Integrated transcriptomic and metabolomic profiling reveals sex-specific regulation of breast muscle development during sexual maturation in Huanglang chicken

To better understand the regulatory mechanisms of breast muscle growth in small-sized local breeds, this study aimed to investigate metabolic and transcriptional networks during the initiation of sexual maturation in Huanglang chickens. We hypothesized that sex-specific metabolic and gene expression patterns regulate muscle growth and fat deposition in these chickens. To test this hypothesis, multi-omics approaches were used to analyze chickens at 80 and 120 days post-hatch (dph). Both male and female chickens showed a significant increase in intramuscular fat (IMF) at 120 dph, but with sex-specific changes: females exhibited a significantly higher liver index, while males had a significantly greater breast muscle index. We identified 2627 differentially expressed genes (DEGs) in males and 2991 in females, along with 473 and 232 differentially abundant metabolites (DAMs), respectively. The sex-shared ABC transporter pathway supports muscle growth via substrate transport, while the Steroid biosynthesis pathway is female-specific, and the Glycerophospholipid metabolism pathway is male-specific. These results demonstrate that sex-specific regulatory networks shape muscle growth and fat deposition during early sexual maturation, and they provide potential molecular targets for improving intramuscular fat content and meat quality in local chicken breeding programs.