Ruminal microbiota determined the high fibre utilization of ruminants: evidance from the ruminal microbiota transplant

The rumen, which contains a series of prokaryotes and eukaryotes with high abundance, determined the high ability to degrade complex carbohydrates in ruminants. Using 16S rRNA gene sequencing, we compared the ruminal microbiota of dairy goats with the microbiota in the foregut and colon of mice, and found more Bacteroides identified in rumen, which help ruminants to utilize plant-derived polysaccharides, cellulose and other structural carbohydrates. Furthermore, high-fibre diets have not significantly increased intestinal fibre-degrading bacteria of mice, but increased rumianl fibre-degrading bacteria in dairy goats. Through ruminal microbiota transplant (RMT), we found that rumen-derived fibre-degrading bacteria can be colonized in the intestines of mice to exert its fibre-degrading function, but its colonization efficiency was affected by diet. Additionally, the colonization of these fibre-degrading bacteria in the colon may invovled in increased content of butyrate in the colon, protected colonic epithelial barrier, promoted energy metabolism. Overall, the fibre degradation function of rumen bacteria through RMT were verified, and our results provided new insights to isolate the functional and beneficial fibre-degrading bacteria in the rumen, and also provided a theoretical basis about the role of dietary fibre in intestinal health.