The influence of microbial phytase on the ileal amino acid digestibility's of three grains, four oilseeds and grain by-products was determined using 5-week old broilers. Supplementing microbial phytase fed at the rate of 1,200 FTU per kg improved the digestibility of protein and amino acids in all feedstuffs, however, the magnitude varied with feedstuff and individual amino acid. The mean digestibility of 15 amino acids in the feedstuff with and without phytase were:
Phytase supplementation increased the digestibility of threonine and valine in all feedstuffs. The researchers concluded that the solubility of phytate salts and protein, and their influence on the phytate-protein complex in the different feedstuffs, may be more important than the ingredient's total phytic acid concentration. They reported that dietary phytic acid levels were negatively correlated with inherent protein (r = -0.81) and mean amino acid (r = -0.85) digestibility's of the feedstuffs evaluated.
(Note: this research confirms other studies on the relatively high digestibility of amino acids of soybean meal and the effects of phytase on soy protein utilization).
Ravindran, V. and co-workers. 1999. Influence of microbial phytase on apparent ileal amino acid digestibility of feedstuff for boilers. Poultry Sci. 78(5):699-706.
