The Effects of Different Amount of Protein and Vitamin E Supplementation in Rations on Lipid and Antioxidant Metabolism of Broilers Exposed to Heat Stress

Heat stress, causes economic losses and has negative effects on both broiler husbandry and animal welfare. Nutritional strategies are applied for minimizing the negative effects of heat stress. In the present study, at the finishing period (24-39 days of age) of heat stress, the effects of diet involving 21% and 19% proteins and vitamin E on lipid metabolism and antioxidant mechanism of action, aimed to be identified. This study was carried out in six groups as: HPC (24 degrees C heat + 21% crude protein (CP)), HPS (34 degrees C heat + 21% CP), LPC (24 degrees C heat + 19% CP), LPS (34 degrees C heat + 19% CP), HPSVE (34 degrees C heat + 21% CP + Vitamin E) and LPSVE (34 degrees C heat + 19% CP + vitamin E) groups. Superficial pectoral muscles (breast) and liver tissues were used for oxidative stress and antioxidant defence determinations. Triglyceride and cholesterol levels have also been determined in blood serums. During the research, it is found that heat stress increased serum triglyceride and cholesterol levels, where Vitamin E has recovered triglyceride levels limitedly and cholesterol levels significantly. It is also observed that the adverse effect of high temperature was directly related to oxidative stress. Protein levels and vitamin supplementation relatively ameliorated these adverse effects, suggesting the tissue specificity. Consequently, the importance of feeding strategies such as the presence of Vitamin E and protein ratios on broiler nutrition in heat stress was established.