Gut Microbiota of Gray Snub-Nosed Monkeys: Adaptation to Seasonal Variations Through Energy Compensation and...

As an extremely endangered species, the gray snub-nosed monkey (Rhinopithecus brelichi) relies on its gut microbiota for adaptation to environmental changes, particularly in coping with fluctuations in energy and nutrient availability. In this study, we employed metagenomic, metatranscriptomic, and widely targeted metabolomic analyses to characterize the gut microbiota of gray snub-nosed monkeys. Based on metagenome-assembled genomes (MAGs), we recovered 1229 non-redundant MAGs. Among them, a total of 103 MAGs exhibited significant seasonal variation, primarily belonging to the phyla Bacillota_A, Bacteroidota, and Bacillota_I. During winter, metagenomic results indicated that the gut microbiota exhibited an enhanced capacity to produce energy substrates such as amino acids, short-chain fatty acids, pyruvate, and acetyl-CoA, with increased conversion of these substrates. Metatranscriptomic analysis further confirmed that key carbon cycle-related genes and metabolic pathways were significantly upregulated in winter. Additionally, metabolite analysis indicated significantly lower levels of amino acids in winter fecal samples, suggesting that gray snub-nosed monkeys efficiently absorb and utilize metabolites, with the gut microbiota likely contributing to energy compensation. Notably, the gut microbiota may also synergistically support the host's non-shivering thermogenesis, helping maintain physiological functions in extreme cold conditions. This study elucidates the cooperative role of the gut microbiota in helping gray snub-nosed monkeys adapt to seasonal environmental fluctuations, providing new insights into how gut microbiota optimize winter energy utilization-an understanding with important implications for the conservation of endangered wildlife.