Fishmealisveryextensivelyused infeedsforfishaswellasother animals.Arecentglobalsurvey estimatedaquacultureconsumption offishmealat3724thousandtonnesin 2006(TaconandMetian2008).Nowitis becoming increasingly evident that such con-tinuedexploitationofthisnaturalresource will ultimately become both environmentally and economically unsustainable.Anysatisfactoryalternativefeedingre-dientsmustbeabletosupplycompara-blenutritionalvalueatcompetitivecost. Conventionalland-basedcrops,especially grainsandoilseeds,havebeenfavoured alternatives due to their low costs, and have provedsuccessfulforsomeapplications whentheywereusedassubstitutesfor aportionofthefishmeal.Butevenwhen theseplant-basedsubstitutes cansupportgoodgrowththey can cause significant changes in the nutritional quality of the fish produced.Why algae?The reader may wonder why algae,includingbothmacroalgae (seaweeds) and microalgae (e.g. phytoplankton),andwhichare popularlythoughtofasplants, wouldbegoodcandidatesto serveasalternativestofishmeal infishfeeds.Onefundamental considerationisthatalgaeare thebaseoftheaquaticfood chainsthatproducethefood resourcesthatfishareadapt-edtoconsume.Butoftenitis notappreciatedthatthebio-chemicaldiversityamongdiffer-entalgaecanbevastlygreater thanamonglandplants,even whenBlue-GreenAlgae(e.g. Spirulina),moreproperlycalled Cyanobacteria,areexcluded fromconsideration.Thisreflectsthevery early evolutionary divergence of different algal groups in the history of life on earth. Only one ofthemanyalgalgroups,theGreenAlgae, producedalineofdescentthateventually gave rise to all the land plants. Therefore it can be difficult to make meaningful generalisations aboutthenutritionalvalueofthisextremely diverse group of organisms; rather it is neces-sarytoconsidertheparticularqualitiesof specific algae.Protein and amino acidsFishmealissowidelyusedinfeeds largelythankstoitssubstantialcontent ofhigh-qualityproteins,containingallthe essentialaminoacids.Acriticalshortcom-ingofthecropplantproteinscommonly used in fish feeds is that they are deficient incertainaminoacidssuchaslysine, methionine,threonine,andtryptophan(Li et al. 2009), whereas analyses of the amino acidcontentofnumerousalgaehave foundthatalthoughthereissignificant variation,theygenerallycontainallthe essential amino acids. For example, surveys of19tropicalseaweeds(Lourenoetal. 2002)and34edibleseaweedproducts (Dawczynskietal.2007)foundthatall species analysed contained all the essential amino acids, and these findings are consist-entwithotherseaweedanalyses(Rosell andSrivastava1985,WongandPeter 2000, Ortiz et al. 2006).Analysesofmicroalgaehavefoundsimilar highcontentsofessentialaminoacids,as exemplifiedbyacomprehensivestudyof 40speciesofmicroalgaefromsevenalgal classes that found that, All species had similar amino acid composition, and were rich in the essential amino acids (Brown et al. 1997).TaurineOneoften-overlooked nutrientisthenon-protein sulphonicacidtaurine,which issometimeslumpedwith aminoacidsindiscussions ofnutrition.Taurineisusu-allyanessentialnutrientfor carnivorousanimals,including somefish,butitisnotfound inanylandplants.However, althoughtaurinehasbeen muchlessofteninvestigat-edthanaminoacids,ithas beenreportedinsignificant quantitiesinmacroalgaesuch asLaminaria,Undaria,and Porphyra(Dawczynskietal. 2007,MurataandNakazoe 2001)aswellascertain microalgae,forexamplethe greenflagellateTetraselmis (Al-AmoudiaandFlynn 1989), the red unicellular alga The use of algae in fish feeds as alternatives to fishmealby Eric C. Henry PhD, Research Scientist, Reed Mariculture Inc., USATable 1: Nutritional profiles of rotifers enriched using optimized protocols based on culture using Reed Mariculture RotiGrow Plus and enriched with N-Rich feedsN-Rich feed type High PROPL PlusUltra PLApplicationsModerate PUFA; overnight gut-load maintenanceOvernight or 2-6 hr enrichmentExtreme DHA 2 hr enrichmentComposition of BiomassLipid (Dry wt. % of Biomass)35% 44% 66%DHA (% of lipids)37% 41% 44%EPA5% 2% 0.5%ARA1.0% 1.0% 1.2%Total PUFAs45% 45% 48%Protein38% 32% 18%Carbohydrate19% 15% 7%Ash8% 9% 10%Dry weight Biomass9% 9% 9%10 | INTERNATIONAL AQUAFEED | September-October 2012FEATURESeptember-October 2012 | INTERNATIONAL AQUAFEED | 11Porphyridium (Flynn and Flynn 1992), the dino-flagellateOxyrrhis(FlynnandFielder1989), and the diatom Nitzschia (Jackson et al. 1992).PigmentsAfewalgaeareusedassourcesofpig-ments in fish feeds. Haematococcus is used to produce astaxanthin, which is responsible for the pink colour of the flesh of salmon. Spirulina is used as a source of other carotenoids that fishessuchasornamentalkoicanconvertto astaxanthinandotherbrightlycolouredpig-ments.Dunaliellaproduceslargeamountsof beta-carotene.LipidsInadditiontoitshighcontentofhigh-qualityprotein,fishmealprovideslipidsrich inPUFAs,orpolyunsaturatedomega-3and omega-6fattyacids.Thesearethefishoil lipids that have become highly prized for their contributiontogoodcardiovascularhealthin humans. But it is not always appreciated that algae at the base of the aquatic food chain in fact originate these fish oil fatty acids. These desirablealgalfattyacidsarepassedupthe food chain to fish, and they are indeed essen-tial nutrients for many fish. Algaehavebeenrecognisedasan obviousalternativesourceofthesefish oilfattyacidsforuseinfishfeeds(Miller etal.2008),especiallyeicosapentaenoic acid(EPA),docosahexaenoicacid(DHA), andarachidonicacid(ARA).Thereisa substantialliteraturedevotedtoanalysis ofthePUFAcontentofmicroalgae,par-ticularly those used in aquaculture, because theyhavelongbeenrecognisedasthe bestsourceoftheseessentialnutrients forproductionofzooplanktonnecessary for the first feeding of larval fish, as well as filter-feeding shellfish.Manyshellfishproducersareaware thesterolprofileoffeedlipidsisofcriti-calimportance,butmuchlessattention hasbeenpaidtotheimportanceofthe Macroalgae (seaweeds) of many kinds can form extensive stands with high biomass density10 | INTERNATIONAL AQUAFEED | September-October 2012 September-October 2012 | INTERNATIONAL AQUAFEED | 11FEATUREwww.evonik.com/feed-additives | feed-additives@evonik.comYour challenge is our passion.MetAMINO The superior methionine source for your aquafeed. sterolprofileoffishfeeds.Asidefrom alterationsinthenormalsterolprofileof thefish,thepossibleendocrineeffectsof plantphytosterolsinfishfeeds(e.g.soy phytohormones)haveyettobethor-oughly investigated (Pickova and Mrkre 2007).Use of algae in aquacultureManydifferentalgaealreadyplayavital roleinaquaculture.Itiswidelyknownthat theadditionofmicroalgaetolarvalfish culturetanksconfersanumberofbenefits, suchaspreventingbumpingagainstthewalls of the tanks (Battaglene and Cobcroft 2007), enhancingpredationonzooplankton(Rocha et al. 2008), enhancing the nutritional value of zooplankton(VanDerMeerenetal.2007), as well as improving larval digestive (Cahu et al. 1998) and immune (Spolaorea et al. 2006) functions. Furthermore,ithasalsobeenshown thatlarvaeofsomefishesbenefitgreatly bydirectingestionofmicroalgae(Reitan etal.1997).Onestudyhasevenshown that that live zooplankton could be elimi-nated from the larval diet of Red Drum if microalgaewerefedalongwithaformu-latedmicroparticulatediet(Lazoetal.). Itisnotsurprisingthatthebiochemical compositionsofcertainmarinemicro-algaearewell-matchedtothenutritional requirementssomemarinefish.Larval feedsareprobablydeservingofthemost attention in efforts to discover how algae canbestbeusedinfishfeeds,because microalgaeareanaturalcomponentof thedietofmanylarvalfish,eithercon-sumeddirectlyoracquiredfromthegut contentsofpreyspeciessuchasrotifers and copepods. Existing protocols that use microalgaetoimprovethePUFAprofile ofliveprey(Table1)demonstratehow effectivelyanalgalfeedcanenhancethe nutritional value of these live feeds.Use of algae in formulated fish feedsVariousspeciesofmacroalgaeandmicro-algaehavebeenincorporatedintofishfeed formulationstoassesstheirnutritionalvalue, and many have been shown to be beneficial: Chlorella or Scenedesmus fed to Tilapia (Tartiel etal.2008);ChlorellafedtoKoreanrockfish (Baietal.2001);UndariaorAscophyllumfed to Sea Bream (Yone et al. 1986); Ascophyllum, Porphyra,Spirulina,orUlvafedtoSeaBream (MustafaandNakagawa1995);Gracilariaor UlvafedtoEuropeanSeaBass(Valente etal.2006);UlvafedtoStripedMullet (Wassefetal.2001);UlvaorPterocladia fedtoGiltheadSeaBream(Wassefet al.2005);Porphyra,oraNannochloropsis-Isochrysis combination fed to Atlantic Cod (Walker et al. 2009, 2010). Unfortunately, ithasrarelybeenpossibletodetermine theparticularnutritionalfactorsrespon-sibleforthesebeneficialeffects,either because no attempt was made to do so, or poor design of the study. For example, in one of the few studies that has focused on the effects of substi-tuting algal protein for gluten protein, the controlandallthetestdietscontained caseinplusaddedmethionineandlysine, noanalysisofthealgalproteinwas provided, and the algal protein (a biofuel processby-product)containedveryhigh levelsofaluminiumandiron(Hussein etal.2012).Moreandbetter-designed studies are necessary before we will have agoodunderstandingofhowalgaecanbest be used in fish feeds.Choosing the right algaeOftenthealgaechosenforfishfeeding studiesappeartohavebeenselectedlargely forconvenience,becausetheyarelow-cost andcommerciallyavailable.Forexample, microalgaesuchasSpirulina,Chlorellaand Dunaliella can be produced by low-cost open-pondtechnologiesandaremarketedasdry powders,andtheirnutritionalprofilesare well-documented. Macroalgae such as the kelpsLaminaria,Undaria,andDurvillea, andthebrownrockweedAscophyllum, occurindensestandsthatcanbehar-vested economically, and they have a long history of use as sources of iodine, as soil amendments, and animal feed additives to supply trace elements. Inrecentyearstherehasbeengreat interestinthepotentialofalgaeasa biofuelfeedstock,andithasoftenbeen proposed that the protein portion remain-ing after lipid extraction might be a useful inputforanimalfeeds(e.g.Chenetal.2010). However, the algae chosen for biofuel produc-tion may not be optimal for use as a feed input, and the economic pressure for the lowest-cost methodsoffuelproductionislikelytoresult inproteinresidueswithcontaminationthat makes them unfit for use as feed (e.g. Hussein et al. 2012).By contrast, the high-value microalgae that are used in shellfish and finfish hatcheries are generally producedinclosedculturesystemstoexclude contaminatingorganisms,andtheycannotbe dried before use without adversely affecting their nutritional and physical properties, greatly reduc-ing their value as feeds. Inevitably their production costs are higher, but their exceptional nutritional value justifies the extra expense. Table 2 presents Table 2: Because these algae are produced using continuous-harvest technology that maintains exponential growth, their protein and lipid contents are comparable to those provided by fish feeds.(Dry Weight)NannochloropsisoculataTetraselmis sp. Pavlova sp. Isochrysis(T-Iso)Thalassiosira weissflogiiProtein52%55%52%47%52%Carbohydrate16%18%23%24%23%Lipid17%14%20%17%14%Various species of microalgae are used as aquaculture feeds, depending on the cell size and nutritional profile needed for particular applications12 | INTERNATIONAL AQUAFEED | September-October 2012FEATURESeptember-October 2012 | INTERNATIONAL AQUAFEED | 13typicalnutritionalprofilesofalgaeproducedby Reed Mariculture Inc.Justasitwouldbesenselesstoarbitrarily substituteoneconventionalcropplantfor another(e.g.potatoesforsoybeans)when formulatingafeed,theparticularattributes ofeachalgamustbecarefullyconsidered. Inadditiontotheprotein/aminoacidprofile, lipid/PUFA/sterol profile, and pigment content, there are important additional considerations. Thetypeandquantityofextracellular polysaccharides, which are very abundant in cer-tain algae, can interfere with nutrient absorption, or conversely be useful binding agents in forming feedpellets.Thethickcellwallsofmicroalgae such as Chlorella can prevent absorption of the nutritionalvalueofthecellcontents.Inhibitory compoundssuchasthephenolicsproduced bysomekelps,andbrominatedcompounds producedbyredalgaesuchasLaurencia,can render an alga with an excellent nutritional analy-sis unsuitable for use in afeed.Dependingon growthandprocess-ingconditions,algae cancontainhighcon-centrationsoftrace elementsthatmaybe detrimental.Fur thercareful studyoftheprop-er tiesofnumer-ousalgaewillbe necessaryinorder to optimally exploit thegreatpotential offeredbythis diversegroupof organisms.Butitis alreadyapparent thatalgaewillplay animpor tantpar t intheeffor tto movetheformula-tionoffishfeed downthefood chaintoamore sustainable future. References available on requestMORE INFORMATION:Eric C. Henry PhD, Reed Mariculture Inc.Tel: +1 408 426 5456Fax: +1 408 377 3498Email: eric@reedmariculture.comWebsite: www.reedmariculture.com12 | INTERNATIONAL AQUAFEED | September-October 2012 September-October 2012 | INTERNATIONAL AQUAFEED | 13FEATURECORPORATE OFFICEP.O. Box 8 100 Airport RoadSabetha, KS 66534, USAPhone: 785-284-2153 Fax: 785-284-3143extru-techinc@extru-techinc.comwww.extru-techinc.comMany leading aquafeed manufacturers in the industry count on Extru-Tech to engineer the perfect aquafeed production solution.Industry leading equipment and engineered production advantages will give you the upper hand over the competition. Could you use a cost effective improvement in performance and fnished product quality? Contact one of the Aquafeed Consultants at Extru-Tech today at 785-284-2153.ET-221A.indd 1 1/20/12 1:57 PMTheannualglobalproductionof fishmealandfishoiliscurrently aroundfivemilliontonnesofmeal andonemilliontonnesofoil (Figure1),exceptinyearswhenthefishing in the South Pacific is disrupted by the warm waters of an El Nio, most recently in 2010. Around22milliontonnesofrawmaterial isused,ofwhichapproximately75percent comes from whole fish and 25 percent from by-productsofprocessingfishforhuman consumption (IFFO estimates). Themajorityofthewholefishusedare small pelagic fish such as anchovy, menhaden, sardines and sandeels for which there are lim-ited markets for direct human consumption. In addition to the estimated 11.5 million tonnes ofsmallpelagicfishusedinfishmealthereis also an estimated five million tonnes of other fish,themajorityfrommixedtropicaltrawl fisheries in East Asia. Going forward Theprospectsforincreasingtheproduc-tionoffishmealandfishoilareverylimited, since most of the underlying fisheries are now beingwellmanaged,usingtheprecautionary principle with tightly set and monitored quo-tas. Also increasingly, markets are being found for at least a proportion of the catches to go for direct human consumption. Inadditionthereisconcernthatsomeof the mixed tropical trawl fisheries are not being well managed and that catches will therefore decrease in the coming years as these become severely depleted. The prospects for increas-ing volumes of fisheries by-products do how-everlookbetterasfishingbecomesconcen-tratedatfewerlandingsitesandaquacultural production also becomes more concentrated. Thiswillbefurtherencouragedbytherising price of fishmeal and stricter laws against the dumping of waste material. So on balance the production of both fishmeal and fish oil over thenextfewyearsislikelytoremainabout where it is or possibly decrease slightly, which will certainly happen in El Nio years.Thelackofgrowthintheproductionof marine ingredients has led some to speculate that the growth of aquaculture would in turn be limited by the shortage of such key ingredi-ents the so-called fishmeal trap. It is certainly truethatduringthe1990sandearly2000s asaquaculturegrew,itusedmoreandmore fishmeal, mostly by taking volumes that in the past had gone into pig and poultry feeds. However,sincearound2005aquaculture requiring feed has continued its strong annual growthofaroundsevenpercentbutthe volumes of fishmeal used in aquaculture have remained steady at around 3.2 million tonnes andthoseoffishoilhaveevenreduced toaround600,000tonnes.(Figure2).This hasledtheFAOtostateintheirrecently released report on the State of Fisheries and Aquaculture(FAO2012):Althoughthedis-cussion on the availability and use of aquafeed ingredientsoftenfocusesonfishmealand fish-oilresource,consideringthepasttrends andcurrentpredictions,thesustainabilityof the aquaculture sector will probably be closely linkedwiththesustainedsupplyofterrestrial animalandplantproteins,oilsandcarbohy-drates for aquafeeds.Becoming a strategic ingredientThisgrowthinaquacultureproduction, Fishmeal & fish oil and its role in sustainableaquacultureby Dr Andrew Jackson, Technical Director, IFFO, UKFigure 1. The Global Production of fishmeal and fish oil from 1964-2011 (IFFO data)Figure 2. The global production of fed aquaculture and the use in the associated diets of fishmeal and fish oil, millions of tonnes (FAO FishStat data and IFFO data and estimates)18 | INTERNATIONAL AQUAFEED | September-October 2012FEATURESeptember-October 2012 | INTERNATIONAL AQUAFEED | 19whilstnotincreasingthetotalamountof fishmealused,iscomingthroughthepartial replacement of fishmeal in the diets of almost allspecies(Taconetal2011,Figure3).This drivetoreplacefishmealisbeingdrivenby the rise in the price of fishmeal and improving nutritionalknowledge,butalsobyconcern aboutthefluctuatingsupplyduetoElNio, etc.Ofcoursethepriceofallcommodi-tieshasrisensteeplyin recentyearsanditis importanttocompare thepriceoffishmeal with the alternatives. The most commonly usedalternativetofish-mealisthatofsoymeal. Figure 4 shows that over the last twenty years the price ratio of fishmeal to soymealhasincreased significantly,whichis indicativeofthefact thatfishmealisbeing reducedinlesscritical areassuchasgrower feeds,butremainsin themorecriticaland less price-sensitive areas ofhatcheryandbrood-stockfeeds.Fishmealis therefore becoming less ofacommodityandmoreofastrategic ingredientusedinplaceswhereitsunique nutritional properties can give the best results and where price is less critical. Fish oil and its fatty acidsAs has been well documented, during the period 1985-2005 fish oil usage moved from beingalmostexclusivelyusedtoproduce hydrogenatedmargarinestobeingalmost exclusively used in aquaculture. Within aqua-culture by far the biggest user was in salmon feed,indeeditreachedthepoint,inaround 2002,whenover60percentoftheworlds fish oil production was being fed to salmon. Thereasonforthisveryhighusagein salmon feeds was that salmon were found to performbestondietswithinexcessof30 percent fat and at the time fish oil was one of thecheapestoilsonthemarket.Inaddition italsogavethefinishedsalmonfilletsavery high level of long chain Omega- 3 fatty acids, specifically EPA and DHA. Duringthelast10yearsincreasingevi-dence has been published on the very impor-tant role these two fatty acids play in human health.EPAhasbeenshowntobecriticalin thehealthofthecardiovascularsystemand DHA in the proper functioning of the nervous system, most notably brain function. This growing awareness within the medical professionandthegeneralpublichasledto manygovernmentsproducingrecommended daily intakes for these fatty acids and compa-nieslaunchingalargenumberofhealthsup-plements,includingpharmaceuticalproducts, with concentrated EPA.The importance placed on EPA and DHA inthehumandiethashadanumberof profound effects on the fish oil market. Firstly over the last ten years a significant market has Figure 3. The dietary inclusion of fishmeal (%) in aquaculture feeds over the period 1995-2010 (after Tacon et al 2011 ) 18 | INTERNATIONAL AQUAFEED | September-October 2012 September-October 2012 | INTERNATIONAL AQUAFEED | 19FEATURESUBSCRIBEwww.aquafeed.co.uk/subscribe.phpInternational Aquafeed is published six times a year, bringing you in-depth features, industry news, events, book reviews and more. As well as your personal copy delivered direct to your address, subscribers to International Aquafeed also receive a free copy of the International Aquafeed Directory worth UK85. For more information please visit our website.For a complimentary trial issue, please contact the Circulation & Subscriptions Manager - Tuti Tan - Email: tutit@aquafeed.co.ukdeveloped for the sale of crude fish oil for its refinement and inclusion into capsules etc. Thishasgrownfromalmostnothing,to thepointwheretodayaround25percent oftheworldsproductionofcrudefishoilis soldtothismarket.Thishasoccurredata timewhenthedemandforsalmonfeedhas gonefrom1.8milliontonnestonearlythree million tonnes. The other critical factor is that to obtain fish oil of the right quality (freshness, lackofoxidationproductsandlevelsofEPA andDHA)thenutraceuticalmarketpaysa premium of 25-30 percent over that for feed oil(currentpriceforfeed-gradefishoilis approximately $1,800/tonne). Inordertoincreasetheproductionof salmon feed in-line with the market (as well astryingtominimiseanypriceeffect)feed producershavebeenincreasinglysubstitut-ing fish oil with vegetable oil. The vegetable oilofchoiceisrapeseed(orcanola)oil, which,whilenothavinganyEPAorDHA, does at least have short-chain omega 3 fatty acidsandfeweromega-6fattyacidsthan mostothercommonlyavailablevegetable oilssuchassoyaoil.Thepointhasnow beenreachedwhereover50percentof theaddedoilinsalmondietscomesfrom vegetablesourcesandthistrendseems likely to continue.Assalmonarepoorconvertersofshort-chainedomega-3fattyacidstolong-chain fatty acids the fatty acid profile of the finished salmonfilletisverymuchareflectionofthe fatty acid profile in the feed. The result is that the EPA and DHA content of farmed salmon isdecreasingandtheomega-6contentis increasing. Thistrendseemssettocontinueinthe years to come. It seems likely that the salmon marketwilldifferentiateintohighEPAand DHAsalmondemandingapricepremium and regular salmon, which, while still contain-ing some EPA and DHA will have levels well below that found in wild salmon. Is it sustainable?Oneofthemostoftenaskedquestions aboutfishmealandfishoiliswhetheror notthepracticeissustainable.Thisisahuge topic for discussion and one that is not easily coveredinthelastsectionofashortarticle. Toanswerthequestiononehastogoback and look at the source of the raw material and look at the matter, fishery by fishery. The most widelyacceptedmeasureofsustainabilityfor afisheryistheMarineStewardshipCouncils standard.However,whilstthishasbeen adoptedbyagrowingnumberoffisheries which can be eco-labelled at the point of sale, there are currently no substantial volumes of whole-fishfromMSCcertifiedfisheriesbeing made available to fishmeal plants.Backin2008IFFObecameawarethat thefishmealandfishoilindustryneededan independentlyset,third-partyauditedstand-ard,whichcouldbeusedbyafactoryto demonstratetheresponsiblesourcingofraw materialandtheresponsiblemanufactureof marineingredients.IFFOconvenedamulti-stakeholder task force including feed produc-ers, fish farmers, fish processors, retailers and environmentalNGOswhooverthenext18 monthscompliedthestandardwhichwas launched late 2009.TheIFFORSstandardhasbeenquickly adoptedbytheindustryandthepointhas nowbeenreachedwhereoveronethirdof theworldproductioncomesfromcertified factories.Thestandardrequiresthatany wholefishmustcomefromfisheriesthat are managed according to the FAO Code of Conduct for Responsible Fisheries. The stand-ard also demands that the factory can demon-strategoodmanufacturingpracticeincluding full traceability from intake to finished product.There are now around 100 certified facto-ries in nine different countries producing IFFO RSfishmealandfishoil.Manyoftheworlds majorfeedfisherieshavebeenapprovedfor use, although some have yet to produce suf-ficient evidence to convince the auditors. Full detailsofcertifiedplantsandapprovedraw materials can be found on the IFFO web site, www.iffo.net . AcontinuingareaofconcernisAsia where, as discussed earlier, there are consid-erablevolumesoffishmealproducedfrom trawledmixedspecies.IFFOisworkingwith anumberofdifferentorganisationsinclud-ingtheFAOandtheSustainableFisheries Partnership to investigate how to bring about fisheries improvement in this critical area. Asia Figure 4. The ratio of the price of Peruvian fishmeal and Brazilian soymeal based on weekly prices for the period 1993-2012 and the calculated trend line (IFFO data)20 | INTERNATIONAL AQUAFEED | September-October 2012FEATURESeptember-October 2012 | INTERNATIONAL AQUAFEED | 21istheregionwhereaquacultureisgrowing fastest and the need for responsibly produced fishmeal is highest.ConclusionsFishmeal and fish oil production is expect-edtoremainaroundcurrentlevels,butthis isunlikelytolimitthegrowthofaquaculture which will continue to have reducing inclusion levelsofmarineingredientsinthedietsof mostfarmedfish.Fishmealwillincreasingly becomeastrategicingredientusedatcritical stagesofthelife-cyclewhenoptimumper-formance is required. The growing importance of EPA and DHA inhumanhealthwillensurethatthereisa strongdemandforfishoil,eitherfordirect humanconsumptionorviafarmedfish,such as salmon. Thereisagrowingneedforfishfeed producersandfarmerstodemonstratethat alltherawmaterialsintheirfeedsarebeing responsiblysourced.Thisisbestachievedby usinganinternationallyrecognisedcertification standard. Increasing volumes of certified marine ingredientsarenowcomingontothemarket whichwillallowfishfarmerstodemonstrate their commitment to responsible aquaculture.ReferencesFAO (2012). The state of the world fisheries and aquaculture 2012. Rome: FAO.Tacon, A. G. J., Hasan, M. R., and Metian, M. (2011). Demand and supply of feed ingredients for farmed fish and crustaceans -Trends and prospects. In: FAO fisheries technical paper, Vol. 564. Rome: FAO. MORE INFORMATION:Website: www.iffo.net"Fishmeal and fish oil production is expected to remain around current levels, but this is unlikely to limit the growth of aquaculture which will continue to have reducing inclusion levels of marine ingredients in the diets of most farmed fish"20 | INTERNATIONAL AQUAFEED | September-October 2012 September-October 2012 | INTERNATIONAL AQUAFEED | 21FEATUREINFORMATION FOR ADVERTISERSWith circulation of the printed magazine to key industry decision makers and heavy promotion at key industry events, working alongside our online distribution strategies - International Aquafeed is the ideal place to promote your products aimed at the global aquaculture industry. Call the team today to hear how we can help you achieve your marketing goalsTHE BEST WAY TO PREDICT THE FUTURE IS TO CREATE IT. Peter F. DruckerTurning ideas into opportunities.PROGRESSIVE AQUAFEED PROCESSINGWhat will tomorrow bringwenger.comBELGIUM TAIWAN BRASIL CHINA TURKEYINDIAWhy retire a workhorse thats still doing the job?Simplyput,yourolddryermaybecostingyouabundle.Infact,todays Wenger dryer could save you enough in operating efciency alone to cover the replacement of your old dryer. Additionally, our new advanced dryer designs give you less potential for cross-contamination and bacteria build-up; feature new direct drive spreaders for level product bed and uniformity of nal prod-uct moisture; and afford quicker, easier inspection and cleaning. Contact us now. With new concepts and fresh initiatives, were ready to help you develop the product possibilities of the future. Wenger12_AQ_210x147mm.indd 1 8/8/12 12:01 PMFeedforfishandshrimpraisedin aquacultureneedshighlevelsof proteinandenergy.Traditionally feedforcarnivorousoromnivo-rousfishandforshrimpprovidesthese mainlyasfishmealandfishoil,which alsocontributestothehealthpromoting aspectsoffishandshrimpinthehuman diet. Aquacultureoffedspeciestodaytakes 6080percentofthefishmealand80per-centofthefishoilproduced,mainlyfrom the industrial pelagic fisheries or, in a grow-ingtrend,fromthetrimmingsproduced duringprocessingforhumanconsumption. Trimmings are defined as by-products when fishareprocessedforhumanconsump-tionorifwholefishisrejectedbecause thequalityatthetimeoflandingdoesnot meetrequirementsforhumanconsump-tion.TheInternationalFishmealandFish OilOrganisationestimatestrimmingsare now used for around 25 percent of fishmeal production. Theindustryis,therefore,heavily dependentonmarineresourcesbutpro-ductionfromtheseresourcescannotbe increased sustainably, either for human con-sumption or the industrial fisheries. At best, sustainablymanagedfisherieswillcontinue toyieldaroundthecurrentharvestoffive milliontonnesoffishmealandonemillion tonnes of fish oil. Feed producers such as Skretting require theirmarinerawmaterialsuppliersto document that the fishmeal and fish oil are derived from responsibly managed and sus-tainable fisheries and do not include endan-gered species. Therefore, to meet a growing demandforfish,aquaculturemustidentify alternatives to these marine ingredients.Rising demandAnalysesofglobaldemographics,widely publicisedbytheFoodandAgriculture OrganizationoftheUnitedNations(FAO), indicate a continuing expansion of the popu-lation passing nine billion by 2050. In parallel, economic development is providing a greater proportionwithanincomethatpermits themtobemoreselectiveabouttheirdiet. Themaintrendistoswitchfromvegetable staples to animal and fish protein. A third, but lesser, factor is the growing awareness ofthehealthbenefitsoffishinthediet, providinglongchainomega-3polyun-saturatedfattyacids(LCPUFAs)EPA andDHA,fishproteinsandimportant vitaminsandmineralssuchasiodineand selenium.Atthesametime,agrowingpropor-tionofthepelagiccatch,whichincludes theindustrialfisheries,isgoingtothe morelucrativemarketsofprocessingfor humanconsumption,asprocessingtech-nologyimprovesandasnewconsumers withdifferenttastesenterthemarket. Simultaneously,theomega-3supplements industryiscompetingforthebestqual-ityfishoilsandreadilyoutbidsthefeed producers.AccordingtotheFAOreport TheStateofWorldFisheriesand Aquaculture2012,aquacultureisset toremainoneofthefastestgrow-ingfeedsectors.Havingdoubledin thepastdecadetoalmost60million tonnesglobally,itisexpectedtogrow byupto50percentinthenext.This makes identifying alternative, sustainable sourcesofproteinandenergyamajor priority.Researchersarelookingfor alternativesthatwillprovidelowfeed conversionratios,maintainhighfish welfareandproducefishthataregood toeat,bothintermsofeatingexperience andnutrition.Ithasbeenamainfocusat Skretting Aquaculture Research Centre for thepastdecade,forexampledetermining thenutritionalvalueofmorethan400 rawmaterials.Theseinvestigationsled toAminoBalance,wherebalancingof aminoacidsincreasesthecontribution such proteins make to muscle growth.Options and challenges of alternative protein and energy resources for aquafeedby Dr Alex Obach, Managing Director, Skretting Aquaculture Research Centre, NorwayFigure 1: Raw material options for fish feed (Source Skretting)Protein raw materialsFatsStarch sources Fish meal Fish oil WheatKrill meal Krill oil BarleyAlgal meal Algal oil SorghumSoya products Rapeseed oil TapiocaSunflower meal Soybean oil Potato starchRapeseed meal Sunflower oil PeasCorn gluten Corn oilFaba beansWheat gluten Linseed oil OatsFaba beansPalm oilLupinsCamelina oilPea meal Poultry fatRice products LardPoultry mealFeather mealBlood mealMeat and Bone mealMicrobial proteinInsect meal Worm mealDDGS Marine origin Vegetable raw materials Animal by-products Other raw materials22 | INTERNATIONAL AQUAFEED | September-October 2012FEATURESeptember-October 2012 | INTERNATIONAL AQUAFEED | 23Recent advanceResearch progress to date means fishmeal levelsinfeedsforspeciessuchasAtlantic salmon have been reduced. Until recently 25 percent appeared to be the limit below which performance suffered, in terms of growth rate and feed conversion ratio. In 2010 researchers at Skretting ARC final-ised a new concept known as MicroBalance. MicroBalancetechnologyisbasedonthe identificationofseveralessentialmicro-nutri-entsinfishmealthatwereshowntobethe limitingfactors,nottheamountoffishmeal. Supplementingthedietwiththerightbal-anceofessentialmicro-nutrientsandother functionalmicro-ingredientshelpedreduce fishmeal content in fish feed.ApplyingtheconceptenabledSkretting companies to produce commercially success-fulfeedswithaslittleas15percentfishmeal withoutdetractingfromfeedperformance, fishwelfareorendproductquality.Akey advantageofMicroBalanceistheflexibil-itytoadapttherawmaterialcombinationin responsetoprices,lesseningforfarmersthe impacts of price volatility. TodaySkrettingcanformulatefishfeed withlevelsoffishmealaslowas510 percent.Fishmealcanbereplacedsolelyby vegetable raw materials or by a combination of vegetable raw materials and non-ruminant processedanimalproteins(PAPs).Itshould be noted that PAPs are widely used in coun-triesoutsidetheEUandprovideextremely goodquality,safenutritiontosupplement fishmeal. Typicalexamplesincludebloodmealalso knownashaemoglobinmeal,poultrymeal, andfeathermeal.PAPswerebannedfrom animalfeedandfishfeedintheEUfollow-ingtheBSEcrisisinthe1990s.Recentlya proposalforthereintroductionofPAPsin fishfeedwasapprovedbyaqualifiedmajor-ityofEUmemberstates,meaningthatnon-ruminant PAPs will be authorised for fish feed from June 1, 2013. Trial resultsA 22-month trial with Atlantic salmon in acommercialscalefarminNorwaydem-onstratedthe practicalityof MicroBalance.It followed a com-pletegenera-tionofsalmon fromsmoltto harvest. The trialwasjointly organi sedby MarineHarvest andSkretti ng andconducted attheCentre forAquaculture Competence (CAC)i n Norwayfrom May2009to February2011 inclusive.CAC is a commercial-scaleR&Dfarm managedby MarineHarvest andisequipped tomeasureall operational parametersjust aspreciselyas inasmall-scale researchsta-tion.Atotal of 780, 000 Atlantic salmon provided were divided and fed on one of three feeds: Conventionalgrowerfeed(pre MicroBalance):25percentfishmealand13 percent fish oil with EPA + DHA comprising about 10 percent of total fatty acids.OptiLinefromSkrettingNorway(using MicroBalance):15percentfishmealand13 22 | INTERNATIONAL AQUAFEED | September-October 2012 September-October 2012 | INTERNATIONAL AQUAFEED | 23FEATUREpercent fish oil with EPA + DHA comprising about 10 percent of total fatty acids.Experimental OptiLine(using MicroBalance):15percentfishmealandnine percent fish oil with EPA + DHA comprising about eight percent of total fatty acids. Theparametersmonitoredwere growth,FCR,quality,health,sustainability andfoodsafety.Thetotalharvestweight was3,517tonnes.Aftertheharvestthe taste,smellandtextureofthefilletswere testedbyapanelofprofessionaltasters. The results showed that both low fishmeal feedsgavethesamegrowthandFCRas thecontroldiet.Therewerenoobserved differencesinfishhealth,orinthequality parameters. Thesalmonfedwiththelowestpropor-tion of marine products (15% fishmeal, 9% fish oil)onlyneeded1.07kgoffishintheirfeed to produce 1 kg at harvest. Calculating protein aloneshowedapositiveratio,withfishout exceeding fish in.MicroBalanceisnowappliedinthediets of several other commercial species, including seabass,seabream,rainbowtrout,turbot and yellowtail.Fish oilResearchtodatehasenabledproduc-ersoffishfeedtosupplementfishoilwith vegetable oils in the diets of carnivorous spe-ciesbyasmuchas50percent.Lowerlevels havebeentestedinexperimentaldietswith nonegativeeffects.Muchoftheprogress results from the EU RAFOA project. RAFOA standsforResearchingAlternativestoFish OilinAquacultureandtheprojectfocused onfourspecies;Atlanticsalmon,rainbow trout,seabassandseabream.Ledbythe InstituteofAquacultureattheUniversityof Stirling,partnersincludeNIFES(theNational InstituteofNutritionandSeafoodResearch) andSkrettingARC,inNorway,theINRA (NationalInstituteforAgronomicResearch) inFranceandtheUniversityofLasPalmas, intheCanaryIslands(Spain).Themainchal-lengeistomaintainadequatelevelsofEPA and DHA, both for the fish and for the health benefits of fish as food. Secondly the EU AquaMax project, coordi-nated by NIFES in Norway with 32 international partners around the world including Skretting ARC, addressed this issue directly, developing dietswithlowlevelsofbothfishmealand fishoilandthusreducingthefish-infish-out ratios.Thiscom-plementswork at Skretting ARC todevelopthe LipoBalance concept,which allowscombina-tionsofoilsto be prepared that willprovidethe correctbalance ofenergyand nutrients,includingEPAandDHA,atlowest cost.Performance ratiosFeedconversionratios(FCRs)have advancedsignificantlyoverthepastthree decades. In Atlantic salmon, for example, the FCRhasdecreasedfrom1.30inthe1980s toslightlyabove1.00today,mainlydueto the development of high-nutrient-dense diets andtoimprovementsinfeedmanagement (reducingfeedwaste).Thisrepresentsmore efficientuseoffeedrawmaterials;especially as fishmeal and fish oil contents were reduced in the same period (Table 1).Anothercontributorhereistheemer-gence of functional diets that maintain or even improveperformanceinadverseconditions suchashighorlowwatertemperaturesand outbreaks of disease. Better growth, reduced FCRandhighersurvivalwillallcontributeto improve the utilisation of feed resources.FeedFishDependencyRatio(FFDR)is thequantityofwildfishusedperquantityof culturedfishproduced.Thismeasurecanbe weightedforfishmealorfishoil,whichever componentcreatesalargerburdenofwild fish in feed. In the case of Atlantic salmon for example,followingtheintroductionofthe MicroBalance concept, the fish oil will certainly bethedeterminingfactorfortheFFDR.The dependencyonwildforagefishresources shouldbecalculatedforbothFMandFO using the following formulae. FFDRm = (% fishmeal in feed from forage fisheries) x (eFCR) / 22.2FFDRo=(%fishoilinfeedfromforage fisheries) x (eFCR) / 5.0Where:eFCRistheEconomicFeedConversion Ratio;thequantityoffeedusedtoproduce the quantity of fish harvested.Onlyfishmealandfishoilthatisderived directly from a pelagic fishery (e.g. anchoveta) is to be included in the calculation of FFDR.The amount of fishmeal in the diet is calcu-lated back to live fish weight by using a yield of 22.2%. This is an assumed average yield. If theyieldisknowntobedifferentthatfigure should be used.The amount of fish oil in the diet is calcu-lated back to live fish weight by using a yield of five percent This is an assumed average yield. If the yield is known to be different that figure should be used.Usingtheseformulaeitcanbeseenthat theFFDRsforAtlanticsalmon,forexample, werehalvedbetween2004and2011.The FFDRmwasreducedfrom1.24to0.56and theFFDRofrom4.28to2.05.Thisdoubles the quantity of salmon produced from a given quantity of fishmeal and fish oil.Health benefitsAsmentioned,maintaininghealthbenefits is a key objective when reducing dependency on marine raw materials. It is being addressed inseveralways.Thefirstistodeterminethe minimum levels of EPA and DHA that the fish require.Thefeedswithhighlevelsofmarine ingredientsproducedfishwithhighlevelsof longchain(LC)poly-unsaturatedfattyacids (PUFAs);morethanneededbythefishso that a proportion was metabolised for energy. At lower inclusion levels the use of these lim-ited nutrients can be optimised, since a higher proportion will be retained in the muscle. At even lower levels (close to nutritional require-ment)thefishcanmaximiseitscapacityto elongate and desaturate, and could become a net producer of LC PUFAs. Figure 2: Supply and use of fish oil (Source IFFO and Skretting)Table 1: Total production of fed species in 2000, 2005, 2010, with total feed used, total fishmeal and total fish oil (x 1,000 tonnes).Year Total production of fed speciesTotal of feeds usedTotal fishmeal usedTotal fish oil used1995 4,028 7,612 1,870 4632000 7,684 14,150 2,823 6082010 21,201 35,371 3,670 764Source:Tacon et al. FAO Fisheries and Aquaculture Paper 56424 | INTERNATIONAL AQUAFEED | September-October 2012FEATURESeptember-October 2012 | INTERNATIONAL AQUAFEED | 25Onaverage100gofsalmonfillethas around16goffatofwhichatleastfourto five percent is omega-3 EPA and DHA (DHA beingthemainfattyacidinthephospholipid fraction). Thus a 130 g portion would provide around930mgofEPAandDHA.Thatis equivalenttoseveralsupplementcapsules. Two portions a week adequately provide the recommended dietary levels of LC PUFAs and importantvitaminsandmineralsinaneasily assimilated form. Asecondapproachistoexplorewaysof formulatingfeedsothattheLCPUFAsare retained in the fillet flesh. Further research at SkrettingARCintothefunctionsofmicro-ingredients recently led to a new salmon feed that significantly improves the feed conversion ratio and fillet yield. Fillet analysis revealed the micro-nutrientsalsoraisedtheproportionof EPA and DHA in the muscle. The third approach is to identify alternative resources.Therearetwomajorcontenders: geneticmodificationstocropplantsand micro-algae.Progressisbeingmonitoredby feed producers keen to reduce their depend-enceonmarineingredients.Someplants produce PUFAs, for example rape (canola) or soya, but the carbon chains are too short. The EPAcarbonchainhas20carbonatomsand DHA 22. The ambition is to introduce genes toextend18-carbonchainsalreadypresent. Limited progress has been with EPA. DHA is a greater challenge.Some micro-algae species are natural syn-thesisersofthelongerchainfattyacids.The challengehereiseconomic;togrowthem inbulk,eitherbyseafarmingorinvatson land,insufficientvolumestomakethem competitiveasafeedingredient.Thereare alsoreportsofextractingLCPUFAsfrom yeast cultures and these would face the same economic challenge.ConclusionAquafeedproducersmustfindalterna-tivestothemarineingredientsfishmealand fishoilwhilemaintainingfishwelfareand aquacultureperformanceasahighlyeffi-cientmeansofproducingnutritiousprotein. Eating quality and health benefits are equally important. However, although the supply of marine ingredientsfromthewildcatchislimited, with appropriate controls they will continue tobeavailable.Akeytaskfortheindustry is to ensure they are used in a manner that spreads the benefits through a combination ofsupplementation,feedformulationand feedmanagementonfarm.Thiswaythe growing demand for fish can be met and the benefitssharedsustainablyforgenerations to come.About the authorAlexObachhasheldtheposition ofManagingDirectoratSkretting AquacultureResearchCentresince May 1, 2007. Originally from Barcelona, Spain, he is a veterinarian with a Master inAquaculturefromtheUniversity ofGirona(Spain)andaPhDinfish pathologyandimmunologyfromthe University of West Brittany (France). He started working at Skretting Aquaculture Research Centre in 1993 as a research-er,initiallywithinfishhealththenas anutritionist.HeHepreviouslywas ManagerofARCsFishHealthdepart-ment. Between 1993-1995, he was also engaged as lecturer at the University of Barcelona,andworkedfortwoyears asManageroftheMarineHarvest Technical Centre.24 | INTERNATIONAL AQUAFEED | September-October 2012 September-October 2012 | INTERNATIONAL AQUAFEED | 25FEATURETheworlddemandforseafoodis increasingdramaticallyyearbyyear, althoughanannualupperlimitof 100milliontonsissetsoasnotto exhaust reserves. It is for this reason that there isaconsiderablemovetowardsmodernising and intensifying fish farming. To be economically viable, fish farming must be competitive, which meansthatfeedcostsamongstothersmust be carefully monitored as the operational cost goes60percentforfeedalone.Therefore selectionofcheaperandqualityingredients isofparamountimportanceforsustainable andeconomicalaquaculture.Identificationof suitable alternate protein sources for inclusion infishfeedsbecomesimperativetocounter the scarcity of fishmeal. Inadditiontoitsscarcityandhighcost, oftenfishmealisadulteratedwithsand,salt andotherundesirablematerials.Allthese factors have forced fish feed manufactures all over the world to look for alternate sources. Inthiscontexttheyhavebeenleftwithno protein but to substitute animal protein with plantproteinsources.Avarietyofplant proteinsourcesincludingsoybeanmeal,leaf proteinconcentrateandsinglecellprotein havebeentested.Thetestshaveshown thatthesecanbeincludedasalternatives tofishmeal(Oginoetal,1978,Applerand Jauncy, 1983). Of various plant protein sources, soybean meal(SBM)isoneofthemostpromising replacementsforpartorwholeoffishmeal. Soybeanmealistheby-productafterthe removalofoilfromSoyabeans(glycine max).Atpresentsoybeanmealisthemost importantproteinsourceasfeedforfarm animalsandaspartialorentirereplacement of fishmeal? Theproductsobtainedfromsoybeansand their processing are as follows:-Soybean meals, solvent extractSoybeanmealfromdehulledseeds,sol-vent extracted,Soybean expellerSoybean expeller from dehulled seedsFull fat soybean mealFull fat soybean meal from dehulled seedsThe chemical composition of soybean meal is fairly consistent (Figure 1).Thecrudeproteinleveldependsonthe soybeanmealquality.Soybeanhasoneofthe bestaminoacidprofilesofallvegetableoil meals. The limiting amino acids in soybean meal aremethionineandcystinewhilearginineand phenylalanine are in good supply (New, 1987).The fat content of the solvent extracted soy-beanmealisinsignificantbutsoybeanexpeller hasoilcontentbetweensixandsevenpercent, whilefullfatsoybeanexpeller has oil content between 18 to 20 percent. Soybean meal and soybeanexpellerarelowerin macro and trace elements than fishmeal. There is no substantial differencebetweentheindi-vidualsoybeanmealproducts. The calcium content is low and thephosphoruslevelisrather higher. However, the phospho-rus is bound to phytic acid and its availability for aquatic animals is, therefore, limited. Soybeanmealsandexpel-lers are reasonable source of B-vitamins. For most vitamins there are insignificant differences between thedifferentproducts.Howeverthefullfatsoy-beanmealtendstobehigherinsomevitamins. Whiletheproductsaremainlyhigherincholine content, the vitamin B12 content is low and pan-tothenic acid is mainly damaged by heat treatment.The digestible energy of soybean meal over all fish species ranges from 2572 to 3340 Kcal/kg (10.8 to 14.0 MJ/kg). The metabolisable and digestible energy of full soybean meal increases with the increase heating temperature at a given time due to the inactivation of trypsin inhibitors.Deleterious constituents of soybean productsTrypsin inhibitors: - About six percent of the totalproteinofsoybeansreducesactivitiesof trypsinandchymotrysin,whicharepancreatic enzymes and involved in protein digestion (Yen etal.,1977).Theactivityoftrypsininhibitoris notfullyunderstood,butisresponsibleforthe poor performance of certain fish species (Alexis et al., 1985, Balogum and Ologhobo., 1989).Lectins: - This type of toxic protein is chemi-callyhemagglutinin,whichcausesagglutination ofRBC's(Liener,1969).Thereareindications that lectins reduce the nutritive value of soybean meal for Salmonids but are inactivated by treat-ment of the meals (Ingh et al, 1991).Otherproperties:-Soybeanisunpalatable for some fishes such as Chinook salmon. While as herbivorous and omnivorous species are less choosy.Thesizeorageofthefishmayalso affect the palatability of soybean meal.Utilisation of Soybean Products in AquacultureComprehensive researchworkhasbeen donetoevaluatesoy-bean meals as a replace-mentofanimalprotein sources in diets for fishes butthereplacementof allfishmealbysoybean mealhasnotbeenvery successfulperhapsdue tothelimitingamino acids and insufficient heat treatment of the soy-bean meals. Smith et al (1980) claimed success infeedingrainbowtroutadietbasedalmost entirelyonrawmaterialsofvegetableorigin containing 80 percent full fat roasted soybean. In a similar report, Brandt (1979) evaluated a diet basedentirelyonplantingredients(containing 50 percent heated full fat soybean + 10 percent maize gluten meal to overcome a possible defi-ciency of S-amino acids).Reinitzetal(1978)observedthatrainbow troutfryfedadietcontaining72.7percentfull fat soybean had a greater daily increase in length andweightwithanimprovedfeedconversion ratiocomparedwiththosefedacontroldiet based on 25 percent herring meal, five percent fish oil 20 percent soybean oil meal. The mortal-ity rate for both groups was similar. Taste panel studiesindicatedthattherewasnoeffectof dietarytreatmentonfirmnessandflavourof the fish.Kaneko (1969) reported that 1/3rd of white fishmealcouldbereplacedbysoybeanmeal withnonegativeeffectsongrowthofwarm Use of soybean products in aquafeeds: a reviewby T. H.Bhat, M. H.Balkhi and Tufail Banday (Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir)Figure 1: The chemical composition of Soyabean meal40 | INTERNATIONAL AQUAFEED | January-February 2012FEATUREJanuary-February 2012 | INTERNATIONAL AQUAFEED | 41waterfishes.Viola(1977)iso-nitrogenously reduced the fishmeal content in the diet of carps containing25percentproteinsupplemented bysoybeanmealwiththeadditionofamino acids,vitaminsandmineralsandopinedthat soybeandietdidnotinducegoodgrowthin carp. Similarly Atack et al (1979) reported poor utilisationofsoybeanproteinbycarpwhenit formed the sole protein source. Gracek (1979) used different qualities of soybean meal to sup-plement ground maize for feeding carp fry and recorded better survival.No difference in growth was observed when common carp (Cyprinus carpio) were fed either with45percentsoybeanmeal(+10percent fishmeal)or20percentsoybeanmeal(+22 percent fishmeal). Other trails however showed that the growth performance and feed efficiency ofcommoncarpwerereducedwhendietary fishmeal was replaced by soybean meals. Therewerenodifferencesinperformance betweenextrudedfullfatsoybeanmealand oilreconstitutedsoybeanmeal(Inghetetal; 1991). A better weight gain was reported when soybeanmealwasincorporatedinthedietsof carp fish (Cristoma et al; 1984). Similarly sklyrov etal(1985)successfullyusedsoybeanmealin rearing carp fish commercially. It is claimed that soybeanmealisdeficientinavailableenergy andlysineaswellasmethionineforcarps. Supplementationofsoybeanmealdietswith methionine coated with aldehyde treated caesin significantly improved utilisation of amino acid by common carp (Murai et al; 1982).Lack of phosphorus rather than the sulphur amino acids may be the cause for poor perform-anceofcommoncarpswhen40percentsoy-bean meal diets were fed to them. Addition of 2.0 percent sodium phosphate did not improve their performances (Viola et al; 1986). Kim and Oh(1985)attributedthepoorperformance ofcommoncarpfedwithadietcontaining40 percentsoybeantolackofphosphorusrather than sulphur and amino acids, since addition of twopercentsodiumphosphatestosoybean meal diet improved their performance to a level obtained with the best commercial feed.Nour et al (1989) studied the effect of heat treatmentonthenutritivevalueofsoybean mealascompletedietforcommoncarpby autoclaving the soybean seeds for 0, 15, 30, or 90minutesandrecordedmaximumaverage dailyweightgainwithdietscontainingsoybean seeds autoclaved for 30 minutes. Nandeesha et al (1989) incorporated soybean meal in the diets of Catla and indicated the possibility of utilising soybean meal in carp diets. Keshavapa et al (1990) used soybean flour in the diet of carp fry and recorded better survival. Senappa (1992) studied protein digestibility from soybean-incorporated diets and recorded better digestibility when fed to fingerlings of Catla. Naik (1998)studiedtheeffectofSoyaflourand fishmeal based diets in the diet of Catla catla & Labeo rohita and observed a better growth and survival of carps when reared together and also in combination with fresh water prawn.Channel cat fish (Ictalurus punctatus) fed on all plant protein diets grew significantly less than fishfeddietscontainingfishmeal(Lymanetal, 1944). Growth was substantially reduced when menhadenfishmealwasreplacedbysoybean mealatanisonitrogenousbasis(Andrewsand Page, 1974). Full fat soybean meal heat treated differently replaced fishmeal at low levels in diets forchannelcatfishshowedthatreplacement gave satisfactory results (Saad, 1979).Growthandfeedefficiencyoffingerling hybridtilapia(Oreochromisniloticus)was significantlydepressedwhensoybeanmeal replacedfishmealattheoptimumlevel(30 percent) in their diet (Shiau et al, 1988). The growthdepressionofthehybridtilapiawas reduced when a 30 percent crude protein diet containing soybean meal but by adding two to three percent dicalcium phosphate to the diet, growth rate of tilapia was comparable to the control (Viola et al, 1986). Soybean meal with supplemental methionine could replace up to 67percentfishmealinthedietsformilkfish (Chanos chanos) (Shiau et al, 1988).Growth,feedconversionandsurvivaloftiger prawn (Penaeus monodon) juveniles fed two levels of soybean meal under laboratory conditions were lowerwithhigherlevelsofsoybeanmeal(Piedad, Pascual and Catacutan, 1990). No significant differ-encesingrowthandsurvivalcouldbeestablished whensoybeanmeal atlevelsfrom15-55 percent replaced par-tially or completely fish mealinthedietsfor tigerprawnsstocked incagesinpondsat 10to20shrimps persquaremeter (Piedad,Pascualet al,1991).Limand Dominy(1991) obtainedcompara-bleresultsinfeeding PenalusVannamel withdietscontaining upto17percentof dryextrudedfullfat soybeanmealasa partialreplacement for fish protein.Generallythe studiesoutlined abovetogether withseveralothers indicatethatthereis anadvantagetobe gainedfromusing properlyprocessed soybeanproducts forformulatingdiets forfishduetotheir better quality protein and higher dietary energy value in full fat soybean which is more advantageous with cold water fish speciesbecausewarmwaterfish(Carp,Catfish etc)canutilisecarbohydratesmoreefficiently. Theonlyrecommendationrelatingtothelimit of inclusion of full fat soybean in fish diets is not toexceedtheknownpracticallimitsrelatingto fats in general in order to avoid problems of feed preparationandtoreducetheriskofhighfat levels in the meal.Recommended Inclusion RatesSoybean may replace animal protein in diets for aquatic animals to a certain extent. However, with increasing substitution of e.g. fish meal by soybean meal the performance of fish decline. Herbivores may tolerate higher levels of soybean meal than carnivores. It appears that full fat soybean meal is more beneficial for cold-water fish than for warm water species due to the better utilization of the energy from the soybean products. Only properly heat-treatedsoybeanproductsshouldbeused foraquaticfeeds.Furthermore,itisadvisableto use only soybean meals processed from dehulled seeds in order to reduce the crude fisher content in the diet. This article originally appeared on40 | INTERNATIONAL AQUAFEED | January-February 2012 January-February 2012 | INTERNATIONAL AQUAFEED | 41FEATUREAquaculture UK 201223-24 May 2012Aviemore, ScotlandThe UKs major Aquaculture exhibition and conference featuring the latest aquaculture products and innovations. Visit www.aquacultureUK.com for further information or contact info@aquacultureUK.comFish_Farming Int_1/8_107X146.indd 1 17/10/2011 12:45Asmoreofworldsnatural fisheriesaredepletedand demandoffishcontinues torise,aquaculturewill continue to grow, thus raising demand forhealthy,commerciallyprepared fish Mostly, aquaculture relies upon extrusion cooking to produce feeds that are good mix and nutritionally available, but also in a form thatiscapableofmovingthroughwater column very slowly (floating) to be ingested. Thus,thebigdependencyinaquacultureis selectingingredientsthatwhenextruded will possess just right buoyancy, not migrate nutrientsintowater,withhighpalatability for specific fish species.Fishfeedpelletsarepreparedeither bypressedcutsheetsorbyExtrusion methods.Thisarticlewilldiscussabout IngredientsandExtrusionprocessforpro-ducing the pellets.Main ingredients include: 1) Fish & Bone Meal 2) Soy protein (though it is not preferred byfarmersbeingnoteasilydigestible by many fish species) 3) Wheat 4) Starch 5) Blood Meal Other ingredients like Vitamins, Minerals andLipids(FatOil)arealsoaddedin producing pellets.FishmealFishmealisawell-knownsourceof proteinswhichisstronglydemandedby the animal feeds industry. This is due to its balancedaminoacidcontent,whichmakes it an ideal feed for many domestic animals. Moreover,itsusetoadjust (improve)theaminoacidcon-tentofotherdietaryprotein sourcesalsocontributesto increasedemandforfishmeal. As its name points out, fishmeal isderivedfromcapturedfish, includingwholefish,fishscraps fromfillets,andpreservesof industries. Mostofthemaincapture fisheryproducersdevotethe mainpartofthisactivitytofish meal production. The raw mate-rialsusedinfishmealmanufac-turecomealmostentirelyfrom species which are not often used forhumanconsumption(either duetheirsize,orbecausethey are very abundant). Thefishmealprocessing systemconsistsofpreserving initialfishproteinsbymeansof acontrolleddehydration,which extractsaround80percentof thewaterandoilscontained when fresh from fish. Thisleadstotheproduc-tionofadryproduct,easyto preserve and easier to transport than the initial product.Fresh fish entering the manu-facturing plant is first ground and thencookedinacontinuousheatingoven at90-95percent,whichin-turncoagulates proteins and lose their water-holding capac-ity. The hot mash is then transported to an by R V Malik, CEO, Malik Engineers, Mumbai, IndiaAquaculture: Producing aqua feed pellets10 | INTERNATIONAL AQUAFEED | March-April 2011 March-April 2011 | INTERNATIONAL AQUAFEED | 11F: Feed pelletsendlessscreworoilexpellerthatpresses itandsqueezesoutmostoftheremaining water and oils. Pressedfishcomingoutofthepress (press cakes) then cut into smaller portions and placed into a dryer on a steam heated surface. During the drying period, the mash isinconstantmotionandsubjecttoan airjetthatremovesallthesteamemitted. The dried mash obtained is now called 'fish meal'andcontainsfrom8to10percent of water. However,ifthemoisturelevelismore than11-12percent,thereisariskofthe fishmealdevelopingmoulds.Generally, antioxidantsareaddedwhenfishmealis introduced and taken out of the dryer, and by so doing ensuring the stability of the oils remaining within the fish meal.Soy proteinNot all fish species have easy digestibility ofsoyprotein,primarilyduetoincreased carbohydratecontentfraction.Itisusually used as supportive additive with other eas-ily digestible protein like fish meal which is rich in fish proteins.Beanprocessingconsistsessentiallyof extractingtheoilsoastoconcentrate theproteins. Thisprocessprovidesavery importantby-product,namelysoyaoil, whichiswidelyusedasarawmaterial andoilforhumanconsumption. Thisproc-essalsocontributestotheeliminationof certainanti-nutritionalfactorspresentin the raw bean.Thefirststepinprocessinginvolves theremovaloftheshell(cellulose)from thegrain.Thebarebeansarethen heated,ontheonehandtoreducethe activityofcertainenzymes,andonthe othertobreakthecellulosestrandsand facilitatethefollowingsteps. Theheated beansarethenmashedtoformthin paste-likeslices,whichfurtherfacilitates the destruction of the cellulose structure and oil extraction.Theproduct,nowtermedwholesoya cake, still contains its oil and has around 40 percent protein, and as such is sold directly for animal feeding.Next, the oil can be extracted from the wholecakebymeansofasolvent(such ashexane). Aftertotalevaporationofthe solvent, there remains the solvent extracted soya cake, which in turn is widely used for animal feeding, and contains 45 - 50 percent protein.BloodmealAbattoirsorslaughterhousesproduce manyimportantby-products,suchas bloodandbones, etcwhichare oftendifficultto commercialize. N o w a d a y s , however,theseby-products constitute the basic raw mate-rial of the bone and blood meals widely used in industry for animal feeding.Consi derabl e amountsofblood areproducedby abattoirs,andthis productisusu-allytransported todryingovens andconverted intobloodmeal. Bloodfromdiffer-entoriginssuch as,sheep,goat,and poultryareusually storedandproc-essedseparately. However,soasto complywithbasic sanitarymeasures, it is generally com-pulsorytostore bloodwithincool-ingchambersand toensurethatthe levelofbacteriais keptwithinpre-scribedmaximum limits.The manufacture of bloodmealFreshblood iskeptcoolat thefactory,and sizeableparticles filteredandthe bloodmassstirred soastoseparate thefibrillarphase fromtheliquid mass.Thefibrinis thenheatedupto coagulation and the coagulatedmass dividedanddried throughahotair stream(thatisby spraydrying).This methodisparticu-10 | INTERNATIONAL AQUAFEED | March-April 2011 March-April 2011 | INTERNATIONAL AQUAFEED | 11F: Feed pelletsQuality control and testing ofraw materialsProduct development and recipe optimizationSmall-scale productionQuick change of test conditionsBrabenderGmbH & Co. KGE-Mail: food-sales@brabender.com www.brabender.comLaboratory Extruderfor Food and FeedFind us on booth no. G 061Extruder_90x270_Kopie von 90 X 27010.02.201116:18Seite 1Formulation of fishfeedAswehaveseen,feedformulatorscan resort to a wide assortment of raw materi-alstomakeupafoodmixturesoasto meetthenutritionalrequirementsofthe fishforenergy,aminoacids,fattyacids, carbohydrates, vitamins and minerals.Theserawmaterialsaregenerallyused inflourorliquidform,andwillhaveto undergo binding by means of a technologi-cal process to obtain a food mixture in the formofdrypellets,whichareeasytouse and preserve.As a guide, salt water marine aquaculture isdependantuponhighlevelsofproteins with high digestibility. The fresh water aqua-culturereliesuponmorecarbohydrates, thatishighlevelsofgrainscoupledwith modesttohighqualityproteins,minerals, vitamins with little or no fiber.Thefirstfactortobeconsideredfor feedformulationisthetotalenergyand protein/energyratioofthefinalproduct. After this, the protein content must be cal-culated according to the amino acid balance desired,andthelipidsincludedtosatisfy thebestfattyacidprofileforthespecies concerned and the energy level desired. All this must be considered taking into account the vitamin and mineral requirements of the cultured species.Thisformulationisnoteasilyreached andsocomputerisedlinearprogramming techniquesmustbeused.Furthermore, itisalsonecessary,aftercoveringallthe nutritionalrequirementsofthespecies within the formula to also produce a range of tasty feeds of different pellet sizes for the different age classes.Manufacturing stages- StorageThe raw materials coming into the feed manufacturing plant are generally stored in silos with an ideal height calculated so as to allow the raw material flow to be conveyed downwards, during the manufacturing proc-ess, until the final product is produced. This is in order to avoid having to pull the prod-uctsupbyverticalconveyorsthatusually cause breaks and dust in the final product.- GrindingGrindingrawmaterialsreducesparticle sizeandincreasesingredientsurfacearea, thus facilitating mixing, pelleting and digest-ibility.Themostcommonlyusedgrinders are hammer-mills, for fish feed manufacture, asplate-grindersdonotgenerallyproduce fine enough ground materials.TheExtrusioncookingprocessutilizes LipidsFishoilsareco-productsofthefish-mealindustry. Theirnutritionalcharac-teristics regarding fatty acids make them indispensableforfishfeedmanufacture, andinparticulartheircharacteristic highcontentofn-3unsaturatedfatty acids (first double bond linkage in posi-tion3),whichareessentialforawell balancedfoodformulaforcarnivorous fish species.Alargeamountoffishoilarisingfrom fishmealmanufacturesisre-processedin specializedfacilitiesfordiversepurposes; partofitbeinghydrogenatedandmixed with other lipids, and transformed into mar-garine, mayonnaise and bakery compounds, and the other part used directly by the feed industry. MineralsMineralsaremeasuredasashinthe recipe. Thoughtheyservenofunctionality in extrusion (on the contrary their abrasive naturewillacceleratewearandtearof workingpartsinextruder),theseareusu-ally added in proportions < 5 percent. They include phosphorous, calcium (from calcium carbonateorgroundlimestone),sodium chloride (salt), magnesium, potassium, etc.Vitamins:They can be water soluble or soil solu-ble. Vitamin B and C are water soluble, A, D, E,andKarefatsoluble. Theyareaddedin proportions