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 e nzymic "cocktail" (phytase + acid phosphatase + pectinase + citric acid), w ere investigated in broilers fed wheat-based diets from day 1 to 43. Broile rs were fed the following four diets: (1) a positive control diet (7.1 g to tal 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 ph ytase (750 units/kg) and acid phosphatase (3156 units/kg); (3), a low phosp horus diet (4.1 g total P/kg, 1.7 g non-phytate P/kg. 6.0 g Ca/kg) suppleme nted with phytase, acid phosphatase, pectinase (1900 units/g) and citric ac id (20 g/kg); and (4) a low phosphorus diet (4.1 g total P/kg, 1.7 g non-ph ytate 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, res pectively. 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 a mong dietary treatments, but total feed efficiency was significantly enhanc ed in birds fed diet 2. At the completion of the experiment chickens fed ph osphorolytic enzymes had the best feed efficiencies, the highest contents o f ash in the toes, and the highest carcass yield. Chicken receiving the coc ktail of enzymes and 8 g Ca/kg (diet 4) performed as well as birds in the c ontrol treatment, but had higher yields of carcass and excreted 56% less ph osphorus. (C) 2001 Elsevier Science B.V. All rights: reserved.