本文旨在通过研究酵母酶解物对大口黑鲈(Micropterus salmoides)生长性能、脂类代谢及肠道组织结构的影响,来评价酵母酶解物在大口黑鲈饲料中的有效性。配制3种等蛋白质(粗蛋白质47%)等能(总能20.0 MJ/kg)的饲料:以含35%低温干燥鱼粉的高鱼粉饲料为对照饲料(命名为FM),在此基础上以混合植物蛋白质(豆粕+谷朊粉)替代50%的鱼粉并平衡必需氨基酸后作为基础饲料(命名为SBM),另在基础饲料中添加3%的酵母酶解物作为试验饲料(命名为HY)。选用初始体重为(20.80±0.04) g的健康大口黑鲈为试验对象,随机分为3组,每组4个重复,每个重复25尾,在室内循环控温系统中进行8周生长试验。结果表明:在增重率、特定生长率、摄食率上,HY组显著高于FM和SBM组(P<0.05);在肝体比上,HY组显著低于FM和SBM组(P<0.05)。FM组的全鱼粗脂肪含量显著低于HY和SBM组(P<0.05)。HY和SBM组大口黑鲈血清高密度脂蛋白胆固醇含量显著高于FM组(P<0.05),而肝脏总胆固醇含量则显著低于FM组(P<0.05)。血清甘油三酯和游离脂肪酸含量及肝脏脂肪含量变化一致,即FM组显著低于SBM组(P<0.05),与HY组无显著差异(P>0.05)。用混合植物蛋白质替代50%鱼粉后,大口黑鲈肠道肌层变薄,绒毛完整齐度下降,在此基础上添加酵母酶解物后,肠道结构损伤的情况有所缓解。由此得出,在本试验条件下,用混合植物蛋白质替代50%鱼粉后添加3%的酵母酶解物能够提高大口黑鲈的生长性能,改善肝脏状态,促进肝脏脂肪和胆固醇的代谢,修复肠道损伤。

This experiment was conducted to study the effects of hydrolyzed yeast on growth performance, lipids metabolism and intestinal structure of largemouth bass (Micropterus salmoides), and to evaluate the efficacy of hydrolyzed yeast in the largemouth bass diet. In the experiment, three isoproteic (47% crude protein) and isoenergetic (20.0 MJ/kg gross energy) diets were formulated: a high fish meal diet containing 35% low-temperature drying fish meal was designed as control diet (named FM), and 50% of the fish meal was replaced by plant protein mixture (soybean meal+wheat gluten) with 3% hydrolyzed yeast (named HY) or not (named SBM) on the basis of amino acid balance. Largemouth bass with the initial body weight of (20.80±0.04) g were as experimental animal, and those were randomly divided into 3 groups which reared in an indoor water-recirculating system lasted for 8 weeks. Each group had 4 replicates and each replicate had 25 fish. The results showed that the weight gain rate, specific growth rate and feed intake in HY group were significantly higher than those in FM and SBM groups (P<0.05), while the hepaticsomatic index in HY group was significantly lower than that in FM and SBM groups (P<0.05). The content of whole body crude lipid in FM group was significantly lower than that in HY and SBM groups (P<0.05). The content of serum high-density lipoprotein cholesterol in HY and SBM groups was significantly higher than that in FM group (P<0.05), while the content of liver total cholesterol in HY and SBM groups was significantly lower than that in FM group (P<0.05). The contents of serum triglyceride and free fatty acids and the content of liver fat showed a similar change, that was FM group was significantly lower than SBM group (P<0.05) and no significant differences were found in FM and HY groups (P>0.05). After 50% of the fish meal was replaced by plant protein mixture, the intestinal tissue appeared muscular layer thinner and villi integrity drop, while the symptoms of intestinal injuries were released by hydrolyzed yeast. This study indicates that 3% hydrolyzed yeast supplementation can significantly improve the growth performance, improve the live healthy status, promote the liver fat and cholesterol metabolism and repair the intestinal injuries of largemouth bass when 50% fish meal substitution by plant protein mixture under this experimental conditions.