Integrated transcriptomic and proteomic analyses reveal muscle fiber-type transformation in meat rabbits

Skeletal muscle fiber composition plays a critical role in determining muscle growth and meat quality in livestock species. However, the molecular mechanisms underlying muscle fiber-type transformation in meat rabbits remain poorly understood.

Here, we integrated transcriptomic and label-free proteomic analyses to investigate skeletal muscle development in Ira rabbits at three developmental stages (D0, D35, and D70). Immunofluorescence staining revealed a gradual increase in slow-twitch muscle fibers in the gastrocnemius during postnatal growth. Enzyme activity assays showed decreased lactate dehydrogenase (LDH) activity and increased succinate dehydrogenase (SDH) activity, indicating a metabolic shift toward oxidative metabolism. Transcriptomic analysis identified thousands of differentially expressed genes across developmental stages, whereas proteomic profiling revealed numerous differentially expressed proteins associated with metabolic pathways. We identified ten candidate genes (NOS1, CASQ2, ANKRD1, ANKRD2, CXCL10, GPC3, NEDD4, MYORG, MYLK2, EZH2) and nine key proteins (TRAF3IP3, APBB2, PGK1, TMCO5A, PKM, PVALB, PDLIM7, PHKG1, PHKA1) that may be associated with muscle fiber-type transformation during postnatal skeletal muscle development. Functional enrichment analysis indicated that these molecules were associated with multiple metabolic pathways including glycolysis/gluconeogenesis and butanoate metabolism.

These findings provide a multi-omics perspective on skeletal muscle development in rabbits and contribute to a better understanding of the molecular basis of muscle fiber-type transformation during postnatal growth.