Seasonal Dynamics of Community and Function of Gut Microbiome in Taihangshan Macaque ( <i>Macaca mulatta tcheliensis</i> ): Inferred From Metagenomic Data

The gut microbiome is a key regulator of host nutritional intake, growth, and health, playing an essential role in mediating host adaptation to environmental changes. The northernmost population of rhesus macaque, Taihangshan macaque (Macaca mulatta tcheliensis), faces severe survival challenges, such as food shortages and harsh temperatures during winter and early spring. Previous studies have shown that they cope with seasonal changes through behavioral adaptations, such as adjusting food resources and flexibly regulating macronutrient intake. However, the role of the gut microbiome in supporting the seasonal adaptation of Taihangshan macaques remains unclear. Herein, we investigated seasonal variations in gut microbiome alpha diversity, composition, and functions from fecal samples of Taihangshan macaques using metagenomic analysis. The results showed that: (1) totally 435 non-redundant metagenome assembled genomes (MAGs) were generated; (2) alpha diversity was significantly higher in spring and winter than in summer and autumn; and (3) in winter, pathways of fatty acid biosynthesis and essential amino acid (EAA) biosynthesis, as well as CAZymes (GH3 and GH5) involved in cellulose and hemicellulose degradation, were significantly enriched. In contrast, pathways related to carbohydrate, energy, and glycan biosynthesis and metabolism, along with CAZymes (GT8 and GH23) potentially facilitating fat synthesis and storage, were enriched in summer. These functional adjustments likely help the host cope with seasonal variations in food availability and environmental conditions. Overall, this study provides new insights into how the gut microbiome responds to seasonal changes in diet and environmental factors in mammals inhabiting temperate forests.