Multi-omics Insights into Postnatal Skeletal Muscle Development in Duroc Pigs

Skeletal muscles, accounting for 40% of mammalian body mass, exhibit pronounced heterogeneity due to distinct anatomical locations. Animal husbandry excessively focuses on longissimus dorsi (LDM) development, while neglecting other muscles. In this study, we integrated Bulk RNA Sequencing (bulk RNA-seq) and Liquid Chromatography-Mass Spectrometery (LC-MS) analyses of Soleus (SOL), Gastrocnemius (GAS), and Psoas major (PMM) across three key stages in Duroc pigs. As a result, we identified 9 critical genes (S100A1, MBOAT2, CA3, GYG2, ACTN3, ENO3, SLC3A2, SLC16A10, and GAPDH) and 8 metabolites potentially involved in regulating both skeletal muscle development and fiber-type transformation. The heterogeneity between SOL and GAS was low at birth but increased gradually during development. In contrast, PMM exhibited high heterogeneity compared to SOL and GAS from birth. Notably, expression levels of MYH7, MYH1, and MYH4 displayed stage-specific and muscle type-dependent variations. Moreover, we observed a developmental shift from the MAPK signaling pathway (1-21 d) to the regulation of actin cytoskeleton (21-120 d). Pairwise comparisons between SOL, GAS, and PMM revealed signaling pathways enriched in muscle fiber-type switching. Collectively, through the integration of bulk RNA-seq and LC-MS data, this study provides novel molecular breeding strategies for genetic improvement in meat-producing animals.