > 50%.

A change in dietary formulations requires paying special attention to effects on TM profiles and consequently their balance across species and life cycle.

Information in aquatic species is still limited, but basic metabolic functions of TMs, except for osmoregulation, are believed to be the same across species. They are key elements for the activation and function of hormones and hundreds of enzymes, foundational to proper development and function of bone, nervous, and reproductive systems, as well as modulation and activation of the immune system. Trace minerals are also critical to epithelial tissue production and maintenance, thus affecting skin, eye, gill, fin, scale, and gut integrity (Fig. 2). Among these, zinc is known to exert beneficial effects beyond growth, namely modulating immune response and resistance to disease,

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reduction of cataract incidence, and oxidative stress. In addition, zinc plays an essential role in wound healing and speeding the re-epithelialization processes in humans (Lin et al., 2018) and fish (Ogino and Yang, 1979; Hughes, 1985; Jensen et al., 2015; Gerd et al., 2018). Selenium deficiency has been shown to increase mortality, anemia, muscular dystrophy, depressed glutathione peroxidase activity, and overall growth and health of multiple aquatic species (NRC, 2011).

Anti-nutritional factors in plant protein sources directly and indirectly impact TM needs of animals Replacement of FM with plant-based ingredients in aquaculture diets has the risk of increasing anti-nutritional factors (e.g. phenols, saponins, phytates, tannins, protease inhibitors and non-starch polysaccharides), which may impair fish and shrimp growth and health. For example, soybean meal saponins have membrane-permeabilizing activity reported to result in enteritis of the distal intestine in Atlantic salmon, thus negatively affecting health and growth.

This may be an indirect impact of plant-protein sources on TM needs of the animal, as those are significantly increased in situations of stress caused by nutritional factors or pathogens. Conversely, phytic acid has the propensity to bind TMs and make them less available for absorption, having a direct and negative impact on the growth and health of the animal. In this regard, TM stability throughout the GI tract, and the way different supplemental TMs are absorbed, affects their availability and ultimately animal performance.

Trace mineral source and its availability to the animal Recent research conducted by Dr. Sauer et al. (2017) helps us better understand why bioavailability and performance of TMs depend on source. Their work looked at different TM absorption pathways, used by gut enterocytes, for zinc uptake. In one model, they utilized human enterocytes, differentiated by mutations in ZIP4, an important zinc ion transporter, for the uptake into the gut lining. Interestingly, no impairment in zinc absorption occurred when zinc as

Figure 3. The enterocyte: Comparison of uptake using the AA transport pathway vs the metal ion transporter pathway.

a zinc amino acid complex (ZnAA) was presented to the apical surface of gut enterocytes vs an inhibition to ZnCl2. These findings demonstrate that ZnAA are taken up via an alternate absorption pathway than inorganic zinc (Fig. 3). Therefore, metal-AA complexes have an absorption advantage over inorganic mineral forms, as they are minimally antagonized by dietary components, like phytic acid, and use AA-transporters instead of common metal ion transporters. These advantages make ZnAA more efficiently absorbed and bioavailable to the animal. Paripatananont and Lovell (1995), were the first to show the zinc-methionine complex (ZINPROÂŽ; a ZnAA) was three to five times more bioavailable than inorganic zinc (ZnSO4) in meeting growth requirements of channel catfish fed purified and practical diets containing phytic acid, respectively.

By better understanding TM functions and bioavailability of supplemental TMs in animals, we will be better prepared to adjust TM recommendations of practical relevance for the aquaculture industry.

References available on request

More information: ClĂĄudia Figueiredo-Silva Aquaculture Nutritionist Research & Nutritional Services Zinpro Animal Nutrition, Inc., USA E: csilva@zinpro.com

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Dietary potassium-diformate affects growth performance and survival rates of vannamei-shrimp in hatchery and grow-out in worldwide aquaculture Christian Lßckstädt, ADDCON GmbH

Intensive production of the whiteleg shrimp, Litopenaeus vannamei (Boone 1931), in Central America and SE Asia is estimated to have almost reached 4.0 million tons (FAO, GOAL, 2019), thus showing strong signs of recovery in the last couple of years.

Despite remarkable progress in shrimp nutrition and feed formulation during the past years, disease outbreaks in shrimp ponds can still lead to farming setbacks and increased use of antibiotics. Growing awareness from consumers and producers of aquaculture species, however, has driven demand for responsible and sustainable aquaculture. Regulatory authorities in most exporting countries now focus on the misuse of antibiotic growth promoters (AGP) in aquaculture, while public attention has shifted towards sustainable production methods. Alternative additives are being developed to replace the AGPs.

Acidifiers to replace AGPs Acidifiers are one of various alternatives spearheading environmentally friendly and nutritive-sustainable aquaculture approaches. Currently, the most widely tested organic acid molecule in aquaculture is potassium diformate (KDF). It has been tested and used successfully, among others, in salmon, trout, tilapia, Asian and European sea bass and pangasius.

Its value to the shrimp production cycle has also been demonstrated in several field and research trials. Potassium diformate is a double-salt formic acid molecule which decreases gastrointestinal pH and thereby intensifies the release of buffering fluids, containing enzymes, from the hepatopancreas. Formate also diffuses into pathogenic bacteria inside the digestive tract and acidifies their metabolism, leading to bacterial cell death. Furthermore, beneficial bacteria (Lactobacilli, Bifidobacteria) are supported (eubiosis), which may lead to improved gut health, resulting in stronger condition of the shrimp.

Acidifiers in vannamei PLs One of the most crucial periods in the life cycle of shrimp is the post-larval stage when shrimp feeding is changed from algae and brine shrimp nauplii to commercially formulated larval diets. Survival rates during this period are critical to later productivity. Pathogenic bacteria can dramatically increase mortality in the shrimp hatchery.

Therefore, the use of potassium diformate was tested during this production stage (He et al., 2006). The group

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Parameter

Control

0.8% KDF

Difference (%)

57

-

Initial BW (mg) 57

Final BW (mg) 256±34 309±35 +21

WG (mg, 40 d) 199

FCR

Survival (%) 92.2±1.6 100

+8

Prod. Index* 0.49

+106

252

+27

3.73±0.6 2.49±0.3 -33 1.01

Table 1. Growth, feed conversion and survival of Litopenaeus vannamei PLs under aquaria conditions after 40 days. *Productivity Index (weight gain (g) × survival (%) / (10 × FCR))

supplied post-larvae of Litopenaeus vannamei, with a body mass of 57 mg, with a formulated diet containing either no or 0.8% potassium diformate (KDF, Aquaform®, ADDCON), for 40 days. Shrimp larvae fed with KDF improved performance dramatically (Table 1).

Shrimp larvae fed with KDF inclusion showed more efficient growth and significantly improved feed utilization, as well as lower mortality (p<0.05), compared to control shrimp, leading to a markedly increased productivity index, which is based on a formula including the three most important production figures in shrimp production (weight gain of shrimp, feed efficiency and survival rate).

KDF improves growth and survival in juvenile whiteleg shrimp As discussed previously, optimal nutrition in the early stage of the shrimp production cycle often leads to an overall improved shrimp productivity. This was demonstrated in another experiment, reported by Jintasataporn et al. (2011). An aquarium-simulated intensive grow-out trial investigated the growth performance of juvenile white-leg shrimp fed with low levels of dietary KDF vs a control diet. While the control diet did not contain KDF, 0.2% and 0.5% KDF were added to two treatment diets, respectively. Shrimp (initial weight 2.4±0.1 g) were fed to satiation three times a day, with a commercial diet containing 32% crude protein.

The trial lasted for 10 weeks.

Growth performance of white leg shrimp fed 0.2% and 0.5% KDF inclusion resulted in significantly (p<0.05) increased body weight, by 7.2% and 7.4%, respectively and in average daily weight gain by 9.26% and 9.17% (p=0.06). Similarly, FCR tended to be improved by 7.1% and 7.0% (p=0.07) compared to the control group. Likewise, survival rates of KDF-fed shrimp were 80.6 vs. 76.1% in the control group.

The data was also analyzed for overall productivity.

Here, the PI showed that inclusion of KDF resulted in a significant improvement compared to the negative control by more than 19% or 24% depending on the dosages. Ly et al. (2019) carried out a rather recent experiment with KDF in vannamei. Here, shrimp with an initial body weight of 0.82±0.09 g were cultured in a research laboratory in Taiwan for 80 days. The researchers used the inclusion of 0.4% of KDF into a shrimp diet vs a negative control. Results as showed on Table 2.

KDF reduces mortality in Vibrio challenges Experiments carried out under controlled laboratory conditions like the one reported above showed unusually high survival rates (73-97%), and thus were not “mimicking” bacterial situations on commercial farms closely enough. Survival rates that do not reflect those found on farm often give an unrealistic picture of the additive’s benefit. Under commercial farm conditions, shrimp can be exposed to many different challenges, including bacterial pathogens.

Therefore, trials were carried out to challenge juvenile white-leg shrimp with the bioluminescent Gramnegative bacterium Vibrio harveyi, which regularly causes increased mortality in shrimp culture (Kühlmann et al., 2011). The trial consisted of a negative control, which was compared against two treatment groups (0.2% and 0.5% KDF, the same dosages as the ones used in the trial reported previously). A total of 90 shrimp (30 shrimp per group), with a mean body weight of 11.0±0.8 g, were used. The trial used the same facility as described above, however this time, the pathogen (V. harveyi) was added to the water at the beginning of the 10-day trial at a rate of 5 × 106 CFU/ml.

At the end of the challenge trial, mortality in the non-treated shrimp was significantly higher (p<0.01;

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Parameter

Control

0.4% KDF

Difference (%)

Final weight (g) 9.21

11.03

+20

Weight gain (g) 8.39

10.21

+22

Weight gain (%) 1123±98

1345±120 +20

SGR (%)

3.34±0.11 3.56±0.12 +6.7

FCR

2.09±0.13 2.00±0.04 -4.3

Survival (%)

73.3±11.6 96.7±5.8 +32

Productivity Index 29.4

49.4

+68

Table 2. Growth performance in juvenile whiteleg shrimp fed a diet with or without KDF for 80 days.

76.6±5.8%) compared to shrimp which had been fed with KDF at both inclusion levels (50.0±10.0% for both 0.2% and 0.5% KDFdosage).

The effect of the acidifier was clear from Figure 1. Impact of Aquaform (3 kg/t) the first day of versus control on the growth of Vibrio spp., the trial, but including V. parahaemolyticus, in shrimp heamolymph (HM) and hepatopancreas (HP): the difference upper left - Aquaform haemolymph; upper between right – Aquaform hepatopancreas; lower left – control haemolymph; lower right – treatment and control hepatopancreas. control became more pronounced from day 4 onwards and remained significantly different until the end of the trial. Both dosages of KDF reduced the mortality in the challenged shrimp to the same extent by day 10. In this context, it can be concluded that dietary potassium diformate is able to reduce mortality in whiteleg shrimp caused by the Gram-negative pathogenic bacteria V. harveyi.

It may be expected that similar results could be found with other Gram-negative bacterial pathogens in commercially reared shrimp.

MIC and ex vivo trials Subsequent trials in Ecuador (2016) were able to quantify with Minimum Inhibitory Concentration (MIC), the needed amount of potassium diformate to stop the growth of Vibrio harveyi and Vibrio parahaemolyticus.

The necessary dosage ranged from 3,500 ppm for V. harveyi to 4,500 ppm for V. parahaemolyticus, agreeing with the earlier trials from Thailand.

The impact of the diformate was furthermore assessed under ex-vivo conditions in Mexico, in which bacterial growth of Vibrio spp., including V. parahaemolyticus, in haemolymph and hepatopancreas was determined and the whole data-set is due for publication at the World Aquaculture Society meeting later this year. For this approach, shrimp were fed for several weeks either a control diet or a diet containing 3 kg /t potassium diformate. After that, haemolymph (HM) and hepatopancreas (HP) were analyzed for bacteria content. The addition of dietary KDF led to a 100% reduction of Vibrio spp. in the haemolymph, while these bacteria were reduced by 85% in the hepatopancreas, as seen in the pictures (Fig. 1), therefore supporting the earlier antibacterial finding of the additive.

Conclusions Finally, in view of the results on growth performance and survivability, it is safe to say that potassium diformate (Aquaform®) is a promising additive for economic and sustainable shrimp production and should be considered in compound feeds for shrimp under commercial “outdoor” conditions. They furthermore suggest that the additive serves as a conditioner for infected shrimps, reducing mortality and leading to improved profitability in the worldwide pond farm operation.

References available on request

More information: Christian Lückstädt Technical Director FEED ADDCON GmbH, Germany E: christian.lueckstaedt@addcon.com

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A prebiotic treatment of edwardsiellosis in striped catfish (Pangasianodon hypophthalmus) Valentin Eckart, Biochem A threat, not only to catfish The pathogenic, gram-negative bacterium Edwardsiella ictaluri is widely known as the causative agent of the enteric septicaemia of catfish (ESC) and was first reported in the United States in channel catfish (Ictalurus punctatus) (Hawke et al., 1981). Subsequent reports have shown that this bacterium also infects non-catfish species like Nile or hybrid red tilapia. In general, clinical signs of E. ictaluri infections may vary between species, but visceral white spots have been described in most of them. The misinterpretation of these symptoms, as those of other diseases (Dong et al., 2019), makes the actual spread of edwardsiellosis somewhat unclear and it should be further monitored.

An economic challenge Today, edwardsiellosis has become one of the most important infectious disease problems in the commercial catfish industry. In Asia, E. ictaluri is causing bacillary necrosis of pangasius (BNP) in striped catfish (Pangasianodon hypophthalmus). Natural disease outbreaks are reported in all ages of fish, with high mortality rates of 50 â&#x20AC;&#x201C; 90% (Crumlish et al., 2002; Dung et al., 2004). The Vietnamese industry highly relies on striped catfish farming, with an annual production volume of about 1.4 million tons (VASEP, 2019). Hence, declining production, high fish mortality and increased costs for the treatment of E. ictaluri infections can lead to huge economic losses.

Lack of specific treatments In order to counteract the economic impact of E. ictaluri, the industry has been working on the development of pathogen-specific vaccines that already reduce the mortality rate during the production of

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Figure 1. Accumulated survival of striped catfish after infection with E. ictaluri. Fourteen days post- infection, 100% of fish from the negative control, 47% from the positive control and 71% from the TechnoMos® survived (p = 0.01). Positive control and TechnoMos® groups were both challenged with E. ictaluri.

Treatment (g/kg) Yeast cell wall extract

Control

TechnoMos ®

0.0

1.0

Nutritional value (g/kg) Crude protein 299.0 309.0 Crude fat

62.9 80.1

Crude fiber

29.4 29.4

Ash

85.2 84.7

Moisture

87.1 77.5

Table 1. Treatment and nutritional value of diets.

fingerlings. In addition, breeders have also made significant improvements in breeding more resistant catfish strains. Unfortunately, these measures are mainly confirmed for the channel catfish (Zhou et al., 2018). To date, comparable treatments are lacking for most Asian catfish species such as striped catfish, leading to an overuse of antibiotics in affected farms.

But work on more advanced vaccines and breeding programs continues (Triet et al., 2019; Vu et al., 2019).

A protective treatment, not only against E. ictaluri A third alternative has presented itself as beneficial to generally increasing the bacterial resistance in aquaculture species: the supplementation of yeast cell wall-based prebiotics in aquafeeds (Meena et al., 2013).

TechnoMos® is a cell wall-extract of the primary grown yeast, Saccharomyces cerevisiae, and thus consists of highly concentrated mannan-oligosaccharides (MOS) and β-1,3-1,6-glucans. The β-glucans act as nonpathogenic polysaccharides which are able to activate white blood cells such as macrophages. As a result, immune functions like phagocytosis (the cellular uptake and digestion of intruding cells and particles), the release of cytokines and finally antibody production are significantly improved. This also enhances the efficacy of vaccines and of adaptive immunity (Meena et al., 2013). Moreover, ß-glucans have been reported to increase the expression of mucin- and defensin coding genes for improved mucus production within the intestine, but also at the outer gills and skin level – a strong physical barrier against pathogens (van der Marel et al., 2012). The MOS content in TechnoMos® is able to block pathogenic adhesins and receptors and thus prevent the binding and proliferation of gram-negative bacteria to the intestinal wall (Aronson et al., 1979).

The challenge It sounds good in theory – but does it work? To investigate the protective effect of TechnoMos® against bacterial diseases like BNP, a feeding trial in striped catfish has been conducted. Over a period of six weeks, two different diets were fed to two groups of young

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negative control and only 47% of the positive control group. The applied direct injection was the favorable method for exact dosing (47% is prove for a very accurate LD50-dose). It also guaranteed that the pathogen invaded the organism. Since the pathogen bypassed the common ways of infection, through the intestine and gills, the protective properties of TechnoMos®, like improved physical barriers such as internal and external mucus production, against E. ictaluri could not be measured by this method.

Nevertheless, the trial confirms the sustained support of the immune system by TechnoMos® resulting in an increased survival rate by nearly 25% compared to the control group (p = 0.01).

striped catfish (~20 g) – five replications with 90 fish per hapa. The control group was fed on a standard diet, while the treatment group had 1 g/ kg TechnoMos® added to its feed. For the following challenge, 20 fish from each iteration were randomly assigned to 100L-fiberglass tanks and then given injections of a 0.15 ml E. ictaluri solution at a previously tested 50%-lethal dose (LD50) with 5.67 x 104 CFU/mL. A third group, taken from the untreated control groups, received an injection of NaCl solution as negative control. At a constant water temperature of 26 °C, optimal for bacterial growth, mortality was monitored and either dead or moribund fish were collected for laboratory testing for E. ictaluri infestation.

Significantly increased survival Fourteen days post-infection, 71% of the TechnoMos®treated fish survived in comparison to 100% in the

There is huge potential A new infectivity model using an immersion bath with E. ictaluri and striped catfish has been established after this study was finished (Ngoc Phuoc et al., 2020).

Paradigms such as these, in which a natural outbreak is better simulated, are likely to show even lower fish mortality in feeding experiments with TechnoMos®.

One reason is the above mentioned improved physical barrier, the other is the pathogen binding ability of MOS. Since E. ictaluri is a gram-negative bacterium, there is a chance for binding to MOS and being removed from the intestine without proliferation. This can significantly reduce the risk of infection.

However, the present results confirmed the protective effect of TechnoMos® against bacterial diseases like BNP in striped catfish.

Acknowledgements Many thanks to the researchers from the Faculty of Fisheries of Nong Lam University in Ho Chi Minh City, Vietnam, who conducted this trial.

References available upon request

More information: Valentin Eckart Research and Development Biochem, Germany E: veckart@biochem.net

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COLUMN

Trends and developments C. Greg Lutz, Ph.D. The best of both worlds: in-pond raceways and split ponds Throughout the globe, most aquaculture is practiced in earthen ponds and with good reason.

Ponds offer a lot of benefits for fish or crustacean production.

They incorporate natural cycles to break down nutrient inputs and support internal productivity while the energy requirement for these treatment processes is easily met by incoming sunlight. But ponds are big and awkward when it comes to harvesting, disease treatment and predator control. And although aeration allows us to push the envelope to some degree, ponds exhibit some pretty inflexible natural limits in terms of intensification.

Now… tanks, on the other hand, are compact, efficient, provide ease of feeding, allow for rapid disease treatments and facilitate or even eliminate the need for predator control. Tanks are great, in their own way. But unless you’re farming sharptooth catfish or some comparable species, the artificially high densities associated with tanks require aeration and water exchange, or in some cases a number of other processes such as mechanical and biological filtration as in the case of RAS. This, of course, leads to the question: what if you could combine the best attributes of both

approaches? Containing the fish crop in a relatively small space, like a tank, and using an open pond area to promote natural waste treatment and nutrient cycling dependent on phytoplankton and benthic processes? Ring a bell? Well, to be fair, this strategy was proposed and explored long ago. As the song says, everything old is new again.

In 1972, Howard J. Freemont was awarded a patent (US Patent number 3653358, application filed by assignee Marine Protein Corp.) for a floating fish grow-out tank composed of a watertight liner with a means to add and remove water from the vessel. In 1977, Arlo Fast was granted a US Patent (No. 4044720A) for a floating fish rearing system that confined fish in raceways and was also constructed of flexible pond liner material. Water circulation was based on airlifts that supplied aerated water from depths below the thermocline with the option to attach a waste settlement tank to each raceway. In 1991, Fast published a summary of the performance of a system adapted from the one described in his patent application.

In the early 1990s, Yoo, Masser and Hawcroft refined and evaluated an in-pond raceway and waste removal system for catfish production at

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 2 2020

Dr. Greg Lutz is a Professor with Louisiana State University Agricultural Center. He is also an author and consultant.

E: lutzaqua@att.net

Auburn University. The research was the basis of Hawcroft’s Master’s thesis, and was largely motivated by both the desire to intensify catfish production systems and concerns over nutrient loads in pond effluents.

Although Masser and Lazur subsequently wrote a factsheet in 1997 outlining a DIY approach to the in-pond raceway system, the concept was not immediately nor widely adopted. During this period, several publications emerged in various parts of the world presenting variations of the raceway-in-a-pond idea, but the strategy did not gain much traction.

Over the past decade, however, Auburn has revisited the approach.

Significant time and resources have been devoted to upgrade and promote this production system in other countries and in conjunction with the US Soybean Export Council.

The systems have been installed in a number of countries in recent

55

years and the concept is quite similar in that fish are confined to a relatively small area in an open pond, solid wastes are concentrated and collected, water circulation is provided to constantly refresh and aerate the culture area and the rest of the pond serves to process wastes generated during grow-out. In most of these systems, air-lift pumps at the head end of the raceways push water through the containment area, aerating it at the point of entry. This approach has been shown to be suitable for any number of species including tilapia, catfish, largemouth bass, grass carp and bluntnose black bream.

But no matter where you try to build one, the state of the art in-pond raceway (currently promoted as the IPRS) requires capital. Actually, a LOT of capital.

However, there are some lower-cost alternatives emerging. Perhaps, the most interesting of these is the Split Pond production method. Although somewhat less productive than in-pond raceways on a per-hectare basis, split ponds are also less capital and energy intensive and can therefore be more easily adopted in developing nations.

So how do split ponds work? It’s not rocket science, but it’s ingenious. An existing (or new) pond is divided into two separate sections in a ratio of roughly 80%-20%. The small section

is used to raise fish, while the larger section serves as a treatment pond to break down and cycle wastes generated throughout the grow-out process. As a rule, the overall pond size should not exceed four to five hectares. A means of circulating high volumes of water between the two sections is required, as is a return channel or culvert. Once the pond is up and running the smaller (20%) section is stocked with the same number of fish that would normally be put into the entire pond area.

Circulation in a split pond configuration requires movement of a minimum of roughly 1 m3 of water per minute for every MT of fish present in the small section – with pumping capacity sized for the maximum load expected at the time of harvest. A number of different means have been used to circulate water between pond sections, including slow moving custom-constructed paddlewheels, commercial paddlewheel aerators set for greater paddle submergence (catfish industry designs – as opposed to shrimp farm aerator designs), high-speed screw pumps (not unlike those used to fill distribution canals in many shrimp farms around the world) and horizontally mounted axial flow pumps. All appear to have tradeoffs between investment costs, maintenance requirements and

operating costs per cubic meter of water moved. Since the paddlewheel designs require large cross-sectional areas, extra accommodations must be made when installing them in the levees separating the split-pond sections. Apart from circulation, energy is also required for nighttime aeration in split-pond based farms, but research suggests that aeration is much more efficient when fish stocks are confined in the smaller area of a split pond system.

Preliminary research with hybrid catfish production in the U.S. suggests that feed prices above $500/MT or farm-gate fish prices below $2 US/kg can result in economic losses when using some split pond designs and management practices. However, when researchbased designs are strictly followed, net yields of 19.1+3.2 MT/hectare and modified internal rates of return (MIRRs) of 15% and 28% could still be achieved, respectively, under each of these difficult scenarios.

With the prevailing market and feed prices, split pond units that tended to stray from the research-based recommendations still exhibited MIRRs ranging from 12% to 21% for a single four hectare split pond.

As pond producers throughout the world strive to intensify production, split ponds may offer simpler design, easier management and reduced environmental impacts per unit of production, at least when compared to in-pond raceways. And in regions where climate and regulatory environments allow the use of tilapia as a primary or polyculture species, producers will have more flexibility not just in converting wastes into phytoplankton, but also in turning that pond algae into edible protein.

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22 – 24:

ILDEX Vietnam 2020, Ho Chi Minh City, Vietnam

www.ildex-vietnam.com

Aquaculture Canada and WAS North America, Newfoundland, Canada

was.org

JULY

AUGUST 30 – Sep 2:

SEPTEMBER 7 – 10:

LACQUA, Guayaquil, Ecuador

was.org

13 – 18:

International Symposium on Fish Nutrition and Feeding, Busan, South Korea

www.isfnf2020busan.com

15 – 18:

SPACE, Rennes, France

space.fr

15 – 17:

Aquaculture UK, Scotland, UK

aquacultureuk.com

18 – 19:

International Conference on Aquaculture and Marine Biology, Kanyakumari, India

www.conferencemind.com

28 – 30:

Aquafeed Extrusion Technology Course, Ås, Norway

www.fie.com.au

29 – Oct 2:

Aquaculture Europe 2020, Cork, Ireland

www.aquaeas.org

1 – 2:

Extrusion Scale-up & Process Transfer, Ås, Norway

www.fie.com.au

6 – 8:

GOAL, Tokyo, Japan

www.aquaculturealliance.org

19 – 21:

IFFO 60th Annual Conference, Lima, Peru

www.iffo.net

26 – 27:

World Aquaculture and Fisheries Conference, Tokyo, Japan

worldaquacultureconference.com

OCTOBER

NOVEMBER 10 – 11:

2nd US Microalgae Industry Summit, Orlando, USA

www.wplgroup.com

28 – Dec 1:

Aquaculture Africa, Alexandria, Egypt

www.was.org

DECEMBER 14 – 18:

World Aquaculture 2020, Singapore

Aquafeed: Advances in Processing & Formulation Vol 12 Issue 2 2020

was.org

AQUAFEED VOL 12 ISSUE 2 2020

CONTACT US Editorial: editor@aquafeed.com Editor: Lucía Barreiro Executive Editor/Publisher: Suzi Dominy Technical Editors: Peter Hutchinson, Albert Tacon, Ph.D Conferences: info@feedconferences.com Advertising Enquiries/request media pack: sales@aquafeed.com Technical Feed Consulting: Senior Technical Consultant: Warren Dominy, Ph.D consulting@aquafeed.com Accounts & All Other Enquiries: info@aquafeed.com

ARTICLE SUBMISSION You are encouraged to submit scientifically/technically-oriented feature articles describing new products, practical nutrition or processing research, applications, feeding trial results, case studies, feed management, storage, handling and delivery.

GUIDELINES l 1,000 words plus tables, charts etc. l

Send text as a Word document.

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Also attach tables and graphs in original Excel document, if possible.

We are grateful to the following companies for sponsoring this issue of the magazine.

Their support allows us to make our publications available without charge. We thank them for partnering with us to support the development of our industry through education and information.

Famsun..................................................................................................... 2 VICTAM....................................................................................................... 5 Wenger....................................................................................................... 9 ILDEX........................................................................................................... 13 Hatchery Feed & Management............................21 SPACE........................................................................................................ 26 Extru-Tech............................................................................................. 28 LIPTOAQUA........................................................................................ 31 Skretting.................................................................................................. 34 Aquaculture Canada and WAS North America.................................................. 58

Please include photos whenever possible (high resolution – at least 300dpi – JPEF preferred).

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References should be included. If extensive, please omit and state "References available by request".

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Follow us:

Author's name, job, title, company, email, photo (+ contact for reader follow-up if different from Author).

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Keep it descriptive and technical with minimal use of product name: please no "sales puff".

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NEWS ITEMS New items are also welcome for publication in our newsletters and magazines. Please include a photo whenever possible (at least 300 dpi – JPEG preferred).

Submission does not guarantee acceptance and the editors reserve the right to edit for content, style, clarity and grammar.

SUBSCRIBE Digital editions are free to industry subscribers. You may also purchase print copies. Subscribe at Aquafeed.com to receive your own digital copy of: l l l

Aquafeed: advances in Processing & Formulation (Quarterly) The Aquafeed Newsletter (Weekly) Hatcheryfeed Magazine (Quarterly)

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Aquafeed.com, LLC., Kailua, Hawai’i 96734, USA. Copyright© Aquafeed.com LLC., 1998-2019 All rights reserved. Copyright & Disclaimer at: http://www.aquafeed.com/disclaimer/

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Aug. 30-Sept. 2, 2020 St. John’s Convention Centre Photo: Mike Norton, Flickr

St. John's, Newfoundland and Labrador, Canada

Aquaculture Canada and WAS North America 2020

CALL FOR PAPERS – DEADLINE: June 1, 2020 For more details: aquacultureassociation.ca | was.org | naia.ca