Evaluation of normal yellow dent corn and high available phosphorus corn in combination with reduced dietary phosphorus and phytase supplementation for broilers grown to market weights in litter pens

A study was conducted to determine the extent fecal P levels could be reduc ed while maintaining performance. Various strategies were employed includin g the use of a high available phosphorus hybrid of corn (HAPC), supplementa tion with phytase enzyme, and reduced dietary P levels. The use of HAPC res ulted in a 50% reduction in phytate-bound dietary P as compared with a norm al yellow dent corn (YDC) diet. Dietary non-phytate P was maintained at eit her NRC (1994) recommendations for appropriate age periods or reduced by 0. 075 or 0.15%. Portions of the diets were supplemented with 1,000 units of p hytase/kg. Male chicks of a commercial strain were grown to 56 d on the tes t diets. Broilers fed diets with HAPC had BW, feed conversion, livability, and tibia ash that were equal to or superior to those fed diets with YDC wi th considerably reduced fecal P content at any dietary level of nonphytate P. Phytase supplementation enabled birds to maintain live performance at lo wer levels of nonphytate P, further reducing the fecal P output. One of the greatest contributions of phytase was a reduction in mortality at the lowe r levels of nonphytate P. Dietary P levels could be reduced by 0.075% under NRC (1994) recommendations without adversely affecting live performance; a reduction of 0.15% in conjunction with phytase supplementation maintained BW, feed conversion, and livability but reduced tibia ash. The extent to wh ich dietary P levels can be reduced over the entire feeding program is subj ect to further research.