EVALUATION OF OXIDATIVE STRESS ON SEMINAL PLASMA FROM FERTILE AND SUBFERTILE DOGS AFTER ORAL SUPPLEMENTATION WITH VITAMIN C AND E

Abstract

Sperm cells are highly susceptible to oxidative stress due to a high concentration of fatty acid in the composition of their membranes. Oxidative stress occurs due to an imbalance between the concentrations of antioxidants and oxidants, which can lead to the loss of sperm fertilizing ability. The aim of this study was to evaluate, in seminal plasma, the rates of lipid peroxidation and concentration of antioxidants: Superoxide Dismutase (SOD), catalase, vitamins C and E, from fertile and subfertile dogs after an oral supplementation of vitamin C and E for 60 days. For that, it was used 13 dogs of different breeds and ages that were fed with commercial food (Max Adulto - Royal Canin) for four months. Over the past 60 days, animals received a diet added to oral supplementation of 500 mg vitamin C and E. Semen was collected by penis digital manipulation in three times before (M1), 30 (M2) and 60 days (M3) of supplementation. Seminal plasma was obtained after centrifugation (18000g) of the ejaculate and stored in Eppendorff tubes in a freezer at -20 º C. It was measured in seminal plasma the index of lipid peroxidation, by analysis of thiobarbituric acid reactive substances (TBARS), and the concentrations of SOD, catalase, vitamin C and E. Analysis of lipid peroxidation, concentrations of SOD, catalase and vitamin C were performed using a spectrophotometer at different wavelengths (532, 530, 230 and 520, respectively) and for the evaluation of SOD it was used a commercial kit (Frutosamina - Labtest ®). The concentration of vitamin E was performed using a high-performance liquid chromatography (HPLC). The results showed significant differences between groups of fertile and infertile dogs only at M1 (before oral supplementation). There was no difference between groups in other moments. Regarding the concentration of antioxidants, there was no significant difference between groups and between moments. Based on the exposed, the oral supplementation with vitamin C and E in dosages of 500 mg / day for 60 days did not interfere on the rates of lipid peroxidation (TBARS) and antioxidant concentrations.