Abstract
This study aimed to evaluate the effects of phytase enzyme supplementation on the thermoregulatory responses of Japanese quails (Coturnix japonica) exposed to different thermal environments. A total of 720 one-day-old laying quails were assigned to a completely randomized design with five dietary treatments (0, 500, 1000, 1500, and 3000 FTU of phytase) and three thermal conditions: thermal comfort (24 °C) and heat stress environments (30 °C and 36 °C). Each treatment had six replicates with eight quails per experimental unit. Data were collected during the early laying phase, peak egg production, and the final laying phase. Measurements included rectal and surface temperatures (assessed via thermographic imaging), allowing the calculation of core-to-surface and surface-to-environment thermal gradients. Quails exposed to severe heat stress (36 °C) showed increased heat dissipation via convection (p = 0.001) and radiation (p = 0.029) when supplemented with phytase doses above 1500 FTU/kg. Additionally, high-dose phytase supplementation reduced the cloacal temperature and optimized thermal gradients, indicating a potential protective effect of exogenous phytase in alleviating heat stress. Overall, these findings highlight phytase supplementation as a promising nutritional strategy to enhance heat tolerance, mitigate thermal stress, and improve the welfare and physiological resilience of quails throughout the production cycle.