饲料中添加枯草芽孢杆菌对草鱼消化酶活性和肠道菌群的影响

研究了饲料中添加枯草芽孢杆菌Bacillus subtilis对草鱼Ctenopharyngodon idellus消化道酶活性和肠道菌群数量的影响。选用体质量为（51．37±0．58）g的健康无病草鱼300尾，随机分为对照组和处理组两组，每组设3个重复，每个重复放50尾鱼，对照组饲喂基础日粮，处理组饲喂含枯草芽孢杆菌（10^8CFU／kg饲料）的基础日粮，日投喂量为鱼体质量的3％，饲养时间为45d。结果表明：处理组肠道内容物中胰蛋白酶、脂肪酶和淀粉酶活性分别比对照组显著提高14．75％（P〈O．01）、13．03％（P〈O．01）和78．95％（P〈0．01）；肝胰脏中脂肪酶和胰蛋白酶活性分别比对照组显著提高17．72％（P〈0．01）和13．81％（P〈0．01）。肠道菌群数量分析显示，与对照组相比，处理组肠道芽孢杆菌和假单胞菌数量极显著提高（P〈0．01），而致病性弧菌和大肠杆菌数量却极显著降低（P〈0．01）。研究表明，饲料中添加枯草芽孢杆菌能够改善草鱼肠道菌群组成，并提高消化道特定消化酶活性。

Effects of dietary Bacillus subtilis on digestive enzyme activity and intestinal microflora in grass carp Ctenopharyngodon idellus

A feeding trial was performanced at water temperature of 18-25℃ to investigate the effects of dietary bacterium Bacillus subtilis on digestive enzyme activity and intestinal microflora in grass carp Ctenopharyngodon idellus with initial body weight of 51.37 g±0.58 g. Three hundred individuals of grass carp were randomly divided into two treatments with three replicate tanks at a rate of 50 fish per tank, and fed the basal diet in the control group, and the basal diet supplemented with bacterium Bacillus subtilis in the treatment groups three times a day at 8：00 hour, 12：00 hour and 19：00 hour at a feeding rate of about 3% for 45 days. There were very significantly 14.75% higher trypsin, 13.03% higher lipase and 78.95% higher amylase activities in the intestinal thyme in the fish fed the diets containing Bacillus subtilis（ P〈0.01 ）compared with those in the control group. The fish fed the diets containing Bacillus subtilis had 17.72% higher lipase and 13.81% higher trypsin activities in hepatopancreas （ P〈0.01 ）. There was significantly higher number of Bacillus sp. and Pseudomonas sp. in the intestine in the trea- ted groups（P〈0.01 ）, while there was significantly lower number of E. coli and Vibrios than that in the control group （P〈0.01）, indicating that supplementation of Bacillus subtilis in diets led to increase in the digestive enzyme activities and improvement of the intestinal microflora in grass carp.