Fig. 1

Non-metric multidimensional scaling (NMDS) ordination plot of microbial community composition in gastrointestinal samples from feedlot steers based on generalized UniFrac distances of 16S rRNA amplicon sequence variants (ASVs). Both luminal and epithelial surface samples are represented from 4 different gastrointestinal tract (GIT) sites: rumen (RU), small intestine (SI), large intestine (LI), feces (F), and from liver abscesses (LA). Ellipses represent the 95% confidence intervals for the group mean values. (A) Ordination of samples colored by individual animal ID (n = 21), showing that microbial communities do not cluster separately by animal. (B) Ordination of samples colored by GIT region and sample type. Clustering by GIT region was statistically significant (PERMANOVA, P < 0.001), with GIT locations showing site-specific microbial community structures and LA samples forming a distinct cluster. RU LC = rumen luminal fluid, RU ES = rumen epithelial surface, SI LC = small intestine luminal fluid, SI ES = small intestine epithelial surface, LI LC = large intestine luminal fluid, LI EC = large intestine epithelial surface.