IMPACT OF ANTIOXIDANTS SUPPLEMENTATION ON METABOLIC STATUS AND REPRODUCTIVE PERFORMANCE OF ABERDEEN ANGUS COWS DURING SEASONAL THERMAL STRESS IN ARID SUBTROPICAL REGIONS

Abstract

This study was performed to investigate the effect of antioxidants supplementation, i.e., vitamin E, selenium (Se) and zinc sulfate administration on metabolic status, biochemical and reproductive performance of Aberdeen Angus cows under hot conditions. Sixteen cows were used and divided randomly into four equal groups (four cows each) and each group was treated for 21 successive days. The first group served as a control. The second group was injected vitamin E and Se at rate of 15ml / head / twice a week (E Sel group) The third group was supplemented with 200 mg/head/ daily zinc sulphate (Zinc group). Whereas, the fourth one was supplemented with 200 mg/head/ daily zinc sulphate in combination with vitamin E and Sel at rate of 15ml / head / 15day. Metabolic and antioxidant parameters were measured on a weekly basis for 21 days from the start of treatment until the end of synchronized ultrasonographic estrous cycle. Ultrasonographic examination of follicular number and size was carried out during estrous cycle every three days. Results showed that number of all types of ovarian follicles was high in all treated groups compared to control group. Moreover, number of services per conception recorded higher (P<0.05) values in control group (1.8) compared to treated groups (1.3). Furthermore, glucose concentration (mg/dl) was high (P<0.05) in zinc group (66.67 ± 5.31) compared to sel zinc group (58.64 ± 4.87) and control group (55.31 ± 5.09) during week 2 post-treatment. Moreover, non-esterified fatty acids (µmol/l) concentration illustrated lower (P<0.05) value in all treatment groups than control group at weeks 2, 3, 4, 5, 6, and 7 post-treatment. Glutathione peroxidase concentration (GSH, U/g Hb) and total antioxidant capacity (TAC, mmol/l) were significantly (P<0.05) higher in all treatment groups than that of control group. From the present result it can be concluded that vitamin E, selenium and zinc could improve reproductive performance, metabolic profiles and antioxidant capacity under subtropical heat stress in Aberdeen Angus cows.