Effect of myosin heavy chain composition of muscles on meat quality in Laiwu pigs and Duroc

In order to explain the mechanism of high meat quality in Laiwu pigs and investigate the relation between myosin heavy chains (MyHC) composition and meat quality, meat quality analysis was conducted and mRNA expression of MyHC I, IIa, IIx, IIb was quantified by real-time fluorescence PCR in longissimus muscle (LM) and semimembranous muscle of Laiwu pigs and Duroc. The result indicated that, compared with Duroc, mRNA expression of MyHC IIa, IIx in LM and semimembranous muscle of Laiwu pigs was significantly increased, mRNA expression of MyHC IIb was dramatically decreased. However, the expression of MyHC I was not significantly affected by breeds. The correlation between mRNA expression of MyHC I, IIa, IIx in LM and meat color, pH value, marbling, intramuscular fat content was positive, but shear value of LM was negative. The relation between MyHC IIb mRNA expression and marbling, intramuscular fat content was dramatically negative, whereas shear value was strikingly positive, as well as fiber diameter, but without reaching statistical significance. Therefore, the composition of MyHC I, IIa, IIx, IIb affected meat quality, furthermore, expression of MyHC I, IIa, IIx, IIb mRNA prominently influenced meat characteristics, especially edible quality of muscle, suggesting that mRNA expression level of MyHC I, IIa, IIx, IIb can exactly and impersonally estimate meat quality.