一株替代粪肠球菌的生产用芽胞杆菌筛选及其性质

目的 筛选1株能够产业化、替代粪肠球菌的芽胞杆菌。方法 从健康鸡、鸭、仔猪的粪便与肠道内容物中筛选，采用选择性培养基和耐酸耐胆盐发酵，通过耐人工肠液和人工胃液试验与粪肠球菌比较得到1株产酸能力较好的替代粪肠球菌的芽胞杆菌，并对其性质进行研究。结果 所筛选的芽胞杆菌（GY0520）对人工胃液、人工肠液有很好耐受性，90 ℃水浴15 min存活率为97%，能够产生大量有机酸，有利于提高动物机体的抗病能力及改善其生理性能，但对抗生素有一定的敏感性，不能配伍使用。结论 所筛选的芽胞杆菌能够替代粪肠球菌用于生产，为养殖业的微生态产品提高稳定性提供参考。

Screening and characterization of a Bacillus strain used for production replacing Enterococcus faecalis

Objective To screen a new strain of Bacillus that can be industrialized and replace the strain of Enterococcus faecalis. Methods Selective media were used to culture the samples of stool and intestinal contents from healthy animals. Artificial intestinal and gastric fluid tolerance tests were performed on the isolated strains, with Enterococcus faecalis as the control. The final strain was evaluated in terms of its tolerance to temperature and resistances to bile salt and artificial intestinal or gastric juice. Results The isolated strain of Bacillus (GY0520) presented better acid-producing ability as well as good tolerance to artificial gastric juice and artificial intestinal juice. 97% of the cells survived after heated at 90 ℃ for 15 minutes, indicating that it was able to resist high temperature during production and storage. The strain was sensitive to some antibiotics. Conclusion The resulted strain of Bacillus(GY0520) can be used instead of Enterococcus faecalis strain in the production to improve the stability of microecological products in aquaculture industry.