Effect of Natuphos (R) Phytase supplementation to feed on performance and ileal digestibility of protein and amino acids of broilers

Nutrient equivalency of Natuphos(R) Phytase for minerals, amino acids, and energy has been estimated elsewhere for broiler chickens. The current study was to evaluate equivalent values of 600 FTU/kg Natuphos(R) Phytase for am ino acids and energy in 3,150 broiler chicks from hatch to 7 wk of age. Tre atments consisted of a 3 x 3 factorial arrangement of three levels of dieta ry amino acids (AA; 100, 92.5, and 85% of Illinois Ideal Protein for Broile r Chickens) and three phytase inclusion approaches (positive control: 0 FTU /kg with no reduction of Lys, TSAA, and ME; negative control: 0 FTU/kg with reduction of 2% Lys, 1% TSAA, and 0.5% ME; and reformulation with phytase: 600 FTU/kg with reduction of 2% Lys, 1% TSAA, and 0.5% ME). The effect of AA was linear on BW gain and feed conversion (FC); a greater AA level impro ved performance. No interaction of AA and phytase inclusion approach was si gnificant in terms of BW gain, feed intake (FI), and FC of growing and fini shing broilers. Birds fed the positive control diet had greater BW gain tha n those fed the negative control diet. Body weight gain of birds fed the di et reformulated with phytase did not differ from those of birds fed the pos itive control. Feed conversion was not affected by phytase inclusion approa ches. Effects of phytase supplement on apparent ileal digestibilities (AID) of CP and AA were not significant. Restoring BW gain lost in the negative control by reformulated feed with 600 FTU/kg phytase indicates that equival ent values estimated elsewhere might be adequate.