An experiment was conducted to evaluate the effects of dietary nonphytate phosphorus level and a novel corn-expressed phytase (GraINzyme, Agrivida Inc., Woburn, MA) supplementation on broiler growth performance and bone mineralization. Broilers were fed graded levels of nonphytate phosphorus from 0.20 to 0.44% increased by 0.06% and 4 levels of corn-expressed phytase (500; 1,500; 3,000; and 4,500 FTU/kg). Dicalcium phosphate was used as the reference for inorganic phosphorous. Increasing dietary nonphytate phosphorus level or supplementation of phytase linearly (P < 0.01) increased the bodyweight gain, feed intake, tibia fat–free dry weight, ash weight, ash percentage, and ash concentration. Feed conversion ratio was linearly (P < 0.01) improved as the dietary nonphytate phosphorus level was gradually increased. Graded nonphytate phosphorus levels were log-transformed and regressed against the bodyweight gain, tibia ash weight, ash percentage, and ash concentration for calculating the nonphytate phosphorus relative to the phytase efficacy. Both raw and standardized responses were regressed against dietary nonphytate phosphorus levels. Bodyweight gain was less sensitive than bone mineralization results. From the regression estimates using standardized responses, bodyweight gain was about 92% of tibia ash concentration in terms of sensitivity. The calculated nonphytate phosphorus relative to the equivalence for bodyweight gain, tibia ash weight, ash percentage, and ash concentration were 0.166, 0.158, 0.163, and 0.183%, respectively. Results suggest that the corn-expressed phytase is effectively released in the P form phytate and improves broiler growth performance and bone mineralization. Bone mineralization is a better indicator for the broiler response to dietary nonphytate phosphorus levels than bodyweight gain.

进行了一项实验，以评估饮食中非植酸磷水平和新型玉米表达植酸酶（GraINzyme，Agrivida Inc.，Woburn，MA）的添加对肉鸡生长性能和骨矿化的影响。肉鸡的非植酸磷水平从0.20提高到0.44％，提高了0.06％，玉米表达的肌醇六磷酸酶水平提高了4（500、1,500、3,000和4,500 FTU / kg）。磷酸二钙用作无机磷的参考。饮食中非植酸磷水平的增加或线性植酸酶的添加（P <0.01）可增加体重增加，采食量，胫骨无脂肪干重，灰分重量，灰分百分比和灰分浓度。饲料转化率呈线性（P<0.01）随着膳食中非植酸磷水平的逐渐提高而改善。对已分级的非植酸磷水平进行对数转换，并根据体重增加，胫骨灰分重量，灰分百分比和灰分浓度进行回归，以计算相对于植酸酶功效的非植酸磷。原始和标准化反应均针对膳食非植酸磷水平进行了回归。体重增加不如骨矿化结果敏感。根据使用标准化响应的回归估计，就敏感性而言，体重增加约为胫骨灰分浓度的92％。相对于体重增加，胫骨灰分重量，灰分百分比和灰分浓度的当量，计算得出的非植酸磷分别为0.166％，0.158、0.163和0.183％。结果表明，玉米表达的肌醇六磷酸酶以P形式的肌醇六磷酸有效释放，并改善了肉鸡的生长性能和骨矿化。与体重增加相比，骨矿化是肉鸡对饮食中非植酸磷水平响应的更好指标。