健康犊牛直肠细菌的多样性

Analysis of Microbial Diversity in Rectum of Health Calves

【目的】研究分析健康犊牛直肠细菌的多样性。【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Msp I和Hha I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,绘制进化树,确定健康犊牛直肠菌群的组成。【结果】克隆阳性率达96.45%(488/506),Msp I得到64种分类操作单元(OTU,Operational Taxonomic Unit),Hha I得到45种OTU,综合获得143种OTU。测序比对表明健康犊牛直肠优势菌群分属梭菌属(13%)、双歧杆菌属(8%)、拟杆菌属(3%)、真杆菌属(3%)、乳杆菌属(2%)、普氏菌属(2%)、埃希菌属(4%)、巨型球菌属(5%)和不可培养菌(8%)。【结论】健康犊牛直肠菌群复杂多样,且多为专性厌氧菌,以梭菌属、双歧杆菌属和巨型球菌属为主要类群。此外,巨型球菌属在1～2周龄犊牛直肠中具有独特性。

[ Objective ] To analyze the diversity of bacterial community in rectum in healthy calves. [ Methods] 16S rRNA clone libraries were constructed, and positive clones were digested by Msp I and Hha I respectively for RFLP, and then a phylogenetic tree was depicted based on the 16S rRNA sequencing, to confirm the composition of microbes in the healthy calf rectum. [ Result ] The positive rate of clone was 96. 45% （488/506）, OTUs ofMsp I were 64, Hha I were 45, and a total of 143, and the result revealed that the dominant position of healthy calves included Clostridium （13%）, Bifidobacterium （8%）, Bacteroides （3%）, Lactobacillus （2%）, Prevotella （2%）, Eubacterium （3%）, Escherichia （4%）, Megasphaera （5%） and Uncultured bacterium （8%）. [ Conclusion] The bacterial population diversity is complex and abundant in rectum, and many of them are obligate anaerobe, of which Clostridium, Bifidobacterium and Megasphaera were the dominant groups. The Megasphaera had speciality in 1 -2 week -old calves.