Effects of phosphorolytic and cell wall-degrading enzymes on the performance of growing broilers fed wheat-based diets containing different calcium levels

A study was conducted to determine the cumulative effects of phosphorolytic enzymes, cell wall-degrading enzymes, and citric add and Ca levels on feed intake, BW gain (BWG), feed conversion, intestinal viscosity, and toe ash of broilers (d 1 to 21) fed wheat-based diets. Broilers were fed the follow ing six diets at either 0.59, 0.69, or 0.79% Ca: 1) a negative control (NC) diet, 0.17% available P;2) NC + 750 phytase units/kg diet; (3) phytase + 3 ,156 units of acid phosphatase/kg diet; 4) phytase + add phosphatase + 1,90 0 units of pectinase/g diet; 5) phytase + acid phosphatase + pectinase + 3% citric acid; and (6) NC plus 0.24% available P. The 18 dietary treatments were fed to four pen replicates of eight birds each. Phytase addition at th e low Ca level increased BWG, improved feed intake and conversion and toe a sh, and reduced intestinal viscosity and Ileal length. Subsequent addition of acid phosphatase, at 0.69% Ca, resulted in increases in BWG, 42%; feed i ntake 32%; feed conversion 7.5%; and toe ash, 63% over the NC diet. Pectina se addition produced further improvements in 21-d BWG and feed intake at 0. 59 and 0.79% Ca, increased toe ash in chicks fed 0.79% Ca, and reduced inte stinal viscosity. Supplementation of wheat-based 0.17% available P diets wi th phytase and acid phosphatase and with appropriate concentrations of pect inase, citric acid, and Ca significantly improved BWG, feed intake and conv ersion and intestinal viscosity over the 0.41% available P diets. Bone mine ralization of chicks fed phytase + acid phosphatase and 0.69% Ca and these fed phytase + acid phosphatase + pectinase + citric add and 0.59% Ca was si milar to that of chicks fed the 0.41% available P diets.