RESUMO
Oxidative stress is defined as an imbalance between reactive oxygen species (ROS) production and antioxidant defense mechanisms of the body. An overproduction of ROS leads to lipid and protein oxidation, injuring the cells both in normal and pathological conditions. Rice bran protein hydrolysates (RBH) has potent antioxidant, anti-inflammatory, anti-angiotensin converting enzyme (ACE) and hypolipidemic effects. Little is known, however, about the effects of RBH in dogs. The present study evaluated the antioxidative, anti-ACE and metabolic effects of RBH in adult dogs. Eighteen adult dogs were divided into 2 groups: control (n=7) and RBH supplemented groups (n=11), received a diet with the same nutritional compositions. The RBH supplemented group was fed with RBH 500 mg/kg body weight (BW) mixed with food for 30 days. BW, blood glucose, lipid profiles, liver enzymes, electrocardiography (ECG), plasma ACE activity, oxidative stress and antioxidant biomarkers were determined on day 0 and day 30 of supplementation periods. Results showed that RBH decreased oxidative stress and increased antioxidant biomarkers by significantly reducing plasma malondialdehyde (MDA) and protein carbonyl, enhanced blood glutathione (GSH) and improved the GSH redox ratio. Moreover, decreased LDL-C and increased HDL-C levels were found after RBH supplementation whereas BW, blood glucose, liver enzymes, plasma ACE activity, plasma catalase (CAT) and superoxide dismutase (SOD) activity and cardiac function were not significantly changed. These results suggest that RBH may help to lower the risk of oxidative stress and dyslipidemia in adult dogs.