Effects of Phytase Addition with or Without a Trace Mineral Premix on Growth Performance, Bone Response Variables, and Tissue Mineral Concentrations in Commercial Broilers1

Microbial phytase has been shown to increase the availability of Ca, P, ME, amino acids, and trace minerals in diets of broilers. By increasing the availability of trace minerals, phytase may be able to replace the trace mineral premix in diets for broilers. Therefore, a 43-d floor pen study that included diets with and without phytase and with and without supplemental trace minerals was conducted to evaluate this possibility. The Ca and nonphytate P concentrations were decreased by 0.10% in diets with phytase. Growth performance was not affected in chicks fed diets with or without the trace minerals, but adding phytase had positive effects on growth performance. Removal of the trace minerals had a negative effect on bone strength. Removal of the trace minerals, addition of phytase, or both had variable effects on tissue trace mineral concentrations.