Integrated multi-omics implicates the gut microbiota and bilirubin in abdominal fat deposition in Huainan yellow chickens

The Huainan yellow chicken is prized for its meat quality, but excessive abdominal fat deposition hampers its production efficiency. To investigate the underlying mechanisms, we compared high-fat deposition (HFD) and low-fat deposition (LFD) chickens using lipid metabolomics and 16S rRNA sequencing. The HFD group exhibited significantly higher carcass weight and abdominal fat index. Concordantly, serum levels of total bilirubin, triglycerides, cholesterol, glucose, and very-low-density lipoprotein were elevated, alongside upregulated expression of hepatic lipogenic genes (FASN, PPARγ, and PPARα). Liver lipidomics identified 144 significantly altered metabolites. Ileal microbiota analysis revealed a substantial enrichment of Lactobacillus and reductions in Escherichia-Shigella and Candidatus_Arthromitus in HFD chickens. The integrated analysis revealed strong correlations between microbial abundance and lipid metabolites, suggesting that gut microbes, especially Lactobacillus, may influence bilirubin metabolism and enterohepatic circulation. Collectively, our findings implicate a synergistic interaction where the gut microbiota (especially Lactobacillus) may modulate bilirubin enterohepatic circulation and hepatic lipogenesis, regulating abdominal fat deposition in Huainan yellow chickens, providing a novel theoretical basis for modulating fat accumulation in poultry through microbial strategies.