Abstract

The composition of muscle fiber types and the development of skeletal muscle are critical determinants of cultured meat quality. L-carnosine, a dipeptide abundant in ruminant muscle, is known to influence meat quality, yet its regulatory mechanisms in bovine skeletal muscle satellite cells (BSCs) for cultured meat production remain unclear. This study aimed to elucidate the effects of L-carnosine on the proliferation, differentiation, and muscle fiber type transformation of Yanbian cattle BSCs. We identified 10 mM as the optimal concentration for enhancing cell proliferation ( p < 0.05), a key finding established by screening L-carnosine treatments from 0 to 40 mm. This enhancement was mediated by the upregulation of cell cycle genes (Pax7, Ki67, CDK1, CDK2, PCNA) and the suppression of inhibitors ( p21, p53, p16 ). Furthermore, L-carnosine robustly promoted myotube formation and specifically upregulated fast-twitch muscle fiber markers (MyHC2a, MyHC2b, MyHC2x) while downregulating the slow-twitch marker MyHC1 ( p < 0.05). Transcriptomic analysis identified 449 differentially expressed genes, which were significantly enriched in the PI3K-Akt signaling pathway. Western blotting confirmed that L-carnosine activates the Akt/mTOR/P70S6K signaling pathway to drive myogenesis. Additionally, L-carnosine demonstrated significant antioxidant capacity by reducing reactive oxygen species (ROS) and lipid peroxidation (MDA) while enhancing antioxidant enzyme activities (SOD and GSH-Px). In conclusion, this study provides the first evidence that L-carnosine promotes BSC proliferation and fast-twitch fiber differentiation via the Akt/mTOR/P70S6K pathway, suggesting its potential as a highly effective, natural additive for cultured meat production.