Survey and analysis of rumen microbiota in yaks at different growth stages

This study investigated changes in the richness and composition of the rumen microbiome in yaks at various developmental stages. Eighteen healthy male yaks at the ages of 5 months (M5), 12 months (M12), and 24 months (M24) had samples of their rumen digesta taken for 16S rRNA gene sequencing. The 11087 amplicon sequence variations (ASVs) in total were found; the M5, M12, and M24 groups had 3585, 1146 and 5545 distinct ASVs, respectively. Alpha diversity indices Chao, Shannon, Sobs, and ace indicated significant differences among the groups. The principal coordinate analysis (PCoA) indicated significant changes in microbial community composition across age stages. Firmicutes and Bacteroidetes were the two most prevalent phyla across all groups at the phylum level; Firmicutes had the highest relative abundance in the M5 group, which declined significantly with age. In contrast, Spirochaetota and Proteobacteria were relatively more abundant in the M24 group. At the genus level, there was a notable increase in Prevotella in the M12 and M24 groups, whereas UCG-005 continued to dominate in the M5 group. Microbial network analysis indicated increasing complexity of microbial interactions from M5 to M12, while the network became more dispersed in the M24 group. LEfSe analysis identified 65 microbial taxa with significant differences. This work provides new insights into the successional changes in yak rumen microbiota and their potential impact on digestive efficiency across developmental stages.