Fig. 2. Fiber-rich and starch-rich treatments select distinct microbial communities.

A principal coordinate analysis (PCoA) profile of ruminal bacterial community based on unweighted UniFrac dissimilarity matrix at the taxa (ASVs) level (PERMANOVA, p = 0.001, R² = 0.19); B random forest analysis of rumen bacterial community. The y-axis, from top to bottom, displays the genera ranked by their relative importance based on mean decrease accuracy in the classification of groups; C relative abundance of the top five phyla; D relative abundance of genus Fibrobacter, Ruminobacter, and Treponema; E the relationships of feed digestibility and volatile fatty acids with bacterial community at genus level (average percent > 0.5%). No rank means there is no specific taxonomic information at the genus level. Only Spearman’s significance levels p < 0.05 are shown, yellow and blue indicate negative and positive correction respectively. OM organic matter; NDF neutral detergent fiber. Significance was tested using independent two-group Wilcoxon rank-sum tests. Data with error bars are expressed as mean ± standard error. **p < 0.01, ***p < 0.001, n = 12/group.