简介：OptimalstockingdensitieswereinvestigatedfortheseacucumberApostichopusjaponicusSelenkaunderfeed-supplementandnon-feed-supplementregimesinnetenclosuresfor333d.Substantialweightlossoccurredduringtheaestivationphase(AE).Decreasedgrowthrateswerealsoobservedduringthewinterphase(WT).Incontrast,seacucumbersshowedrapidgrowthduringthespring(SP)andautumn(AU)phases.Feedingregimesconsiderablyinfluencedthegrowthperformance,i.e.,seacucumbersgrewfasterunderfeed-supplementregimethanundernon-feed-supplementregime(P<0.05).Theaveragesurvivalratesofseacucumbersunderfeed-supplementregimewerehigherthanthoseundernon-feed-supplementregimeforboththeautumnphaseandspringphase,butthedifferenceswereonlysignificantforthelatterphase(P<0.05).ThefittedB-Ncurvesshowedthattheoptimalstockingdensities,intermsofnetproduction,were22.3ind.m-2forfeed-supplementregimeand14.1ind.m-2fornon-feed-supplementregime.

简介：OnthebasisoftheresearchofDObudgetorkineticsinshrimppond,themaininfluenceprocessofDOanditsseasonalvariationsarequantitativelydescribedthroughredividingthebudgetprocessandmodifyingthequantitativemethodoftheprocess.Thepercentagesofoxygendemandofvariousprocessesinthetotaloxygendemandaredifferentinshrimpcultivationseasons.Itisshowedthatthedissolvedoxygendemandofmini-organismsisthemajoraffectedfactorofDOinthisenvironmentandapproximatelyaccountsfor64.1～74.1%ofthetotaloxygendemand.Intheearlyperiodofshrimpculture,thedissolvedoxygendemandofallotrophicbacteriadegradingorganicmattersismuchlowerthanthatofphytoplanktonrespiration.Butinthemidterrnandlaterperiod,itisabout50%ofthetotaloxygendemandbecauseofthehigherwatertemperatureandmoreseriousself-pollution.Thedissolvedoxygendemandofsedimentislowerandjust19.1～28.8%,whilethepercentageofshrimpoxygendemandislower.TheeffectofphytoplanktononDOinshrimpculturingwaterhasdualism.Oneistheoxygenproducingprocessofphotosynthesisandtheotheristheoxygenconsumptionprocessofrespiration.Itisestimatedthatthedissolvedoxygendemandofphytoplanktonrespirationisapproximatelyone-fifthoftheoxygenproducedbyphotosynthesisundernormalilluminationconditions.Thedissolvedoxygendemandofallotrophicbacteriadegradingorganicmattersandthetotaloxygendemandofsedimentincrease4timesand1.7timesrespectivelyfromtheearlyperiodtothemidtermandlaterperiod.Obviously,theDOofculturingwatercanbealsogreatlyimprovedbycontrollingtheselfpollutionoforganicmattersduringshrimpculture.

简介：Topreparecalcium-bindingpeptides,thefleshresidueofMactraVeneriformiswassubjectedtoenzymatichydrolysis.Bycomparingthecapabilityofcombiningcalciumofthehydrolyzates,pepsinwasconfirmedtobethemostsuitableenzymeforhydrolyzingthefleshresiduetoreleasecalcium-bindingpeptidesamongtheseventestedproteases.Thepepsinhydrolyzate(PHM)wasdividedintothreefractionsaccordingtothemoleculeweightofitscomposition,whichrangedfrom0.5to15kDa.Thelow-molecule-weightfractionnamedPHM-3hadthehighestcapabilityincombiningcalcium.ThepeptidesexistinginthePHM-3fractionconsistedofhighercontentsofGlu,AlaandLeu,andcouldproduceonetypeofcalcium-peptidecomplexbypowerfullychelatingcalciumions.PHM-3productscouldeffectivelyincreasecalciumabsorptionandretentionwhiletheydecreasedthecalciumexcretioninanimaltests.Additionally,symptomscausedbylowcalciumbioavailabilityinovariectomizedrats,suchasbonemineraldensityreductionandmechanicalstrengthlosscouldbesignificantlyamelioratedbythehydrolyticproductsadditionindiet.