The effect of phytase enzyme and level on nutrient extraction by broilers.

Three experimental phytase enzyme preparations derived from the same Escherichia coli gene but produced in Saccharomyces cerevisiae (A), Pichia pastoris (B), and Pseudomonas fluorescens (C) were compared with a commercial enzyme preparation by addition to wheat-soybean meal diets fed to broiler chicks. A positive control diet contained sufficient available phosphorus for normal broiler growth and a negative control diet was phosphorus deficient. The 4 enzymes were added to the negative control diet at 3 levels each (150, 450, and 1,250 U/kg), and all diets were pelleted above 80 degrees C. Broiler chicks were fed experimental diets from 4 to 21 d. Chick performance and nutrient digestibility showed that the pel leting process inactivated enzymes A and C and the commercial enzyme. When added to the negative control diet, enzyme B had positive effects on broiler performance and calcium and phosphorus digestibility, and increasing levels of enzyme had greater positive effects. Enzyme B also increased the AME and protein digestibility over those of either control diet. These results suggest that enzyme B was not inactivated by pelleting above 80 degrees C, whereas the other enzymes were.