A phytase is any type of phosphatase enzyme that catalyses the hydrolysis of phytic acid – an indigestible, organic form of phosphorus. The major feed ingredients that are commonly used in commercial poultry feed are cereal grains, oil seed meal and grain by-products. A major portion (60 – 80%) of the total phosphorus present in these ingredients, occur in the form of phytic acid. Phytic acid (phytate) is a complex of Ca or Mg with myo-inositol and is an essential component of all seeds. Phytic acid is considered as an anti-nutritional factor in poultry because it binds with phosphorus and other important nutrients and thereby decreases their availability.
Phytase increases bioavailability of P, Ca and amino acids. Microbialphytase supplementation improves body weight gain, feed intake, FCR and overall growth performance in broiler birds. The improvement in growth performance in chickens fed with phytase may be due to increased bioavailability of phosphorus by phytase, increase in feed intake and feed efficiency, increase utilization of inositol, improvement in starch digestibility, improved utilization of protein and amino acids and overall utilization of nutrients.