[Comparative study on lipogenic and lipolytic gene expression in intramuscular fat tissue between growing Erhualian...

To investigate the mechanism of difference in intramuscular fat deposition between Erhualian and Large White pigs,single tube relative-quantitative RT-PCR method was used to investigate the development patterns of lipogenic (ACX, LPL, ME) and lipolytic (HSL) gene expression with 18S internal standard control. Sixteen Large White boars and twenty Erhualian boars were selected and raised according to normal nutrition standard respectively. The animals were selected randomly and slaughtered at 15 kg, 40 kg, 60 kg and 90 kg for Large White pigs and at 18 kg, 40 kg, 60 kg, 80 kg and 90 kg for Erhualian pigs respectively; with four animals of each breed at each time. The supraspinatus and semimembranosus muscles were removed for total RNA extraction and longisimus dorsi muscle for intramuscular fat (IMF) analysis using ether extract method. The results showed: (1) The property of IMF between Erhualian and Large White boars was similar during early growing period (before 40 kg) (P > 0.05) ,thereafter, IMF level of Erhualian boars increased dramatically to 4% at 60 kg and over 5% at 90 kg while Large White boars kept steadily at about 2% (P < 0.05); (2) The pattern of lipogenic and lypolytic gene expression was similar between semimembranosus and supraspinatus muscle in each breed; (3) The tendency for LPL and ME mRNA expression coincided with that of IMF development among 20 approximately 60 kg in Erhualian pigs. The results suggest that the development of IMF between 20 kg and 60 kg in Erhualian pigs may play a meaningful role in deposition of IMF,and that the expression of ME and LPL mRNA may contribute to fast sediment of IMF in Erhualian pigs.