Efficacy of a Bacterial Phytase in Diets for Laying Hens on Productive Performance, Egg Quality, Biochemical and Endocrine Parameters, and Bone Quality

The objective of this study was to evaluate the effects of a novel bacterial phytase in diets for laying hens on productive performance, egg quality, biochemical and endocrine parameters, and bone quality. A total of 700 Hy-Line W-36 laying hens, 24 weeks of age, were distributed in a completely randomized design with seven treatments: a positive control, a negative control with reduced calcium and phosphorus levels, and five levels of phytase supplementation (75, 150, 300, 600, and 1200 FTU/kg). The reduction in dietary minerals impaired egg production and egg mass, whereas phytase supplementation, particularly at 150 and 300 FTU/kg, improved these responses. Feed conversion showed a quadratic response, with the optimal level estimated at approximately 500 FTU/kg. Phytase supplementation reduced parathyroid hormone concentrations and increased osteocalcin and calcitonin concentrations, accompanied by improvements in tibial and femoral strength and mineralization, particularly at higher supplementation levels. Phytase also restored eggshell thickness and increased yolk pigmentation linearly. Overall, bacterial phytase supplementation improved productive performance and specific parameters related to bone and egg quality in laying hens fed diets with reduced calcium and phosphorus levels. Phytase levels of 150–300 FTU/kg were particularly effective in improving egg production and egg mass, whereas higher levels, particularly 600 and 1200 FTU/kg, promoted favorable responses in specific bone parameters, including bone strength and mineralization.