Thermo-stable Escherichia coli phytase improves growth performance and nutrient utilization in broilers fed mash and pelleted corn-soybean-meal-based diets

The bio-efficacy of Escherichia coli-derived phytase produced by thermo-protective coating technology (coated phytase) was evaluated in mash or pelleted broiler diets. Three hundred and twenty-four broilers were divided into 54 groups of six birds and fed nine corn-based diets (six replicates per diet) from 1 to 22 d of age. The nine diets were a positive control (PC) (calcium, 0.9% and non-phytate phosphorus, 0.45%) fed as mash plus 2 x 4 factorial of a negative control (calcium, 0.78% and non-phytate phosphorus, 0.26%) fed as mash (NC-M) or pellet (NC-P) and with coated phytase at 0, 500, 600 or 700 FTU kg(-1). The diets were pelleted at 80 degrees C, and pressure load of 40 psi. Body weight gain (BWG) for the PC diet was higher (P < 0.001) than that for the NC-M or NC-P diet. The BWG and tibia ash were linearly increased (P < 0.001) by increased level of the phytase in NC-M or NC-P diet. The BWG for NC-M or NC-P diet reached that of the PC diet when phytase was supplemented at 600 or 700 FTU kg(-1). In conclusion, the coated phytase improved nutrient utilization in broilers, and its bio-efficacy was unaffected by the pelleting process.