Phytase Superdosing in the Diet of Lightweight Replacement Pullets: Performance, Organ Biometry and Bone Characteristics

ABSTRACT The aim of this study was to evaluate the effect of two types of phytases (the 1st produced from Escherichia coli and the 2nd from Aspergillus oryzae) with different dosages (300 and 900 Unit Phytase or FTU) on performance, organ biometry and bone quality of replacement pullets in the period of 8 to 17 weeks of age. A total of 288 Hy-Line White laying hens were used at 8 weeks of age. A completely randomized design was adopted in a 2 x 2 factorial scheme, totaling 4 treatments with 8 replicates of 9 birds each. Performance, biometric variables and bone characteristics were evaluated. There was no significant interaction between the factors for any of the evaluated variables. The conversion and the accumulated consumption were influenced (p摘要 本研究旨在评估两种植酸酶（phytase）——第一种由大肠杆菌（Escherichia coli）制备，第二种由米曲霉（Aspergillus oryzae）制备——在不同添加剂量（300与900单位植酸酶，即FTU）下，对8至17周龄后备蛋鸡生产性能、器官生物测量指标及骨骼品质的影响。本试验共选取288只8周龄的海兰白（Hy-Line White）蛋鸡作为试验材料，采用2×2因子完全随机设计，共计设置4个处理组，每组设8个重复，每个重复包含9只鸡。试验测定了生产性能、形态学指标及骨骼特性相关参数。所有测定指标均未发现因子间存在显著交互作用。料重比与累计采食量受到显著影响（p