ABSTRACT
Heat stress can affect the health and performance of sheep. Researchers have investigated various methods to prevent the harmful effects of heat stress. In this study, injection of vitamin C on some biochemical parameters, red blood cells [RBC], hemoglobin [Hb], hematocrit [HCT] and white blood cells [WBC] in sheep under hyper acute heat stress were studied. Eight healthy male sheep in similar range of age [5 +/- 1 months] and weight [28.75 +/- 3.17 kg] were enrolled in this study. The sheep were divided into two groups. Both groups were placed in an environment with hyper-acute heat stress based on temperature-humidity index [THI].Vitamin C was injected intramuscularly on days 0, 1, 3 and 5.Blood samples were collected from the jugular vein on days 0. 1, 3, 5, and 7. Glucose, cortisol, cholesterol, triglycerides and blood components were measured and evaluated. Results were analyzed using statistical software SPSS [version 16]. The results showed that vitamin C injection has a significant effect on serum cortisol, glucose, hematocrit and white blood cells [p<0.05]. Vitamin C injection has lowering effects on serum cortisol and glucose during heat stress. Mechanism for attenuating the levels of cortisol and glucose by vitamin C is not well known. However, it may be done by decrease in cortisol synthesis or degradation. Increased hematocrit provided sufficient water to cool the body through perspiration. The present study probably shows a beneficial effect of injection of vitamin C on adaptation mechanisms against of heat-stressed sheep