Yan F, Kersey J H, Waldroup P W
Poultry Science Department, University of Arkansas, Fayetteville 72701, USA.
Poult Sci. 2001 Apr;80(4):455-9. doi: 10.1093/ps/80.4.455.
Two studies of identical design were conducted in battery brooders utilizing male chicks of a commercial strain. The birds were grown to 3 wk on diets with adequate P and from 3 to 6 wk were fed diets ranging from 0.10 to 0.45% nonphytate P (nPP) in increments of 0.05%, with or without supplementation with 800 units of phytase per kilogram of diet. Measurements included BW gain, feed conversion ratio (FCR), mortality, tibia ash, and fecal P content. Nonlinear regression was used to estimate nPP needs for optimizing BW gain, feed conversion, and tibia ash. In the absence of phytase, nPP levels of 0.33, 0.186, and 0.163% were required to optimize tibia ash, BW gain, and FCR, respectively. The estimated level for optimum tibia ash is in close agreement with current NRC (1994) recommendations. In the presence of 800 units of phytase per kilogram, nPP levels of 0.24, 0.151, and 0.109% were needed to optimize tibia ash, BW gain, and FCR, respectively. Fecal phosphorus levels were markedly reduced at the lower P levels. Further studies are needed to determine whether maximum tibia ash values are needed to sustain optimum production of market broilers.
在笼养式育雏器中，使用商业品系的雄性雏鸡进行了两项设计相同的研究。这些鸡在含磷量充足的日粮中饲养至3周龄，从3周龄到6周龄，分别饲喂非植酸磷（nPP）含量为0.10%至0.45%、增量为0.05%的日粮，部分日粮每千克添加800单位植酸酶。测量指标包括体重增加、饲料转化率（FCR）、死亡率、胫骨灰分和粪便磷含量。采用非线性回归估计优化体重增加、饲料转化率和胫骨灰分所需的非植酸磷量。在不添加植酸酶的情况下，优化胫骨灰分、体重增加和饲料转化率所需的非植酸磷水平分别为0.33%、0.186%和0.163%。估计的最佳胫骨灰分水平与美国国家研究委员会（1994年）目前的建议密切一致。在每千克日粮添加800单位植酸酶的情况下，优化胫骨灰分、体重增加和饲料转化率所需的非植酸磷水平分别为0.24%、0.151%和0.109%。较低磷水平下粪便磷含量显著降低。需要进一步研究以确定维持商品肉鸡最佳生产是否需要最大胫骨灰分值。
