Keshavarz K
Department of Animal Science, Cornell University, Ithaca, New York 14853, USA.
Poult Sci. 2000 May;79(5):748-63. doi: 10.1093/ps/79.5.748.
An experiment was conducted to reevaluate the nonphytate P (NPP) requirement of laying hens with and without phytase. The experiment involved 12 treatments in a 6 x 2 factorial design. The hens of the control group (T1) were fed a sequence of 0.40-0.35-0.30% NPP during 30 to 42, 42 to 54, and 54 to 66 wk, respectively. The NPP was reduced in increments of 0.05% in T2 to T6. The hens of T7 to T12 were fed NPP regimens similar to T1 to T6 but with 300 units phytase/kg diet. Two digestion trials were conducted during 42 and 66 wk, and nitrogen, phytate, and total P retention were determined. In the absence of phytase, production traits were not different for hens fed a NPP regimen of 0.25-0.20-0.15% than for the unsupplemented phytase control group for the entire experiment (P > 0.05). However, production traits were inferior for hens fed the lower NPP regimens (P < 0.05). In the presence of phytase, production traits were not different for hens fed the lowest NPP regimen (0.15-0.10-0.10%) than for the unsupplemented phytase control for the entire experiment (P > 0.05). The overall effect of NPP regimens and phytase on specific gravity for the entire experiment was significant. Specific gravity was greater for hens fed the regimens with less NPP than for hens fed regimens with greater NPP, and phytase had an adverse effect on specific gravity. However, specific gravity of hens fed the lowest NPP regimen with phytase was not significantly different from the unsupplemented phytase control group. The overall effect of phytase on phytate P retention was significant during digestion trials; phytase increased phytate P retention by about 15%. Daily total P excretion was 34 to 47% less for hens fed the lowest NPP regimen with phytase than for the unsupplemented phytase control group. Significant interactions existed for a number of traits and are discussed in the text.
进行了一项实验，以重新评估添加和不添加植酸酶的情况下蛋鸡对非植酸磷（NPP）的需求。该实验采用6×2析因设计，共12个处理。对照组（T1）的母鸡在30至42周、42至54周和54至66周期间，分别饲喂含0.40% - 0.35% - 0.30% NPP的日粮。T2至T6组的NPP以0.05%的增量递减。T7至T12组的母鸡饲喂与T1至T6组相似的NPP日粮，但每千克日粮添加300单位植酸酶。在42周和66周时进行了两次消化试验，测定了氮、植酸盐和总磷的保留率。在不添加植酸酶的情况下，整个实验期间，饲喂0.25% - 0.20% - 0.15% NPP日粮的母鸡与未添加植酸酶的对照组相比，生产性能没有差异（P > 0.05）。然而，饲喂较低NPP日粮的母鸡生产性能较差（P < 0.05）。在添加植酸酶的情况下，整个实验期间，饲喂最低NPP日粮（0.15% - 0.10% - 0.10%）的母鸡与未添加植酸酶的对照组相比，生产性能没有差异（P > 0.05）。整个实验中，NPP日粮和植酸酶对蛋比重的总体影响显著。饲喂较低NPP日粮的母鸡的蛋比重高于饲喂较高NPP日粮的母鸡，且植酸酶对蛋比重有不利影响。然而，饲喂最低NPP日粮并添加植酸酶的母鸡的蛋比重与未添加植酸酶的对照组没有显著差异。在消化试验期间，植酸酶对植酸盐磷保留率的总体影响显著；植酸酶使植酸盐磷保留率提高了约15%。与未添加植酸酶的对照组相比，饲喂最低NPP日粮并添加植酸酶的母鸡的每日总磷排泄量减少了34%至47%。许多性状存在显著交互作用，文中对此进行了讨论。
