Super-Dosing of Bacterial Phytase (EC 3.1.3.26) in Laying Hens’ Diets

Despite the acknowledged advancements in the utilization of phytase super dosing, limited research has been conducted on commercial laying hens. To assess the effectiveness of superdoses of exogenous phytase, a total of 320 laying hens aged between 44 and 64 weeks were utilized. These hens were divided into five treatments, which were then distributed using a completely randomized design with eight replicates, each containing eight birds. The treatments consisted of phytase supplementation levels of 0, 500, 1000, 1500, and 3000 FTU/kg. Quadratic regression equations were utilized to determine the maximum and minimum values for the levels of phytase supplementation. A significant difference was observed in the levels of phytase supplementation, where a quadratic model was fitted to various variables including egg weight (g), egg mass (g/bird/day), feed conversion per egg mass (g/g), yolk concentration (%), albumen concentration (%), shell thickness (μm), shell strength (kgf), specific gravity, yolk color, and also an increased supplementation improved the digestive tract of the hens, thereby providing a better villus: crypt ratio. Considering the advantageous effects of phytase super dosing, it is recommended to supplement corn and soybean meal-based diets with 1500 FTU/kg of bacterial phytase for laying hens during the 44 to 64 weeks of production period.