Comparison of Normal and High Available Phosphorus Corn With and Without Phytase Supplementation in Diets for Male Large White Turkeys Grown to Market Weights

Abstract

Large White turkeys were fed diets containing either normal yellow dent corn (YDC) or a corn mutation containing low phytate phosphorus and high available phosphate corn (HAPC). Diets were considered nutritionally adequate in all respects with various degrees of reduction in available phosphorus content ( - 0.0, - 0.05, - 0.10  or - 0.15% of NRC (1994) recommendations for different feeding periods). These diets were fed with or without the addition of 1000 U/kg of phytase enzyme (Natuphos<SUP>&reg;</SUP>, BASF), resulting in a total of 16 dietary treatments. Each treatment was assigned to three pens of 20 male turkeys from day-old to 20 wk of age. Body weight, feed consumption, and tibia ash were determined at 28 d intervals during the study. Male turkeys fed diets with HAPC did not differ significantly in BW or feed conversion (FC) from those fed diets with YDC, and had significantly higher tibia ash at 4, 8, and 12 wk of age. Addition of 1000 U/kg of phytase resulted in significantly higher BW at 4, 8, 12, and 16 wk of age as compared to unsupplemented controls with no significant differences in FC. The addition of phytase significantly improved tibia ash at every age. Dietary phosphorus content had no effect on BW or FC at any age. Reduction of phosphorus generally did not impair tibia ash until reduction of 0.15% below NRC (1994) recommendations. Addition of phytase aided in overcoming the reduction in phosphorus content. The combination of HAPC, addition of phytase, and reduction in dietary phosphorus content should aid in reducing phosphorus excretion without impairing performance.