The relationship between muscle fiber characteristics, postmortem metabolic rate, and meat quality of pig longissimus dorsi muscle.

The aim of this study was to investigate the histochemical parameters of muscle fibers, and to estimate the correlation of muscle fiber characteristic to postmortem metabolic rate and meat quality traits in pigs. A total of 231 crossbred pigs were evaluated. Samples of the longissimus dorsi muscle were taken to evaluate the histochemical characteristics, postmortem metabolic rate and meat quality. Fiber type composition was mainly related to postmortem metabolic rate and meat quality traits among various muscle fiber characteristics. The percentage of type IIb fiber was negatively related to pH(45min) (r=-0.33) and positively to R-value (r=0.32). Drip loss was negatively related to fiber area percentages of type I and IIa (r=-0.25 and -0.26, respectively) and positively related to type IIb percentage (r=0.39). A similar tendency was found between lightness and fiber area percentage. In conclusion, increasing the percentage of type IIb fiber is related to increasing the postmortem metabolic rate, and is related to the deterioration of meat quality.