Broiler diets based on ingredients of plant origin contain
large amounts of unavailable P in the form of
phytate-P, which is poorly hydrolyzed by the endogenous
enzymes of monogastric animals (Ravindran et al.,
1995). Dietary supplementation of inorganic phosphate
is often necessary to meet available P requirements for
poultry. However, the addition of inorganic P increases
the cost of the feed and results in high concentrations
of P in the manure. As a consequence, animal waste
applied to the soil leads to environmental pollution,
allowing excreted P to wash into overland water systems,
which causes eutrophication (Boling et al., 2000;
McGrath et al., 2005). Supplementation of exogenous
phytase in broiler chicken rations has been
proven to improve the hydrolysis of phytate-P, increase
P digestibility, reduce P excretion into the
environment, and lower the cost of inorganic phos