Functional differentiation related to decomposing complex carbohydrates of intestinal microbes between two wild zokor...

The intestinal microbes in mammals play a key role in host metabolism and adaptation. As a subterranean rodent, zokor digs tunnels for foraging and mating. These digging activities of zokors increase the energy expenditure relative to their aboveground counterparts. However, relatively little is known regarding intestinal microbes of zokor and how they make full use of limited food resources underground for high energy requirements.

Eospalax cansus and Eospalax rothschildi had distinct intestinal microbes. Although the composition of intestinal microbes is similar in two species, the proportion of bacterium are distinctly different between them. At phylum level, 11 phyla were shared between two species. Firmicutes and Bacteroidota were two dominant microbes in both of two species, while Eospalax cansus have a significantly high proportion of Firmicutes/Bacteroidota than that of Eospalax rothschildi. At genus level, norank_f_Muribaculaceae were dominant microbes in both of two zokor species. The relative abundance of 12 genera were significantly different between two species. Some bacterium including unclassified_f__Lachnospiraceae, Lachnospiraceae_NK4A136_group, Ruminococcus and Eubacterium_siraeum_group associated with cellulose degradation were significantly enriched in Eospalax cansus. Although alpha diversity was with no significant differences between Eospalax cansus and Eospalax rothschildi, the intestinal microbes between them are significant distinct in PCoA analysis. We have found that trapping location affected the alpha diversity values, while sex and body measurements had no effect on alpha diversity values. PICRUSt metagenome predictions revealed significant enrichment of microbial genes involved in carbohydrate metabolism in Eospalax cansus rather than Eospalax rothschildi.

Our results demonstrate that Eospalax cansus harbor a stronger ability of fermentation for dietary plants than Eospalax rothschildi. The stronger ability of fermentation and degradation of cellulose of intestinal microbes of Eospalax cansus may be a long-time adaptation to limited food resources underground.