A review of dietary interventions to alleviate harmful effects of stress on poultry health and production

Stress is a condition that can negatively affect poultry health, physiological state, and productivity. Poultry must therefore be kept out from factors that may cause stress in order to optimize productivity and health. After the ban on antibiotic growth promoters (AGP), the use of AGP alternatives has become increasingly popular to maintain health and maximize poultry production potential, especially in stressful conditions. The use of natural antioxidant sources for stressed-poultry is also increasingly popular as farmers become aware of the potential for synthetic antioxidant residues in poultry products which may have a negative impact on consumer health. Various kinds of dietary interventions have been proposed to ameliorate the negative effects of stress on poultry, including probiotics, prebiotics, synbiotics, herbs (plant-derived products), vitamins, propolis, amino acids, postbiotics, essential oils, trace minerals, betaine and chitosan. Each dietary component exhibits different modes of action in improving the poultry under stress conditions. Typically, dietary intervention improves stress response, reduces corticosterone concentration, increases the activity of the growth hormones, insulin-like growth factor-l (IGF-1) and thyroxine, improves antioxidant status, maintains intestinal ecology and morphology, increases enzyme activity, supports the development of immune tissue and organs and prevents cell death. This current narrative review provides an update and comprehensive overview about some dietary interventions in attempt to ameliorate the adverse effects of stress on poultry production, health and physiological conditions.