In plant seeds, the primary storage form of phosphorus (P) is phytic acid (InsP6), which is usually present in salt form (phytate). Utilization of P from InsP6 and lower forms of InsPx by animals requires stepwise cleavage of P from the inositol ring by phytases. In broiler chickens, the potential to utilize InsP6-P is very high. However, degradation of InsP6 in the gastrointestinal tract is variable and affected by supplements of calcium, P, and other dietary factors. Fine adjustment of feed ingredients and supplements of P, calcium, and phytase are crucial for practical feed formulation to be sustainable through high utilization of InsP6-P and low inclusion of feed phosphates. The potential of turkeys to utilize InsP6-P is lower compared to broiler chickens.
Table of contents
2 Phytate and phytase
3 InsP 6 degradation in the digestive tract
4 The relevance of dietary and genetic variation to InsP 6 breakdown in broilers
5 Consequences of changes in InsP 6 breakdown for P digestibility
6 Brief comparison of broiler chickens and turkeys
8 Where to look for further information