Reduction of protein and phosphorus in diets containing phytase for broilers from 22 to 42 days of age

The effect of the inclusion of phytase in reduced crude protein (CP) and available phosphorus (aP) diets on performance, carcass and cut yields and the amount of pollutant elements in the litter of broilers from 22 to 42 days of age was evaluated. One thousand and two hundred male broilers at 21 days of age, initial weight of 646 +/- 8g, were distributed in randomized block design in factorial scheme 3x3+1 (three levels of aP - 0.2, 0.3 and 0.4% - and three of CP - 14, 16 and 18% - and an additional treatment, standard) in six repetitions of 20 birds each. Phytase (500 FTU/kg) was added in reduced phosphorus (0.2 and 0.3%) diets. At 42 days of age, the birds were sacrificed and samples of the litters were sent to the laboratory for analysis. In reduced-CP diets, the best performance and carcass yield and lesser quantity of phosphorus, calcium, potassium and zinc in the litter was obtained with 0.3% aP + phytase diets. The minor quantity of nitrogen and potassium in the litter, with higher abdominal fat deposition and excretion of cupper were obtained with 14% CP diets. Compared to control, diets with 14% CP and 0.3% aP reduced the excretion of phosphorus in 34%. It was concluded that diets with 14% CP and 0.3% aP, supplemented with phytase and crystalline amino acids, can be used in broilers from 22 to 42 days old.