益生菌地衣芽孢杆菌治疗鸡腹泻机理初探

目的：探讨益生菌地衣芽孢杆菌饲喂鸡腹泻的治疗效果以及分子机理。方法：从养鸡场土壤中选择性分离芽孢杆菌，通过优 化条件提高产生芽孢的比例；利用芽孢和大米混合后饲喂腹泻鸡，通过克隆测序分析腹泻鸡肠道微生物群落在饲喂前后的差异。 结果：我们分离到一株地衣芽孢杆菌，通过优化条件使产芽孢的比例提高到60 %。利用芽孢饲喂一周后能够有效地治疗鸡腹泻。 分析鸡肠道微生物群落发现：鸡腹泻后其肠道细菌群落的多样性和均匀度降低。造成腹泻鸡肠道主要菌群为动胶杆菌（Zoogloea sp.）；经芽孢饲喂后，主要菌群转变为拟杆菌（Bacteroides sp.），与健康鸡的肠道微生物主要菌群相似。结论：我们筛选到一株可能 治疗鸡腹泻的芽孢杆菌，通过优化培养条件能够提高其产芽孢比例；腹泻鸡经芽孢饲喂后，其肠道中致病菌被益生菌所代替，形 成正常的肠微生物菌群而恢复健康。

Research on the Mechanism of Bacillus Licheniform Probiotic in Treating Chicken Diarrhea

Objective:To evaluate the efficiency of antibiotics Bacillus Licheniformis in treating diarrheal chicken and to investigate its molecular mechanisms.Methods:We isolated Bacillus sp. from chicken farm soil with selective medium, and then optimized incubation conditions to improve the ratio of spore. Using clone and subsequent sequencing technique, we compared the chicken intestinal bacterial communities before and after remedy with spores.Results:We isolated one Bacillus licheniformis strains, and enhanced its spore ratio to 60 %by optimizing the cultural condition. The chicken diarrhea was recovered effectively after treatment with spore for one week. The intestinal bacterial diversity and evenness were significantly decreased in the diarrhea chicken, and after treatment, the diversity gradually recovered to normal level. The intestinal bacteria of diarrhea chicken were dominated by Zoogloea sp., which changed to a Bacteroides sp.dominated community after spore treatment, convergent with these of healthy chicken.Conclusion:We isolated a candidate probiotic bacterium, and improved its spore ratio by optimizing culture condition. It was likely that the pathogenic bacteria in diseased chicken were replaced by probiotic species, and returned to normally intestinal microflora, thus enabling the diseased chicken recuperated its health.