Enhancing calcium and phosphorus utilization in broiler chickens with phytase in sequential calcium-phosphorus-deficient diets

In this trial, a 3 × 2 factorial design was implemented with dietary treatments consisting of Diet-1 (1.00% calcium [Ca], 0.45% available phosphorus [P]), Diet-2 (0.80% Ca, 0.35% P), and Diet-3 (0.70% Ca, 0.30% P), alongside two phytase levels: 0 and 5,000 FTU/kg. A total of 540 Ross-308 broilers were used. Significant improvements (P < 0.05) in body weight gain, feed intake, feed conversion ratio (FCR), live weight, carcass weight, and yield were observed in Diet-1 and Diet-2 when supplemented with phytase compared to Diet-3. Gross energy (GE) increased significantly (P < 0.05) with phytase in Diet-1 and Diet-2. Bone ash content was significantly higher (P < 0.01) in Diet-1 and Diet-2, with tibia Ca levels notably improved (P < 0.05) in Diet-1. Phytase supplementation also resulted in significantly elevated (P < 0.05) serum Ca and available P in Diet-1. The application of phytase restored body weight gain, live weight, carcass weight, GE, and tibia P in Diet-2. Overall, the findings highlight the beneficial effects of phytase supplementation on growth performance, bone mineralization, and nutrient utilization.