Ascorbic acid and acetylsalicylic acid (aspirin) in the diet of broilers maintained under heat stress conditions.

Male broiler chicks were grown to 21 days of age under normal conditions, then placed in environmental chambers maintained under constant (24 C) or cyclic (24 to 35 C) heat conditions. Chicks were acclimated for 1 wk on a standard grower basal diet. Standard grower basal diets were fortified with 0, 125, 250, 500, or 1,000 ppm coated ascorbic acid (AA) or 0, 125, 250, or 500 ppm acetylsalicylic acid (ASA). Test diets were fed for 14 days in two separate studies. Cyclic heat conditions reduced feed intake and significantly reduced weight gains in both trials. Feed efficiency was not significantly affected by heat stress. Neither AA or ASA had beneficial effects on broiler growth or feed efficiency.