Effects of Extra-Dosing Phytase in Combination with Multi-Carbohydrase on Growth Performance and Bone Mineralization Using Dual-Energy X-Ray Absorptiometry in Broilers

摘要

This study aimed to evaluate the effect of the combination of extra-dosing phytase and multi-carbohydrase (MC) on growth performance and bone mineralization in broilers. A total of 640 one-day-old Cobb male broilers were randomly allocated to 8 dietary treatments (4 replicates with 20 birds each) consisting of positive control (PC); negative control (NC; -0.15% Ca and non-phytate-P (nPP)); NC with phytase (500, 1000, and 1500 FTU/kg) with or without MC (500 mg/kg). Feed intake, BW, and FCR were measured at days 7, 21, and 35. At day 35, 3 birds per pen were euthanized to measure body composition using dual-energy X-ray absorptiometry, and right femurs were collected for bone ash. Supplementation of 1000 and 1500 FTU/kg of phytase improved BWG (P 0.05) from days 0 to 7 compared to NC. There were no differences in BWG, FI and FCR during periods 0-21d and 0-35days respectively. NC birds had reduced (P 0.05) body mineral density, body mineral content, femur ash weight, femur ash percentage, and femur ash concentration compared to PC while phytase at 1,000 or 1,500 FTU/kg, and phytase plus MC restored these metrics to the same levels as PC birds. The results indicate that bone mineralization parameters are more sensitive to evaluate the P sufficiency, and extra-dosing phytase or combined phytase with MC could improve phytate-P release and bone health in broiler chickens.