Expression of Lipid Metabolism and Myosin Heavy Chain Genes in Pigs is Affected by Genotype and Dietary Lysine

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.