This study was conducted to investigate the effect of heat stress on performance, digestibility, and molecular transporters of amino acids in broilers. Cobb 500 chicks were raised from hatch till 13 days in floor pens. At day 14, 48 birds were randomly and equally divided between a control group (25°C) and a heat stress treatment group (35°C). Birds in both treatment classes were individually caged and fed ad libitum on a diet containing 18.7% CP and 3,560 Kcal ME/Kg Five birds per treatment at one and 12 days post-treatment were euthanized and the Pectoralis major (P. major) and ileum were sampled for gene expression analysis. At day 33, the ileal contents were collected and used for digestibility analysis.

Results confirmed that broilers under heat stress had reduced growth and feed intake compared to control birds. The amino acid consumption and retention were significantly lower in the heat stress group when compared to the control group. The study indicated that the dynamics of amino acid transporters in the P. major and ileum tissues were influenced by heat stress. These changes in amino acid transporters may explain the reduced growth in meat type chickens under heat stress.