november december international aquafeed full edition
TRANSCRIPT
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WHO CARES...If prots in the aquaculture industry are as appetising as a salmon dinner?As feed prices soar and formulation moves towards sustainability, aquaculture producers
must think differently to stay on the menu.
In all phases of the shs life, proper nutrition will improve health. With decades of dedicated research,
the Aqua AdvantageProgramme responds to the challenges of todays aquaculture producersthrough nutritional innovation, addressing issues such as growth and performance, feed efciency,
esh quality and immunity.
So, when asked who cares about your protability? Remember
DOES!
alltech.com | facebook.com/AlltechNaturally | @Alltech
Visit us at booth #219
Nashville, Tennessee
February 21-25, 2013
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An internAtionAl mAgAzine for
the AquAculture feed industryCONTENTS
aqua
I n t e r n a t I o n a l
feed
Volume 15 / Issue 6 / November-December 2012 / Copyright Perendale Publishers Ltd 2012 / All rights reserved
International Aquafeed is published six 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
Aqua News
3 Lindeopensworldleading
aquacultureinnovationcentreinNorway
4 VIVChina:
Wildcaughtfishstilltoplayacriticalroleinfeedingpeopleintherunupto2050
5 Newglobalpartnershiptopromoteaquacultureinfightinghunger
6 AQUACULTUREUPDATES
7 AnewpartnershippromisesamoreefficientandsustainablefutureforEuropeanaquaculture
8 Expertsclosingthenetontargetedfishgenes
9 AcquisitioninEcuadortakesNutrecotoglobaltopthreeshrimpfeedproducer
Features
10 AnoverviewoftheUKfishvaccinationindustry
14 Yeastinaquaculture
20 Extrusiontechnologyfortheproductionofmicro-aquaticfeedsandshrimpfeeds
26 Whycheckselenomethioninelevelsinseleniumyeast?
28 EffectofSangrovitonthegrowthandperformanceofseabass
38 INDUSTRYPROFILES
Regular items
8 THEAQUACULTURISTS
24 PHOTOSHOOT
30 EXPERTTOPIC-SALMON
42 INDUSTRYEVENTS
BiominWorldNutritionForum2012
Aqua2012
ISRMAXIndia49 CLASSIFIEDADVERTS
50 THEAQUAFEEDINTERVIEW
52 INDUSTRYFACES
Cover image courtesy of Bryce Groark - brycegroark.com
www.perendale.co.uk
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Editor
ProfessorSimonDavies
Email: [email protected]
Associate Editors
ProfessorKrishenRana
Email: [email protected]
AliceNeal
Email: [email protected]
Editorial Advisory Panel
Abdel-FattahM.El-Sayed(Egypt)ProfessorAntnioGouveia(Portugal)ProfessorCharlesBai(Korea)ColinMair(UK)DrDanielMerrifield(UK)DrDominiqueBureau(Canada)DrElizabethSweetman(Greece)DrKimJauncey(UK)EricDeMuylder(Belgium)
DrPedroEncarnao(Singapore)
Subscription & Circulation
TutiTan
Email: [email protected]
Design & Page Layout
JamesTaylorEmail: [email protected]
International Marketing Team
DarrenParris
Email: [email protected]
LeeBastin
Email: [email protected]
Latin American OfficeIvnMarquetti
Email: [email protected]
More information:International Aquafeed
7 St George's Terrace, St James' Square
Cheltenham, GL50 3PT
United Kingdom
Tel: +44 1242 267706
Website: www.aquafeed.co.uk
Forme,thislastmonthhasbeenquitehectichavingcrossedseveraltimezonesmakingtwoseparatevisitstoSEAsia,attendingVIVinBeijingandtheBIOMINWorldNutritionForuminSingapore.IhadthepleasuretooofmakinganinterimbriefvisittoNottinghamTrentUniversityinEnglandwhereIwastheexaminerforaPhDstudentworkingonpoultrynutritionwhichisactuallysosimilarinmany
waystomyspecialisedsubjectoffishnutrition.Wecaninterchange
manygoodideasherewithapplicationsinaquaculturebyappreciatingthe fundamental biochemistry and physiology common to avianspeciesandfish.AsIsettheclocksbackforwinter,thedaysaregettingdistinctlyshorterandthewarmthandmemoryoftropicalSingaporeisalasfadingawayasIreachformycardiganandmugofcocoa.NomoreSingaporeSlingsforawhile,justtheoddweedram!
NonethelesstheBiominmeetingwasamostexcitingeventandverywellorganisedindeedwithmanyfriendsattendingtheaquaculturesessionincludingmyformerstudentShaneHunterwhooperatesahighlysuccessfulbusinessfromMaltaasanaquacultureconsultantandwhogaveamostenlighteningtalkon21stcenturyaquaculturelisting
anddiscussingnewsystemsandtechnologiesthatcouldrevolutionisetheindustry.IattendedthecompleteBIOMINprogrammeand learnedsomuchabouttheirformidableportfolioofactivities forallfarmedlivestockandIamsogratefulfortheirinvitation.Iwillreportlater.AnothergreattreatwastheBioMarineBusinessConventionheldinLondonatFishmongersHallandareceptionintheHousesofParliamentontheterracesoverlookingtheThames.IwasabletohelparrangethelocationforthisprestigiousvenueandIoweaspecialthankstotheRightHonourableDouglasCarswellMPrepresentingClactonuponSeaforhissupportandwhotakessuchaninformedinterestinaquacultureespeciallytilapiaandfishnutrition.
BioMarineattractedmorethan200delegatesandwaslastheldinNantes,France.Thismeetingwasabletosetanagendaforasustainableaquacultureindustrywithahostofleadingexpertsfromacrossthespectrumofdisciplinesrangingfrommacro-algae,microalgae,shellfish,fishandtheaquafeedindustry.Stake-holdersfromgovernment,legalandfinancialorganisationstogetherwithcommercewereabletoshareanddebateideasandbringaboutanagreedvisionandstrategythatcanbeforwardedtothose
whocanbringaboutchangeandmakedecisionsforthefuture.NextyearitwillbeheldinHalifax,NovaScotiaandIcantwaitsincetheCanadianHighCommissionersaysthelobstersaresogood!!
Turningtoourcurrentissue,weannouncenewsaboutauniqueInnovationCentreforAquacultureinNorwaybytheLindeGrouptoserveR&Dandtoactashubforthedisseminationofadvancedtech-nologiesandademonstration/facilityplatform.Thisisthetypeofvisionaryapproachthatothersshouldbeundertakingifwearetoseeaquacultureprosperandwouldbeattractiveforuniversityinvolvementonawiderlevel.WegetanindustryreviewfromDominiqueBureauandanoverviewoftheUKfishvaccinationindustrybyKathyTaylorofSalmovacwhereitisvitaltonotethathealthyfisharecentraltoefficientproductionandutilisationoffeed.Theinteractionofdietandimmunologyisincludedlater.
AcomprehensivefeatureontheuseofvariousyeastsispresentedbyPhilippeTaconPhDofLesaffreFeedAdditives,Franceandthisisamosttimelyarticlegiventhemassiveinterestsinprebiotics,probioticsandSCPtypefeedingredientsderivedfromspecificfermentationprocesses
suchapotablealcohol(beerandwhisky)andnowtherapidexpan-sion of bioethanolrefineriesusing cornorwheat as substrates.Talkingofyeastitisimportantthatwemakenoteofthespeciationoftraceelementsandthattheformofseleniumandothermineralsmust be correct.Wilbert Litjens,Technical manager Optimin &Betaine and Paul Perucchietti, Product manager Optimin, SelkoFeedAdditives adviseusof these facts in their technicalarticlefocusingonseleniuminyeastasseleno-methionine.
Fish nutrition and feed technology is a complex blend ofsciencesandasaneditorandacademic,Ilearnmuchfromthistradeand technical journal.Itcanbe heavyreading buthighlyinformative,itisourlastfor2012andsohaveagood
festiveseasonandwewillmeetagainin2013.
Professor Simon Davies
Croeso (Welcome in Welsh)
InthelastissueofInternationalAquafeed,themainpictureonpages26and27wascaptionedincorrectly.Thecorrectcaptionreads,theCACisjointlyownedbyMarineHarvestNorway,SkrettingandAkvaGROUP.Itisalargescaleexperimentalfishfarmusedfordocumentationpurposes,locatedinHjelmelandintheCountyofRogalandinNorway,anditisoperatedfortheownersbyMarineHarvestNorwayregionSouth.Thedocumenta-
tionpurposesareprimar ilyrelatedtodiets,butalsotechnicalequip-
mentandproduction(inlinewiththeinterestsofthe owners).ThereisclosecollaborationwithNIFES(NationalInstituteofNutritionandSeafoodResearch)andNVI(theNorwegianVeterinaryInstitute).
A big thank you to all of our supporters
in 2012 ......wewishyouallahappyandprosperousnewyear.
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Linde Gases, a division ofT he L inde G ro up , ha sannouncedtheopeningoftheir state-of-the-ar t InnovationCentreforAquaculture,apio-
neering R&D and testing unitlocatedatlesundinNorway.ThecentrewasformallyopenedbyNorway'sViceMinisteroftheMinistryofFisheriesandCoastalAffairs, Kristine Gramstad, atan inauguration ceremony onSeptember20,2012.
Theinnovationcentre,withitslocationbasedintheheartofthe wor ld's most industr iali sed
fishfarmingcommunity,willbealeadingaquacultureR&Dcentreglobal ly. In addit ion to highlyequippedlaboratories,thecentrewillfeatureanumberoftestand
demonstrationaquaculturetanks,the largest of which is 55 cubicmetresandhasbeenbuilttoahighly innovativespecification.Ahighlightoftheinnovationcentre,the tank will allow both aquac-ulture technologists and cus-tomersalike toobservehowthelatestoxygenationtechnologiesimpactfishdevelopmentwithinanoptimalon-landfarmingenclo-
sure.Inadditiontoanoverhead wa lkway
e xt end ing t he f u lldiameterlengthofthetank,Linde has max-imisedobservationalo p po r t u n i ti e s v i aeye-level inspectionwindowsandunder-waterlighting.
"Both the researcha n d d e ve l op m en tand the subsequenttes ting of the lat est
oxygenationtechnolo-giesisunquestionablyneededtoensurethefuturesuccessofland-based aquaculture,"saysStefanDullstein,
HeadofAquacultureandWaterTreatment,LindeGasesDivision."Linde's dedicated InnovationCentreforAquaculturewillplayaleadingroleinthedeliveryofsuchtechnologiesandgivecus-tomer s the oppor tunity to seefirsthandpioneeringoxygenationsystemsinoperation."
L inde 's advanced aquacul-ture technology has been devel-
opedinresponsetoaprogres-sivetrendthatisseeingaquacul-tureproductionbeingtransferredfromseacagestoland-basedsitesforthefulldurationofamarinefishs life. Itis this changethat
hasconfrontedthefishfarmingindustrywiththechallengeofefficientlyoxygenatinglargefishtankstoaccommodatefish stockfrominfancytomaturity.
Inparticular,thelesundcentrefeaturesLinde'sinnovativefishfarmingoxygenationtechnology,SOLVOXOxyStream,aunique
low-pressureoxygenationsystemwhichsignificantlyincreasesfish
production volume, optimisesfishmeatqualityandconsider-ablyimprovesfishfarmingoper-ations from an environmentalstandpoint.
www.linde.com
Linde opens world leadingaquaculture innovation centre in Norway
Along with the Linde
aquaculture specialists, the
inauguration of the centre was
attended by Kristine Gramstad,
Norwegian Vice Minister of
Fisheries and Costal Affairs
In addition to highly equipped
laboratories, the innovation centre
will feature a number of test and
demonstration aquaculture tanks.
A highlight of the innovation centre, the 55 cubic metre
tank, with its overhead walkway and inspection windows
will allow aquaculture technologists and customers to
observe how the latest oxygenation technologies impact fish
development.
Nvmb-Dcmb 2012 | INterNatIoNal AquAFeed | 3
Aqua News
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Wildcatchhasawrongimage, says GorjanNikolik, AssociateadirectorAnimalProteinwithR a bo b an k I n te r na ti o na l i nSingapore.
It 's being seen as i f we arerobbingnatureandasaresultisindecline,hetoldaninternationalaudience attending a one-dayInternationalChinaSummiton
the day preceding the openingofVIVChina,whichtookplaceintheNewChinaExhibitionCentreinBeijing.
"Thesectorischangingandisdynamicandshouldbecomparedwith forestry rather than anexploitativeoperation.Wecanremoveacertainamount."
Hesaidthatwherepressurehadbeenappliedtoafisheryandthefishingoperationsweresubstan-
tial there was a vested interestinmaintainingstocks,managingthe resource and adopting reg-ulationstocontroloverfishing.HepointedtofisheriesinNorthAmerica, Australia, Japan andotherswhereregulationscontrol-lingindustrymeantthatindustrycould invest in larger vessels,operatesecurelywithquotasandbecomeprofitableandsustain-ablebusinesses.
"Unfortunately,thatisnotthe
norm.ThroughoutAsiaandAfricainparticularthereisstillaneedfor regulation.Anywhere whereyouhavesmallartisanfisheriesyou have damageto sustaina-bility.Wearedoingagoodjobinseveralplacesbutmoreneedstobeachieved."
Withoutthedevelopmentofaquacultureoverthepast40-50years,therewouldnothavebeenanygrowthinfishconsumption,
hetoldtheaudienceof300rep-resentativesfromtheintensivelivestockindustries.Hesaidaqua-culturenowmakesupabouthalfofallfishprocessedforhumanconsumption.
Whilewildcapturefishwouldnotincreasein the years ahead,aquaculturewouldseethetotalfishproducingindustryincreasebyfourtosixpercentgrowthforthenextfourtofiveyears.However, after that growthwould declineto about threepercentperyear.
He says the FAO forecaststhe world needing between 20
millionto25milliontonnesoffishby2020.That'saone-thirdincreaseinlessthanadecade;atarget that is unlikely to bemet,hesuggested.
However,MrNikolikdoesseefish playingan increasing roleinthehumandietastheworldaddressesthefoodneedsofninebillionpeopleby2050.Hesaysthere are some 300 species offishworldwidethatarecurrentlyincludedinthehumandietofwhichsome50-60speciesareof primary importance.Whilethe west and Japan havea pref-erenceformarinespeciesintheirdiets,Chinainparticularenjoysfreshwaterspeciesandcarpinparticular.Sixtypercentoftheworld'saquaculturetakesplaceinChinaandthemajorityofthefishproducediscarp.
Whencomparedwithterres-trial animals, fish are particular ly
efficientinconvertingfeedintoflesh.Whilethefeedconversionrateforpigsisnowaround2.5:1andpoultryat1.8:1andleaderinthe animal world, tilapia records1.6:1,shrimpat1.5:1andsalmonat1.1:1.Thelatteristhemostadvancedandmaysoonachievea1:1conversionrate!
"Whyisitpossibleforfishtoachievetheseextraordinarycon-versionrates?"heposedrhetor-
ically.F ish l ive in a world wherethere's littleeffectof gravity andasaresultexpendnoenergytofightgravity.Thereforethereisnoneedtobuildmassivebonestruc-
tures to support their weight. Inaddition,fishareendothermic-meaningtheyneedtoexpendnoenergytowarmtheirbodies.
"Everythingtheyeatgoesintomotion and growth. Also theyhavehighfecundity,meaningtheyhavelotsofoffspring."Pigsmightbeabletoachieveanimpres-sive27pigletsperyear,butfishcanproduce50,000eggstwiceayearwithmortalityratesof
betweentwoandthreepercent,"headds.
OtherfactorsthatMrNikolikfeels with swingthe balanceinfavouroffishistheimpos-s i bi l it y o f d i se a se s m ov i ngacross thespecies barrier ascanhappenbetweentesterialanimals; "Thereis no diseasethat canmovefromfish speciesto a human."The str ucture ofthe res ource also favours fish
suchassaltwater,"whichcan'tbeusedforanythingelse";manyland-basedfishfarmingopera-tions do not need fresh watersupplies;aminimalCO2andmethanegasemissioncontri-
butionisalsoanadvantageoverterrestr ial species.
For aquaculture to achievei ts p o te n ti a l, t h e i n du s tr yneeds huge investments. It 'sanindustrythatisfragmented,ranges f rom the deve lopedto de ve lo pi ng co un tr ies, ha sno g l ob al o r r eg io nal m ar-ketingpolicyandisuncoordi-nated.Therearecurrentlytoomany spec ies be ing farmed
and resources into researchanddevelopmentisspreadtoothin,he adds. "Wehaven't evenchosenthespeciestofocuson,"hetoldtheaudience.
Mr Nikol ik says terrestr ia lan ima l product ion systemshave been deve loped over2000yearswhileaquacultureislessthan40yearsoldandforsomespeciesjust15yearsold.Whileaquaculturedoesoffera
valuablesourceofproteinforthe human diet in the decadesahead,ithasmanyobstaclestoovercomewiththeaccesstoresourcessuchascoastlineallo-cation,beinglimitingfactors.
VIVChina:Wildcaughtfishstilltoplayacriticalroleinfeedingpeoplein
therunupto2050
4 | INterNatIoNal AquAFeed | Nvmb-Dcmb 2012
Aqua News
Mr Gorjan Nikolik of Rabobank International (right) with the
editor of International Aquafeed, Professor Simon Davies at the
International China Summit in Beijing
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Aqua News
TheAquaculturistblog is a great placeto keepup-to-datewith the latest aquaculture news inbetween printeditions ofInternationalAquafeedmagazine. Theblog, likethemagazine,hasan internationalfocuswitharangeofstories,newsandevents.
SamoaTheRedwoodRegionEconomicDevelopmentCommission,Samoaissetto receive$70,000fromtheHumboldtCountyBoard
ofSupervisorstoestablishanaquaculturecentreinSamoa.Thecenterwillpotentiallygrowbothfreshwaterandsaltwaterspeciesofplantsandanimals,includingabalone,fishandvegetables.-http://bit.ly/TCA5Ys
JamaicaJamaica'saquacultureindustr yissettoreceiveaboostthanksto30millionEU-fundeddevelopmentplan.Thefourandahalfyear
ACPFishIIProgrammeincludesplansforlandandwateruseandablueprintforaquaculture.TheaimistorevitaliseJamaica'saquac-ulturesub-sector,whichhasdeclinedbyalmostfiftypercentinthepastfiveyears- http://bit.ly/PlMKnt
USANewYorkis knownforits experimentalfoodscene soit comesas nosurpriseto learnthatproductsfrom vertical farmsare
appearingonmenusacrossthecity.Verticalfarminginvolvesgrowsamultitudeofaqualifeinacolumn.Seaweed,mussels,andscallopsgrowatthetopofthewaterwithshellfishsuchasclamsandoystersbelow.Besidessavingspace,verticalfarmersclaimthepracticehelpsrestockmarinelife.Verticalfarmingisgrowinginpopularitysolookoutforproductsinarestaurantnear
yousoon.-http://bit.ly/T6WHQl
KenyaNormallywereportonthegulfbetweenfishdemand
andsupplybutinKenyathestoryisreversed.Kenyansare not eatingenoughfishtosustainthe fishfarmingindustry.Thegovernmenthasbeenpushingaquacul-turedevelopmentforsometime,investingSh5.7billionoverthreeyears.ButthishasnotpersuadedKenyanstoserveupfishathome;theaveragefishconsumptioninthecountryisjust3.7kgperpersonayear.-http://bit.ly/QNH0gY
ScotlandAnewworld-classsalmonfarmatLochailort,Scotland
issetforcompletionin2013.TheMarineHarvestsitewillhousea smolthatcherywhich willbeoneof thebiggestfacilitiesintheworld.-http://bit.ly/RgLv5L
SwedenResearchersattheUniversityofGothenburg,Sweden
arestudyingthepotentialeffectsofaccumulatingantibi-oticsintheseabed.Morethan10,000tonnesofantibi-oticsareconsumedinEuropeeachyear,30-60percentofwhichpassthroughanimalsandhumanscompletely
unchanged.Thedifferentsubstancesthenreachtheocean viahospitals, municipal sewage, fish farms andrun-offfromagricultureandlandfills.- http://bit.ly/Rpvdar
www.theaquaculturists.blogspot.com
Aregularlookinsidetheaquacultureindustry
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view
AQUACULTURE
by Dominique P Bureau, member
of the IAF Editorial Panel
On the Estimationof the DigestibleNutrient Contentsof Finished Feeds
Averylargeproportionofaquaculturefeedmanufacturers
arenowformulatingtheirfeedsonadigestiblenutrientbasis.Thisprogressivemovefromformulatingonatotalnutrientbasistoformulatingondigestiblenutrientsispraiseworthysinceitisprovidingamorerationalbasisfortheproductionofcost-effectivedietsadequatelymeetingthenutrientrequirementsofanimals.
Everyyear,anincreasingamountofinformationof
thedigestibilityofnutrientsofdifferentingredientsisbecomingavailable.Thisinformationisinformallycompiledinanumberofreferencedocumentsandincreasinglyusedbycommercialfeedformulators.Thequestionarisesastohowreliableistheavailableinformationandhowitisbestused.Inacontextofveryhighfeedcommoditiesprices,theimpactofoverestimatingorunderestimatingdigestiblenutrientcontentsoffeedingredientscantranslateintosignificanteconomicalimpacts.
Forexample,variationsaslowastwoorthreepercentage
pointsinthedigestibilityofproteinorlipidsourcescantranslateintovariationsofasmuchas$10to30pertonneoffeedproduced,clearlynotsomethingnegligible.
Foryears,thedebatearoundestimatesofapparentdigestibilitywasonmethodologicalissues(e.g.,fecescollectionmethods)and
perhapsmoreimportantissueshavebeenneglected.Iwishtobrieflyhighlighttwooftheseissuesinthiscolumn.
Ingredients,suchaspoultryby-productsmeal,feathermeals,meatandbonemeals,andDDGSareincreasinglyusedincommercialaquaculturefeedformulations.Asubstantialamountofinformationoftheapparentdigestibilityofprotein,aminoacidsandenergyoftheseingredientsisavailableinthereferenceliterature.However,theseingredientsareproducedusingawidevarietyofequipmentandprocessinganddryingconditions.Consequently,significantdifferencesmayexistintheapparentdigestibilityofnutrientsamongstlots(batches)oftheseingredients.Verylittleworkhasbeendonetomeaningfullycharacterisethevariabilityofthedigestibility
andnutritivevalueofdifferentlotsofthesameingredient.Thisisamajorissueforfeedmanufacturerssincetheseingredientsarefrequentlysourcedfromseveraldifferentsuppliers(brokers)andthesesuppliers,inturn,frequentlysourcetheseingredientsfromdifferentmanufacturingfacilities.
Anotherimportantissueisthewaybywhichthedigestiblenutrientcontentsoffinishedfeedscanbecomputed.In
feedformulation,thenutrientcontributionsofdifferentingredientsareusedtopredicttheconcentrationofnutrient(orenergy)inthefinishedfeed.Thecontributionofnutrientsofdifferentingredientisthusassumedtobeadditive.Itiscommonfornutritioniststoassumethatthedigestiblenutrientsandenergycontentsoffeedscanalsobecalculatedasthesumofdigestiblenutrientandenergycontributionsofdifferentfeedingredients(calculatedfromthequotientofincorporationlevelinthefeed,theapparentdigestibilitycoefficient(ADC)andthenutrientcontentofthe
ingredient).Whilepracticalandgenerallyeffective,anincreasingamountofevidencesuggeststhatthistypeofapproachmaynotbesuitableforseveraltypesofnutrients.
AseriesofpublicationsfromtheUniversityofGuelph(HuaandBureau.2006.Aquaculture,254:455-465;HuaandBureau.2009.Aquaculture,294:
282-287;HuaandBureau.2009.Aquaculture,286:271-276;HuaandBureau2010.Aquaculture,308:152-158)showedthatthedigestiblephosphorus(P),starchandlipidcontentsoffinishedfeedscouldnotbecomputedfromthesumofexpecteddigestiblenutrientcontributionsofthedifferentingredients.Thisresearchindicatedthattheformsunderwhichthesenutrientsweresupplied(or
foundinthefinishedfeeds),thelevelsandinteractionsbetweendifferentformsofthenutrients,andtheeffectofsomeexogenousfactors(e.g.,watertemperature,%gelatinization)hadtobetakenintoaccounttoaccuratelypredictthedigestiblenutrientcontentsoffinishedfeeds.
Fortunately,thisresearchalsoshowedthatmultipleregressionequationsprovided
asimpleandpracticalapproachofaddressingthischallenge.EquationswherethusdevelopedforpredictingthedigestibleP,starchandlipidcontentoffeedsmanufacturedusingawidearrayoffeedingredients.Unfortunately,mostleast-costfeedformulationsoftwarepackagesarenotcurrentlydesignedtocarryoutanoptimization(least-costing)ofthedigestibleP,starchand
lipidcontentsoffeedsonthebasisoftheseequations.However,thesesimpleequationscanbeprogrammedintofeedformulationsoftwareandtheeffectsofchangesinfeedformulationonthedigestibleP,starchandlipidcontentsofthefinishedfeedsbeeasilycomputed.
Theseissuesshouldbeontheradarscreenoffeedmanufacturersandmoresystematicandcommerciallyrelevantworkneedstobedonebyfishnutritionresearchersontheimportanttopicofestimatingthedigestiblenutrientcontentsoffeeds.
AQUACULTUREUPDATES
Climate change may make the
bodiesoffishsmaller,reportstheBBC.Scientistspredictthatfishcouldshrinkbyupto24percentifwatertemperaturescontinuetorise.Warmerwatermeanslowerlevelsofoxygenwhichreducefish
bodyweight.AstudypublishedbytheInstituteofFoodTechnologistshasfoundthat using fish oil as an alternativeto cano la oi l in nutr it ion barscanprovideomega-3fattyacidswithoutchangingthetaste.
Anindooraquaculturefacilitywiththecapabilitytoproduce17millionpounds offish a yearcould becoming to Montgomery County,NewYorkState,USA.Ifgiventhego-ahead, 'ProjectAqua' wouldcreate175jobsandreceivemorethan $175 million in initial privateinvestment.
An abalone trafficker in New
SouthWales,Australiahaslandedthetoughestsentenceinthestate'shistoryforfisheriesoffences.The55-year-oldmanwassentencedtofouryearsinjailandaAU$1000f ine after being convicted onfourcountsofabalonetraffickingandonecountofthreateninganfisheriesofficer.
The Ukrainian parliament hasapprovednew aquaculture laws.Thelawswillmapoutplansforaquaculturedevelopmentandthelegalframeworkforbodiesinvolvedinit.
Salmon farmexpansiongiventhegoaheadinwestcoastTasmania.ThethreemajorsalmonproducersinTasmania ,Tassal, Petuna andHuonAcquacultureplantoalmostdoublethesizeoftheirfarmsin
Macquar ie Harbour from thecurrent5.5squarekilometrestoninesquarekilometres.
TheGlobalAquacultureAlliance
hascertifieditsfirstsalmonfarmsinAustralasia.TheBestAquaculturePracticesprogrammehascertifiedtwo Mt.CookAlpine Salmon Ltd.farmsintheMackenzieBasinareanearTwizel,NewZealand.
TheBritishColumbiaaquacultureindustryistoreceiveacashinjectionof$1.25millionfromtheHarperGovernment.Elevencompanieswillbenefitfromthemoney,whichisearmarkedforsustainableandinnovativeaquacultureprojectsintheprovince.
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Anewpartnershippromisesamore
efficientandsustainablefutureforEuropean
aquaculture
Itiswelldocumentedthataqua-culturefacesincreasingpres-suresasdemandforseafoodproductsgrowswhiletraditionalwildfisheriesareindecline.
A new European researchprojectcalledIDREEM(IncreasingIndustrialResourceEfficiencyinEuropeanMariculture)hasbeenlaunchedtoprotectthelong-term
sustainabilityofEuropeanaquac-ulturebydevelopinganddemon-stratinganewinnovativeproduc-tiontechnology,Integrated Multi-TrophicAquaculture(IMTA).
The 5 .7 mi ll ion project ,whichstartedinOctober2012,iscoordinatedbytheScottishAssociationforMarineScience(SAMS) and delivered in col-
laborationwithfourteenindus-trial and research partners fromacrossEurope.
For the next four years, theIDREEMconsortiumwilldeveloptools and methods to help theEuropean aquaculture industryadoptmoreenvironmentallyandeconomicallyefficientpracticesusing
IMTAonacommercialscale.IMTA is the combined culti-
vationofmultiplecommerciallyfarmedspeciesthatbelongtodif-ferentlevelsonthefoodchain.InanIMTAsystem,fisharefarmedto ge th er wi th ot herspecies includingshellfish (suchas musse l s)andalgaeors e a w e e d ,
creat ing amore e f fi -cient,cleanera n d l e s swasteful pro-duction system.IMTAallowsnutrientsfromfishfarmsthatareoth-erwiselosttotheenvironmenttobeturnedintousefulproducts
astheyareutilisedbytheseaddi-tionallygrownspecies.
IMTAaddressesconcernsaboutthe future sustainability of aqua-culture by increasing produc-tivity and profitabili ty while alsoreducingwasteandover-relianceonrawmaterialsfromwildfishstocks.
TheIDREEMprojectwilldem-onstrate the benefitsof IMTAthrough pilot commerc ial -scaletesting, field research and mod-elling.InterdisciplinaryresearchwithinIDREEMwillexaminethe
obstaclesandriskstotheuseofIMTAsystems
anddeveloptoolsto ov ercomet h e s e c o n -
s t r a i n t s ,
whethertheyareeconomic,environmental,
t e c h n i c a l ,socialorregula-
tory.IDREEMpairsaquac-
ulturebusinessesandresearchinstitutionsinstrategicpartner-shipstopromoterapidimple-
mentat ion , a l lowing ins tanttr ans fe r bet we en researchfindings and commercial appli-
cations.Thetoolsandmethodsdevelopedwithin IDREEM willhelpaquacultureenterprisesandpolicymakersgainabetterunder-standingoftherisksandbenefitsassociatedwithIMTA.
Theendresultoftheprojectwillbethecreationofamoreefficient Europeanaquacultureindustry,basedonthedevelop-
mentofmoreeconomicallyandenvironmentally efficient tech-nology. IDREEM wil l delivertools and evidence to suppor tthe adoptio n of IMTA acrossthe aquaculture industry,helpingcreateemploymentandwideningamarketnicheforIMTA-grownseafoodproducts.
www.sams.ac.uk
"The end result of the projectwill be the creation of amore efficient European
aquaculture industry"
Nvmb-Dcmb 2012 | INterNatIoNal AquAFeed | 7
Aqua News
ASIAN GATEWAYTO ANAQUATIC WORLD OF WONDER
www.aquarama.com.sgFor more information, please contact:
Iman Tam [email protected]
co-located with
The 4th International Pet
& Accessories Exhibition
-
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10/568 | INterNatIoNal AquAFeed | Nvmb-Dcmb 2012
Aqua News
Scottish scientists are
hominginontheelusive
genes that could create
the perfect salmon and
revolutioniseaquaculture.Experts
at Landcatch Natural Selection,
basedinArgyll,andtheirresearch
partners,areaimingtobethefirst
intheworldtolocatethegenes
that determine how susceptibleindividualAtlantic salmon are to
certaindiseases.
ItisanotherpioneeringadvancefromLandcatchwhoin2007werethe first aquaculturecompanytobeinvolvedinworktopinpointa gene influencing InfectiousPancreaticNecrosis(IPN)whichposesamajorthreattoAtlanticsalmon.Theylateralsoprovedthatsealiceresistanceisinherited,sub-
sequentlyproducingjuvenilefishwhichwerelesssusceptible.Thisallowedbreeding fromselectedpedigree families and increasedgeneticresistanceineachnewgen-eration.
ThenewworkmeansLandcatchand partners are getting evernearertotheall-importantgenesandare on target to have thisscienceforsaleandalreadyappliedtotheirsalmoneggsby2014.
Healthier, diseaseresistant salmon
Inwhatwillbeamajorbreak-throughforthe industry, eggsandsmoltswillthenbeproducedto
selectivelybreedhealthier,diseaseresistantsalmonandotherfishas
thetechnologycancrossover tootherspecies.
It will mean improved qualityproductsandanaccelerationofgenetictechniquesinfarmedfishwhichtheindustryandcommenta-torsbelieveisnecessarytoaddress
worldfoodshortagescausedbyclimatechange.Theworkacceleratesthepaceof
progressandwillhelpbreedersandresearchersexaminetraitsinindi-vidualfishandbetterunderstandtheirgeneralsurvivability, omega-3levelandgrilsingormaturingrates.
This involves a cutting-edgegenomicselectiontooltheSNPChipaglassslideusedtoanalysevariationsinDNAsequences,or
SingleNucleotidePolymorphisms(SNPs), which act as biologicalmarkersandhelpscientistslocatearangeofgenesassociatedwithdisease.
Hundreds of thousandsof genetic markers
Therearemanymillionsofthesevariationsin every species, andthesecanbeusedasmilestonesontheDNAmap.Scientists,whopre-
viouslyexaminedonlyfivemarkersfor one salmon gene, can nowinterrogatehundredsofthousandsof markers for 20,000-30,000genes.
Inessence,Landcatchcandiscover
moreinformationononefishthanwaspreviouslyavailableonthou-sands.Thislevelofbreedingexper-
tise would normally take manydecadestoreach,butLandcatchwilldoitinjusttwo.
DrAlanTinch,directorofgeneticsatLandcatchse-centreinAlloa,saysexpertshavenarrowedthesearchdowntoabout100possiblegeneshaving identifiedQuantitativeTraitLoci(QTL)stretchesofDNAcontainingorlinkedtothegenesthatunderlieatrait.Hesays,Weareclosinginonthegenesallthetime. Itsabitlikeus knowingthe
street where they live but wejust dontknow yetwhichhouses,whereaspreviouslyweonlyknewwhattowntheylivedin.
Weknowthatinthatarea(ofDNA)thereissomethingthathasaneffectondiseaseresistanceandthere is a technicalargument fortherebeingagenethere.
TheprogresshasbeenwelcomedbyArgyllandButeconstituencyMSPMichaelRussellwhosays,I
amverypleasedtoseeanArgyll-basedcompanyattheforefrontofimportantresearchthatshouldhavestrongcommercialandenvi-ronmentalbenefit.
Landcatch suppl ies genet ic
servicesandAtlanticsalmoneggsand smolts to the aquacultureindustry.Itusesselectivebreedingto develo p stra ins of sa lmo nwhichcanperformtoever-higherlevelsateverystageofproduc-tion fromeggs to adult fish. ThefirmispartoftheglobalHendrixGeneticsmulti-speciesfoodpro-duct ion organisat ion whosemissionistohelptheworldmeetitsfoodneedsthroughinnovativeandsustainablegenetictechniqueswhichinformtheirbreedingproc-esses.
Theworktofindthegeneis
beingundertakenwithanumberof commercial and academicpartners, including EdinburghUniversity,RoslinInstitute,StirlingInstitute of Aquaculture andGlasgowUniversity,withsupportfromtheUKTechnologyStrategyBoard.
LandcatchgeneralmanagerNeilManchestersays,ThemissinggenesarelikeourHolyGrailandfindingthemwillhavewidespreadpositive
implications.Breedingfishthatareresistanttoliceanddiseasewillbeanincredibleachievementandamajorcommercialbreakthroughforaquacultureandeffortstofightthewaronhunger.
Expertsclosingthenetontargetedfishgenes
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Iamsure everyone involvedin any fish
vaccinationwould really rather prefer
thattheydidnthavetovaccinate.Itis
an expensive, timeconsuming, hazard-
ous and stressful process. So why do we
vaccinatefish?
CertainlyinthesalmonfamingIndustry,ithasbecomeapartofthefreshwaterproduc-tionprocessformanyyearsnowanditisonlysomeof the mostmaturemembers ofthesalmon industry remember what it was likebeforeoil-basedvaccinesweredeveloped.
Priorto theseeffectiveoil-basedvaccines,salmonproducerscouldbeexpectedtoloosemaybe50percentoftheirstockstothemaindiseasethreat,Furunculous.Somefarmssuf-
feredmorethanothersbutallhadproblemsofsomeformorother.Theonlyrealsolutionwastreatmentwithantibiotics,whichwasnotonlyextremelyexpensivebutledtoproblemswithresistance.
The other problem was the negativepublicperceptionofhighusageofantibioticsinafoodanimal.This,inconjunctionwithafew high profile cases of use of unlicensedantibiotics on fish farms, led tothe industryseekingafreshapproachtodiseasemanage-ment.Theoil-basedvaccinesusedtodayinthe aquaculture industry are all multivalent,
meaningtheypreventavarietyofdiseases,abitliketheMMRvaccineinhumans.
Why vaccinate?Economics, logistics and risk involved
in injection mean that many alternativeapproacheshavebeentried.Dipvaccinesandin-feedvaccineshaveallbeentrialledbutdueto the nature of how fish immune systemswork, these only have limited effects. If itwerethateasy,Iamsurehumanwouldprefertohave atablet insteadof aninjection when
theygoonholiday!The problem with putting vaccines in-feed is that the in order for vaccines toworktheyneedtocreatearesponseintheimmunesystem-thebodyhastoreacttoaforeignsubstanceinthebodytoproduce
the ant igens to give the immunesystem the correct defences. If thesubstancethatcreatesthisreactionin
thebodyisput intothefeed,thebodyisdesignedtodealwiththisbydigestingand
excreting it through the digestive system,and i t does not stimulate the immunesystemandthushasnoeffectinpreventingdisease.
Who vaccinates?The Atlantic salmon industry through-
out the world has been familiar with intra-peritoneal (by injection)vaccinations for manyyears. Trout farmersoccasionally vaccinate
for Enteric RedmouthDisease(ERM)onhigh-risksitesbutbecausetheproductioncycleismuchquicker for trout thansalmon, most diseasecanbemanagedthroughdipvaccination.
The sea-bass industryin the Mediterranean isabiggrowthareaatthemoment but is sufferinginthe same way salmon
farmersdid25yearsagowith many sites loosingmaybe 50 percent oftheirstocks.Recentcom-mercialproduction of aneffectiveoil-basedvaccinehaveledtomanyseabassfarmers now consideringvaccinationbyinjectionastheonlyeffectivemethodtocontroldisease.Thosefew that have invested
in a vaccination strat-egyhaveseenbigfinancialbenefits from it and aswordspreads,itislikelytobecomecommonplaceinthisindustrytoo.
How is the procedure
carried out?The fish are starved for 24 or 48 hours
(depending on time of year) prior to vac-cinationtoemptythegut.Thefisharethencrowded in the tank or cage before beingpumpedorhandnettedintoananaestheticbath. The fish take one to two minutes tobecomefullyanaesthetised.Thisisextremely
An overviewof the UK fish vaccination industryby Kathy Taylor, Salmovac, UK
Melanisation (a permanent bruise like mark in the
flesh of the fish) causing downgrades at harvest.
Permanent damage and scarring inside the fish due
to damage by needle movement during vaccination
process.
10 | INterNatIoNal AquAFeed | Nvmb-Dcmb 2012
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important for vaccinator safety but also the
safety and welfare of the fish.
The fish are then delivered onto a stainless
steel table where the fish then are vaccinated
in a very specific area, with only a 3 mm toler-
ance. The team must achieve a 96 percent
accuracy target and considering most vaccina-
tors handle between 15-20,000 fish each this
is quite some achievement!
The fish are then returned to a recovery
tank and should come round from the anaes-
thetic within about two to three minutes.
There is always some level of mortality after
this high risk, stressful process but usually it is
just a few fish, around 100 for every 100,000
fish vaccinated. High mortalities immediately
after vaccination are usually attributed to poor
anaesthesia rather than the injection.
The consequences of poor vaccination
usually only become apparent months after
vaccination and can last up until harvest where
the financially consequences become appar-
ent. The main problems are:Incorrect needle depth resulting in either
intra-muscular injection (needle too short) or
internal organ damage, including granuloma
(needle too long) which results in the fish not
growing properly due to damage to the gut.
Fish not being immune to the disease
because of incorrect dosage (or no vaccine)
being delivered.
Two of the main problems Salmovac
encounters as a
contract vaccina-
tion team, is poor
anaesthesia of the
fish and also poor
grading, prior to vac-
cination of the fish.
Poor anaesthesia of
the fish can lead to
high mortalities. If
fish are under anaes-
thetised, the whole
process becomes
stressful and danger-
ous for them (imag-
ine having a major
operation whilst
only partly sedated!).
On the other hand,
if they are over
anaesthetised, they
risk not recover-
ing quickly enough,resulting in piles of
fish in the recovery
tank causing suffoca-
tion or even worse,
not recovering at all.
The other risk
factor here is to the
vaccinators. If the
mineral oils used in
november-December 2012 | IntnatInal AquAFeed | 11
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thevaccines areaccidentally injectedinto thefinger,thevaccinatorwillrequireurgentmedi-calattention.Thefingerwillhavetobecutopenandthevaccineflushedout,otherwisethe resulting inflammation could result inthe blood supply to the finger tissues beingreducedandpossiblelossofthedigit.
How has vaccination developed?
Whenthefirstoil-basedvaccinesbecameavailable for the salmon industry, quite afewcompaniesstartedvaccinatingtheirownfish believing (mistakenly) that this wouldkeep costs down, as they wouldnt haveto contract in extra labour. The problems
encountered and thesometimes devastatingresults of this quicklyled to most companiesemploying contract vac-cinationspecialists.
The main problemswere a lack of knowl-edge about needledepths and the results
of inaccurate vaccina-tion, along with theprocess taking a longtime because of theinexperienceandslow-ness of untrained vac-cinators. An inexperi-encedteamofsixcouldprobably manage tovaccinatebetween150-200 ,000 f ish a weekwhereasourteamscan
do 400-500,000 fish aweek!
Vaccines havedevel-oped tremendously inthe past 20 years, thedoseperfishusedtobe0.2mlandthevaccineswerevery thick, difficulttoadministerandcauseshigh side effects in thefish.Theyarenow0.1mlandmuchthinnerandcausefewersideeffects.Someofthenewervac-cines are now a 0.05mldoseandagainhavereduced side effects forthe fish while also giv-ingincreasedprotectionagainstdisease.
Theimprovementsinvaccinetechnologyhavenot only reduced theside effects for the fishbut have also improved
theeaseofuseforvacci-nators.Thesmallerdosesize is much easier to
administer,resultinginfewercasesofrepeti-tivestressinjuryandcarpeltunnelsyndrome.
Which species areworth vaccinating?
Allspeciesareworthvaccinatingiftheeco-nomicsofpreventingdiseaseratherthantreatingitstackup.Withthesalmonindustry,itisessen-tialthatallfisharevaccinatedandastheseabass
industryexpandsandimprovesitislikelythatallseabasswillhavetobevaccinatedto.Thekeytowhetheritisworthvaccinatingornot,reliesonwhetherthenisaneffectivevaccineatapricethat makes itviableto vaccinate andpreventsthelostofmarketsizefishtodisease.
How does vaccinationprovide value for money?
The expense and hassle ofvaccinationisfaroutweighedbypotentiallossesatseaorthe heavy costs and logistics involved withtreatingfish atsea. The otherfactor tobearin mind is fish welfare and the associatedregulations.MostScottishsalmonfarmsnowsubscribe to the RSPCA freedom foodsstandard,whichlaysdownwelfarestandards
for the aquaculture industry and vaccinationplaysakeyroleinthis.Itcostsafewpencetovaccinatea smoltat 30gbut theprice oflosingamarketsizesalmontoapreventabledisease is many, many times that amount.Prevention isnot only preferable,but finan-ciallyessential,tocure.
Vaccination in action at Salmovac
The fish are delivered onto a stainless steel table
where the fish are vaccinated in a very specific area,
with only a 3 mm tolerance. The team must achieve
a 96 percent accuracy target and considering most
vaccinators handle between 15-20,000 fish each this
is quite some achievement!
About the authorSalmovac was founded in 2003 in
the north of Scotland in response to
agrowingdemandforqualitycontractvaccinationserviceswithintheScottishsalmon industry. The directors, KathyandJohnFosterbothhadhadpreviousvaccination experience and a wealthof knowledge of both fish health andaquaculturepracticesalongwithaback-groundinqualityandbusinesssystems.Theystartedwithjustoneteamoffivepeople and successfully vaccinated fivemillionsalmoninthefirstyear.Becauseof the high quality and professional-
ismdeliveredbySalmovac,wordsoonspreadandcontractscamefloodingin.However,theywerecarefulnottooverstretchthemselvesinthefirstfewyears,preferringtoincreasethebusinessatasustainable rate, in order to keep thequalityofserviceandreputationofthecompanyhigh.
Asaresultofthissustainablegrowthof the business, they currently employover40peoplefromallovertheworldand successfully vaccinated 60 millionfishlastseason!
In2010,KathyFoster(nowTaylor)purchased the business from her ex-husband and now is the sole directorofSalmovac.Whatwasadifficulttimeforthebusinessbackthenhasprovedtobeabenefit forthe longertermandthe business has continued to growandprosperwithcontractsnotonlyinScotland but also in Ireland, Norway,Spain,FranceandSwitzerland.
More InforMatIon:
Kathy Taylor, SalmovacTel: +44 1381 621914
Email: [email protected]
Website: www.salmovac.com
12 | INterNatIoNal AquAFeed | Nvmb-Dcmb 2012
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Yeast products are getting more
andmorepopularinaquaculture.
However many products (as a
wholeorasfractions)areonthe
aquaculturemarketatthemomentanddif-
ferentiatingbetweenonefromanothercan
bedifficult.Thissmallarticleaimsatshadingsomelightsonthesubjectandexplainsthat
allyeastproductsarenotequal.
Yeastisaunicellularorganismbelongingtothekingdomof Fungi.Morethan athousandspecieshavebeenfoundintwomajorphyla:Basidiomycota and Ascomycota in whichbelongspeciesabletoduplicatebybuddingsuchasSaccharomycescerevisiae.
Due to their unique properties to growunder aerobic conditions and produce gas
andethanolunderanaerobicconditions,someyeast (mostly S. cerevisiae) have been usedforthemanufactureoffermentedfoodssuchasbread , beer and wine for a long time.Yeasts are also used as single sell proteinsourceinanimalnutritionandinaquacultureundervariousformsandspecies(Torulaspora,Torulopsis,Kluyveromyces, Saccharomyceetcaetera). It can be found for example in
shrimpandmarinefishlarvalfeedsorincludedasaproteinsourceinaquafeeds.
The reasons for this extensive use is itsexcellentnutritionalcontents,itseasysupplyin dried form or under liquid form whenbakery yeast plants or breweries are near
aquafeedplants,andnowadaysacompetitivepriceinregardstootherproteinsourcessuchasfishorsoybeanmeal.Furtherapplicationsare being developed for yeast as functionalfeed additives as probiotic live yeast, yeastfractions(yeastcellwalls,yeastextracts)orasasourceformorepurifiedproductssuchasbeta-glucansandnucleotides.Theproductionprocess ofyeast canallow the possibilitytoincorporatetracemineralsandthenproducehighlybioavailableorganictraceminerals,alsoknownasseleniumandchromiumyeast.
ThepinkyeastPhaffiarhodozyma,isnatu-rallyrichinastaxanthinandhasbeenusedforsometimeasnaturalsourceofthepigmentin salmonids. Although now it tends to bereplacedbybacterialproductswhichhaveahigher concentration and whose cell wall ismoreeasilydegraded.WewillonlyreferinthefollowingarticleonproductscomingfromS. cerevisiaeorigin.
Nutritional properties of yeast:Typical dry yeast composition is 93-97
percentdrymatterandcancontainfrom40%to60percentcrude proteinnitrogen, 35-45percentcarbohydrates,and5-9percentlipids.Aquiteimportantfractionofthenitrogenis
undertheformonnucleicacids(upto12%)that can lead to produce significant level ofuric acid if consumed at high concentra-tion, like meat. The Amino acid profile ofyeastisclosetosoybeanmealandthereforewelladaptedto animal nutrition; itis richinGlutamic acid and Lysine (up to8%).YeastisnaturallyrichinBvitaminssuchasbiotin,thiamineandfolicacid. ItalsoproducesniacinbutcontrarytosomebeliefdoesnotproduceB12Vitamin.Ergosterolwhichisasignificantfractionofyeastcellwall,alsoisalsoaprecur-
sorofVitaminD2byusingUVtreatments.
Bakers yeastEveniftheirnameremainsSaccharomyces
cerevisiae (cerevisiae for beer), mostof thestrains of Bakers yeast have been selectedfortheirhighfermentativepower,particularlyuseful for bakers.Strains are specific to the
typeofbreadandtheregionwhereitissold,inordertorespondtodifferentbreadmaking
conditions (French bread, white bread, flatbread,croissant,etc.)andresisttodifferentprocess conditions (osmotic pressure from
highsugaredbread,freezing,acidityofsourdough,).
Bakers yeast comes as a pure and pri-maryculturegrownonsugarsubstratesuchas molasses. The production is performedunderverystrictconditionsinordertomain-tainthegeneticpurity,consistency,specificityandefficacyofthestrains.(Figure1).Itcanbesoldunderdifferentformsandpackaging(instant dried yeast, active dry yeast, com-pressed,cream).
The primary grown culture controlled
processmakesalsoaveryconsistentbaseforthe production of yeast extracts, autolysedyeast, yeast cell walls and their derivate:nucleotides and beta-glucans. Yeast cellwalls produced from Bakers yeast usuallyhaveahighcontentofmannans.Theyare
Yeast in aquacultureby Philippe Tacon PhD, Lesaffre Feed Additives, France
14 | INterNatIoNal AquAFeed | Nvmb-Dcmb 2012
FEATURE
Figure 1: Yeast manufacturing process (primary grown culture)
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recognised as good toxin binders. Fractionscomingfrombakersyeasthavealightbeigecolour.
ThemostpopularaquacultureapplicationofBakersyeastisinhatcherieswhereitisamajorfeedsourceforartemiaandrotifer(seeforexampleCouteauetal1990).
Brewers YeastBrewers yeast can be identified either
as the ferment used in brewery industries(Yeastprimaryproduction)ortheby-productofthese industries which istheformmainlyusedinaquaculture.Inthelattercase,yeastbiomass is harvested from the fermentationvatsattheendofbeerfermentation.Itcanbesoldunderliquidform(18-20%ofdrymatter)but preferentially as inactive yeast spray or
drum dried. It canalsobeengrownasamorecontrolled product andspecific strains and finditswaytohumancareasafoodsupplementandholistictherapeutic,alsoknownasnaturalbrewersyeast.
Brewers yeast for aquafeed applications
issoldbytradingcompaniesasacommoditybased on the protein content, or by localbreweriesinneedtodispatchtheirslurry.Thequalityandthesupplyoftheseproductscanbe inconsistent and depends greatly on thesourceofsupply.
The nutritional content is similar as theoneinbakersyeast,butcontainsmoretraceminerals such as selenium and chromium.Theproteincontentofbreweryeastisrela-
tively high and and its amino acid content issimilar to bakers yeast. Numerous workshaveshowntheefficacyofBrewersyeasttoreplacepartiallyortotallytheproteinsfound
infishandvegetablemealinfishandshrimp.Shrimpfeedsformulatorstypicallyincorporatebrewersyeastintheirformulaattherateoftwotofourpercent.
Brewers yeast can be used to produceyeastfractions,howeverduetothenatureofbrewersyeastandthespecificityofthepro-ductionprocesses,thequalityislessconsistentthan inbakersyeast. Productscoming frombreweryyeasttendtohaveadistinctivebitter
table 1: ffect of live yeast ctisaf on growth parameters in tilapiaunder stress conditions. (n=3, P
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smellandtasteandadarkercolourthantheonescomingfrombakersyeast.
Ethanol YeastEthanol Yeast are harvested after hav-
ing performed alcoholic fermentation anddistillation for the conventional productionof Bioethanol from sugarcane, beet sugaror grains syrup. In the first case, the yeastbiomass is harvested and then dried withtherecycledenergy usedto heatthe vegetalmaterial.ThemajorityofethanolyeastcomesfromBrazil.
Production prices and selling prices arevery low, however the quality, such as theproteincontentisveryinconsistent.Thesup-plydependsontheactivityofthebioethanol
plantsandcanalsobeinconsistent.Anotherconcernisthesanitarysafetyoftheseprod-ucts.Antibioticsaresometimesaddedtotheprocessinordertopreventbacteriacompet-ingwith the yeast for nutrients andavoidingyield decrease. It is therefore possible thatsome antibiotic residues and possibly othertoxinsmightbeleft inthefinaldriedproduct.
AutolysedyeastInactiveDriedYeastInactive and Autolysed yeast come from
primary grown cultures or Brewers yeast.They are major products within the foodindustryasflavourenhancersandinpetfood
asfeedattractants.Theyareusedinaquacul-turefeedsasasourceofproteinandnitrogen.Brewers yeast, and itsethanol equivalent,ismostlyfavouredasitischeaperthanbakersyeast.Theyarealsoeasiersuppliedasyeastsuppliers prefer to sell the more controlledandtailoredBakersyeastonfoodmarkets.
Inactive yeast is a yeast that has beendeactivatedbyhightemperaturedrying(oftenspray drying). The cells come as a wholeandthecellwallisnotrupturedmakingtheaccess to intracellular material (amino acids,
vitamins) difficult. A way to access thesematerials is to partially hydrolyse the yeastcellwalltoletthecellularcontentbepartiallyreleasedfromthecell.Thiscanbefacilitatedby activating the internal autolytic enzymesof the live yeast (autolysis), adding external
enzymes (notably pro-teolysis) or playing onthe osmotic pressureto rupture the cell wall(plasmolysis). Differentgrades of autolysedyeast can be obtaineddepending on the levelofautolysis(frompartialtototal).Thefinalprod-
uctisamixtureofcel-lular content and yeastcell wall. Furthermorethe autolysis processdegrades protein andforms peptides (dipep-tides to tetra peptides)
andoligonucleicacidswhicharereadilydigest-iblebytheanimal.Againheredependingontheoriginalyeastmaterialused,autolysedandinactiveyeastqualitycanbeverydifferent.
Live Yeast as probioticsLiveyeasthelpsregulatethegutmicrobio-
ta.Itseffectshavebeenshown,first inhumanwhere it can reduce diarrhoea, especiallywithchildren.SpecificstrainshavethenbeendevelopedandproducedindustriallysuchasS.cerevisiae boulardii orS. cerevisiae Sc47(Actisaf)fortheanimalnutritionmarket.Itisacommonpracticenowtosupplementfeedsto increase milk production in dairy cowsor help pigletssurvival.
L ive yeastare charac-ter ized bythe ir liv ingcells count,expressed bycolonyformingunit (cfu pergram),typicallyten bil lionscfu/g. Dosagesare made inthe feeds as
dilutionstogetanefficientcfucountpergoffeed,a1000folddilutiongivinga10e107pergoffeedforexample.Viabilityoftheyeastismandatory for its effect and cfus should becheckedbeforeandafterpelletingusingplatecounts.
Despitetheincreasinguseofyeastasa probiotic in terrestrial animals, thereareonlyafewnumbersofworksstudyingits effect in fish as a gut functions stabi-
liser. The major reason is that live yeastdoes not resist the severe conditions ofthe manufacturing processes of aquafeeds(high temperatures, steam, long condi-tion ing times, see Aguirre -Guzzman et al2002). The studies are then diff icult to
transfer from lab condit ions to farm usingcommercialfeeds.
Alltheworkpublishedso far was madewith yeast either top dressed on feeds orincorporated in pressed (uncooked) feeds.NeverthelesssomedirecteffectstothegutmaturationhavebeenfoundinseabasswithaspeciesextractedfromtherainbowtroutgutDebaryomyceshansenii(seetheworksfromTovar-RamirezandalsothereviewsbyChiet
al2006andGatesoupe2007).Marineyeastsand yeasts isolated from fish seem a verylogicalchoicetouseinspeciesofaquacultureinterest.However,suchmaterialisoftendif-ficulttogrowunderindustrialconditionsanddidnotleadtothedevelopmentofanactualproductyet.TheproductsonthemarketarethereforeoftenfromS.cerevisiaeorigin.Ithastobenotedthatuptonow,noyeastprod-uctshavebeenregisteredinEUasaprobioticinaquaculture.
As an example of S. cerevisiae effects,
(LaraFloresetal2003,2010)Table2showssomeworksdoneintilapiafryfedfor3weekswith feeds supplemented with Actisaf (alsoknwnas Biosaf)at1 kg/Tintwodiets(40%and27%proteins)andat2crowdedcondi-tions(1fryperLor1 fryper2L).
AlltheyeasttreatmentsalsoincreasedthealkalinePhosphataseactivity,andwecanseeabetterimprovementoffeedconversionratio(FCR)andsurvivalunderstressfulconditions
(lowproteinpercentageandcrowdedcondi-tions).Thereisalsoabetterproteinefficiencyratio (PER) and digestive enzyme activitywhenActisafisused.
Live yeast canbe used directly on farm,where it has been showed (empirically) toimprove water quality in shrimp and fishponds.Itiseitherusedaloneormixedwithbacteria. Farms producing mash feed onsite
alsoaddyeastinordertodegradecellulolyticmaterialtoensureabetterdigestion.
Yeast Culture or fermented yeast.Yeast culture is a particular product in
whichyeastisallowedtoferment.Yeastbio-
16 | INterNatIoNal AquAFeed | Nvmb-Dcmb 2012
FEATURE
Figure 4: Cumulative mortality after immersion
with L. anguiilrum (blue line is control, orange line
is Pronady at 0.5g/kg. n=3, Pronady significantly
decreases mortality at 120h. P
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mass, substrate and fermented extracellularmetabolitesarethendried.
Yeast Extracts.Yeast extracts (YE) come from the
fur ther hydro lysi s and pur if icat ion ofautolysed yeast. Insoluble yeast cell wallsare separated from the cel lular contentby centr ifugat ion. YE are very soluble ,r ich in peptides (up to 65%-70% of theproduct), free amino-acids like glutamicacidandvitamins.Theyalsocontainahighlevelofnucleicacidwhichcanbefurtherpurified to increase the level of tasty 5nucleotides.Theyareusedinaquaculture
in functional feeds, and hatcheries, as asourceof nucleotidescomplementing thedenovosynthesisofcellsinmultiplicationandhelpingboostimmunityandanti-stressmechanisms.
Autolysed yeastand inactive yeastarecommonly mistakenly sold on the labelyeastextractinaquaculture.Agoodwayto dif ferent iate them is to look at thecarbohydrate levels. Autolysed yeast hasaround20-22%(mostlyfromtheremainingYCW)whereasYEcontainonlythreetosixpercentofcarbohydrates.
ThesmallpeptidesandfreeaminoacidsinYEcanalsoproveapotentattractantfor
aquafeedinshrimp.InatrialperformedinThailand with white shrimp L. vannamei.FeedcontainingYEat2kg/Toffeedwaspresentedinfeedingtraysatthecornerofhapasandtheremainingfeedwascounted
afteronehour.Wecanseeafasterfeed-ing when YE are included. (Tacon andSuyawanish2011).
Yeast Cell wallsYeast Cel l Wal ls (YCW) represent
the shell of the yeast cel l and are roughly40-50 percent of the mass of the cell .YCW are composed mainly of f ibrouspolysaccharidesglucanswithbeta1,3and
Nvmb-Dcmb 2012 | INterNatIoNal AquAFeed | 17
FEATURE
Figure 5: Yeast rich in organic selenium manufacturing process
MADE IN HOLLAND
AL30O
Almex b.v., Verlengde Ooyerhoekseweg 29, 7207 BJ Zutphen, The Netherlands, tel. +31 (0)575 572666, e-mail [email protected], www.almex.nl
High capacity extruders and expanders.
AD System
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beta1,6links,(50%and8%respectively),mannansundertheformofMannoproteins(40%) and chit in (2%) (see Lippke andOvalle1998).Furtherpurificationcanleadto the product ion of either pur ified beta-glucans (50% and up) and mannoprotein(often used in wine making for clarifica-tion). The presence of these compoundsoftenleadstothemislabellingofYCWasMOSorBeta-glucans.
These two carbohydrate types are veryinterestingfortheaquaculturemarket,beta-glucansaredirectstimulatorsoftheimmunesystemsinshrimpandfish,uponthestimula-tion of specific blood cells (granulocytes ormacrophages).Mannansareinvolvedinthebinding to pathogenic bacteria (especiallythose with pili having mannose receptors)and eliminate them from the intestine. Itisalsosuspectedthatthemannanesactasprebioticspromotingthegrowthofbeneficialbacteria.
YCWhavebeenshowntobeeffectiveto improve the resistance to bacterial chal-lengesinnumerousaquaculturespecies.Betaglucanshavetobeusecarefullyinaquacul-ture as some experiments report negativeeffects in fish when used for prolongedperiodsathigh concentrations..Thiscan beavoided by careful choosing the source ofYCWandusingthemeitherathighconcen-
tration (2 kg/T) only for a short period, oralowconcentrationcontinuously(0.5g/Kg).
Anexampleofsea-bassjuvenilesfedwithPronady(aYCWoftheLesaffregroup)at0.5 g/kg of feed for8 weeks can be seeninFigure4,showingasignificantprotectionagainst L. Anguillarum without any growthdifferencewiththecontrol.Howeveramini-mal amount ofYCWseemsneededto beingestedbeforechallengeinordertoprovide
anefficientimmunostimulationandsotheremightbeagapperiodwhentheproductisnotefficient.(datafromDr.MorganeHenry,HellenicCenterformarineResearch,2011)
YCWproducts,dependingonthequalityof the autolysed yeast separation, containalsosignificant percentages of proteinsandlipids.Itshouldbenotedthatthelowerthelevelofproteins,thehigheroflevelofcarbo-hydrates,andthenthebetterimmunostimu-lationfromtheYCWis.VariousqualityofYCWareontheanimalproductionmarket
andmajordifferencescanbefoundbetweenproductsdependingonthestrain,thesub-strateusedtoproducetheyeast,andeventthedryingprocess.
Mannans represent as most 25-27 per-centofYCWingoodqualityYCWfrompri-marygrownyeastsbutcanbefoundaslowas 9 percent in crude preparation comingfromindustryby-products.Glucansorpoly-glucosecan rangefrom 18To 40percent.
YCW Prote inlevel remainsthe most con-venient indica-tor of qual ity,the best prod-uctsbeingthosehaving lowern it rogen con-tent. The vari-ability betweenbatchescanalsobe very h igh.Texture shouldbecheckedfirst.
Good YCWoften have asmooth, finetex ture , lowgranulometryandalightbeigecolour.Thereisalsothetenden-cy to believethat all YCWare the sameand that dif-
ferentiation ofproducts mustbedonetothehighest level ofglucans (some-times measured
as both alpha and beta forms)or mannans.NotalltheYCWareequal.Efficiencyshouldbe checked as a prerequisite to use, orchange,YCW.
At LFA we have conducted a surveyof four YCW (2 bakery and 2 breweryyeasts)producedin4ofourownfactoriesinthesameL.Anguillarumchallengeinseabass supplemented at 0.5 g/kg of feed for8 weeks. Only2 responded significantly (1
bakery,1brewery),theremaining2hadevennegative results at 4 weeks (lower survivalthancontrol).ThisresultshowsfirstthatnotallisunderstoodinthewaytheseproductsworkandthatoneparticularYCWcannotbereplacedbyanother.
Selenium YeastYeastcanbeinducedtobeasourceof
organicselenium,mainlyundertheformofseleniomethionine, which is then stored inproteins.Duringthegrowthofbakersyeast,
selenium is added to the medium and isreplacingsulphurinmethionine.Theexcessof selenium is then eliminated by carefulwashingsteps(seeFigure5)toensurethatthe selenium left is 97-99 percent organic .Seleniumyeastshouldbethencheckedforthe highest percentage of selenomethio-nineand theconsistency between batches.Seleniomethionineis themain carbon-asso-ciatedformofseleniumintheanimalsbodyand then allow making organic seleniumwhich are readily available when oxidative
stressreactionsoccur.Themainapplicationwouldbeinaquacul-tureasf ishmeali samainsupplyofseleniumandthedevelopmentofdietswithlessfishmealwillrequirecompensationofseleniumin aquafeed formulae. Such an applicationcouldbeusefulinpreventingtheoxidationof poly unsaturated fatty acids (PUFA) infishflesh.Chromiumyeastisseldomusedinaquaculturediets.
Conclusion Yeast products are getting more fre-
quently used in aquaculture. Some appli-cat ions are promis ing as the use as analternativesourceofproteinsorasasanitaryandwelfareenhancer.Howevermanyprod-ucts ranging from crude ethanol yeast by-productstomorepurifiedbeta-glucansareavailableonthemarket.Thereforepotentialusers must accurately select them in func-tion of their targeted application. It is alsoas important toselect a reliablesource of
the products toensure aconsistency of thesupply.
More InforMatIon:
Website: www.lesaffre.com
18 | INterNatIoNal AquAFeed | Nvmb-Dcmb 2012
FEATURE
Upcoming
Eventsfor2
013
Making Sense of Science
February 21 - 25, 2013
Nashville, Tennessee
USAFor all info contact us on
www.was.com
The international triennial
conference & exposition of
World Aquaculture Society
August 9 - 12, 2013
Trondheim, Norway
Organised by European Aquaculture
Society
For all info contact us on
www.easonline.org
Asia Pacic Aquaculture
December 10-13th,
2013
Ho Chi Minh City, Vietnam
Aquaculture Europe
World Aquaculture
For all info contact us on
www.was.com
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March 13 - 15, 2013 BITEC Bangkok, Thailand
Register now forFREE entrance
www.aquatic-asia.net
Eager to meet up with dedicated Aquaculture exhibitors?
Want to boost your Aquaculture business?
Check out this new event, in co-location with VIV Asia 2013
Aquatic Asia 2013: Find your suppliers of innovative
products and services in the Fish, Molluscs,
Crustaceans and Algae business.
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Nowadaysweoftenhearstartling
news such as, seven billionth
babybornorworldpopulation
mayreach 9.2 billionby2050
(world news, msnbc.com). Hunger is the
worldsnumberonehealthrisk,itkillsmore
people thanAIDS every year, one in seven
peopleintheworldwillgotobedhungry
tonight.
To overcome these issues, farmers mustproduce70percentmorefoodby2050tofeedthepopulation.Buttheimpendingcrisisisthattheearthmayrunoutoffoodby2050.2.4billion extrapeople,no moreland,howwillwefeedtheworldin2050?
Atthesametimewealsohearinthenewsthatglobal fishconsumptionhashitarecordhigh. We have seen the commercial fishingtrendisdecliningwhereasaquaculturefarmingisgrowingrapidlyallovertheworld.
Is this supply enough to feed the future
population? May be not, but fish demandisgrowingeverydayallovertheworld.Tomaintainbaselineconsumptionineverycoun-try,159milliontonsoffish isneededto feedthe world population in 2030. This demandisdriven bypopulation and income growth.Ifacountrysaquacultureproductionfollowsthe recent trend, the expected aquaculturegrowthratewillneedafourpercentincreaseannually.Tofeedagrowingworldpopulation,the required aquaculture growth rate is 5.6percentannually.
Some of the main challenges to achievethese goals are proper and large-scale feedproduction systems for micro aquatic feed.Recently extruder manufacturers came upwithnewtechnologieswhichcansolvesomeof the aquaculture issues related to large
andcommercial-scalefeed,whichisthekeyforgrowthofaquacultureindustry.Thefun-damental components of extrusion systemshave consisted of the following items for anumberofyears:
1)Feeddeliverysystem2)Preconditioning3)Extruder4)Dieandknifeassemblies
Althoughexistingextrusionsystemswereabletoproduceawiderangeofgoodqualityaquaticfeeds(bothfloatingandsinking),smalldiameterpelletsizesweredifficulttoproduceat reasonable or cost-effective throughputs.Recent innovations in the basic hardwarecomponentspermitsmallerdiameterfeedsatattractiveproductionthroughputs.
Feed delivery systemHoppers or bins are an integral part of
a feeding device and are used to hold thedryingredientsabovethefeeders.Thefeed
delivery system must be able to uniformlyfeedbothadryand/orliquidingredientorablendofingredients.
Generally,whentheaddedfatcontentofarawformulationexceeds12percent,thepor-tionof fatabove the12 percentlevel shouldbe introduced into the extrusion system ina separate ingredient stream. The dry feedportionisdeliveredtotheextrusionsystemthroughaspecialisedmeteringdevicecapableof providing uniform flow at any desiredextrusionrate.
Dryingredientsareusuallyfreeflowing,andthereareanumberofcapablefeedingdevices which vary in their relative costand complexity. However, gravimetric orloss-in-weightsystemsarenecessaryforthestable,precisemeteringofdryfeedforthe
productionofmicro-aquaticfeeds.Therawrecipe is very finely ground or pulverizedanddoesnotpossessgoodflowproperties.The feed system must be able to handlethese fine ly ground formulations and avoidbridging and non-uniform metering of thefeed.
Automated feed delivery systems withPLCcontrolarethenorm.Slurrytanksand
liquidfeedingdevices(pumps)areutilizedtoaccomplishuniformmeteringofliquidingre-dients. The slurry tanks are often jacketedforheatingorcookingandareequippedwithagitators as required. Positive displacementmetering pumps deliver metered liquids atconstantratesbyvaryinglengthofstrokeorspeedof rotation.Slurries orliquids canbepremixedwithdryingredientsbutareprefer-ablyinjectedintopreconditioningdevicesorthe extruder barrel. The nutrient profile oflarvalfeedsiscriticalandtheprecisemeteringensurescorrectformulations.
PreconditioningThe dry portion of the feed and the
liquidportionareseparatelyintroducedintoa preconditioning device where they arecontinuouslymixed,heated,andmoisturisedbytheinjectionofhotwaterand/orsteam.Theintensemixingofwaterandsteamaddedtothe dryfeed andthe abilityto extendtheretention time during the preconditioningphaseallowsthemoistureleveltobemain-tainedatanoptimum.
Thisabilitytomaintainoptimummoisturedistributionnotonlyinitiatespropercookingbut alsois reportedas asignificantfactorinthe reduction of extruder barrel wear andextruder shaft power per ton of productprocessed.Thehighermixingintensityofnew
Extrusion technology for theproduction of micro-aquatic
feeds and shrimp feeds
by Mian N. Riaz, Ph.D, Head of Extrusion Technology Program,Food Protein R&D Center, Texas A&M University, USA
Image courtesy of Wenger
Manufacturing, USA
20 | INterNatIoNal AquAFeed | Nvmb-Dcmb 2012
FEATURE
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preconditioner designs improves hydrationandcooking,helpingtocapturethesteamin
the raw material. Excess steam can escapethe preconditioner and create fugitive dustwhichcreateshousekeepingconcernsintheplantenvironments.
Bettercookingwithnewprecondition-ers gives lower product viscosities which
improves extrudate flow through smalldie orifices. The result is smaller pelletsandmoreuniformpelletsize.Thehighermixing intensities in new preconditionerdesigns is the result of unique beaterdesigns and more beater contacts perretentiontime.
ExtrusionExtrudersaregenerallyclassifiedaseitherbeingasingleortwin-screwdesign.Inbothdesigns,theimpactoffinalproductcharacteristicsareaffectedbyscrewandbarrelprofile,screwspeed,process-ingconditions(temperature, moisture,etc.), rawmaterialcharacteristics,anddie/knifeselection.
Thefeedingzoneoftheextruderisthatareawherethelow-densitydiscreteparticlesof raw material are transported into theextruderbarrel inlet. This low-density, oftenpreconditioned, material is then transportedintotheinterioroftheextrusionprocessing
chamber. The flow channel of the screw istypically not filled in this zone due to theair entrapped in the incoming material. Theincomingmaterialiscompressedslightlyinthiszonewiththeairbeingexpelled.
Water, an excellent plasticizer, is typicallyinjected into the barrel in the feeding zoneto facilitate textural development, viscositydevelopment,andtoenhanceconductiveheattransfer. The kneading zone of the cookingextruder continues the compression startedinthefeedingzone,andtheflowchannelsof
theextruderscrewhaveahigherdegreeoffill.Asthedegreeofscrewfillincreasesandpressure begins to develop in the extruderbarrel, leakage flow (flow over the outsidediameterofthescrewinadirectiontowardthe extruder inlet) and pressure flow both
increase. The mechanismof sheardoes notbegintoplayadominantroleuntilthescrewflow channel is full. This full flow channelconditionbeginsinthekneadingzone.
The flow channel fil ls, first, with loosegranular material which is compressed andworked by shear as it passes through thekneading zone. It is in the kneading zone
wherethediscreteparticlesofmaterialbegintoagglomeratebecauseof theirtemperatureincrease resulting from conduction, directsteam injection, and viscous energy dissipa-tion.Here,thediscreteparticlesbegintoformamoreintegralflowingdoughmass.
At the dischargeend of the knead-ingzone,theextru-date most typicallyreaches its maxi-mum compaction.The shear in thisareaoftheextruderbarrel is moderateand the extrudatetemperature beginsto increase. Thefinal cooking zoneis that area whereamorphousizing and
texturis ing occur.Temperature andpressure typical lyincrease most rap-idly in this regionas shear rates arehighest because ofthe extruder screwconfiguration andmaximum compres-sion of the extru-date. The pressure,
temperature, andresultingfluidviscos-ityaresuchthattheextrudatewill expelfrom the extruderdie to form the
desired final product texture, density, color,andfunctionalproperties.
Twin-screw systems are preferred forextrusion of aquatic feeds smaller than 2mmdiameterduetotheirpositivetransportandself-wipingcharacteristicswhichpreventssignificant product build-up in the extruderbarrelwhichcouldlaterdislodgeandplugthe
smalldieorifices.TheCTXsystemisaco-rotatingsystemthatincludesataperedscrewdiameterwhichde-aeratestheextrudateandmakesiteasiertocreatehighdensityfeedsforgoodsinkingcharacteristicswithouttheneedforventedbarrels,pressurizeddensitycontrol
Image courtesy of Wenger Manufacturing, USA
Nvmb-Dcmb 2012 | INterNatIoNal AquAFeed | 21
FEATURE
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devices,ordoubleextrusion.ByaddingaBPV(BackPressureValve)aftertheextruder,thenecessary restriction is provided to expand
theproductif floatingpelletsaredesired.
Die assembliesThedieisthemostcriticalpartofthe
complete system as it determines prod-uct shape and size, but also determinesthroughputs and buoyancy properties of
the fina l aquatic feed. As pellet diametersbecame smaller , the die created morerestrictionanddrasticallyreducedthrough-puts.
One die assembly design that allowedan increasein throughputs byincreasing die
openareais the OTD (ObliqueTubeDie).Thisdieactuallyincreaseddieopenarea(thenumber of orifices) by two to three timeswhichmaintainedhighthroughputsevenforsmalldiameterproductsduetolargerdieholepopulations.Thetubescreatedlongerreten-
tion times for improved cooking. Pressuredropinthetubescreatedadenserproductsothatmicro-aquaticfeedscouldbecookedthoroughly but still maintain high densitiesfor sinking characteristics. The process wasstill a short time/high temperature process,
which mini-mised nutrientdestruction.Floating prod-ucts are pos-sible by simplydecreasing dieopenarea.
Processguidelines
Processguidelinesrequiredfordieholes smallerthan 1.2 mmdiameter:1) Recipe tocontain ade-quate starchlevelsforbind-ing (at least
25%starchforfloatingfeeds).
2) Maximum particle size of the recipemustbesmallerthanonethirdthedieholesizes.
3) A spring-loaded knife blade isrecommended.
4) All massflow inputs must be free ofmaterial that is large enough to blockorpartiallyblockthedieopeningsandthis includes the steam, water, fat, andotherliquidinputs.Thewaterandsteam
linesgoingtotheextrudersystemneedto be fitted with screen filters having30mesh(0.6mm)openingsandtheseshould be adequate if maintained. Thefatline (and fat source) also needs tobefilteredtoremovedebrislargerthan
30mesh(0.6mm).Allstrainersor filters must beeasy to cleanortheywillgetremovedintheheatofarunwhereliquidflowsare interrupted due to pluggedfilters. It may be necessary tohaveadualfiltersetupforfish
solubles and fat lines. With thisinstallation,ifonefilterispluggedyoucanclosethevalvestotheprimary filter for cleaning andopen the valves for the secondforcontinuedoperation.
5)Thedryfeedmustpassthroughavibrat-ing sifter after the grinder and beforetheextruderlivebin.Thissiftermustbesizedtoremoveparticlesthesamesizeor larger than the die openings. Highfishmealdietsplugvibratingsifterscreens
veryeasilyandtheindustryoftenemploysrotarysifterstoavoidthisbottleneck.6) Pneumatic conveying is required from
the extruder die to the dryer inlet forseveralreasons:
a) For product containment around the
die/knifearea.Thesmalldiameterfeedsresults in spillage in this area and willcausesanitationproblems.
b) For product separation. Floating feedshave a tendency to stick togetherwhen wet on belt or HVH conveyorsand pneumatic conveying enhancesseparation.
c) For separation of tails from pellets.Pneumatic systems scrub the product
and remove tails for later separationduringsifting.
7) Fluid bed dryers are recommendedfor products under 1.2 mm diameterin size although horizontal dryers withpolyesterscreenscanworkwithsomeproducts.
8) Final product sifting after dryer andbeforecoating.Thissiftingoperationiscriticalforthreereasons:
a) To remove overs ( large tai ls anddoubles)forregrind.
b) To remove fines for regrind. Thisprevents a mess during coating stepwhere the fines are also coated andcausebuildup.
c)Toseparategoodpelletsintoseveraldifferent diameters depending on theclient criteria for size. The expecta-tions from the industry will be fortight specs on pellet size and this caneasily be controlled at this point bysifting product and producing severaldifferent sizes at the same time andsetting the standard for the industry.Theprimary-sizedproductcanbesentonthroughthesystemforcoatingandintofinalproductbins.Thesecondarysizescaneitherbereworkedorsavedseparatelyintotebagsforcoatingandbagginglater.
9)Productionprocedures.Thissmalldiam-eterproduct requires a dedicatedline,strictstartupandshutdownproceduresto avoid die plugging, and thoroughcleanup techniques. The extruder andcoater areas should be considered as
wet areas for cleaning. The coatermayneedtobecleanedbetweeneachdifferent pel let size to avoid crosscontamination.
By following these guidelines and usingnewlyinnovativeextruderpartsmicro-aquaticfloating feed can be produced on a largescale basis. This micro-aquatic floating feedwillbethefoundationtostartfishfarmingoncommercialscaletofulfillthefishdemandintheworld.
More InforMatIon:
Email: [email protected]
"This micro-aquatic floating
feed will be the foundation
to start fish farming on
commercial scale to fulfill the
fish demand in the world"
22 | INterNatIoNal AquAFeed | Nvmb-Dcmb 2012
FEATURE
ImagecourtesyofWengerManufacturing,
USA
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FEATURE
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Digestibility enhancers
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NUTRI-BIND AQUA
Low inclusion binders
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smart aqua additivesfor sustainable and cost-efficient aquafeed
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Your challenge is our passion.MetAMINO The superior methionine source for your aquafeed.
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26/5624 | INterNatIoNal AquAFeed | Nvmb-Dcmb 2012
TheVelellaResearchProject,whichranfromsummer2011toFebruary2012,raisedfishthroughto
harvestsizeforthefirsttimeinUSFederalwaters.Kampachi(atropicalyellowtail)wereraisedina
singleunanchored,submersiblenetpentetheredtoamannedsailingvessel,inwaterupto12,000feet
deep.Thefinalharvestcompletedthegrow-outcycleofsashimi-gradekampachifishfromthedrifterpen
thathasbeenridingeddiesintheopenocean,threeto75milesoffshoreoftheBigIslandofHawaii.
Thisfinalharvestfarsurpassedourexpectations,saysNeilAnthonySims,Co-CEOofKampachiFarms.
Thefishthrivedintheresearchnetpenfarfromshore,withphenomenalgrowthratesandsuperbfish
healthandwithoutanynegativeimpactonwaterquality,theoceanfloor,wildfishormarinemammals.
Thekampachiwerefedasustainablecommercialdietthatreplacedasignificantamountoffishmealandfish
oilwithsoyandotheralternativeagriculturalproteins.Noantibiotics,hormonesorpesticideswereused
throughouttheseven-monthtrial.
Thekampachireachedanaverageof5.6lbsinsixmonths,resultinginafirstharvestafullthree
monthsaheadofscheduleandafinalFCRof1.6:1.
Simssaysthatfishhealthwassuperbthroughoutthetrial,withanoverallmortalityrateoftwopercent
comparedwithastandardaquaculturemortalityrateof15percent.Sampletestingshowedthat
thekampachihadafatcontentof33percent,makingthisanextraordinarilyhealthyfishforhuman
consumption,highinheart-healthyOmega-3swithnodiscerniblemercuryorothercontaminants.
Itmakesperfectsensetoraisefishintheocean,wheretheybelong,saysSims.Thiswasahealthy,low-stressenvironmentforthefish,andwethinkthatthisallowedthemtochanneltheirenergyintogrowingfaster.
ThemajorityofthesupportforthetrialcamefromtheIllinoisSoybeanAssociation,whichprovided
fundingfromtheIllinoisSoyCheckoffProgram.Theprojectgarneredadditionalsupportfromawidevarietyhoto courtesy of Rick Decker
TheVelellaResearchProjectPHotoSHoot
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ofstakeholders,includingNationalScienceFoundation,InternationalCopperAssociation,
Lockheed-Martin,OceanFarmsTechnologiesandNOAA.
ThesuccessoftheVelellaresearchdemonstratesthatwecangrowfishintheopenoceanwith
nonegativeimpactonpristineoceanecosystems,saysSims.Wemustnowapplyourselvesto
responsiblyscaleupthisindustry,tomeetthegrowingglobaldemandforhigh-qualityseafood.
Thenextphaseoftheresearchwilltestasingle-pointmooringsixmilesoffshoreinwater6,000
feetdeep,wherethepencanmovefreelyincurrentsandstillbewithineasyrangeofshorefor
supplydeliveryandtelecommunicationssupportforremotecommandandcontrol.Thisnext
iterationoftheresearchwilltestanunmannedVelellaonasinglepointmooringsixmilesoffshore.
Photos above text: Courtesy of Bryce Groark - Photos around text: Courtesy of Jeff Milisen
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Selenium yeast is commonly used
in aquaculture to improve animalperformance and meat quality.
Samplesofdifferentselenisedyeast
products were sourced in the EU and
USA.QAdepartmentsofTrouwNutrition
Internat ional and Selko
Feed Additives performed
a laboratory analysis on
these. Outcomes revealed
remarkable d if ferences
between product samples
on most effective and
active compound, namelyselenomethionine(SeMet).
Selenium is one of theessential trace elements inaquaculture.Itcanbeaddedto aquafeed in two forms;as inorganic selenite or asorganic selenium yeast. Eachform has different metabolicroutesandeffects.
Organicselenium-selenisedyeast-isregardedasamore
effectivewayofsupplementingselenium.Withmorefrequentusage of selenised yeast andincreasingamountofsuppliers,benchmarking on quali tybecomes relevant. Selenisedyeast mainly consists ofselenomethionine (SeMet),which can be convertedinto selenocysteine (SeCys)by natural turnover frommethionine into cysteine.
SeMet is regarded by animalsas normal methionine andabsorbed and processedfol lowing the methioninepathway. The SeMet willbe stored as methionine in
proteinsandsubsequently,tissuessuchasfillet
ororgans will be enriched with the selenium.Thisseleniumiseasilyavailablewhenrequiredfor the synthesis of selenoproteins (Figure 1).Thissavesvaluabletimeandensuresafastandeffectivereactionincaseofstressoradisease.
Benchmark
Several samples of selenised yeast weresourced from the market and analysedfor the most relevant selenium species atthe University of Pau, CNRS, France. Thisresearch lab is known as professional and
repeatable for organic seleniumspeciesdetermination.
Thevalueofselenisedyeastwas determined by the levelsoftotalselenium,SeMet,SeCysandinorganic selenium. A totalof 11 samples from different
batches of a number of pro-ducerswereexamined.Sampleswere randomly numbered andsent to the lab for analysesby HPLC ICP-MS. Results areshowninTable1.Mostinterest-ing is the variation in levels ofSeMet.Somesamplescontainedonly half the level of SeMetcompared to other samples(range from 24.8% to 69.7%).SeCys levels are, as expected,marginally present at all equal
levels. Unexpectedly, Sample 6containedarelativehighlevelofinorganicselenium(13.3%).
Need ofselenomethionine
Yeastisenrichedwithseleni-umthroughgrowingitinamedi-um with a controlled amountof selenium and a shortage ofsulphur. If the yeast grows, itmustsynthesisemethioninewith
selenium incorporated; SeMet.ThehighertheSeMetlevels,themorebeneficialtheyeastwillbeas an organic selenium sourceforaquaspecies.
It is widely accepted in
Why check selenomethioninelevels in selenium yeast?
by Wilbert Litjens, Technical manager Optimin & Betaine and Paul Perucchietti, Product manager Optimin, Selko Feed Additives,The Netherlands
table 1:
Sample otalSelenium SeMet SeCys InorganicSelenium
ppmppm as
Se% of
total Seppm as
Se% of
total Se% of total
Se
1 3000 2090 69.7 140 4.6 < 2%
2 2260 1460 64.6 100 4.4 < 2%
3 2250 1110 49.1 70 3.3 < 2%
4 1910 920 48.3 190 9.7 < 2%
5 1890 1160 61.2 670 3.5 < 2%
6 1990 490 24.8 < 10 - 13.3%
7 2217 1069 48.2 51 2.3 < 2%8 2377 1278 53.8 87 3.7 < 2%
9 2191 1092 49.8 59 2.7 < 2%
10 2027 854 42.1 49 2.4 < 2%
11 2239 1275 57.0 81 3.6 < 2%
26 | INterNatIoNal AquAFeed | Nvmb-Dcmb 2012
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scientific literature that SeMet is the mosteffective and active compound in selenisedyeastbringingbeneficialeffectstoorganism.ThepercentageofSeMetoftotalSeisthebestindicatorforthevalueandbioavailabilityoftheseleniumoutoftheyeast.
Theanalysisofthemainorganicseleniummetabolites (SeCys and SeMet) in relationto the total selenium level gives a strongevaluationonthesuccessoftheenrichmentprocess during production. Most selenisedyeastproductscontain97-99percentorganicseleniumoftotalselenium.
ThedominantorganicseleniumformisSeMet,whichcanbeaccurately(