The gut microecology of the two sympatric gerbil species varies with diet

The gut microbiota of mammals providesa range of benefits to their hosts; however, knowledge of interspecific differences in gut microecology remains limited. In this study, we employed 16S rRNA sequencing combined with metagenomic functional prediction to comparethe gut microbial composition and functional adaptability of two sympatrically distributed gerbil species with distinct diets—the herbivorous Rhombomys opimus ( RO) and the omnivorous Meriones meridianu s ( MM ). Our findings revealed that MM possessed greater microbial diversity, whereas RO exhibited a significant enrichment of norank_f__Muribaculaceae, a taxon associated with fibre degradation, along with a greaterabundance of genes involved in complex fibre breakdown. Notably, Lachnospiraceae_NK4A136_group and Desulfovibrio, which were markedly enriched in MM, may play pivotal roles in maintaining gut health and enhancing the efficiency of chitin degradation. Functional network analysis demonstrated that the cellulose-degrading gene networks in both gerbil species were predominantly synergistic; however, compared with RO, MM displayed significantly greater abundances of genes related to monosaccharide and chitin degradation. Further analysis indicated that the monosaccharide- and chitin-degrading gene networks of MM exhibited cooperative interaction patterns, whereas in RO, these networks were primarily antagonistic. This disparity reflects the heightened adaptability of MM to starch derived from plant seeds and chitin from insect exoskeletons, potentially linked to its omnivorous feeding habits and digestive constraints associated with smaller body size. Overall, this study advances our understanding of gut microecological adaptation mechanisms in rodents fed differentdiets and provides a valuable foundation for future research into the microbial ecology of wild rodents.