Characterization of the microbial community structure in intestinal segments of yak (Bos grunniens).

Yak (Bos grunniens), a ruminant, has a complex gastrointestinal microbial ecosystem, which is essential for host nutrition and health. However, not much is known about gut microbial communities of yak. This study was conducted to characterize the gut microbial diversity and composition of small intestinal and cecal contents of yaks through high-throughput sequencing targeting V3-V4 hypervariable region of 16S rRNA gene. A total of 916,934 high-quality sequences were obtained and 224 core operational taxonomic units (OTUs) shared all samples. The result showed that the microbial community in the small intestine was different from cecum sample. In all samples, the majority of bacterial phyla were Firmicutes, Bacteroidetes and Proteobacteria. A large proportion of anaerobes in the families Peptostreptococcaceae, Prevotellaceae, Flavobacteriaceae, Lachnospiraceae, and Succinivibrionaceae were present in the various intestinal segments. The relative abundance of Ruminococcaceae, Bacteroidaceae and Muribaculaceae were significantly higher in cecum than in other segments of intestines. At the genus level, Bacteroides was the most predominant genus in cecum. The results indicated that yak have abundant and diverse gut microbial community. In conclusion, this study characterized the profiles of microbial communities across intestinal segments and provide better insight into microbial population structure and diversity of yak.