Comparation of the muscle of the antioxidant defence enzymes in pigs and bulls

Abstract

Anti-oxidant defence (AD) system prevent oxidative cell damage through the coordinated expression of antioxidant defence enzymes. Main AD enzymes are: Mn SOD –mitochondrial manganese containing superoxide dismutase and CuZn-superoxide dismutase (SOD, EC 1.15.1.1), catalyses the dismutation of superoxide (O2.-) to hydrogen peroxide (H2O2) which is then independently converted to water by catalase (CAT, EC 1.11.1.6) or by selenium-dependent glutathione peroxidase (GSH-Px, EC 1.11.1.9) (Chance at al., 1979). Glutathione reductase (GR, EC 1.6.4.2) catalyses the reduction of oxidised GSH back into GSH, the latter being the co-substrate of GSH-Px (Gul et al., 2000). An imbalance between oxidative stress and the cell’s anti-oxidant defence system may have adverse effects on cell membranes through the indiscriminate oxidation of susceptible molecules such as polyunsaturated fatty acids (PUFAs), the main substrates for lipid peroxidation (Crastes de Paulet, 1987). Some investigators (de Haan et al., 1995; Percy et al., 1990) have suggested that the alteration in the SOD/GSHPx + CAT ratio correlate well with increases in lipid damage. Animals (pigs and bulls) have different lipid metabolism, different plasma lipid profiles and different erythrocyte anti-oxidant defence compositions, but have similar content of cholesterol in meat (Nikolić et al., 2006; Turubatović et al., 2006). Since mitochondrias are both the main source and the main target for ROS in skeletal muscle, the comparative study on specific mitochondrial antioxidative defence systems (e.g. mitochondrial superoxide dismutase) and citosolyc antioxidative defence enzymes in pigs and bulls is of particular interest. Therefore, the aim of the task was the comparative study on specific mitochondrial antioxidative defence systems (mitochondrial SOD) and citosolyc antioxidative defence enzymes (CAT, GSH-Px and GR) in the selected identical groups of beef and pork muscles ( thick flank, loin and neck).