ABSTRACT

Expression of lipid metabolism and myosin heavy chain genes was evaluated in skeletal muscle of pig’s genotypes submitted to different dietary digestible lysine contents. Fifty-two barrows and fifty gilts from three genotypes (G: Piau, Duroc and Pietrain crossbreds) were assigned to three dietary digestible lysine contents (DL: Low, Medium and High). Ten genes were evaluated, being six involved with lipid metabolism: Fatty acid synthase (FAS), Stearoyl-CoA desaturase (SCD), Protein kinase AMP-activated γ1 subunit (PRKAG1), Protein kinase AMP-activated γ3 subunit (PRKAG3), Hormone sensitive lipase (HSL), Heart fatty acid-binding protein (H-FABP), and four in Myosin heavy chain: MyHC I, MyHC IIa, MyHC IIb and MyHC IIx. There were no G × DL interactions. The expression levels for FAS, SCD, PRKAG1, HFABP, MyHC IIb and MyHC IIa were affected by G (P<0.05). A higher expression were observed for FAS in Pietrain barrows and gilts (P<0.05); for SCD in Duroc barrows, and in Duroc and Pietrain gilts (P<0.05); for PRKAG1 in Piau barrows and gilts (P<0.05); for H-FABP and MyHC IIb in Duroc and Pietrain barrows (P<0.05); and for MyHC IIa in Duroc and Pietrain gilts (P<0.05). The expression levels for MyHC IIb, PRKAG3 and MyHC IIa were affected by DL (P<0.05). A higher ex’pression were observed for MyHC IIb in barrows fed High and Medium DL, and in gilts fed High DL (P<0.05); for PRKAG3 in barrows fed Low DL (P<0.05); and for MyHC IIa in gilts fed High DL (P<0.05). Our results indicate that genotype and dietary lysine appear to affect the expression of lipid metabolism and myosin heavy chain genes of barrows and gilts in different ways.