Abstract: As a member of the transforming growth factor-β (TGF-β) superfamily, myostatin (MSTN) plays a critical role in regulating skeletal muscle development and lipid deposition. Due to the rapid advancement of gene editing technology and the need for high production performance in practical applications, a growing number of studies have carried out MSTN knockout in different pig breeds. This review summarized the important function of MSTN in breeding and systematically analyzed the phenotypic outcomes of MSTN-knockout pigs, including muscle development, carcass traits, fat deposition, and meat quality. Overall, MSTN-knockout pigs generally exhibit higher lean meat yield, lower fat content, improved tenderness, and enhanced nutritional profiles—particularly in terms of polyunsaturated fatty acids and amino acids. At the molecular level, MSTN knockout activates the PI3K/AKT/mTOR pathway to promote protein synthesis and modulates lipid metabolism via the ERK1/2 signaling pathway, thereby significantly improving meat quality and metabolic characteristics. In conclusion, obtaining a deeper understanding of the role and mechanisms of MSTN is crucial for animal breeding and provides promising strategies to enhance meat production in livestock.

Key words: pig, MSTN, gene knockout, meat quality, fat deposition, molecular regulatory