Transcriptional Knock-down of mstn Encoding Myostatin Improves Muscle Quality of Nile Tilapia (Oreochromis niloticus)

Abstract

Myostatin (encoded by mstn) negatively regulates skeletal muscle mass and affects lipid metabolism. To explore the regulatory effects of mstn on muscle development and lipid metabolism in Nile tilapia (Oreochromis niloticus), we used antisense RNA to transcriptionally knock-down mstn. At 180 days, the body weight and body length were significantly higher in the mstn-knock-down group than in the control group (p < 0.05). Additionally, fish with mstn-knock-down exhibited myofiber hyperplasia but not hypertrophy. Oil red O staining revealed a remarkable increase in the area of lipid droplets in muscle in the mstn-knockdown group (p < 0.05). Nutrient composition analyses of muscle tissue showed that the crude fat content was significantly increased in the mstn-knock-down group (p < 0.05). The contents of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids were all significantly increased in the mstn-knock-down group (p < 0.05). Comparative transcriptome analyses revealed 2420 significant differentially expressed genes between the mstn-knock-down group and the control group. KEGG analysis indicates that disruptions to fatty acid degradation, glycerolipid metabolism, and the PPAR signaling pathway affect muscle development and lipid metabolism in mstn-knock-down Nile tilapia: acaa2, eci1, and lepr were remarkably up-regulated, and acadvl, lpl, foxo3, myod1, myog, and myf5 were significantly down-regulated (p < 0.05). These results show that knock-down of mstn results in abnormal lipid metabolism, acceleration of skeletal muscle development, and increased adipogenesis and weight gain in Nile tilapia.

Alterations in the fillet quality of myostatin-knockout red sea bream Pagrus major: Preliminary insights into nutritional, compositional, and textural properties

“…Furthermore, it has been demonstrated that the mstn mutations caused a decreased lipid mass in mammals such as mice, cattle, and sheep [ 25 , 26 ]. In contrast, gene disruption or knockdown of mstn induced an increase in lipid content of skeletal muscle in some fish species, such as zebrafish ( Danio rerio ), loach ( Misgurnus anguillicaudatus ), and Nile tilapia [ [27] , [28] , [29] ]. MSTN plays two distinct roles: promoting adipogenesis [ 30 ] and inhibiting adipogenesis [ 31 ], however, its specific function in adipogenesis is currently controversial.…”