简介：Thepresentstudywasconductedtoevaluatethefeasibilityofreplacingfishmeal(FM)withbioactivepeptides(BPs)indietofwhiteshrimp(Litopenaeusvannamei).Thechangesingrowthperformance,bodycomposition,non-specificimmunity,andwaterqualitywereexaminedaftertheshrimpwerefedfourdiets,inwhich0%(control),33.3%,66.7%and100%ofFMwasreplacedbyBPs,respectively.ThegroupsweredesignatedasCon,1/3BPs,2/3BPs,and3/3BPs.Atotalof720shrimpwithaninitialbodyweightof1.46±0.78gwerefedtheexperimentaldietsfor56days.Theresultsrevealedthat:1)theweightgainrate(WGR)in1/3BPs,2/3BPs,and3/3BPswassignificantlyhigherthanthatinCon(P<0.05),whilenosignificantdifferencewasfoundonsurvivalrateandfeedconversionratio(FCR);2)thewhole-bodycrudeprotein(CP)andcrudelipids(CL)weresignificantlydifferentamonggroups,whiletherewasnosignificantdifferencebetweencrudeashandphosphoruscontents;3)thelevelsofacidphosphatase(ACP),lysozyme(LZM),superoxidedismutase(SOD),phenoloxidase(PO)andbactericidalactivityincreasedsignificantlywiththeinclusionofBPs;4)intermsofwaterquality,nosignificantdifferencewasfoundinpHanddissolvedoxygenamongdietsduringthewholeexperimentalperiod.Moreover,eventhoughnitriteandammoniumlevelstendedtoincreasewithtime,therewasnosignificantdifferenceamonggroups.TheresultsindicatedthatBPsisanapplicablealternativeofproteinsource,whichcansubstituteFMinthedietsofL.vannamei;itisabletoeffectivelypromotegrowthperformanceandimproveimmunity.Moreover,BPsinthedietshadnonegativeimpactonwaterquality.

简介：Toobtainthemaximumangiotensin-Iconvertingenzyme(ACE)inhibitoryactivity,theproteinhydrolysisconditionsofthejellyfishRhopilemahispidumwereoptimizedusingresponsesurfacemethodology(RSM).TrypsinwasselectedtoproduceR.hispidumproteinhydrolysates(RPH)withACEinhibitoryactivity.TheoptimalparametersforproducingproteinhydrolysateswiththehighestACEinhibitoryactivitywereasfollows:hydrolysistime5h,hydrolysistemperature50℃,andtheenzyme-to-substrateratio6%.Undertheseconditions,theACEinhibitoryrateofRPHcouldreach64.28%±5.72%.Inaddition,RPHcontainedhighlevelsofGly,Glu,Pro,Ala,AspandArg,withamolecularweightdistributionrangeof0.32–6.84kDa.ThefollowingthreenovelACEinhibitorypeptideswereisolatedandidentified:Ile-Gly-Glu-Thr-Gly-Pro,Gly-Ala-Thr-Gly-Pro-Ala-Gly-Tyr-ValandGly-Ala-Phe-Gly-Pro-Gly-Gly-Leu-Val-Gly-Arg-Pro.TheIC50valuesoftheACEinhibitoryactivityofthesethreepurifiedpeptideswere19.07,27.42and31.26μmolL^-1,respectively.TheseresultssuggestedthatproteinsandpeptidesisolatedfromR.hispidumcouldbeutilizedasantihypertensivefunctionalfoodsources.