Phosphorus requirements of laying Japanese quails.

Available phosphorus (AP) is a crucial nutrient for laying quails, influencing eggshell quality and overall production performance. This study investigated the optimal levels of dietary AP in laying quails from 10 to 16 weeks of age. A total of 375 laying quails were used in a completely randomized design with five experimental diets (0.25, 0.30, 0.35, 0.40, and 0.45 % AP) and five replicates. Dietary AP levels did not affect feed intake, feed conversion ratio (FCR), egg mass (EM), or egg production (EP) percentage (P > 0.05). Egg characteristics were influenced by AP levels, with significant effects observed for egg width (P = 0.011), egg volume (P = 0.025), and shell thickness (P = 0.041), all displaying linear trends. Serum alkaline phosphatase (ALP) concentration exhibited a nonlinear response, decreasing with increasing AP levels, supporting an estimated AP requirement of 0.357 % based on the broken-line model. Estimated P requirements indicated that optimal AP levels for FCR, EP, and ALP were 0.374 %, 0.383 %, and 0.357 %, respectively. Overall, an AP level of approximately 0.38 % was identified as optimal for maximizing egg production while maintaining efficient feed utilization and eggshell quality in laying quails.