Effects Of Taurine On Growth And Immunity In Juvenile Black Carp (Mylopharyngodon Piceus) At Different Stocking Density

The study conducted to study effects of taurine on growth and immunity in Juvenile Black Carp (Mylophaiyngodon piceus) at different stocking density. A multi-factor experimental design was adopted(fishmealx taurine xstocking density). At the beginning of the initial average weight 2.50±0.02g randomly assigned to three groups, each group set up three repeat, the net cages is 1.5 m×1.5 m ×1.5 m. Black carp was fed for two stages of cultivation(16 weeks) under 3 different stocking densities with 22.2g/m3,44.4 g/m3 and 88.9g/m3.And on this basis studied two fishmeal level feed (FM 20%,10%), and then supplemented taurine with concentration of 0,0.1%, respectively.The experimental results are as follows:Growth resulted indicators that the growth of the black carp is restrained with the increase of breeding density and decrease of fish meal content, and added taurine promoted the growth of fish. The interaction effect of fishmeal and taurine had significant on weight gain rate and survival rate of juvenile black carp (P<0.05). The interaction effect of fishmeal and stocking density had significant on weight gain rate and survival rate of juvenile black carp. (P<0.05) The interaction effect of taurine and stocking density had significant on weight gain rate and survival rate of juvenile black carp (P<0.05). The interaction effect of fishmeal, taurine and stocking density had significant on weight gain rate and survival rate of juvenile black carp (P<0.05).Physiological and biochemical indicators that the serum total antioxidant capacity decreased, amylase activity of increased, trypsin activity decreased, and the content of TC and TG decreased with the increase of breeding density. Meanwhile, the content of TG,TC decreased, lipase activity decreased, and the enhanced of amylase activity with the reduced of fish meal content, but taurine added that enhanced he amylase activity of black fish. The interaction effect of fishmeal and taurine had significant on serum TG,TC and T-AOC of juvenile black carp. The interaction effect of fishmeal and stocking density had significant on serum MDA of juvenile black carp (P<0.05). The interaction effect of fishmeal and taurine had significant on intestines enzyme activity of juvenile black carp. (P<0.05) The interaction effect of taurine and stocking density had significant on intestines lipase specific and enzyme activity of juvenile black carp (P<0.05). The interaction effect of fishmeal, taurine and stocking density had significant on intestines protease activity of juvenile black carp (P<0.05).For the immunity and anti-stress level, the content of C3, C4 and IgM reduced and the content of S-IgA in intestinal increased with the decreased of fish meal content. The content of IgM reduced and the content of S-IgA, GLU increased with the decreased of fish meal content. Meanwhile, the LSZ activity increased and GLU in serum reduced with added taurine. The interaction effect of fishmeal and taurine had significant on intestines S-IgA of juvenile black carp (P<0.05). The interaction effect of stocking density and taurine had significant on intestines S-IgA of juvenile black carp (P<0.05). The interaction effect of fishmeal and taurine had significant on serum complement C3 of juvenile black carp (P<0.05).The interaction effect of fishmeal and taurine had significant on serum GLU of juvenile black carp (P<0.05).(Conclusion)These results suggested that high density cultivation decreased weight gain rate, immunity. low fish meal diet decreased weight gain rate, immunity. Dietary taurine supplementation can enhance growth performance of black carp, improve immunity, and increase the ability of black carp's resistance stress.