Integrated transcriptomic and WGCNA analyses identify RBP7 as a regulator of skeletal muscle development in chickens.

Skeletal muscle development determines meat yield and quality in chickens. We performed transcriptomic profiling of breast muscles from fast-growing Arbor Acres (AA) and slow-growing Lushi blue-shelled-egg (LS) chicken - an indigenous dual-purpose type breed - at 1, 3, and 5 weeks. A total of 1727 differentially expressed genes (DEGs) were identified. Functional enrichment indicated that AA-specific DEGs were enriched in MAPK signaling, whereas LS-specific DEGs were associated with Hedgehog signaling and branched-chain amino acid degradation. Weighted gene co-expression network analysis identified nine modules, with the turquoise module showing the strongest correlations with growth and muscle traits. RBP7 was identified as a hub gene, highly expressed in AA chickens, and positively associated with these phenotypes. Functional assays showed that RBP7 promoted chicken primary myoblasts proliferation and viability without significantly altering their myogenic differentiation under our standard in-vitro conditions, pointing to RBP7 as a candidate regulator of chicken skeletal muscle development.