工厂化养殖系统中不同密度对鳜鱼生长、抗氧化及免疫能力的影响OA

In order to investigate the effects of different stocking densities on the growth performance,antioxidant capacity and immune function of Siniperca chuatsi in a factory farming production system,and to preliminarily determine its suitable stocking density.Three stocking density groups of low(M1,150 ind./m3),medium(M2,200 ind./m3)and high(M3,250 ind./m3)were set up to carry out the 180 d culture experiment.The growth indexes of Siniperca chuatsi were measured and the expression levels of antioxidant enzyme activities and related immune factors in the head kidney and spleen were analysed.The results showed that at the end of the culture period(180 d),the M2 group was significantly better than the M1 and M3 groups in terminal body mass,body length and weight gain rate(P＜0.05).The antioxidant capacity tended to decrease with increasing density,with a significant decrease in superoxide dismutase(SOD)activity and total antioxidant capacity(T-AOC)content,and a significant increase in malondialdehyde(MDA)content;the activities of non-specific immunoenzymes(AKP,ACP,LYS)and the activities of pro-inflammatory factors(TNF-α,IL-8),interferon pathway-associated molecules(IRF11,IFP35)and T-cell receptor(TCRα)content were significantly upregulated with increasing density.It was shown that excessive high density induces oxidative stress and chronic inflammation,although it can stimulate the immune response.The present study suggests that the density of Siniperca chuatsi in factory culture should be around 28.61 kg/m3 in order to achieve a balance between culture efficiency and fish health.