Garrine CMLP^{1, 2,}, Fernandes TH³, Yoshikawa CYC¹, Correa LB¹, Bell V⁴, Netto AS¹, Zanetti MA¹

Two levels of copper sulphate and copper-methionine were evaluated on lipid oxidative stability in liver and Longissimus thoracis (LT) muscle, measured by thiobarbituric acid reactive substances (TBARS) and activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) in liver. 40 Merino x Texel lambs were randomly distributed into 5 treatments with 8 animals each. Treatments were: control, without copper addition; 10 or 30 mg of Cu/Kg DM complete diet in the form of Cu-sulphate or Cu-methionine. After 120 days period, animals were slaughtered and samples collected, for analyses on activities of SOD, GPx and TBARS in livers. LT muscle was collected for TBARS analysis at carcass dressing, 3 and 6 days after chilling at 4°C and 12 months after vacuum freezing. SOD and GPx activities were higher in animals receiving copper. TBARS values in muscle were higher in the control group at the time of boning but did not differ after 12 months of vacuum freezing. TBARS values in muscle during shelf life, with a linear increase over the days, did not vary. It was found that copper supplementation, even at considered toxic levels of 30mg/kg DM, plus 9mg/kg basal diet, resulted in increased hepatic concentration of liver antioxidant enzymes and showed no detrimental effects on muscle oxidative stability.

copper supplementation, fatty acids, lipid oxidation, lamb meat