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Welcome to Expert Topic, a new feature for International Aquafeed. Each issue will take an in-depth look at a particular species and how its feed is managed.

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  1. 1. November | December 2012 EXPERT TOPIC - SALMON International Aquafeed is published five times a year by Perendale Publishers Ltd of the United Kingdom. All data is published in good faith, based on information received, and while every care is taken to prevent inaccuracies, the publishers accept no liability for any errors or omissions or for the consequences of action taken on the basis of information published. ©Copyright 2012 Perendale Publishers Ltd. All rights reserved. No part of this publication may be reproduced in any form or by any means without prior permission of the copyright owner. Printed by Perendale Publishers Ltd. ISSN: 1464-0058The International magazine for the aquaculture feed industry
  2. 2. EXPERT T●PIC EXPERT TOPICSALMON Welcome to Expert Topic, a new feature for International Aquafeed. Each issue will take an in-depth look at a particular species and how its feed is managed. 30 | InternatIonal AquAFeed | november-December 2012
  3. 3. EXPERT T●PIC ᕡᕣ ᕤ ᕥ ᕢᕡ Atlantic seaweeds from integrated multi-trophic aquacul- ture farms. Of the fish farmed in Atlantic Canada, approximately 60 percent is exported to the ed association that has been working on behalf of the salmon farming industry in the mari- time region since 1987. The ACFFA representsCanada United States. Canada has vast and dynamic ecosystems and while some farm management practices vary over 95 percent of salmon production in New Brunswick and Nova Scotia in addition to a wide range of businesses and organization in the supply depending on the environment, no Canadian and service, technological and research Pamela Parker, Executive Director, salmon producer uses hormones, dyes or chemi- The ACFFA takes a leadership role in theAtlantic Canada Fish Farmers cals in their feed and our farmed salmon is not development and implementation of strategiesAssociation, Canada genetically modified. Less than three percent of that are focused on fish health and welfare, salmon feed contains an antibiotic. environmental stewardship, innovation and socialA Because salmon farming is science-based, responsibility within our communities. tlantic Canada is the birthplace of our environmental and fish health management Canada’s salmon farming industry. practices are continually changing and improving More InforMatIon: Canada’s first commercial harvest of as new research or technology emerges. Website: farmed Atlantic salmon in took place Canada leads the development of fishmeal andin Lord’s Cove, Deer Island in 1979. fish oil replacement in salmon feed. In the 1990s, wild fish based ingredients in feeds were as high as Today, aquaculture is a $2.1 billion industry in 80 per cent. Today, it’s as low as 20 per cent.Canada, employing over 15,000 workers. Atlantic Canadian feed producers work with Atlantic Canada produces approximately top researchers to develop their own feed using55,000 metric tonnes of salmon annually, 30 per local ingredients whenever possible. The fishcent of Canada’s farmed salmon production. The waste from our processing facilities is nowsector is one of the region’s biggest economic being used to produce other animal feedsdrivers generating over $435 million in revenue (pets, poultry) so that we are a net proteinand employing over 3,500 people. In many rural producer.coastal communities, salmon farming is the major All the salmon farming companiesemployer and further growth potential exists. operating in eastern Canada are pri-Both production and employment are poised vately owned and operated by Atlanticto grow significantly in the near future with the Canadians. Our salmon farmers are pas-launch of Nova Scotia’s aquaculture development sionate and hardworking people who arestrategy and with continued focus on develop- committed to building a locally based,ment in Newfoundland. Salmon is already the globally competitive and environmentallylargest agri-food export in New Brunswick. sustainable industry that will continue Although the vast majority of finfish farmers to bring prosperity to our coastal com-grow salmon, many companies are growing munities.other finfish species such as cod, trout, arctic The Atlantic Canada Fish Farmerschar, sturgeon and halibut as well as mussels and Association (ACFFA) is an industry-fund- november-December 2012 | InternatIonal AquAFeed | 31
  4. 4. 2 EXPERT T●PIC located in areas selected for their isola- tion, water quality and flow. After being placed within a seawater farm, a salmon generally takes 19 - 31 months to grow to an optimum market size of around 3.5 – 4 kg. There are also a number of small fresh water farms operating in the McKenzie Country hydroelectric- canals. New Zealand producers (New Zealand King Salmon, Sanford, Akaroa Salmon, Mt Cook Alpine Salmon, Benmore Salmon and High Country Salmon) are focused on nurturing the salmon throughout their natural growth cycle to ensure fish welfare and guaran-New tee high quality and safe salmon for the consumer. International feed production com-Zealand panies Skretting, Ridley, Biomar and Reliance supply the majority of New Zealand’s salmon feed. The food is specially blended for King Salmon withby Adam Hicks, Aquaculture New fishmeal and fish oil, with some produc-Zealand, New Zealand ers also incorporating plant proteins andS oils and by-products from the poultry ince its beginnings in the and meat industries, from animals raised 1970s, New Zealand’s for human consumption. salmon farming industry has The New Zealand salmon farming evolved from a group of industry now produces more fish pro-innovative pioneers, to a profes- tein than it consumes – with some pro-sional, specialised and quality food ducers achieving conversion rates betterproduction sector focused on envi- than 1:1.19. Information supplied byronmental sustainability, food safety feed producers show the wild fish pro-and value added marketing. tein used in feed production is sourced primarily from the well-managed and We are the world’s largest pro- sustainable Peruvian anchovy fisheryducer of the premium Chinook (King) (, with our 2011 harvest of Core to the industry, is an uncom-14,000 tonnes accounting for roughly promising commitment to the respon-84 percent of total global production. sible management of our resources. Last year the New Zealand salmon Our Environmental Codes of Practiseindustry generated $128 million in are independently recognised as worldrevenue and provided employment leading, and our farming operations arefor hundreds of Kiwis. highly regulated and closely monitored Roughly half of all salmon farmed to meet the strict environmental condi-in New Zealand, is consumed in New tions of the New Zealand ResourceZealand. It is readily available at local Management Act.supermarkets and restaurants – much Salmon farming is an industry thatof it served in family kitchens and New Zealand can be proud of and atbackyard barbecues. The remainder is the same time be excited about forexported to over 30 countries includ- our Japan, US, Australia, Hong Kongand Canada. The premium species of salmon,King Salmon is prized for its char-acteristic rich flavour, delicate softtexture and high Omega-3 content. More InforMatIon:King Salmon is much harder to grow Website: or www.than Atlantic salmon, but yields a higher quality product. The history of New Zealand salmon farming history has been captured in Our farmed King Salmon are Swimming Upstream, and is available bygrown in the pristine, colder waters off emailing South Island with the majority insea pens in Marlborough, Canterburyand Southland regions. The farms are 32 | InternatIonal AquAFeed | november-December 2012
  5. 5. 3 EXPERT T●PIC people, of which 2,000 are IHN outbreak, the association developed a employed directly by farming viral management plan designed to respond companies. The domestic to future incidents of disease more effectively. demand for BC salmon This plan was implemented in May 2012, is strong but the fish also when IHN was detected at a farm in north of exported to the USA and Tofino. There were culls at three farms and some specialty markets in weekly farm tours were postponed but the Japan, Asia and India. spread of the disease was halted. There is a strong environmental move- The BC Salmon Farmers ment in BC. The association is committed to Association works in various ways providing good information and engaging with to look after the needs of its members. questions from the public. It has also worked For example, regulatory responsibility for with the WWF on its Salmon Aquaculture the industry has recently been transferred Dialogue.British from the provincial to the federal govern- ment. However, there is no specific aqua- culture legislation in Canadian law. This More InforMatIon Website: www.salmonfarmers.orgColumbia, means farmers have to work within existing, older acts which are not always relevant to the industry. The association is workingCanada with the Canadian Aquaculture Industry Alliance to advocate for national regulation for aquaculture. Bringing the industryby Mary Ellen Walling, Executive Director, together to effec-BC Salmon Farmers Association, Canada tively manageS fish health is almon farming is the largest agricul- also a prior- tural business in British Columbia. ity for the It produces around 80,000 metric association. tonnes annually with a value of US Following$450 million. The industry employs 6,000 the 2002-03 B I O S U S TA I N W O R L D C LA S S F I S H F E E D A sustainable approach to aquaculture The BioSustain programme targets the need for a sustainable approach in food production, by evaluating and documenting the sustainability profile of different feed types. For further information please visit november-December 2012 | InternatIonal AquAFeed | 33
  6. 6. 4 EXPERT T●PIC needed to give a suite of approaches ised by specific activity, which is not a heritable to disease control to farm managers. trait but reflects the immune experience of This article will focus on one such each individual. The response of the adaptive approach, involving the optimisation immune system is relatively slow initially but of the mineral component of the is long lasting and has a memory component, diet. Knowledge of the impact of giving faster and larger responses on a second mineral nutrition on immunological encounter. The main effector cells are a differ- function and health status of fish, ent white blood cell type called lymphocytes. together with our greater understand- During infection, the fast but generally short- ing of the salmonid genome and a new lived innate immune response precedes the suite of molecular tools, may offer a new longer lasting more specific adaptive immune perspective enabling better prophylactic con- response. In fish this lag period can be as much trol of stress and disease. as 10-12 weeks, which has to be kept in mind when considering prophylactic immunological Fish immunology control of fish disease (Magnadottir, 2010).Immunonutrition The immune system protects an organismin fish farming: against disease and participates in the main- Immunonutrition tenance of stable conditions during develop- Traditionally the use of antimicrobials ment and growth, inflammatory reactions and and vaccination has been used to fightA natural and tissue injury. As in the human immune system, the fish immune system is divided into innate disease in fish farms. Today, farmed Atlantic salmonsustainable and adaptive components. The innate system is an ‘ancient’ system are routinely vaccinatedsolution that is based on a non-specific recognition of a pathogen, that gives an instant reaction but has a short duration. The innate immune against a system is of prime importance in the immuneby D. Pacitti, S. A. M. Martin, C.J. defence of fish and is commonly divided intoSecombes , Scottish Fish Immunology three compartments: the epithelial/mucosalResearch Centre, Institute of Biologicaland Environmental Sciences, University of barrier, secreted soluble mediators (e.g.Aberdeen, United Kingdom complement system, interferons, anti-T microbial peptides) and the cellular he rise of aquaculture has been components (e.g. phagocytic cells one of the most profound develop- such as macrophages and granu- ments in global food production locytes). over the past 100 years, with pro- The epithelial andduction approximately doubling each decade. mucosal barrier of theAquaculture now delivers 39 percent of skin, gills and alimentaryaquatic food products with the FAO record- tract is an extremelying 310 species under culture in 2010. important bar- rier in fish, being Among these, salmonid fish (primarily constantlyrainbow trout and Atlantic salmon) are the immersed inmost intensively farmed fish in more than 30countries representing 90 percent of globalmarine aquaculture production. Salmonidproduction, particularly Atlantic salmon, numberincreased from 299,000 tonnes in 1990 to of bacte-1.9 million tonnes in 2010, at an average rial and viral diseasesannual rate exceeding 10 percent. Salmon before seawater one of the food categories that is growing However, fish vaccinology is still aat a significantly higher rate than the world’s young and maturing science, and vac-human population (FAO, 2012). cines for many pathogens have not yet been However, the salmon farming industry is media con- developed.vulnerable to the adverse impacts of disease. taining poten- It is a well-accepted concept that appro-For example, in 2007 an outbreak of infec- tially harmful priate feed and feeding regimes supporttious salmon anaemia (ISA) in Chile caused agents. The optimum health. However the sustainabilitymore than $2 billion in losses and reduced by humoral and cel- of fishmeal and fish oil stocks has broughthalf the Chilean production of Atlantic salmon lular defences repre- about changes in aquafeed formulations that(Godoy et al,, 2008). The common causative sent the first response are demanding a greater understanding of theagents of infectious diseases in aquaculture of the organism once sub- role that alternative ingredients, feed addi-include a range of bacteria, viruses, parasites ject to pathogen attack. However, a second tives, macro- and micro-nutrients and theirand oomycetes. encounter with the same pathogen will not balance plays as they can directly or indirectly Whilst vaccines exist for some of these dis- result in an enhanced response. influence fish health and immune functioneases, it is clear that additional measures are In contrast, the adaptive arm is character- (Figure 1). 34 | InternatIonal AquAFeed | november-December 2012
  7. 7. EXPERT T●PIC In terms of macronutrients, the protein metabolism. However in certain circumstanc- can be given during aquaculture operations(and amino acids), carbohydrate and lipid/ es, when the fish is exposed to certain kinds that are stressful and potentially immunosup-fatty acid components can all impact on of stress, the required amount may be two to pressive. They are essential for a variety ofhealth status. Dietary proteins provide essen- three times higher. biological and physiological functions includingtial and non-essential amino acids, which have Vitamin A has essential roles in vision, increased disease resistance and wound heal-a central role in defence mechanisms, as they growth, bone development, reproduction and ing. A study conducted in rainbow trout fedare required for the synthesis of an array of normal maintenance of epithelial tissue. Some diets supplemented with vitamin C, showedproteins involved in immune functions. The important functions of vitamin A include regula- that this molecule increased complementuse of alternative plant proteins has still to be tion of cellular differentiation and proliferation, activity and lymphocyte proliferation. Otheroptimised for growth and immune function. studies have revealed that ascorbic acid sup-Lipids provide energy plementation is able to alleviate the adverseand meet the effects due to hypoxic conditions and tem- perature fluctuations (Oliva-Teles, 2012). Carotenoids Carotenoids (tetraterpenoid organic pig- ments) are naturally occurring in plants and some other photosynthetic organisms (some types of bacteria and fungi). They protect cells against oxidative injury and ensure optimal cellular functions, including apoptosis, cell sig- nalling and gene regulation. The immunopro- tective functions of the carotenoids depend resist- very much on the equilibrium between the ance to intra- and extracellular milieu and on the type infection as and concentration of the carotenoid. well as embry- Despite the role of carotenoids have in the onic development and nutrition of several fish and crustacean species, growth. only few studies have considered them in rela- Vitamin C (or ascorbic acid) tion to the health of the organism. In rainbow is a co-factor for several enzymatic trout, activities of lysozyme, complement, reactions, including col- lagen synthesis and the produc- Healthy essen- tion of stress tial fatty acid hormones by requirements of the interrenal and animal. It is known that chromaffin cells. Fish several polyunsaturated or Vitamin C itself monounsaturated fatty acids are is also a reduc- involved in different immune functions, tive compoundexerting their influence through changes in that acts as anmembrane fluidity, eicosanoid synthesis, for- antioxidant dur-mation of lipid peroxides, regulation of gene ing oxidativeexpression, apoptosis, alteration of antigen stress. With the most convincing health feed products in the market EWOS offers:presentation, or modulation of intestinal Vitamin E - Solid documentationmicrobiota. All of these processes and path- compounds are - Proven performance in the waterways have significant roles in inflammation and the major chain- - Compelling cost/benefit analysisdisease resistance. breaking antioxi- The micronutrients also represent a funda- dant; they havemental component of fish diets. Micronutrients an importantcomprise of vitamins (e.g. A, C and E), role in maintain-carotenoids (e.g. β-carotene, α-carotene and ing the home-γ-carotene) and minerals (e.g. calcium, mag- ostasis of labilenesium, iron, copper, zinc and selenium). Since metabolitesmany micronutrients are involved in several (such as vitaminsbiological pathways, an inadequate intake can and unsaturatedlead to adverse effects on fish health due to fatty acids) anddeficiency. in protecting the cell membranesVitamins from oxidative Contact your local EWOS representative Vitamins are organic compounds required damage. for details. Visit ewos.comin small amounts in the diet, because they Vitamin sup-play major roles in growth, physiology, and plemented diets november-December 2012 | InternatIonal AquAFeed | 35
  8. 8. EXPERT T●PICphagocytes and non-specific cytotoxicity can immunity. Among the wide range of minerals both in mammalian and fish models, havebe elevated upon β-carotene and astaxanthin essential for organism welfare, zinc and selenium shown that Se augmentation is able to alleviatesupplementation. These effects can be further have received particular attention. They are a inflammatory reactions, boost the phagocyticenhanced when using diets enriched for vita- required component for more than 300 differ- and killing capacity of the cell mediated immunemins A, C and E. In a subsequent investigation, ent enzymes, which makes them fundamental response, and increase the expression of cellularthe same researchers validated the benefits for the proper functioning of many metabolic components responsible for efficient antiviral-of carotenoids derived from marine algae, processes in the organism, including the immune defences.which improved humoral as well as cellular response (Ferenčík and Ebringer, 2003). Typically the dose range between levelsresponses (Kiron, 2012). Zinc is essential due to its vital structural and/ giving deficiency and those giving toxicity for or catalytic importance in several proteins that different minerals is quite narrow, and doesMinerals play important roles in fish growth, reproduc- not leave a big margin for their supplementa- Minerals are another important component tion, development, vision and immune function. tion. Apart from concentration level, anotherin the fish diet. In many cases their importance Consequently for fish, of the essential metals, important aspect is the bioavailability of theseis under-estimated and as a consequence their zinc is second in quantitative importance only micronutrients in the diet.amount in fish diets can be below the required level. to iron. Dietary zinc minimum requirements Factors influencing bioavailability include theMoreover, several studies have shown that certain range between 15–60 mg kg–1 dry mass of diet level and form of the nutrient, particle size andminerals, when provided to fish at doses marginally (it varies slightly amongst different fish species), digestibility of the diet, nutrient interactions whichabove essential levels can effectively boost immune with the maximum level that is permitted in fish may be either synergistic or antagonistic, stress andresponses and increase stress resistance. diets by the European Union being 250 mg kg-1. pathological conditions of the fish, waterborne However, it is important not to exceed Previous studies have shown a toxic effect in mineral concentration and the species under con-the tolerated level with mineral augmenta- rainbow trout fed zinc at concentrations ranging sideration. Of these factors, those related to thetion, because toxic effects may occur (Figure between 500-1000 mg kg–1. It may exert its toxicity chemical state are particularly important. If the2). In higher vertebrates minerals are known by interfering with intracellular calcium homeostasis, mineral is present in the diet in insoluble andto impact general organism homeostasis and and affecting hepatic copper and haemoglobin levels. indigestible form, uptake can be affected. In contrast, zinc supports a Moreover, the element can form insoluble and healthy immune system and is non-absorbable substances in the gastrointestinal needed for wound healing. Indeed, tract of the animal that may either prevent or reduce zinc deficiency has been shown its uptake, transport and metabolism. Commonly, to compromise antibody produc- minerals can be provided to the fish either as inor- tion, leading to reduced titres post- ganic salts or as chelated or organic forms. immunisation. Adequate zinc status In recent years, there has been considerable is essential for proliferation, matu- interest in the use of organic trace minerals rather ration and differentiation of cells than salts, on the grounds that they are more bio- of the adaptive immune response. available or more similar, than inorganic sources, Studies conducted on dietary zinc to forms that occur in the organism. If the metal supplementation have shown an chelate or complex is stable in the digestive tract, increased level of circulating lym- the metal would be protected from forming phocytes in the blood and chemo- complexes with other dietary components that Figure 1: The concept of immunonutrition in health maintenance (modified from taxis of macrophages, leading to an can inhibit absorption, allowing greater assimilation. Kiron, 2012) overall improved disease resistance. Moreover, the ingestion of metals in the inor- Selenium (Se) is another important ganic form might facilitate the formation of reactive trace element for fish because it is a ions which can promote oxidative stress in the constituent of more than 30 seleno- gastro-intestinal tract. The use of organic chelated proteins with fundamental structural minerals is regarded as a more natural method of and enzymatic roles in the cell. Se trace element supplementation and may give a is primarily involved in antioxidant larger safe range for supplementation (Watanabe defences, reproduction, synthesis of et al., 1997). thyroid hormones and the immune In the case of zinc and selenium, two prod- response. The Se requirement is esti- ucts called Bio-Plex® and Sel-Plex® have been mated to be 0.15-0.38 mg kg–1 (it produced by Alltech, to provide respectively zinc also slightly varies amongst different and selenium augmentation into the animal diet. fish species), with the maximum level Both contain a relatively higher amount of these in fish diets permitted by the European two metals complexed into organic compounds Union being 0.5 mg kg-1. derived from yeast. Numerous studies have already Selenium toxicity occurs in rain- been conducted in different models (mice, poultry, bow trout when the dietary intake pigs and fish) showing the benefits of mineral-yeast Figure 2: Schematic representation of the relationship between element intake, tissue exceeds 13 mg kg-1. Se-deficient diets enriched diets on animal welfare. The mineral- element concentration and health indices. can profoundly affect the antioxi- enriched diets can provide a relatively inexpensive, The curve represents an essential trace dant defences, metabolism and the sustainable and consumer friendly approach to element which may produce adverse health immune response in fish. In Se defi- improve fish production, with a negligible impact effects in conditions of deficiency or excessive ciency, cell/tissue integrity can more on the environment. exposure. Intake A & B represent intakes which produce minimal statistical significant easily be compromised by oxidative Moreover, a better tolerance of higher con- changes from normal value of one or more stress and inflammatory disorders centrations of these two metals as yeast-derived health indices due to deficiency or toxicity can occur. ingredients in animal feed has been found. This respectively (Modified from Spivey et al, 1982) Different studies, conducted combined with an increased activity of cellular 36 | InternatIonal AquAFeed | november-December 2012
  9. 9. EXPERT T●PICcomponents involved in stress resistance and Managing AGD (Amoebic 5immune responses in animals fed such diets,leads to the conclusion that farmed animal feeds Gill Disease) in Atlanticenriched with organic metal compounds are safe athigher Se/ Zn doses. However, more investigations salmon:are needed to better elucidate to what extent Still a long way to gothese compounds can improve the fish immuneresponse and resistance to stressors. by SmartAqua, AustraliaConclusions A It is important to ensure that diet composition moebic gill disease (AGD) order for us to develop more effectivemeets the fish required level of essential nutrients. first emerged as a problem control strategies for AGD, we need toThis has been done to a large extent with growth in the 1980s in Tasmania; it improve our knowledge of the organismin mind but it is also a possible strategy that could is now a disease of inter- itself and the epidemiology of the disease.effectively increase fish health status. Micronutrient national significance. AGD has now As examples – where does the amoebaaugmentation in particular may represent a sus- been identified on the west coast of live when a site is fallowed? Does it havetainable and environmental/consumer friendly USA, Chile, New Zealand, Japan, South a reservoir in wild populations of fish?approach to improve fish responses to many kinds Africa, Ireland, Scotland, France, Spain Can it live independent of a host, forof stress (farm operations and disease outbreaks). and Norway. how long? What depths does it prefer?The concentration and the form in which these Is it phototactic? What environmentalmicronutrients are delivered to fish must be taken Current methodologies of controlling conditions favour amoeba proliferation?into account and be optimised. New ingredients this disease involve bathing the fish in Does AGD have a link with biofouling orand additives are emerging on the market, and give either freshwater for an extended period harmful algae? Under normal culture situ-an opportunity to produce new formulations to of time; or in hydrogen peroxide for a ations, Chinook salmon are immune toensure a higher assimilation of these components short period of time. AGD, why? Will ingredient substitutionand reduce the potential for adverse affects of Despite the fact that AGD has been in the feed have any influence on AGD?micronutrient augmentation. around for several decades, there are Despite the disease being around for still significant gaps in our knowledge almost 30 years, we have still a long wayReferences about this disease. The causative agent to go before we have total understanding was only identified relatively recently. In of the disease we are trying to defeat.Available on request november-December 2012 | InternatIonal AquAFeed | 37
  10. 10. This digital re-print is part of the November | December 2012 edition of International LINKSAquafeed magazine. Content from the magazine is available to view free-of-charge, both as a fullonline magazine on our website, and as an archive of individual features onthe docstoc website.Please click here to view our other publications on VO L U M E 1 5 I S S U E 6 2 0 1 2 • See the full issue An overview of the UK fish vaccination industry • Visit the International Aquafeed website Why check selenomethionine levels in selenium yeast? Extrusion technology for the production of micro-aquatic feeds • Contact the International Aquafeed Team and shrimp feeds EXPERT TOPIC – Salmon • Subscribe to International Aquafeed THE INTERNATIONAL MAGAZINE FOR THE AQUACULTURE FEED INDUSTRYIAF12.06.indd 1 07/11/2012 17:39To purchase a paper copy of the magazine, or to subscribe to the paperedition please contact our Circulation and Subscriptions Manager on the linkabove. INFORMATION FOR ADVERTISERS - CLICK HERE