壳聚糖和营养小肽对大口黑鲈幼鱼生长性能、抗氧化能力及免疫基因表达的影响

Effects of chitosan and nutritional peptides on growth performance,antioxidant capacity,and immune gene expression of juvenile Micropterus salmoides

试验旨在研究饲料中添加壳聚糖和营养小肽对大口黑鲈生长性能、抗氧化能力和免疫基因表达的影响。选取规格一致的3000尾大口黑鲈幼鱼,随机分为两组,对照组投喂基础饲料,试验组在基础饲料中添加2 g/kg壳聚糖及20 g/kg营养小肽,每组3个重复,每个重复500尾幼鱼。试验期60 d。结果表明:第30 d,试验组大口黑鲈的增重率和特定生长率极显著高于对照组(P<0.01);肠道淀粉酶、脂肪酶、过氧化氢酶(CAT)、总抗氧化能力(T-AOC)、血清免疫球蛋白M(IgM)、溶菌酶(LZM)、碱性磷酸酶(AKP)水平显著高于对照组(P<0.05);中肠的组织结构明显优于对照组;肠道中封闭蛋白-4(Claudin-4)的表达量显著高于对照组(P<0.05),白细胞介素-34(IL-34)和肿瘤坏死因子(TNF-α)的表达量显著低于对照组(P<0.05)。试验第60 d,试验组大口黑鲈肝脏丙二醛(MDA)含量显著低于对照组(P<0.05),AKP水平极显著高于对照组(P<0.01),肠道形态优于对照组,闭合小环蛋白-1(ZO-1)、封闭蛋白-1(Claudin-1)、Claudin-4、闭合蛋白(Claudin)、白细胞介素-10(IL-10)的表达量极显著高于对照组(P<0.05),肿瘤坏死因子-α(TNF-α)的表达量极显著低于对照组(P<0.01)。研究表明,饲料中添加2 g/kg壳聚糖和20 g/kg营养小肽能够提高大口黑鲈的生长性能、消化酶活性、抗氧化能力及免疫基因表达。

This experiment was conducted to investigate the effects of dietary chitosan and nutrient peptides on the growth performance,antioxidant capacity,and immun gene expression of Micropterus salmoides.A total of 3000 juvenile Micropterus salmoides with the same specifications were randomly divided into two groups,the control group was fed a basic diet,while the experimental group was fed the basic diet supplemented with 2 g/kg chitosan and 20 g/kg nutritional peptides.There were three replicates for each group,with 500 juveniles per replicate.The test period was 60 days.The results showed that on the 30th day,the weight gain rate and specific growth rate of Micropterus salmoides in experimental group were extremely higher than those in control group(P<0.01).The levels of intestinal amylase,lipase,catalase(CAT),antioxidant capacity(T-AOC),serum immunoglobulin M(IgM),lysozyme(LZM),and alkaline phosphatase(AKP)were significantly higher than those of control group(P<0.05).The structure of midgut was significantly better than that of control group.The expression level of Claudin-4 in intestinal tract was significantly higher than that in control group(P<0.05),and the expression levels of interleukin-34(IL-34)and tumor necrosis factor(TNF-α)were significantly lower than those in control group(P<0.05).On the 60th day,the liver malondialdehyde(MDA)content of experimental group was significantly lower than that of control group(P<0.05),the AKP level was extremely higher than that of control group(P<0.01),and the intestinal morphology of experimental group was better than that of control group.The expression levels of closed small cyclic protein 1(ZO-1),closed protein-1(Claudin-1),Claudin-4,closed protein(Claudin)and interleukin-10(IL-10)were significantly higher than those of control group(P<0.05).The expression of tumor necrosis factor-α(TNF-α)was extremely lower than that of control group(P<0.01).The study indicates that 2 g/kg chitosan and 20 g/kg nutritive peptides can improve the growth performance,digestive enzyme activity,antioxidant capacity and immune gene expression of Micropterus salmoides.