The abstract for a paper performing a meta-analysis of phosporus utilization with different forms of P, and the effect of calcium and phytase. The amount of P leading to digestible P was 21% when phytate P, 73% when non-phytate P (NPP), and 80% when NPP from minerals. Addition of microbial phytase was twice as efficient as plant phytase, and produced a curvilinear response. Calcium reduced P retention in low P diets, but increased retention in high P diets.