Boling S D, Douglas M W, Johnson M L, Wang X, Parsons C M, Koelkebeck K W, Zimmerman R A
Department of Animal Sciences, University of Illinois, Urbana 61801, USA.
Poult Sci. 2000 Feb;79(2):224-30. doi: 10.1093/ps/79.2.224.
In the first of two experiments (20 to 70 wk of age), eight treatments consisted of corn-soybean meal diets (0.34% total P, 3.8% Ca, 17% CP, 2,758 kcal ME/kg) containing 0.10, 0.15, 0.20, 0.25, or 0.45% available P (AP), with the three lowest AP diets supplemented with 300 units of phytase/kg of diet. A second experiment evaluated the effect of feeding the 0.10% AP diet with and without phytase on performance and time required for onset of P deficiency in older hens (70 to 76 wk of age). In Experiment 1, the 0.10% AP diet with no supplemental phytase depressed performance by 28 wk of age. No other significant differences in performance were observed among treatments for the entire 20- to 70-wk period except that the 0.15% AP diet with no phytase resulted in body weights and tibia ash that were lower (P < 0.05) than those of hens fed the 0.45% AP diet during the last 30 wk. The mean daily AP intake of hens fed the 0.10% AP, 0.15% AP, 0.45% AP, or 0.10% AP + phytase diets was 94,159, 499, or 108 mg, respectively. Excreta P concentration was decreased by approximately 50% in birds consuming 0.10% AP + 300 U/kg phytase compared with those consuming 0.45% AP. In the second experiment, P deficiency signs occurred within 3 wk of consuming the unsupplemented corn-soybean meal diet (0.10% AP) compared with 8 wk in Experiment 1. The results of this study indicate that phytase improves P utilization in corn-soybean meal diets for laying hens and that a corn-soybean meal diet containing 0.15% AP (159 mg AP/d) or containing 0.10% AP + 300 units of phytase/kg (108 mg AP/d) supported optimal egg production from 20 to 70 wk of age. Additionally, results suggested that older hens may exhibit P deficiency symptoms sooner than younger hens.
在两项实验的第一项（20至70周龄）中，八种处理包括玉米 - 豆粕型日粮（总磷0.34%、钙3.8%、粗蛋白17%、代谢能2,758千卡/千克），其有效磷（AP）含量分别为0.10%、0.15%、0.20%、0.25%或0.45%，三种最低AP含量的日粮每千克日粮补充300单位植酸酶。第二项实验评估了在70至76周龄的老龄母鸡中，饲喂添加和不添加植酸酶的0.10%AP日粮对生产性能以及出现磷缺乏所需时间的影响。在实验1中，不添加植酸酶的0.10%AP日粮到28周龄时生产性能下降。在整个20至70周期间，除了在最后30周内，不添加植酸酶的0.15%AP日粮导致母鸡体重和胫骨灰分低于（P<0.05）饲喂0.45%AP日粮的母鸡外，各处理之间在生产性能上未观察到其他显著差异。饲喂0.10%AP、0.15%AP、0.45%AP或0.10%AP + 植酸酶日粮的母鸡平均每日AP摄入量分别为94、159、499或108毫克。与饲喂0.45%AP的鸡相比，采食0.10%AP + 300单位/千克植酸酶的鸡粪便磷浓度降低了约50%。在第二项实验中，采食未补充植酸酶的玉米 - 豆粕型日粮（0.10%AP）的母鸡在3周内出现磷缺乏症状，而在实验1中为8周。本研究结果表明，植酸酶可提高蛋鸡玉米 - 豆粕型日粮中磷的利用率，并且含0.15%AP（159毫克AP/天）或含0.10%AP + 300单位/千克植酸酶（108毫克AP/天）的玉米 - 豆粕型日粮可在20至70周龄时支持最佳产蛋性能。此外，结果表明老龄母鸡可能比年轻母鸡更早出现磷缺乏症状。
