Correlation between Meat Quality and Muscle Fiber Types of Tibetan and Large White Pigs

This research was designed to explore the differences of meat quality and their causes of pigs in different regions. In this study, natural raised Tibetan pigs in different regions (Linzhi of Tibet, Gannan of Gansu, and Aba of Sichuan) and large white pigs were selected, the meat quality of their longissimus muscle (pH, color, cooking loss, shear force), myoglobin concentration, hydroxyproline content, relative expression of different Myosin Heavy Chain (MyHC) mRNA were determined, and correlation analysis were adopted. The results showed that the pH_{3 h} of Tibetan pigs was significantly lower than that of large white pigs 6.0 (P<0.05), and there was no significant difference among different regions (5.7~5.8). The redness value (a^*) and myoglobin content of Tibetan pigs were significantly higher than those of large white pigs (2.12±0.87, 0.004 μmol/g). Among them, Aba Tibetan pigs had the highest a^* (8.10±0.99). The shear force and hydroxyproline content of Tibetan pigs were significantly higher than those of large white pigs (41.81±0.83, 5.92%±0.52%) (P<0.05), the proportion of type IIa muscle fibers in Tibetan pigs was significantly higher and the proportion of type IIb muscle fibers was significantly lower than their of large white pigs (P<0.05). Correlation analysis showed that a^* was significantly negatively correlated with L^* and type IIb muscle fibers (P<0.01), and significantly positively correlated with myoglobin content, type I and type IIa muscle fibers (P<0.01). Shear force and hydroxyproline content were extremely significantly correlated (P<0.01). In conclusion, the color of Tibetan pig is redder and the tenderness was worse than that of large white pig, the great differences between Tibetan pigs and large white pigs and the differences among Tibetan pigs from different regions in meat quality would be highly related to their muscle fiber type.