Heat stress in chickens: Genetic variation and the use of antioxidant supplementation in prevention of oxidative damage

The purpose of the present study was to determine the influence of heat stress on the laying hens’ physical and physiological functions and test the genetic predisposition for variation of these functions. Response to a given stressor is dependent on the genetic background of the animal. Two genetic strains of laying hens were used, each with a uniquely different stressor response. A novel stressor, heat stress, was introduced to these lines and genetic variation of the heat stress response was recorded. The results of this study pose a strategy for genetic selection to a heat stress resistant strain of laying hens. Use of this knowledge can allow for us to develop selection programs aimed at improving the thermotolerance of the hen. Additionally, the present study was conducted to determine differences in the heat stress response under the affect of antioxidant supplementation. Animals under heat stress simultaneously exhibit oxidative stress, which causes further cellular damage. Limiting or inhibiting the resulting oxidative damage can be accomplished by improving antioxidant status, the body’s natural defense to oxidative stress. Our results provide evidence of oxidative stress under heat stress conditions. Furthermore, antioxidant supplementation improved the hen’s capacity to cope with heat stress. These data are useful for further research involving the effect of antioxidant supplementation on hens under heat stress