Assessment of M. longissimus fibre types and metabolic enzymes in Bama miniature pigs and Landrace swine

Overt differences exist between Chinese local pigs and exotic pig breeds, especially in muscle growth rate and meat quality. However, the underlying molecular mechanisms remain unclear. This study aimed to assess muscle fibre types and metabolic enzymes in Bama miniature pigs and Landrace swine. Meat quality traits, including intramuscular fat content, and muscle colour, conductivity, and tenderness, were assessed in these pig breeds. Then, muscle fibre types were classified, and mRNA amounts and activities of lactate dehydrogenase (LDH), succinate dehydrogenase (SDH), and malate dehydrogenase (MDH) assessed, in M. longissimus from the two pig breeds, at various ages. Our data showed significantly higher back fat thickness, muscle conductivity, and intramuscular fat content in samples from Bama miniature pigs compared with the values obtained for Landrace pigs (p < .05). In addition, SDH activity was significantly higher, and LDH activity overtly lower in Bama pigs compared with Landrace swine (p < .05). Furthermore, myosin heavy-chain (MyHC) II A, II B, and II X mRNA levels in Bama miniature pigs at 180 were significantly higher than values obtained for Landrace pigs of the same age. Although MyHC I gene expression levels were similar in Bama miniature and Landrace pigs at 180 days of age, significantly higher amounts were obtained in 300 day old Bama miniature pigs compared with 180 day old Landrace pigs (p < .05). Collectively, these preliminary findings indicated that skeletal muscles from Bama miniature pigs may contain more oxidative fibres compared with those from Landrace pigs, which might explain the meat quality differences between the two pig breeds.