规模化牛场犊牛直肠细菌多样性分析

【目的】研究腹泻犊牛直肠细菌多样性,以及与健康犊牛直肠细菌多样性的差异。【方法】通过建立直肠菌群16S rRNA基因克隆文库,分别用限制性内切酶MspⅠ和HhaⅠ对阳性克隆的PCR产物进行限制性酶切片段长度多态性(RFLP)分析,通过测定16S rRNA基因序列,绘制系统发育树,确定犊牛直肠菌群的组成。【结果】腹泻组克隆阳性率达98.75%(474/480),优势菌群以乳杆菌属(14%)、肠球菌属(10%)和埃希菌属(8%)等需氧和兼性厌氧菌为主,健康组克隆阳性率达96.45%(488/506),优势菌群以梭菌属(13%)、双歧杆菌属(8%)和巨型球菌属(5%)等专性厌氧菌为主。【结论】2周龄犊牛直肠菌群复杂多样,并且具有自己的独特性菌群,且腹泻时乳杆菌属、肠球菌属、埃希氏菌属等显著增加。

Analysis of microbial diversity in rectum of calf in largescale cattle farm

Objective] To analyze the diversity of bacterial community in rectum of diarrheic calves,and differences with health calves.Methods] 16S rRNA clone libraries were constructed,positive clones were digested by Msp I and Hha I for restriction fragment length polymorphism(RFLP),and then a phylogenetic tree was depicted based on the 16S rRNA sequencing,to confirm the compose of microbe in the diarrheic calf rectum.Results] The positive rate of clone was 98.75%(474/480) in diarrheic calves,the dominant bacteria included Lactobacillus(14%),Enterococcus(10%) and Escherichia(8%).The positive rate of clone was 96.45%(488/506) in health samples,the dominant bacteria included Clostridium(13%),Bifidobacterium(8%),Megasphaera(5%).Conclusion] Complexity and diversity of bacterial community in rectum in 2 weeks old calves had their own features,and significant increase of Lactobacillus,Enterococcus and Escherichia was found in diarrhea calves.