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目的探讨三株枯草芽孢杆菌在胃肠道中的耐受性以及作为益生菌的功能特性。方法人工模拟胃肠道环境,研究芽孢杆菌的耐受存活情况。同时对肠道中致病性金黄色葡萄球菌、大肠杆菌、肠炎沙门氏菌的拮抗特性、产酶特性和急性毒性安全试验进行了研究。结果在4h内,人工胃液中存活率在15%～50%之间,活菌数保持107cfu/ml以上,胆汁盐和人工肠液中存活率在50%以上,活菌数保持在108cfu/ml以上。3株芽孢杆菌对病原菌抑菌圈直径在10mm以上;具有较好的蛋白酶和淀粉酶活性;急性毒性试验LD50>20g/kgbw。结论枯草芽孢杆菌能较好的耐受胃肠道环境,能抑制病原菌生长,急性毒性试验安全,可以作为饲用微生态制剂的候选菌种。
Objective To investigate the tolerance of three strains of Bacillus subtilis in the gastrointestinal tract and their functional properties as probiotics. Methods The artificial gastrointestinal environment was simulated and the tolerant survival of Bacillus was studied. At the same time, the antagonistic properties, enzyme producing characteristics and acute toxicity safety tests of pathogenic Staphylococcus aureus, Escherichia coli and Salmonella enteritidis in the intestine were studied. Results In 4h, the survival rate of artificial gastric juice was between 15% and 50%, the viable cell count was above 107cfu / ml, the survival rate of bile salts and artificial intestinal juice was over 50%, and the viable cell count was maintained above 108cfu / ml . The bacteriostasis diameter of the three strains of Bacillus to the pathogen was above 10mm; the protease and amylase activities were good; the acute toxicity test LD50> 20g / kgbw. Conclusion Bacillus subtilis can tolerate the gastrointestinal tract environment better, inhibit the growth of pathogenic bacteria and make the acute toxicity test safe, which can be used as the candidate strains for feeding probiotics.