This study investigated the role of lipogenic enzyme expression in breed-specific fat deposition in pigs. Objectives: (i) determine effect of breed on the relative abundance of the key lipogenic enzymes stearoyl-CoA desaturase (SCD), delta-6 desaturase (Δ6D), and fatty acid synthase (FAS) in pig subcutaneous adipose tissue. (ii) Investigate breed-specific relationships between lipogenic enzyme abundance and fatty acid composition. Large White × Piétrain, Piétrain, and Duroc × Piétrain pigs were used. Expression of SCD, Δ6D, and FAS was analyzed by Western blotting. Fatty acid composition was determined by gas chromatography. FAS protein in Large White × Piétrain pigs was similar to the Piétrain breed, but was significantly higher than Duroc × Piétrain. A positive relationship was found between FAS abundance and the saturated fatty acids (SFAs), for Large White × Piétrain pigs, but not for the other breeds. Δ6D was significantly higher in Large White × Piétrain compared with Duroc × Piétrain and Piétrain. This was accompanied by significantly higher total n−3 poly-unsaturated fatty acids (PUFAs) in the Large White × Piétrain when compared to the other breeds. Conclusions: (i) increased subcutaneous adipose tissue SFA content in Large White × Piétrain pigs (but not Piétrain and Duroc × Piétrain) is related to increased abundance of FAS protein; (ii) high n−3 PUFA content in Large White × Piétrain pigs is related to activation of Δ6D protein synthesis; (iii) SCD and Δ6D abundance does not contribute to between-breed differences in MUFA and n−6 PUFA content of pig subcutaneous adipose tissue.
This study reports new data on the abundance of enzymes responsible for fat synthesis and deposition in pigs. Better understanding of the reasons for differing quantity and composition of fat in pigs is important for the development of strategies for successful selective breeding toward a more desirable fatty acid composition of pork. This will improve its nutritional quality and healthiness for human consumption.