Stearoyl-CoA Desaturase Activity in Adipose Tissues and Liver of Growing Large White and Meishan Pigs

Abstract

Stearoyl-CoA desaturase activity was measured in adipose tissue (backfat and neckfat) and liver microsomes of Large White and Meishan pigs. Preliminary assays have shown that Δ9-desaturase activity cannot be measured on frozen tissues, because freezing involves a loss in activity of 40–50%. The specific activity of liver Δ9-desaturase was much lower than that of the adipose tissues in both breeds, indicating that the liver is not a major site of oleate synthesis in the pig. The hepatic Δ9-desaturase activity was higher in Meishan than in Large White pigs. However, Δ9-desaturase activity in the adipose tissue of Large White pigs was much higher than that of Meishan pigs, even though the percentage of oleate was slightly higher in the adipose tissues of the latter. This investigation has demonstrated that differences in fatty acid composition of adipose tissues between Large White and Meishan pigs cannot be attributed to differences in Δ9-desaturase activity at this stage of maturity. These results suggest that the higher oleate percentage in Meishan adipose tissues would result from a higher Δ9-desaturase activity at an earlier age.