Figure 6. (A) Relative abundance of dominant bacteria family of the total number of ASVs in muskox adults and calves. Bar plot showed the relative abundance of adults (n=6) and calves (n=4), t-tests; Asterisks indicate the significance of the statistical test of differences between adults and calves (Asterisks * means p < 0.05, ** means p < 0.01, *** means p < 0.001; Ruminococcaceae, p = 0.0004; Lachnospiraceae, p = 0.0012; Christensenellaceae, p = 0.070; Mogibacterium_f, p = 0.009; Akkermansiaceae, p = 0.270). Points show the relative abundance of adults (n=4) and calves (n=4) with paired samples. (B) Distribution of bacterial families across all fecal samples from muskox individuals.
At the phylum level, the muskox gut microbiome was dominated by Firmicutes (on average 94.36%, 94.03%) and Verrucomicrobia (1.77%, 3.31%) respectively in both adults and calves. These two phyla accounted for 91.16% of the total sequences from all the samples. At the family level, we found that five families were dominant: Ruminococcaceae (73.90%, 56.25%), Lachnospiraceae (8.27%, 24.00%), Christensenellaceae (8.28%, 5.76%), Mogibacterium_f (0.65%, 2.86%), and Akkermansiaceae (1.72%, 3.30%) (Figure 6AB). Three microbial families were significantly different in their relative abundances between muskox adults and calves (Ruminococcaceae, p = 0.0004; Lachnospiraceae, p = 0.001; Mogibacterium_f, p = 0.009; t-tests; Figure 6A). Although the four pairs of adult and calves did not show significances (paired t-tests; indicated by colored lines in Figure 6A), Ruminococcaceae and Christensenellaceae showed consistent increases and Lachnospiraceae, Mogibacterium_f and Akkermansiaceae showed consistent decreases in all pairs.