Mechanisms of Action for Phytase Enzymes in Poultry Diets for enhanced Phosphorus availability to Birds.?1. Since first commercial utilisation, phytase has mainly been considered to be a tool to increase phosphourus (P) availability/digestibility from vegetable sources and so to reduce the inclusion of higher cost P sources. ??2. Here, phytase releases the P bound in the phytate molecule, increasi ...