The Effects Of Three Selenium Sources On Growth Performance And Immune Indexes Of Penaeus Vannamei

The effects of different levels of sodium selenite,yeast selenium and nano-selenium on the growth performance and immune index of Penaeus vannamei were studied respectively in the feed,and the best selenium source and suitable addition level in the diet of Penaeus vannamei were determined.In this experiment,1200 juvenile shrimps with an initial weight of 1.99 ± 0.02 g were randomly divided into 10 groups,3 replicates in each group,40 shrimps per replicate.The control group was fed with prawn basic feed,and the experimental group was fed with 0.3,0.5 and1.0 mg/kg sodium selenite,yeast selenium and nano-selenium,respectively.The growth performance of Penaeus vannamei was measured after 8 weeks of culture.The activities of alkaline phosphatase(AKP),acid phosphatase(ACP),total superoxide dismutase(T-SOD),glutathione peroxide(GSH-Px)and total antioxidant capacity(T-AOC)in hepatopancreas and serum of Penaeus vannamei were measured on the30 th and 56 th day of culture.The experimental results are as follows:1.Adding proper amount of nano-selenium,yeast selenium and sodium selenite could significantly improve the growth performance of Penaeus vannamei(P<0.05),but had no significant effect on the survival rate of Penaeus vannamei(P>0.05).The weight gain rate and specific growth rate of Penaeus vannamei in the experimental group with selenium addition were significantly higher than those in the control group(P<0.05),and the weight gain rate and specific growth rate were the highest at the 1.0mg/kg nano-selenium of experimental group.At the same selenium level,the weight gain rate and specific growth rate of the nano-selenium and yeast selenium experimental groups were higher than those of the sodium selenite experimental group.Furthermore,in the same selenium source,the weight gain rate and specific growth rate of the sodium selenite experimental group has a trend that it first increasing and then decreasing with the increase of selenium level.However,the experimental group of yeast selenium and nano-selenium showed a gradual increase.2.Adding proper amount of nano-selenium,yeast selenium and sodium selenite to feed can improve the immune-related enzyme activity of Penaeus vannamei.The activity of AKP,ACP,T-SOD,GSH-Px and T-AOC in the hepatopancreas and serum of each experimental group added with selenium was higher than that of the control group in the middle and late experimental period,and the maximal value of each immune index was obtained in the 1.0 mg/kg nano-selenium experimental group.At the same selenium level,the indices of AKP,ACP,T-SOD,GSH-Px and T-AOC in hepatopancreas and serum of Penaeus vannamei showed the same trend that the order from high to low is nano-selenium experimental group,yeast selenium experimental group,sodium selenite experimental group and control group;in the same selenium source,the activities of AKP,ACP,T-SOD,GSH-Px and T-AOC in hepatopancreas and serum in the selenium experimental group showed a trend of increasing first and then stabilizing with the increase of selenium level in the feed.In summary,adding proper amount of nano-selenium,yeast selenium and sodium selenite can improve the growth performance and immune-related enzyme activity of Penaeus vannamei.According to the results of growth performance and immune index of this experiment,nano-selenium is an excellent selenium source in the feed of juvenile Penaeus vannamei,in the range of 0.5～1.0 mg/kg,nano-selenium has a good effect on the growth performance and immune level of Penaeus vannamei.the best addition level is 1.0 mg / kg in this experiment.