Effect of dietary Betaine, L-glutamine supplementation and cold water on productive performance and physiological responses of Japanese quail under heat stress conditions

This study aimed to investigate the impact of dietary betaine (Bet), L-glutamine (L-Gln), and cold water supplementation on productive performance and physiological responses of Japanese quail under heat stress conditions. A total of 225 quail chicks aged 14 days were assigned to five dietary treatments: a basal diet (control), and a basal diet supplemented with betaine, L-glutamine, a combination of both, or cold water. Growth performance, carcass traits, blood parameters, and economic efficiency were evaluated during the growing periods. The results revealed that quails receiving cold water exhibited the highest growth performance, feed conversion efficiency, and carcass yield, outperforming dietary supplementation groups. While betaine and L-glutamine individually improved nutrient utilization and physiological resilience to heat stress, their combination demonstrated synergistic effects, enhancing growth and carcass traits further. Blood analyses indicated improved metabolic profiles, with reduced hepatic stress and enhanced protein metabolism in supplemented and cold water-treated groups. Moreover, cold water proved to be the most cost-effective intervention, significantly boosting economic efficiency compared to feed additives. These findings highlight the practicality of cold water supplementation as an economical and effective strategy to mitigate heat stress in quails, providing a sustainable approach for enhancing productivity and profitability in poultry farming.