THE USE OF PHYTASE IN BROILER CHICKEN DIETS: A REVIEW

摘要

The paper gives an overview of phytic acid in feed for broiler chickens, phytate sources in feedstuffs and also provides information about sources of the enzyme phytase. Phytate is present in cereals, legumes and oilseeds as a storage form of phosphorus, which contains approximately 14 – 28 % phosphorus. Phytases are phosphohydrolases, and they are the only known enzymes which can initiate the step-wise removal of phosphate from phytate. Phytases can be derived from a number of sources including plants, animals and microorganisms. Recent research has shown that microbial sources are more promising for the production of phytases on a commercial level and on cereal based feeds for broiler chickens. There are only 3 source organisms from which the most commonly encountered phytases in the animal feed industry emanate. They are Peniophora lycii (6- phytase), Aspergillus niger (3-phytase) and Escherichia coli (6-phytase). Addition of phytase in broiler diets decreased phosphorus content in poultry litter by 23 – 30 %. Some studies reported that the microbial phytase increased weight gain and thus feed efficacy. According to other authors, addition of phytase reduces weight gain, feed intake, feed efficacy and percentage ash.