IMPROVEMENT OF PHOSPHORUS AVAILABILITY BY MICROBIAL PHYTASE IN BROILERS AND PIGS

Techniques have been developed to produce microbial phytase for addition to diets for simple-stomached animals, with the aim to improve phosphorus availability from phytate-P in plant sources. The activity of the crude microbial phytase showed pH optima at pH 5.5 and 2.5. The enzyme was able to degrade phytate in vitro in soya bean meal, maize and a liquid compound feed for pigs. When microbial phytase was added to low-P diets for broilers the availability of P increased to over 60 % and the amount of P in the droppings decreased by 50%. The growth rate and feed conversion ratio on the low-P diets containing microbial phytase were comparable to or even better than those obtained on control diets. Addition of microbial phytase to diets for growing pigs increased the apparent absorbability of P by 24%. The amount of P in the faeces was 35% lower. Phosphorus availability: Microbial phytase: Broilers: Pigs. © 1990, The Nutrition Society. All rights reserved.