The effects of fish-based and milk-based diets on liver tissue antioxidant enzymes and lipid peroxidation in female Wistar rats: A pilot study

Abstract

Background/Aim. Recently, there has been an increased interest in novel dietary antioxidants, including omega-3 fatty acids and bioactive proteins present in milk. The aim of this study was to examine potential antioxidant effects of four-weeks long fish-based and milk-based diets in female Wistar rats. Methods. Four-months old rats were divided into three groups receiving either: control diet, diet enriched with fish meal, or diet enriched with milk. The activities of antioxidant enzymes: glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT), and concentration of thiobarbituric acid reactive substances (TBARS) were determined in liver homogenates obtained at the end of the treatment period. Results. Statistically significant higher activities of GPx (3.52 ? 0.73 U/mg) and CAT (147.25 ? 15.93 U/mg) were detected in rats fed with fishbased meal in comparison with both the control (GPx: 1.93 ? 0.11 U/mg; CAT: 99.37 ? 10.03 U/mg) and the group fed with milk-based diet (GPx: 1.72 ? 0.52 U/mg; CAT: 104.18 ? 37.49 U/mg). Despite somewhat lower concentration of TBARS in the milk-treated group (0.88 ? 0.23 nmoL/mg), no significant differences were detected in comparison with other groups (the control group: 1.00 ? 0.08 nmoL/mg; the fish-based diet group: 1.13 ? 0.15 nmoL/mg). Conclusion. Diet enriched with fish could improve one?s oxidative status by enhancing activities of antioxidant enzymes in the liver tissue. On the contrary, we failed to obtain results suggesting that milk could serve as a source of dietary antioxidants.