Supplemental phytase derived from E. coli in different concentrations on performance, bone mineralization and cost of broilers diets.

The trial was conducted to evaluate the supplementation of E. coli phytase on performance, weight and ash of bones, as well as to determine the bioavailability of P and cost/benefit of its use in diets. A total 1,890 Cobb male day old chicks were assigned to six treatments and seven replicates with 45 birds each, distributed in a completely randomized design. The treatments were: Positive Control; Negative Control (NC1) - reduction of 0.06% avP; Negative Control 2 (NC2) - reduction of 0.12% avP; NC2 + Phytase (120 OTU); NC2 + Phytase (180 OTU); NC2 + Phytase (240 OTU), being 1 OTU equivalent to approximately 2 FTU. With different phytase inclusions, it was possible to verify a gradual increase on body weight gain, feed intake, feed conversion ratio, viability and even the bone characteristics of broilers fed diets containing reduction of P. The closest levels to the highest studied (240 OTU) showed the best results. The replacement of dicalcium phosphate by phytase supplementation is economically viable when the cost per OTU does not exceed US$ 1.4 × 10-5, US$1.2 × 10-5 and US$ 1.0 × 10-5 for the concentrations of 120, 180 and 240 OTU, respectively.