Efficacy of different doses of phytase on performance, nutrient digestibility and tibia mineralization in broiler chickens

This study evaluated the effects of different phytase supplementation levels on performance, nutrient digestibility, bone mineralization, and carcass characteristics in broilers fed diets with reduced available phosphorus (P). A total of 840 one-day-old male Ross 308 broilers were randomly allocated to six dietary treatments: T1, positive control (PC; adequate P and Ca); T2, negative control (NC; low P and Ca); T3, NC + 167 FTU/kg phytase; T4, NC + 500 FTU/kg; T5, NC + 1,500 FTU/kg; and T6, NC + 4,500 FTU/kg (high dose). The trial lasted 35 days. Body weight (BW), average daily gain (ADG), feed intake, and feed conversion ratio (FCR) were recorded, while apparent ileal digestibility of dry matter (DM), Ca, and P, as well as tibia ash and carcass traits, were assessed. Phytase supplementation significantly improved BW, ADG, and FCR compared with the NC. The highest BW, ADG, and lowest FCR were observed in the T6 group, followed by T5, whereas the NC birds showed the poorest performance. Phytase enhanced P digestibility at all application rates, and DM digestibility at the high inclusion level. Tibia ash content increased linearly with phytase dose, indicating improved bone mineralization. The NC group exhibited elevated Footpad Dermatitis Index values and reduced carcass yield, which were mitigated by the addition of phytase. Overall, phytase supplementation improved performance and nutrient digestibility. Dosing phytase at 1,500 and 4,500 FTU/kg fully compensated for P deficiency, improved performance and skeletal integrity, and reduced environmental P impact, supporting its use as a nutritional strategy in broiler production.