Responses of Broiler Chickens Under Dexamethasone-Induced Stress with or Without Seleno Methionine and Vitamin E Supplementation

Abstract

Heat stress poses a significant threat to the health and productivity of both humans and animals, with modern commercial broilers being  particularly susceptible. This study explored the physiological responses of broiler chickens under chronic heat stress conditions with  antioxidant supplementation. A total of 135 unsexed Arbor acre broiler chicks were randomly assigned to three experimental groups: control, dexamethasone (DEX) only, and dexamethasone with selenomethionine and vitamin E supplementation (DEX+SeMet+Vit.E) and  replicated three times in a completely randomized design. The birds were exposed to daily doses of dexamethasone for 14 days.  Temperature-Humidity Index (THI) measurements revealed severe heat stress in the afternoons, impacting (p<0.05) respiratory rates and  body temperatures. Supplementation with selenomethionine and vitamin E improved (p<0.05) body temperature of the broiler  chickens. DEX significantly (p<0.05) affected all growth performance indices (feed intake, weight gain and feed conversion ratio), despite  antioxidant supplementation. SeMet and Vitamin E showed significantly (p<0.05) positive effect on leukocytes in spite of DEX administration. Intestinal morphometry revealed negative effects on villi area, perimeter, and width due to dexamethasone. It was  concluded that dexamethasone influenced thermoregulation, growth, blood and intestinal indices in broiler chickens, with antioxidant  supplementation with SeMet and Vitamin E partially ameliorating these effects.