Diet-Driven Divergence in Gut Microbiota Variation Between Two Sympatric Gerbil Species

Gut microbiota provide various benefits to their mammalian hosts; however, knowledge regarding interspecific differences in gut microecology remains limited. This study employed 16S rRNA sequencing combined with metagenomic functional prediction (potential functions or functional potential) to conduct a comparative analysis of the gut microbial composition and functional adaptability of two sympatrically distributed gerbil species with distinct diets: the herbivorous Rhombomys opimus (RO) and the omnivorous Meriones meridianus (MM). The results revealed that the omnivorous MM exhibited a level of gut microbial alpha diversity comparable to that of the herbivorous RO, whereas RO showed significant enrichment of norank_f__Muribaculaceae, a taxon associated with fiber degradation, and demonstrated higher abundance of genes related to complex fiber degradation. Notably, bacterial genera significantly enriched in the gut of MM, such as Lachnospiraceae_NK4A136_group and Desulfovibrio, may play important roles in maintaining gut health and enhancing chitin degradation efficiency. Furthermore, the abundance of genes related to monosaccharide and chitin degradation was significantly higher in MM than in RO. Functional network analysis indicated that the cellulose degradation gene networks in both gerbil species were predominantly synergistic, but the synergistic effect was stronger in RO than in MM (ratios of positive to negative correlation edges: 2.44: 1.59). Further analysis revealed that the monosaccharide and chitin degradation gene networks in MM both exhibited synergistic interaction patterns (ratios of positive to negative correlation edges: 1.69 and 2.95, respectively), whereas these two networks in RO were primarily antagonistic (ratios of positive to negative correlation edges: 0.831 and 0.73, respectively). This suggests that the gut microbiota of RO are more conducive to digesting complex plant fibers, while those of MM are better adapted for digesting starch and chitin. This differentiation in gut microbiota optimizes the utilization of different food resources by the two species, thereby promoting their sympatric coexistence. This study enhances our understanding of the adaptive mechanisms of gut microecology in rodents with different diets and provides an important foundation for further research on the microbial ecology of wild rodents and the mechanisms underlying sympatric species coexistence.