Comparative Analysis of Gut Metabolites in Meles leucurus Across Different Seasons

Seasonal changes in ambient temperature and food supply constantly challenge the nutritional homeostasis of wild mammals. Intestinal metabolites bridge host physiology, gut microbiota and external environments, and help uncover wildlife adaptive mechanisms. As an omnivorous burrowing hibernator, Meles leucurus shows obvious seasonal variation in feeding and body weight. Here, 24 fecal samples (8 per season) were collected from wild badgers at Culai Mountain (Shandong) in spring, summer and autumn. Untargeted metabolomics based on liquid chromatography-mass spectrometry (LC-MS) was combined with multivariate statistical models including principal component analysis (PCA), partial least-squares discriminant analysis (PLS-DA), and KEGG pathway functional annotation to systematically investigate gut metabolite composition, seasonal variations, and core regulatory pathways across the three seasons. Lipids and lipid-like molecules dominated the fecal metabolome. Summer metabolic profiles were clearly separated from the more similar spring and autumn profiles. Spring samples were enriched in putative tissue repair-related metabolites; summer samples accumulated fatty acyls and plant secondary metabolites; autumn samples were marked by antioxidant and energy-storage markers. Core pathways including α-linolenic acid, linoleic acid, riboflavin and tryptophan metabolism mediated seasonal physiological adjustment. This study reveals gut metabolic remodeling for seasonal adaptation and provides molecular evidence for mustelid conservation research. As no independent functional validation was performed, the proposed functional interpretations of the differential metabolites remain tentative hypotheses to be tested through targeted metabolomics and multi-omics integration.