Gene expression of calpain 3 and PGC-1 α is correlated with meat tenderness in the longissimus dorsi muscle of Sutai pigs

To investigate the effects of skeletal muscle characteristics on meat tenderness, meat quality of a total of 100 Sutai pigs was evaluated in the present study. Myofibre composition in longissimus dorsi (LD) was investigated by determining the ratios of mRNA abundance of four myosin heavy chain (MyHC) isoforms (MyHC I, IIa, IIx and IIb) to detect the influence of myofibre type on meat tenderness. The expression of candidate genes was analysed to elucidate their possible relationship with meat tenderness. The results showed that under the same tenderization condition in the same breed of pigs, meat tenderness demonstrated the largest amount of variation compared with other meat traits. The proportion of MyHC I fibres was significantly higher in the lowest shear force group, whereas the proportions of MyHC IIa, IIb, IIx fibres did not differ significantly between the two extreme meat tenderness groups. The mRNA expression of myostatin, myogenin, myoD and growth hormone receptor (GHR) genes also did not significantly differ between the two tenderness groups. However, the mRNA expression of calpain 3 and peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1 alpha) changed with the shear force, showing a negative correlation with the shear force (r= -0.38 and -0.65, respectively, P < 0.05). Our results showed that the increased percentage of myofibre type I and high expression of calpain 3 and PGC-1 alpha are positively related to meat tenderness. The results provide useful data for meat tenderness selection in pig breeding. (C) 2012 Elsevier B.V. All rights reserved.