Abstract: This experiment was conducted to study the development changes of fatty enzymatic hormone-sensitive lipase (HSL) and malate dehydrogenase (MDH) activities and their association with intramuscular fat in F1 hybrids with Mount Changbai Boar and Duroc pigs. To investigate the development changes of fatty enzymatic activities and their association with intramuscular fat and meat tenderness when the body weight got 20,35,50,70 and 90 kg levels F1 hybrids with boar and Laiwu pigs and white pigs of Landrace and Yorkshire (each 40 heads and male, female in the same evenly). The results indicated that with gaining of body weight, the activity of HSL and MDH were significantly different in muscle (P<0.05). The activity of HSL in F1 hybrids with Mount Changbai boar and Duroc pigs was significantly higher than Laiwu pigs at 35 kg (P<0.01); the activities of MDH in muscle in F1 hybrids was increased firstly and then decreased, and reached a peak at 70 kg of weight. The activity of MDH in F1 hybrids with Mount Changbai boar and Duroc pigs was significantly lower than Laiwu pigs at 90 kg (P<0.01). Correlation analysis showed that the activities of MDH in muscle were highly correlated to IMF content of F1 hybrids with Mount Changbai boar and Duroc pigs at 90 kg (r=0.97,P<0.01), the activities of HSL and MDH in muscle were highly correlated to the meat tenderness (P<0.01). The results suggested that the depositions of IMF could be improved by controlling the activity of fatty enzymatic HSL and MDH in muscle and there was some immanent contact between the depositions of IMF and the meat tenderness.

Key words: Mount Changbai boar×Duroc pigs; Laiwu pigs; HSL; MDH; intramuscular fat; meat tenderness