September | October 2012

Options and challenges of alternative protein and energy resources for aquafeed

The International magazine for the aquaculture feed industry

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: 1464-0058

Feed for fish and shrimp raised inaquaculture needs high levels ofprotein and energy. Traditionallyfeed for carnivorous or omnivo-

rous fish and for shrimp provides thesemainly as fishmeal and fish oil, whichalso contributes to the health promotingaspects of fish and shrimp in the humandiet.

Aquaculture of fed species today takes60–80percentof the fishmealand80per-cent of the fish oil produced, mainly fromtheindustrialpelagicfisheriesor,inagrow-ing trend, from the trimmings producedduring processing for human consumption.Trimmingsaredefinedasby-productswhenfish are processed for human consump-tion or if whole fish is rejected becausethequalityat the timeof landingdoesnotmeet requirements for human consump-tion. The International Fishmeal and FishOil Organisation estimates trimmings arenowusedforaround25percentoffishmealproduction.

The industry is, therefore, heavilydependent on marine resources but pro-duction from these resources cannot beincreasedsustainably,eitherforhumancon-sumptionortheindustrialfisheries.Atbest,sustainably managed fisheries will continueto yield around the current harvest of fivemillion tonnes of fishmeal and one milliontonnesoffishoil.

FeedproducerssuchasSkrettingrequiretheir marine raw material suppliers todocumentthatthefishmealandfishoilarederivedfromresponsiblymanagedandsus-tainablefisheriesanddonotincludeendan-geredspecies.Therefore,tomeetagrowingdemand for fish, aquaculture must identifyalternativestothesemarineingredients.

Rising demandAnalyses of global demographics, widely

publicised by the Food and AgricultureOrganizationof theUnitedNations (FAO),indicateacontinuingexpansionofthepopu-lationpassingninebillionby2050.Inparallel,economicdevelopmentisprovidingagreaterproportion with an income that permitsthemtobemoreselectiveabout theirdiet.Themain trend is to switch fromvegetablestaplestoanimalandfishprotein.Athird,butlesser,factoristhegrowingawarenessof the health benefits of fish in the diet,providing long chain omega-3 polyun-saturated fatty acids (LC PUFAs) EPAand DHA, fish proteins and importantvitaminsandminerals suchas iodineandselenium.

At the same time, a growing propor-tion of the pelagic catch, which includesthe industrial fisheries, is going to themore lucrative markets of processing forhuman consumption, as processing tech-nology improves and as new consumerswith different tastes enter the market.Simultaneously, theomega-3supplementsindustry is competing for the best qual-ity fish oils and readily outbids the feedproducers.

According to the FAO report‘The State of World Fisheries andAquaculture 2012’, aquaculture is “setto remain one of the fastest grow-ing feed sectors”. Having doubled inthe past decade to almost 60 milliontonnes globally, it is expected to growby up to 50 percent in the next. Thismakesidentifyingalternative,sustainablesources of protein and energy a majorpriority. Researchers are looking foralternatives that will provide low feedconversion ratios, maintain high fish

welfare and produce fish that are goodtoeat,both intermsofeatingexperienceand nutrition. It has been amain focus atSkrettingAquacultureResearchCentreforthepast decade, for exampledeterminingthe nutritional value of more than 400raw materials. These investigations ledto AminoBalance™, where balancing ofamino acids increases the contributionsuchproteinsmaketomusclegrowth.

Options and challenges of alternative protein and energy resources for aquafeed

by Dr Alex Obach, Managing Director, Skretting Aquaculture Research Centre, Norway

Figure 1: Raw material options for fish feed (Source Skretting)

Protein raw materials Fats Starch

sources

Fish meal Fish oil Wheat

Krill meal Krill oil Barley

algal meal algal oil Sorghum

Soya products rapeseed oil tapioca

Sunflower meal Soybean oil Potato starch

rapeseed meal Sunflower oil Peas

Corn gluten Corn oil Faba beans

Wheat gluten linseed oil oats

Faba beans Palm oil

lupins Camelina oil

Pea meal Poultry fat

rice products lard

Poultry meal

Feather meal

Blood meal

Meat and Bone meal

Microbial protein

Insect meal

Worm meal

DDGS

Marineorigin

Vegetablerawmaterials

Animalby-products

Otherrawmaterials

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September-October 2012 | InternatIOnal AquAFeed | 23

Recent advanceResearchprogresstodatemeansfishmeal

levels in feeds for species such as Atlanticsalmonhavebeenreduced.Untilrecently25percentappearedtobethelimitbelowwhichperformancesuffered,intermsofgrowthrateandfeedconversionratio.

In2010researchersatSkrettingARCfinal-isedanewconceptknownasMicroBalance™.MicroBalance™ technology is based on theidentificationof several essentialmicro-nutri-ents in fishmeal that were shown to be thelimiting factors, not the amount of fishmeal.Supplementing the diet with the right bal-ance of essential micro-nutrients and otherfunctional micro-ingredients helped reducefishmealcontentinfishfeed.

Applying the concept enabled Skrettingcompaniestoproducecommerciallysuccess-ful feedswithas littleas15percent fishmealwithout detracting from feed performance,fish welfare or end product quality. A keyadvantage of MicroBalance is the flexibil-ity toadapt the rawmaterial combination inresponse toprices, lessening for farmers theimpactsofpricevolatility.

Today Skretting can formulate fish feedwith levels of fishmeal as low as 5–10percent. Fishmeal canbe replaced solelybyvegetablerawmaterialsorbyacombinationofvegetablerawmaterialsandnon-ruminantprocessed animal proteins (PAPs). It shouldbenotedthatPAPsarewidelyusedincoun-triesoutside theEUandprovideextremelygood quality, safe nutrition to supplementfishmeal.

Typicalexamples includebloodmealalsoknown as haemoglobin meal, poultry meal,and feather meal. PAPs were banned fromanimal feed and fish feed in the EU follow-ing the BSE crisis in the 1990s. Recently aproposal for the reintroduction of PAPs in

fish feedwasapprovedbyaqualifiedmajor-ityofEUmember states,meaning thatnon-ruminantPAPswillbeauthorisedforfishfeedfromJune1,2013.

Trial resultsA22-monthtrialwithAtlanticsalmonin

a commercial scale farm in Norway dem-onstrated thepracticality ofMicroBalance. Itfollowedacom-plete genera-tion of salmonfrom smolt toharvest. Thetrial was jointlyorganised byMarine Harvestand Skrettingand conductedat the Centrefor AquacultureCompetence(CAC) inNorway fromMay 2009 toFebruary 2011inclusive. CACisacommercial-scale R&D farmmanaged byMarine Harvestand isequippedto measure alloperationalparameters justas precisely asin a small-scaleresearch sta-tion. A totalof 780,000

Atlanticsalmonprovidedweredividedandfedononeofthreefeeds:

Conventional grower feed (preMicroBalance): 25 percent fishmeal and 13percentfishoilwithEPA+DHAcomprisingabout10percentoftotalfattyacids.

OptiLine from Skretting Norway (usingMicroBalance): 15 percent fishmeal and 13

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percentfishoilwithEPA+DHAcomprisingabout10percentoftotalfattyacids.

Experimental OptiLine (usingMicroBalance): 15 percent fishmeal and ninepercentfishoilwithEPA+DHAcomprisingabouteightpercentoftotalfattyacids.

The parameters monitored weregrowth, FCR, quality, health, sustainabilityand food safety. The total harvest weightwas 3,517 tonnes. After the harvest thetaste, smellandtextureof the filletsweretested by a panel of professional tasters.Theresultsshowedthatbothlowfishmealfeeds gave the same growth and FCR asthecontroldiet.Therewerenoobserveddifferences in fish health, or in thequalityparameters.

The salmon fed with the lowest propor-tionofmarineproducts(15%fishmeal,9%fishoil)onlyneeded1.07kgof fish in their feedtoproduce1kgatharvest.Calculatingproteinalone showed a positive ratio, with fish outexceedingfishin.

MicroBalance is now applied in the dietsofseveralothercommercialspecies,includingsea bass, sea bream, rainbow trout, turbotandyellowtail.

Fish oilResearch to date has enabled produc-

ers of fish feed to supplement fish oil withvegetableoilsinthedietsofcarnivorousspe-ciesbyasmuchas50percent.Lower levelshave been tested in experimental dietswithno negative effects. Much of the progressresultsfromtheEURAFOAproject.RAFOAstands for Researching Alternatives to FishOil in Aquaculture and the project focusedon four species; Atlantic salmon, rainbowtrout, sea bass and sea bream. Led by theInstitute of Aquaculture at the University ofStirling,partners includeNIFES (theNationalInstituteofNutrition andSeafoodResearch)and Skretting ARC, in Norway, the INRA(National Institute for Agronomic Research)in France and the University of Las Palmas,intheCanary Islands(Spain).Themainchal-lenge is to maintain adequate levels of EPA

andDHA,bothforthefishandforthehealthbenefitsoffishasfood.

SecondlytheEUAquaMaxproject,coordi-natedbyNIFESinNorwaywith32internationalpartnersaroundtheworldincludingSkrettingARC,addressedthisissuedirectly,developingdiets with low levels of both fishmeal andfish oil and thus reducing the fish-in fish-outratios.Thiscom-plements workatSkrettingARCto develop theLipoBalance™concept, whichallows combina-tions of oils tobepreparedthatwill provide thecorrect balanceof energy andnutrients, includingEPAandDHA,at lowestcost.

Performance ratiosFeed conversion ratios (FCRs) have

advanced significantly over the past threedecades. InAtlanticsalmon,forexample,theFCR has decreased from 1.30 in the 1980sto slightly above 1.00 today, mainly due tothedevelopmentofhigh-nutrient-densedietsand to improvements in feed management(reducing feedwaste).This representsmoreefficient useof feed rawmaterials; especiallyasfishmealandfishoilcontentswerereducedinthesameperiod(Table1).

Another contributor here is the emer-genceoffunctionaldietsthatmaintainorevenimprove performance in adverse conditionssuchashighor lowwater temperaturesandoutbreaksofdisease.Bettergrowth,reducedFCRandhigher survivalwill all contribute toimprovetheutilisationoffeedresources.

Feed Fish Dependency Ratio (FFDR) isthequantityofwildfishusedperquantityofcultured fishproduced.Thismeasurecanbeweighted for fishmeal or fish oil, whichevercomponent creates a larger burden of wildfishinfeed.InthecaseofAtlanticsalmonfor

example, following the introduction of theMicroBalanceconcept,thefishoilwillcertainlybethedeterminingfactorfortheFFDR.Thedependency on wild forage fish resourcesshould be calculated for both FM and FOusingthefollowingformulae.FFDRm=(%fishmealinfeedfromforage

fisheries)x(eFCR)/22.2FFDRo = (% fish oil in feed from forage

fisheries)x(eFCR)/5.0Where:eFCR is the Economic Feed Conversion

Ratio; the quantity of feed used to producethequantityoffishharvested.

Only fishmeal and fish oil that is deriveddirectlyfromapelagicfishery(e.g.anchoveta)istobeincludedinthecalculationofFFDR.

Theamountoffishmealinthedietiscalcu-latedbackto livefishweightbyusingayieldof22.2%.Thisisanassumedaverageyield. Iftheyield isknowntobedifferent that figureshouldbeused.

Theamountoffishoilinthedietiscalcu-latedbacktolivefishweightbyusingayieldoffivepercentThisisanassumedaverageyield.

Iftheyieldisknowntobedifferentthatfigureshouldbeused.

Using these formulae it can be seen thatthe FFDRs for Atlantic salmon, for example,were halved between 2004 and 2011. TheFFDRmwas reduced from1.24 to0.56 andthe FFDRo from 4.28 to 2.05. This doublesthequantityofsalmonproducedfromagivenquantityoffishmealandfishoil.

Health benefitsAsmentioned,maintaininghealthbenefits

isakeyobjectivewhenreducingdependencyonmarinerawmaterials.Itisbeingaddressedinseveralways.Thefirst istodeterminetheminimumlevelsofEPAandDHAthatthefishrequire.Thefeedswithhigh levelsofmarineingredients produced fish with high levels oflong chain (LC) poly-unsaturated fatty acids(PUFAs); more than needed by the fish sothataproportionwasmetabolisedforenergy.Atlowerinclusionlevelstheuseoftheselim-itednutrientscanbeoptimised,sinceahigherproportionwillberetainedinthemuscle.Atevenlowerlevels(closetonutritionalrequire-ment) the fish can maximise its capacity toelongateanddesaturate,andcouldbecomeanetproducerofLCPUFAs.

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 species

total of feeds used

total fishmeal used

total fish oil used

1995 4,028 7,612 1,870 463

2000 7,684 14,150 2,823 608

2010 21,201 35,371 3,670 764

Source: Tacon et al. FAO Fisheries and Aquaculture Paper 564

24 | InternatIOnal AquAFeed | September-October 2012

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September-October 2012 | InternatIOnal AquAFeed | 25

On average 100 g of salmon fillet hasaround16 gof fatofwhich at least four tofivepercentisomega-3EPAandDHA(DHAbeingthemain fattyacid inthephospholipidfraction).Thusa130gportionwouldprovidearound 930 mg of EPA and DHA. That isequivalent to several supplement capsules.TwoportionsaweekadequatelyprovidetherecommendeddietarylevelsofLCPUFAsandimportant vitamins and minerals in an easilyassimilatedform.

Asecondapproach istoexplorewaysofformulating feed so that the LC PUFAs areretainedinthefilletflesh.FurtherresearchatSkretting ARC into the functions of micro-ingredientsrecentlyledtoanewsalmonfeedthatsignificantlyimprovesthefeedconversionratioandfilletyield.Filletanalysisrevealedthemicro-nutrientsalsoraisedtheproportionofEPAandDHAinthemuscle.

Thethirdapproachistoidentifyalternativeresources. There are twomajor contenders:genetic modifications to crop plants andmicro-algae. Progress is being monitored byfeedproducerskeentoreducetheirdepend-ence on marine ingredients. Some plantsproducePUFAs,forexamplerape(canola)orsoya,butthecarbonchainsaretooshort.TheEPAcarbon chainhas20 carbon atoms andDHA22.Theambitionistointroducegenesto extend 18-carbon chains already present.

LimitedprogresshasbeenwithEPA.DHAisagreaterchallenge.

Somemicro-algaespeciesarenaturalsyn-thesisersof the longer chain fatty acids. Thechallenge here is economic; to grow themin bulk, either by sea farming or in vats onland, in sufficient volumes to make themcompetitive as a feed ingredient. There arealso reports of extracting LC PUFAs fromyeastculturesandthesewouldfacethesameeconomicchallenge.

ConclusionAqua feed producers must find alterna-

tives to themarine ingredients fishmealandfish oil while maintaining fish welfare andaquaculture performance as a highly effi-cientmeansofproducingnutritiousprotein.Eatingqualityandhealthbenefitsareequallyimportant.

However,althoughthesupplyofmarineingredients from the wild catch is limited,withappropriatecontrolstheywillcontinuetobeavailable.Akey task for the industryistoensuretheyareusedinamannerthatspreadsthebenefitsthroughacombinationof supplementation, feed formulation andfeed management on farm. This way thegrowingdemandforfishcanbemetandthebenefits shared sustainably for generationstocome.

About the authorAlex Obach has held the positionof Managing Director at SkrettingAquaculture Research Centre sinceMay1,2007.OriginallyfromBarcelona,Spain,heisaveterinarianwithaMasterin Aquaculture from the Universityof Girona (Spain) and a PhD in fishpathology and immunology from theUniversityofWestBrittany(France).HestartedworkingatSkrettingAquacultureResearchCentrein1993asaresearch-er, initially within fish health then asa nutritionist. He He previously wasManager of ARC’s Fish Health depart-ment.Between1993-1995,hewasalsoengagedaslecturerattheUniversityofBarcelona, and worked for two yearsas Manager of the Marine HarvestTechnicalCentre.

24 | InternatIOnal AquAFeed | September-October 2012 September-October 2012 | InternatIOnal AquAFeed | 25

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Volume 15 I s sue 5 2 012

the international magazine for the aquaculture feed industry

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