Analysis of the Gut Microbial Diversity of Dairy Cows During Peak Lactation by PacBio Single-Molecule Real-Time (SMRT) Sequencing.

BACKGROUND: The gut microbes of dairy cows are strongly associated with their health, but the relationship between milk production and the intestinal microbiota has seldom been studied. Thus, we explored the diversity of the intestinal microbiota during peak lactation of dairy cows.

METHODS: The intestinal microbiota of nine dairy cows at peak lactation was evaluated using the Pacific Biosciences single-molecule real-time (PacBio SMRT) sequencing approach.

RESULTS: A total of 32,670 high-quality 16S rRNA gene sequences were obtained, belonging to 12 phyla, 59 families, 107 genera, and 162 species. Firmicutes (83%) were the dominant phylum, while Bacteroides (6.16%) was the dominant genus. All samples showed a high microbial diversity, with numerous genera of short chain fatty acid (SCFA)-producers. The proportion of SCFA producers was relatively high in relation to the identified core intestinal microbiota. Moreover, the predicted functional metagenome was heavily involved in energy metabolism.

CONCLUSIONS: This study provided novel insights into the link between the dairy cow gut microbiota and milk production.