209 Effects of heat stress on the intestinal tract of poultry
Abstract Stress is a biological adaptive response to restore homeostasis, and occurs in every animal production system, due to the multitude of stressors present in every farm. Heat stress is one of the most common environmental challenges to poultry worldwide. It has been demonstrated that heat stress negatively impacts the welfare and productivity of broilers and laying hens. However, our knowledge of basic mechanisms associated to the reported effects, as well as related to poultry behavior and welfare under heat stress conditions is in fact scarce. The adaptive response of poultry to a heat stress situation is complex and intricate in nature, and it includes effects on the intestinal tract. Intervention strategies to deal with heat stress conditions (e.g., management practices, feed additives, diet formulation, and others) have been the focus of most published studies. Nevertheless, effectiveness of most of the interventions has been variable or inconsistent. This review focuses on the scientific evidence available on the effects of the heat stress response on different facets of the intestinal tract of poultry, including its integrity, physiology, immunology and microbiology.