酵母水解物对凡纳滨对虾生长、消化酶活性和肠道形态的影响

本实验旨在研究饲料中添加酵母水解物对凡纳滨对虾(Litopenaeus vannamei)生长性能、血清生化指标、肝胰腺消化酶活性以及肠道形态的影响。酵母水解物添加量分别为0%、1%、3%和5%,配制4种等氮等脂(42.5%粗蛋白和8.5%粗脂肪)的实验饲料。选取初始体重为(1.86±0.02)g的凡纳滨对虾480尾,随机分为4组,每组4个重复,每个重复30尾,进行为期8周的养殖实验。结果表明饲料中添加5%酵母水解物组的增重率(WGR)、特定生长率(SGR)和蛋白质效率(PER)显著高于对照组(P0.05),而该组饲料系数(FCR)最低(P0.05)。对虾全虾粗蛋白含量随饲料中酵母水解物的增加而呈上升趋势,且5%酵母水解物添加组显著高于对照组(P0.05)。添加5%的酵母水解物显著提高了凡纳滨对虾血清总蛋白(TP)和甘油三酯(TG)含量,降低了谷草转氨酶(AST)和谷丙转氨酶(ALT)的活性(P0.05)。各处理组肝胰腺淀粉酶活性和对照组相比差异不显著(P0.05),但3%酵母水解物添加组的胰蛋白酶和脂肪酶活性显著高于对照组(P0.05)。3%酵母水解物添加组的对虾肠道皱襞高度和皱襞宽度显著高于对照组(P0.05),而5%添加组的微绒毛高度显著高于对照组(P0.05)。综上所述,在本实验条件下,饲料中添加3%~5%的酵母水解物能有效改善凡纳滨对虾生长性能、提高饲料利用率、促进消化吸收以及改善肠道形态学指标。

Effects of yeast hydrolysate on the growth performance, digestive enzyme activity, and intestinal morphology of Litopenaeus vannamei

An 8-week feeding trial was conducted to evaluate the effects of yeast hydrolysate (YH) on the growth performance, serum biochemical indices, digestive enzyme activity, and intestinal morphology of Litopenaeus vannamei. Four isonitrogenous and isolipidic practical diets (42.5% crude protein and 8.5% crude lipid) were formulated to contain 0%, 1%, 3%, and 5% YH (named Y0, Y1, Y3, and Y5, respectively). A total of 480 Litopenaeus vannamei, with an average initial body weight of about 1.86±0.01 g, were randomly allocated to four groups with four replicates per group and 30 shrimps per replicate. The results indicated that the shrimp fed the diet containing 5% YH had a significantly higher weight gain rate, specific growth rate, and protein efficiency rate than those fed the control diet (P<0.05), and that the lowest feed conversion ratio occurred in the Y5 group (P<0.05). Crude protein of whole shrimp significantly increased with increasing YH levels in the diet (P<0.05). Dietary supplementation with 5% YH significantly increased the contents of total protein and triglyceride and decreased the activities of aspartate aminotransferase and alanine aminotransferase (P<0.05). However, serum glucose and total cholesterol were not significantly influenced by YH (P>0.05). Shrimp fed the Y3 diet had higher hepatopancreas trypsin and lipase activities than those fed the control diet (P<0.05), but there were no significant differences in amylase activity among all the treatments (P>0.05). Shrimp fed the Y3 diet had significantly higher fold heights and widths in their intestines than those fed the control diet (P<0.05), and microvillus height in the Y5 group was significantly higher than that in the Y0 group. In conclusion, a 3%-5% YH supplementation in shrimp diet can effectively promote digestion and improve the growth performance, feed utilization, and intestinal morphology of Litopenaeus vannamei.