Influence of supplemental enzymes on the performance and phosphorus excretion of broilers fed wheat-based diets to 6 weeks of age

Efficacies of phosphorolytic enzymes (phytase+acid phosphatase), and an enzymic “cocktail” (phytase+acid phosphatase+pectinase+citric acid), were investigated in broilers fed wheat-based diets from day 1 to 43. Broilers were fed the following four diets: (1) a positive control diet (7.1 g total P/kg, 4.1 g non-phytate P/kg, 9.8 g Ca/kg); (2) a low phosphorus diet (4.1 g total P/kg, 1.7 g non-phytate P/kg, 6.0 g Ca/kg) supplemented with phytase (750 units/kg) and acid phosphatase (3156 units/kg); (3), a low phosphorus diet (4.1 g total P/kg, 1.7 g non-phytate P/kg, 6.0 g Ca/kg) supplemented with phytase, acid phosphatase, pectinase (1900 units/g) and citric acid (20 g/kg); and (4) a low phosphorus diet (4.1 g total P/kg, 1.7 g non-phytate P/kg, 8.0 g Ca/kg) supplemented as in diet 3. For the grower period (22–43 days), the contents of P and Ca were lowered by 0.2 and 0.3 g/kg, respectively. The dietary treatments were fed to three floor pen replicates of 50 birds each. For the starter period, there were no differences observed among dietary treatments in terms of body weight gains or feed efficiency. Total body weight gains for the starter and grower periods did not differ among dietary treatments, but total feed efficiency was significantly enhanced in birds fed diet 2. At the completion of the experiment chickens fed phosphorolytic enzymes had the best feed efficiencies, the highest contents of ash in the toes, and the highest carcass yield. Chicken receiving the cocktail of enzymes and 8 g Ca/kg (diet 4) performed as well as birds in the control treatment, but had higher yields of carcass and excreted 56% less phosphorus.