An experiment was conducted to investigate the effectiveness of sequential feeding of a very low non-phytate P (NPP) diet supplemented with varying doses of phytase to broiler chickens. A total of 450 one-day-old male broiler chickens were fed a standard diet up to 14 d of age, then allotted to 6 dietary treatments (with 5 replicates of 15 broiler chickens each) from d 14 to 42. Dietary treatments included a positive control [PC; 4.35 g NPP/kg (d 14 to 28) and 3.95 g NPP/kg (d 28 to 42)], a negative control without any inorganic P source [NC; 1.50 g NPP/kg (d 14 to 28) and 1.36 g NPP/kg (d 28 to 42)], and a negative-positive control (NPC), in which broiler chickens received the PC for 24 h and then fed the NC (including 0, 500, 1,500, or 3,000 FTU phytase/kg) for the following day in a 48-h-cycle sequential feeding program. The Ca to NPP ratio was maintained at 2 to 1 in all formulations. The NC diet decreased overall feed intake (FI) and serum P compared to those of the PC diet (P = 0.047 for overall FI; P < 0.001 for serum P). Broiler chickens fed the NC diet had lower overall body weight gain (BWG), carcass yield, tibia ash, and tibia P than those fed the PC diet (P < 0.001), and the NPC diet failed to fully restore such losses. The inclusion of 500 FTU phytase/kg in the NPC diet recovered BWG, carcass yield, tibia ash, tibia P, and tibia strength losses by feeding the low-P diet to the PC values. Overall feed conversion ratio (P = 0.031), total P retention (P < 0.001), tibia ash (P < 0.001), and tibia P (P = 0.001) were improved linearly with increasing doses of phytase in the NPC diet. It was concluded that sequential feeding of the very low-NPP diet failed to recover all growth losses noted on the NC, but the inclusion of 500 FTU phytase/kg in the NPC diet restored the growth and bone mineralization losses to the PC values. Also, sequential feeding of the very low-NPP diets with increasing phytase doses had increasingly beneficial effects on overall growth performance.

进行了一项实验，以研究向肉鸡连续饲喂补充了不同剂量植酸酶的极低非植酸磷（NPP）日粮的有效性。总共对450只1日龄的雄性肉鸡进行了14日龄以下的标准饮食喂养，然后在14天到42天之间分配了6种饮食疗法（每组15个肉鸡重复5次）。阳性对照[PC; 4.35 g NPP / kg（d 14至28）和3.95 g NPP / kg（d 28至42）]，阴性对照，无任何无机P源[NC; 1.50 g NPP / kg（第14至28天）和1.36 g NPP / kg（第28至42天）]，以及一个阴性-阳性对照（NPC），其中肉鸡接受PC 24小时，然后喂NC （包括0、500、1,500或3,000 FTU植酸酶/ kg）在48小时连续喂食程序中的第二天。在所有配方中，Ca与NPP的比例均保持在2：1。与PC饮食相比，NC饮食降低了总的采食量（FI）和血清P（对于整体FI，P = 0.047；血清P的P < 0.001）。饲喂NC饲料的肉鸡的总体体重增加（BWG），car体产量，胫骨灰分和胫骨P含量低于饲喂PC饲料的肉鸡（P < 0.001），而NPC饲料不能完全弥补这种损失。通过将低磷饮食饲喂至PC值，NPC饮食中包含500 FTU植酸酶/ kg可恢复体重，WG体产量，胫骨灰分，胫骨P和胫骨强度损失。总饲料转化率（P = 0.031），总磷保留量（P < 0.001），胫骨灰分（P < 0.001）和胫骨P（P =0.001）随NPC日粮中植酸酶剂量的增加而线性增加。结论是，非常低NPP饮食的连续喂养不能恢复NC上提到的所有生长损失，但是NPC饮食中包含500 FTU植酸酶/ kg可使生长和骨矿化损失恢复到PC值。同样，随着植酸酶剂量的增加，非常低NPP的日粮的饲喂对整体生长性能产生越来越有利的影响。