Waldroup P W, Kersey J H, Saleh E A, Fritts C A, Yan F, Stilborn H L, Crum R C, Raboy V
Poultry Science Department, University of Arkansas, Fayetteville 72701, USA.
Poult Sci. 2000 Oct;79(10):1451-9. doi: 10.1093/ps/79.10.1451.
A study was conducted to evaluate the ability of the young (0 to 3 wk) broiler chicken to utilize the P provided by a high available P corn [HAPC; 0.27% total P and 0.17% nonphytate P] in comparison with yellow dent corn (YDC; 0.23% total P and 0.03% nonphytate P), and to determine the extent to which supplementation with exogenous phytase enzyme could reduce the demands for dietary P and subsequently reduce P excretion. Diets prepared using the two types of corn differed in the amount of phytate-bound P, with the HAPC diets containing approximately 50% less phytate-bound P. Treatment diets were prepared by varying the amount of dicalcium phosphate, and ranged from 0.10 to 0.50% nonphytate P for YDC diets, and from 0.18 to 0.50% nonphytate P for HAPC diets. Sublots of each diet were supplemented with 800 units/kg phytase. Each diet was fed to six pens of five male chicks of a commercial broiler strain from 1 to 21 d of age. Regression analysis was used to estimate nonphytate P requirements for each corn type with and without phytase supplementation. The greatest need for nonphytate P was for maximum tibia ash, with requirements of 0.39, 0.29, 0.37, and 0.32% in diets with YDC, YDC plus phytase, HAPC, and HAPC plus phytase, respectively. Addition of phytase liberated approximately 50% of the phytate-bound P from each diet. These levels were sufficient to support body weight, feed conversion, and livability. Fecal P content of broilers fed diets with YDC at the NRC (1994) recommended level of 0.45% nonphytate P was 1.21%, whereas at the respective requirement points indicated above, the P content was 1.09, 0.87, 0.78, and 0.64% in feces from broilers fed diets with YDC, YDC plus phytase, HAPC, and HAPC plus phytase, respectively. Thus, fecal P output could be reduced while maintaining optimum performance by the use of reduced dietary nonphytate P, introduction of HAPC, and phytase supplementation. One of the greatest benefits of phytase supplementation appeared to be maintaining livability at lower dietary levels of nonphytate P.
开展了一项研究，以评估幼龄（0至3周）肉鸡利用高有效磷玉米[HAPC；总磷0.27%，非植酸磷0.17%]提供的磷的能力，并与黄马齿玉米（YDC；总磷0.23%，非植酸磷0.03%）进行比较，同时确定补充外源植酸酶能够在多大程度上降低对日粮磷的需求，进而减少磷排泄。使用这两种玉米配制的日粮中植酸结合磷的含量不同，HAPC日粮中的植酸结合磷含量约低50%。通过改变磷酸二钙的添加量来配制试验日粮，YDC日粮的非植酸磷含量为0.10%至0.50%，HAPC日粮的非植酸磷含量为0.18%至0.50%。每种日粮的小区补充800单位/千克的植酸酶。从1至21日龄，将每种日粮喂给6栏，每栏5只来自商业肉鸡品系的雄性雏鸡。采用回归分析来估计添加和不添加植酸酶时每种玉米类型对非植酸磷的需求量。对最大胫骨灰分而言，非植酸磷的需求量最大，在含YDC、YDC加植酸酶、HAPC和HAPC加植酸酶的日粮中，需求量分别为0.39%、0.29%、0.37%和0.32%。添加植酸酶可使每种日粮中约50%的植酸结合磷被释放出来。这些水平足以支持体重、饲料转化率和成活率。饲喂非植酸磷含量为NRC（1994）推荐水平0.45%的YDC日粮的肉鸡粪便磷含量为1.21%，而在上述各自的需求点，饲喂含YDC、YDC加植酸酶、HAPC和HAPC加植酸酶日粮的肉鸡粪便磷含量分别为1.09%、0.87%、0.78%和0.64%。因此，通过使用低非植酸磷日粮、引入HAPC和补充植酸酶，可在维持最佳生产性能的同时减少粪便磷排放。补充植酸酶的最大益处之一似乎是在较低日粮非植酸磷水平下维持成活率。
