酵母水解物与小肽对大口黑鲈幼鱼生长性能、肝肠健康与抗感染能力的影响

为比较研究酵母水解物与小肽在饲料中的添加效果，在基础饲料中分别添加1%的酵母水解物与小肽，配制三种实验饲料，对大口黑鲈(Micropterus salmoides)幼鱼开展为期56 d的饲养实验，考察其生长性能、肝肠健康及抗感染能力。结果显示：1%酵母水解物与小肽对大口黑鲈幼鱼生长性能均不产生显著性影响，酵母组能显著降低中、后肠淀粉酶活性并提升前、后肠脂肪酶活性，小肽组能显著降低前、后肠淀粉酶活性并提升前、中、后肠脂肪酶与中肠蛋白酶活性(P<0.05)；且小肽组的肠道结构更加光滑清楚，刷状缘表面细胞排列紧密，杯状细胞更加清晰可见。血清生化指标中，酵母组与小肽组白蛋白含量显著低于对照组，谷丙转氨酶含量显著高于对照组；小肽组总胆固醇、甘油三酯含量最低(P<0.05)。肝脏总抗氧化能力与过氧化氢酶活性酵母组最强(P<0.05)。头肾溶菌酶活性小肽组最强(P<0.05)，感染嗜水气单胞菌后小肽组累计死亡率最低。结果表明，添加1%小肽与酵母水解物均能改善肝肠健康，提高抗感染能力，但各具优势，小肽在促进大口黑鲈肠道健康、提升鱼体免疫保护能力方面优势显著；酵母水解物在增强肝脏抗氧化能力上更为突出。因此，在大口黑鲈幼鱼养殖阶段，选择性地使用小肽或酵母水解物，将更有效地提升机体健康水平。

Effects of supplemental yeast hydrolysates and small peptides on growth performance, liver and intestinal health and anti-infection ability of juvenile largemouth bass(Micropterus salmoides)

To compare the effects of supplemental yeast hydrolysates and small peptides in the feed of juvenile largemouth bass (Micropterus salmoides), the fish were fed with basal diet, diet supplemented with 1% yeast hydrolysates(YH) or 1% small peptides(SP) respectively to conduct 56-day feeding trial and the growth performance, liver-intestine health and anti-infection ability were investigated.The results showed that 1% yeast hydrolysates and small peptides had no significant effect on growth performance of juvenile largemouth bass, but the YH significantly reduced the amylase activity of mid and hindgut, and increased the lipase activity of fore and hindgut, while the SP significantly reduced the amylase activity of fore and hindgut, and increased the lipase and protease activity of fore, mid and hindgut (P<0.05). In the SP group, the intestinal structure was smoother and clearer, and the cells on the surface of brush border were closely arranged, then the cup-shaped cells were more clearly visible. As for the serum biochemical indexes, the albumin content in YH and SP groups was significantly lower than the control group, and the alanine aminotransferase content was significantly higher than the control group, the lowest cholesterol and triglyceride content was observed in SP group (P<0.05). There was the strongest total antioxidant capacity and catalase activity of the liver in YH group (P<0.05). The strongest lysozyme activity of the head kidney and the lowest cumulative mortality rate after infection with Aeromonas hydrophila were shown in SP group (P<0.05). In summary, the addition of both 1% SP and 1% YH could improve liver and intestinal health and anti-infection ability, but each had its own advantages. SP had significant advantages in promoting the intestinal health and the immune protection of largemouth bass, while YH were more prominent in enhancing the antioxidant capacity of the liver. Consequently, it would be more beneficial to the overall health of juvenile largemouth bass when YH and SP were added in the feed selectively.