Microbiomics and metabolomics reveal microbial–metabolic signatures associated with body weight variation in chickens

Body weight is a complex quantitative trait regulated by the combined effects of polygenic inheritance and environmental factors. Among non-genetic determinants, the gut microbiota and its associated metabolic processes play critical roles in influencing growth performance in poultry. However, the microbiota-metabolite associations underlying growth-related phenotypes in chickens with divergent body weights remain insufficiently characterized. In this study, we integrated 16S rRNA gene sequencing with untargeted serum metabolomics to systematically characterize the cecal microbial communities and host metabolic profiles associated with body weight variation in hybrid chickens. Our results showed that significant divergence in body weight between groups emerged from 8 weeks of age onward. The high-body-weight group was significantly enriched in potentially functional taxa, including Lactobacillus, Subdoligranulum, Megasphaera, Negativibacillus, and Sutterella. Metabolomic analysis identified 60 differentially abundant metabolites. The high-body-weight group was characterized by upregulation of glycerophospholipid metabolites and enrichment of lipid metabolism pathways, whereas the low-body-weight group exhibited enrichment primarily in amino acid and pyrimidine metabolism pathways. Correlation analysis revealed that taxa enriched in the high-body-weight group were positively associated with lipid-related metabolites, whereas characteristic taxa of the low-body-weight group, such as Colidextribacter and Pseudoflavonifractor, were positively correlated with specific amino acid-related metabolites. Collectively, these findings provide novel multi-omics evidence of microbiota-metabolite associations underlying growth traits in poultry and offer potential insights into the development of microbiota-based strategies to improve production performance.