简介：AstudyonthenonspecificimmunityofLitopenaeusvannameieverinhabitingfreshwaterandseawaterwascarriedoutatdifferentmoltstagesbycomparingtheirtotalhemocytecount(THC)andrespiratoryburst(RB)andactivityofphenoloxidase(PO),nitricoxidesynthase(NOS)andlysozyme(LY).Two-wayANOVAshowedthatsalinityandmoltstageindependentlyaffectedTHCandRBandtheactivityofPO,NOSandLYofjuvenileL.vannameisignificantly(P<0.05).TheTHCandRBandtheactivityofNOSgraduallyincreasedfromthepost-moltstages(AandB)tothepre-moltstages(D0–D3),whichwerecommoninshrimpsinhabitingfreshwaterandseawater.TheactivityofPOpeakedattheinter-moltstage(C),andtouchedthelowestatthepost-moltstageinfreshwaterandpre-moltstageinseawater.TheactivityofLYwasstableoverthemoltcycle.TheRBandtheactivityofPO,NOSandLYofjuvenileL.vannameiweresignificantlylowerinfreshwaterthaninseawater;whereasTHCwassignificantlyhigherinfreshwaterthaninseawater(P<0.05).Itwasconcludedthatthepost-moltstage(especiallystageA)wascriticaltoshrimpculture,whichshouldbeintensivelyattendedwhenL.vannameiwasculturedinfreshwater.