Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada.
Department of Animal Science, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada.
Poult Sci. 2018 Feb 1;97(2):557-567. doi: 10.3382/ps/pex313.
Dietary phosphorus (P) oversupply is costly to the poultry industry and represents a point source of excessive P discharge to the environment via manure application to soils. The current study was conducted to investigate the effects of dietary available P (AP) level on growth performance, plasma biochemistry, bone characteristics, and P flow in order to assess minimal AP needs of pullets during the pre-lay period. A total of 192 Lohmann pullet chicks were randomly allocated to one of 4 treatments with 8 replicate cages of 6 birds per cage. The pullets of Low (L; the lowest AP regimen) were fed diets in a sequence of 0.200, 0.175, and 0.150% AP for the age period of 0 to 4 wk, 4 to 8 wk, and 8 to 16 wk, respectively. The AP level was increased by an increment of 0.1% in each phase in Low-Medium (LM), Medium-High (MH) and High (H), thus making H (control) consisting of 0.500, 0.475, and 0.450% AP. Overall, there were no main effects of treatment on body weight gain (BWG), feed intake (FI) and feed conversion ratio (FCR). However, compared with the H treatment, BWG or FI of the L treatment was lower during the first 8 wk post-hatch, but became comparable or higher over the last 8 wk (P < 0.05); FCR of L birds was greater over wk 0 to 4 but became smaller over wk 8 to 16 (P < 0.05). Plasma P was lower in L than H treatments at wk 8 but turned comparable at wk 16 (P < 0.001). Bone characteristics were not different for pullets fed various AP regimens. Total P intake and excretion were reduced with lowering dietary AP (P < 0.001), but its retention percent was not affected. The results indicated that the lowest AP regimen (0.200-0.175-0.150%) in the current study was adequate to support healthy growth and development of pre-lay pullets, while reducing P excretion in manure.
日粮磷（P）过量对家禽养殖业来说代价高昂，并且代表了粪便施用于土壤后 P 过度排放到环境中的一个点源。本研究旨在调查日粮有效磷（AP）水平对生长性能、血浆生化特性、骨骼特性和 P 流量的影响，以便评估产蛋前期母鸡的最低 AP 需要量。将 192 只罗曼母鸡雏鸡随机分配到 4 种处理中的 1 种，每个处理 8 个重复笼，每个重复笼有 6 只鸡。低磷（L；最低 AP 方案）组的雏鸡在 0 至 4 周、4 至 8 周和 8 至 16 周龄期间分别饲喂 0.200、0.175 和 0.150% AP 的日粮序列。在低-中（LM）、中-高（MH）和高（H）组中，AP 水平在每个阶段都增加 0.1%，因此 H（对照）组由 0.500、0.475 和 0.450% AP 组成。总的来说，处理对体重增重（BWG）、采食量（FI）和饲料转化率（FCR）没有主要影响。然而，与 H 处理相比，L 处理的雏鸡在孵化后前 8 周的 BWG 或 FI 较低，但在最后 8 周时变得相当或更高（P<0.05）；L 鸟的 FCR 在 0 至 4 周时较高，但在 8 至 16 周时较小（P<0.05）。L 组在第 8 周时血浆 P 低于 H 组，但在第 16 周时变得相当（P<0.001）。饲喂不同 AP 方案的母鸡的骨骼特性没有差异。随着日粮 AP 的降低（P<0.001），总 P 摄入量和排泄量减少，但保留率不受影响。结果表明，本研究中最低的 AP 方案（0.200-0.175-0.150%）足以支持产蛋前期母鸡的健康生长和发育，同时减少粪便中 P 的排泄。
