Supplementation with rice bran hydrolysates reduces oxidative stress and improves lipid profiles in adult dogs.

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.

Protective effects of rice bran hydrolysates on heart rate variability, cardiac oxidative stress, and cardiac remodeling in high fat and high fructose diet-fed rats

Objective: To examine the ameliorative effect of rice bran hydrolysates (RBH) on metabolic disorders, cardiac oxidative stress, heart rate variability (HRV), and cardiac structural changes in high fat and high fructose (HFHF)-fed rats.Methods: Male Sprague-Dawley rats were daily fed either standard chow diet with tap water or an HFHF diet with 10％ fructose in drinking water over 16 weeks. RBH (500 and 1000 mg/kg/day) was orally administered to the HFHF-diet-fed rats during the last 6 weeks of the study period. At the end of the treatment, metabolic parameters, oxidative stress, HRV, and cardiac structural changes were examined. Results: RBH administration significantly ameliorated metabolic disorders by improving lipid profiles, insulin sensitivity, and hemodynamic parameters. Moreover, RBH restored HRV, as evidenced by decreasing the ratio of low-frequency to high-frequency power of HRV, a marker of autonomic imbalance. Cardiac oxidative stress was also mitigated after RBH supplementation by decreasing cardiac malondialdehyde and protein carbonyl, upregulating eNOS expression, and increasing catalase activity in the heart. Furthermore, RBH mitigated cardiac structural changes by reducing cardiac hypertrophy and myocardial fibrosis in HFHF-diet-fed rats. Conclusions: The present findings suggest that consumption of RBH may exert cardioprotective effects against autonomic imbalances, cardiac oxidative stress, and structural changes in metabolic syndrome.

Production and properties of two collagenases from bacteria and their application for collagen extraction.

Two collagenolytic protease (collagenase) producing bacteria, a Gram positive Bacillus cereus CNA1 and a Gram negative Klebsiella pneumoniae CNL3, were isolated under alkaline and acidic conditions, respectively. The production of collagenase by these two bacteria was optimized. Glycerol was the suitable carbon source for collagenase production by both strains. The optimal initial pH values for collagenase production by CNA1 and CNL3 were 7.5 and 6.0, respectively, and the optimal temperature was 37°C for both strains. The maximum activity of the partially purified collagenase from CNA1 was at pH 7.0 and 45°C. Its pH and thermal stability were in the range of 6-8 and below 40°C, respectively. The maximum activity of the partially purified collagenase from CNL3 was at pH 6.0 and 40°C. Its pH and thermal stability were in the range of 5-7 and below 37°C, respectively. The collagenase from CNL3 was more stable at a low pH compared with that from CNA1. Collagenases from both strains were used to extract collagen from salmon fish skin. The use of collagenases from CNA1 and CNL3 combined with acid treatment yielded a high collagen extraction of 54.6% and 53.0%, of the fish skin dry weight, respectively.