The objective was to evaluate the effects of different levels of phytase in diets with varying amounts of phytate on live performance and bone characteristics of broiler chickens at 21 D. The treatments consisted of a 3 × 5 factorial arrangement, with 3 levels of phytate, high (HP), medium (MP), and low (LP), and 5 diets consisting of a positive control (PC); negative control (NC, with a reduction of 0.15% of calcium [Ca] and 0.15% of phosphorus [P]), and NC diet plus 0, 500, 1,000, or 1,500 FTU kg⁻¹ of phytase. Feed intake peaked with supplementation of 1,051 FTU kg⁻¹ phytase to the LP diets. Bone ash of broilers receiving LP showed a maximum response at 1,101 FTU kg⁻¹. Birds receiving the NC diet had a larger hypertrophic cartilage zone (P < 0.05) than those receiving the PC diet. Serum Ca and P of birds receiving the NC treatment and LP diet were lower than those in broilers fed with the MP and HP diets. Broilers in the NC plus 500 FYT kg⁻¹ treatments had lower tibia P levels than those in the PC treatment; also, broilers receiving HP diets had a higher tibia Ca content than those receiving LP diets (P < 0.05). In general, bone P of birds fed with diets containing HP was higher than that of birds on a LP or MP diet (P < 0.05). The use of 1,101 FTU kg⁻¹ resulted in better bone characteristics when fed with the lowest phytate level, and this level does not negatively affect the other parameters evaluated.

目的是评估日粮中不同植酸水平的植酸酶水平对21 d肉鸡的生活性能和骨骼特征的影响。治疗方法包括3×5阶乘布置，3种植酸水平，高（HP），中（MP）和低（LP），以及5种由阳性对照（PC）组成的饮食；阴性对照（NC，减少0.15％的钙[ Ca ]和0.15％的磷[ P ]）和NC饮食加上0、500、1,000或1,500 FTU kg ^-1的植酸酶。饲料摄入达到峰值，补充1,051 FTU kg ^-1植酸酶的LP饮食。接受LP的肉鸡的骨灰在1,101 FTU kg ^-1下表现出最大反应。接受NC饮食的鸟类比接受PC饮食的鸟类具有更大的肥大软骨区（P <0.05）。接受NC处理和LP饲喂的家禽的血清Ca和P低于饲喂MP和HP饲喂的肉鸡。NC和500 FYT kg ^-1处理的肉鸡胫骨P水平低于PC处理。同样，接受高脂饮食的肉鸡胫骨钙含量高于低脂饮食的胫骨钙含量（P <0.05）。通常，饲喂含HP饲料的鸟类的骨骼P高于LP或MP饲喂的鸟类的骨骼P（P <0.05）。使用1,101 FTU kg ^-1 饲喂最低肌醇六磷酸水平可导致更好的骨骼特性，并且该水平不会对评估的其他参数产生负面影响。