Effect of skeletal muscle fibers on porcine meat quality at different stages of growth.

In this study, we examined changes in meat quality and content of muscle types during porcine growth. The influence of the longissimus dorsi muscle fiber composition on meat quality and the correlation between 2 fiber-typing methods (histochemistry and real-time quantitative polymerase chain reaction) were examined. Type IIx and type IIb fibers accounted for most of the total number of fibers; the proportion of these fibers increased during porcine growth (75.42, 80.09, and 79.88%, respectively, at 3 different stages of growth). There was a strong positive correlation between the 2 fiber-typing methods; the correlation coefficients of type I, IIa, and IIx+IIb fiber contents were 0.65, 0.88, and 0.92, respectively. The a* value of meat color was significantly lower at 98 days and negatively correlated with white fiber content (r = -0.69, P < 0.01). Water-holding capacity decreased during porcine growth. The drip loss parameter was positively correlated with type IIx+IIb fiber content (r = 0.55, P < 0.05). Decreased pH was strongly positively correlated with type IIx+IIb fiber content (r = 0.61, P < 0.01) and negatively correlated with type IIa fiber content (r = -0.44, P < 0.05). Therefore, we found that the composition of muscle fibers influenced the establishment of meat quality and its alteration during the early postmortem period.