Biochemicalcompositionofzooplanktoncommunitygrowni

Biochemicalcompositionofzooplanktoncommunitygrowninfreshwaterearthenponds:NutritionalimplicationinnurseryrearingoffishlarvaeandearlyjuvenilesGopaMitraa,⁎,P.K.Mukhopadhyaya,S.AyyappanbaCentralInstituteofFreshwaterAquaculture,Kausalyaganga,Bhubaneswar-751002,Orissa,IndiabKrishiAnusandhanBhawan-II,ICAR,Pusa,NewDelhi-110012,IndiaReceived8November2006;receivedinrevisedform7August2007;accepted8August2007AbstractThisstudywasconductedtoobtainadatabasedescribingthenutritionalvalueoffreshwatermixedzooplanktonthatarewidelyusedforlarvalandgrow-outrearingoffreshwaterfish.Themacroandmicronutrientcompositionofmixedzooplanktonsamplescollectedfrom6fertilizedearthenpondswereanalysedforprotein,lipid,carbohydrate,ashandtheserangedfrom73–79%,10.79–14.55%,3–4.79%and3.20–10.07%,respectivelyonadrymatter(DM)basis.Aminoacidprofileshowedthepresenceofallthetenessentialaminoacidswithlowlevelofmethionine.Thecontentofsaturatedfattyacids(SAFA),monounsaturatedfattyacids(MUFA)andpolyunsaturatedfattyacids(PUFA)rangedfrom64–81%,7–15%and6–20%oftotalfattyacids,respectively.ThepredominantfattyacidswereSAFA(16:0),MUFA(18:1n-9),PUFAviz.linoleicacid(LA18:2n-6)andlinolenicacid(LNA18:3n-3).Amongthevitamins,ascorbicacid(15–40.01μg/gDM)waslessthantherequirementoffishespeciallyforlarvae,vitamin-A(13.61–63.95μg/gDM)andvitamin-E(218–348μg/gDM)weremorethantherequirementoffish.MineralandtraceelementcontentshowedthepresenceofP,Ca,Fe,Cu,ZnandMn.Seasonalvariationofallbiochemicalcomponentswasevaluatedinthestudy.VitaminEhadstrongco-relation(r1=0.72;r2=0.88;r3=0.83;r4=0.86;r5=0.36andr6=0.88)withseasonalvariationinlipidcontentofzooplanktonofdifferentpondsandvariedinverselywiththatofrisingtemperature.Enzymecontentfromthemixedzooplanktonofdifferentpondsshowedavailabilityofprotease(6.21–7.92μgleucine/mgprotein/h),lipase(25.82–39.1μgα-naphthol/mgprotein/h)andamylase(100–226.1μgmaltose/mgprotein/h),whichcouldbeusedasanexogenoussourceofdigestiveenzymesforfishandshellfishduringontogenesis.Absenceofl-gulonolactoneγ-oxidaseactivityconfirmedtheincapabilityofthesezooplanktontosynthesizeascorbicacid(AA)denovo.Theaveragedryweightinzooplanktonindifferentpondswas1.2–4.2mg/landdifferentspeciespresentinthesepondswereMoina(Moinadubia),Daphnia(Daphnialumholtzi,Daphniacarinata);Cyclops(Mesocyclopshyalimus,Mesocyclopsleuckarti);Diaptomus(Heliodiaptomusviddus,Neodiaptomushandeli);Rotifer(Brachionus).Theseresultsindicatethatthebiochemicalcompositionandsubsequentlythenutritionalvalueoftheseplanktonicorganismsarenotonlygeneticallydeterminedbutalsoinfluencedbyitsmaturitystageandtypeofingestedfood.Thesedatamaybehelpfulforreferencepurposeandforformulatedfeedpreparationaccessingthenutritionalpotentialityofthesefreshwaterzooplanktoninthenurseryrearingoffreshwaterfishlarvaeandearlyjuveniles.©2007ElsevierB.V.Allrightsreserved.Keywords:Mixedzooplankton;Protein;Lipid;Vitamins;Minerals;Aminoacids;FattyacidsandenzymesAvailableonlineat(2007)346–360⁎Correspondingauthor.Tel.:[phone];fax:[phone].E-mailaddress:[e-mail](G.Mitra).0044-8486/$-seefrontmatter©2007ElsevierB.V.Allrightsreserved.doi:10.1016/j.aquaculture.2007.08.0261.IntroductionZooplanktonoccupyacentralpositionbetweentheautotrophsandotherheterotrophsmaintaininganim-portantlinkinthesustainabilityofthefoodchainform-ingoneofthemostimportantcomponentsoffreshwateraquaculturespecies(ChakrabartiandSharma,1998).Larvaeofallcultivablefishspeciesrequireliveplank-tonicorganismsasfirstfood(Garcia-Ortegaetal.,1998).Insemi-intensiveorintensivecultureconditions,aqua-culturespeciesderiveasubstantialpartoftheirdietarynutrientneedsfromnaturallyavailablezooplanktonastheyareavaluablesourceofprotein,aminoacids,lipid,fattyacids,vitaminsandenzymes(Millamenaetal.,1990;Munilla-Moranetal.,1990;Pillay,1990;Evjemoetal.,2001).Thustherelativecontributionsofzoo-planktoninthenutritionoffreshwaterfishlarvaehaveimmensesignificance(JanaandChakrabarti,1993).Despitetheeffortthathasbeenputinthedevelopmentofformulatedstarterfeed(Verrethetal.,1987)forlarvalfish,livefoodstillremainsabetteroptionintermsofsurvivalandgrowthcomparedtoformulateddietalone.Livefoodseemstoprovideagoodsourceofexogenousenzymes,andalsohelpsinchemoreceptionandvisualstimuli(Kolkovskietal.,1995).However,thenutritionalqualityofzooplanktonvariesconsiderablyandthusplaysamajorroleinproducingqualitylarvaeandjuve-niles(vanderMeerenetal.,2001)aswellastheywouldaidindeterminingthesuitabilityoftheorganismsinfishlarvaeculture(Kibriaetal.,1999).Althoughinsemi-intensivefishculturetheculturedspeciesdrawsasignificantpartofnourishmentfromzoo-planktongrowninponds,howeverquantitationofitsnutritionalcontributiontofishgrowthislimited.Howeverthedependenceonlivefoodasstarterfeedratherthanonformulatedfeedinfishlarvaemakesitpertinenttoevaluatethenutritionalcompositionoflivefoodinaquaculture(Srivastavaetal.,2006).DuetoescalationinthecostofArtemiacysts,generallyusedduringlarvalrearing,useofpondgrownzooplanktonisjustifiablygainingmoreimportanceintheha