Dietary energy level modulates cecal microbiota to influence amino acid composition of local chicken meat

This study comprehensively investigated the effects of different dietary energy levels-low energy (LE, 10.62 MJ/kg), medium energy (ME, 11.87 MJ/kg), and high energy (HE, 13.06 MJ/kg)-on growth performance, meat quality, muscle metabolite profiles, and cecal microbiota in a local Chinese chicken breed (Guangyuan gray chicken). Growth and carcass traits, including interpubic width and liver weight, responded positively to increasing dietary energy. Compared to the ME control, the HE diet significantly increased drip loss, whereas the LE diet reduced both intramuscular fat and protein content (<i>P</i> <0.05). Untargeted metabolomic analysis identified 188 differentially abundant muscle metabolites across the dietary groups, revealing distinct metabolic profiles. The biosynthesis of the amino acids pathway was significantly affected by different dietary energy levels. Targeted metabolomics further demonstrated the differences in muscle amino acid composition: essential, sweet-taste, and umami-taste amino acids increased progressively with dietary energy, with the HE group achieving the most favorable profile for flavor and nutrition. Cecal microbiota analysis indicated that dietary energy levels significantly altered microbial community structure. Specific bacterial taxa, including <i>Spirochaetota</i> and <i>Bacteroides</i>, were positively correlated with muscle amino acid concentrations. Our findings demonstrate that dietary energy level modulated the cecal microbiota, which in turn influenced muscle amino acid deposition and overall meat quality. This study provides a comparative multi-omics perspective for optimizing dietary energy strategies in local chicken production to meet varying market demands for meat quality and nutritional value.IMPORTANCEThis comparative study established a crucial link between dietary energy intake and the final quality of poultry meat through a multi-omics lens. We demonstrate that low, medium, and high dietary energy levels elicit distinct phenotypic, metabolic, and microbial profiles in a local chicken breed. The findings provide a scientific framework for selecting dietary energy strategies tailored to specific market demands: HE for premium quality segments, LE for lean or cost-driven production, and ME for efficient conventional production. We identified specific correlations between the cecal bacteria (<i>Spirochaetota</i>, <i>Bacteroides</i>) and muscle metabolites (key amino acids). Thus, this work offered the scientific data to optimize meat quality through targeted feeding interventions.