Dietary drivers of gut microbiota diversity and function in wildlife of Wolong Nature Reserve: a metagenomic study

Abstract While diet is known to regulate the composition, function, and diversity of the human gut microbiome, its effects on wildlife remain understudied. Here, noninvasive sampling methods were first used to conduct metagenomic analyses of the gut microbiomes of 10 protected wild animals in the Wolong Nature Reserve. There were significant differences in microbiota composition and function between herbivores and carnivores. Herbivores exhibited higher microbial diversity and evenness (Shannon and Pielou indices), with Bacillota and Acinetobacter predominating, whereas carnivores were enriched in Pseudomonadota and Escherichia. Cellulose-degrading bacterium Ruminococcus champanellensis was abundant in herbivores, while Rhodococcus and Pediococcus, which were associated with toxin degradation and pathogen inhibition, were more prevalent in carnivores. Carnivores showed higher lipid metabolism and protein degradation, as evidenced by the enrichment of leucyl aminopeptidase and oligopeptidase B, while herbivores demonstrated superior cellulose and starch digestion, characterized by the enrichment of cellulose 1,4-beta-cellobiosidase. Stochastic processes shaped gut microbiome assembly, especially in herbivores. Potential health risks from pathogens such as Escherichia and Listeria were identified, and Escherichia abundance was positively correlated with niche width. Furthermore, the findings suggest that high-altitude environments may promote the persistence and spread of pathogens. Overall, our findings underscore the intricate linkages between diet, gut microbiota composition, assembly processes, and host ecology in protected wildlife, address a key knowledge gap, and provide important theoretical and practical insights for ecological conservation, species restoration, and environmental management.