本试验旨在研究饲粮氮、磷水平对肉仔鸡生长性能、胴体性状和血清生化指标的影响,为制订肉仔鸡适宜饲粮粗蛋白质(CP)、磷供给量提供依据。选取1日龄健康的罗斯308肉仔鸡1 200只,分1~7日龄、8~21日龄、22~35日龄和36~40日龄4个阶段饲养,试验饲粮为玉米-小麦-豆粕型,每个阶段按饲粮氮、磷水平分成4组,即高氮高磷组[HH组,CP:22.70%、21.60%、19.50%、17.50%;非植酸磷(NPP):0.45%、0.40%、0.35%、0.30%]、高氮低磷组[HL组,CP:22.70%、21.60%、19.50%、17.50%;NPP:0.30%、0.25%、0.20%、0.15%;耐高温植酸酶(TP):500、1 000、1 500、2 000 U/kg]、低氮高磷组(LH组,CP:20.70%、19.70%、17.70%、15.70%;NPP:0.45%、0.40%、0.35%、0.30%)、低氮低磷组(LL组,CP:20.70%、19.70%、17.70%、15.70%;NPP:0.30%、0.25%、0.20%、0.15%;TP:500、1 000、1 500、2 000 U/kg),每组10个重复,每个重复30只,公母各占1/2。结果表明:1)1~35日龄,HH组和HL组35日龄平均体重极显著高于LH组(P<0.01),显著高于LL组(P<0.05),HH组和HL组平均日增重(ADG)显著高于LH组(P<0.05),HL组料重比显著低于LH组和LL组(P<0.05),HH组平均日采食量(ADFI)极显著高于LH组(P<0.01),显著高于LL组(P<0.05);1~40日龄,HH组40日龄平均体重显著高于LH组(P<0.05),HH组ADG和ADFI显著高于LH组(P<0.05);其他指标各组间差异不显著(P>0.05);2)HH组和LH组血清碱性磷酸酶活性显著高于HL组(P<0.05),极显著高于LL组(P<0.01),HH组血清尿酸含量极显著高于LH组(P<0.01),显著高于LL组(P<0.05),HL组血清尿酸含量显著高于LH组(P<0.05)。饲粮氮、磷水平对肉仔鸡血清其他生化指标和胴体性状无显著影响(P>0.05)。分析表明,罗斯308肉仔鸡采用4阶段饲养法,1~35日龄,HL组(CP:22.70%、21.60%、19.50%、17.50%;NPP:0.30%、0.25%、0.20%、0.15%;TP:500、1 000、1 500、2 000 U/kg)增重效果最好,经济效益最高;1~40日龄,LL组(CP:20.70%、19.70%、17.70%、15.70%;NPP:0.30%、0.25%、0.20%、0.15%;TP:500、1 000、1 500、2 000 U/kg)经济和生态效益最高。

This experiment was conducted to assess the effects of dietary nitrogen and phosphorus levels on growth performance, carcass traits and serum biochemical indexes of broilers, and to provide reference for the recommended allowance of crude protein and phosphorus in diets of broilers. One thousand and two hundred 1-day-old healthy Ross 308 broilers were reared under four feeding phases system: 1 to 7 days of age, 8 to 21 days of age, 22 to 35 days of age and 36 to 40 days of age, and those in each feeding phase were randomly divided into 4 groups with 10 replicates per group and 30 birds per replicate, male and female half and half. The experimental diets were corn, wheat and soybean meal, and according to the dietary nitrogen and phosphorus levels, the four groups were higher-nitrogen-higher-phosphorus group [HH group, crude protein (CP): 22.70%, 21.60%, 19.50% and 17.50%; non-phytate phosphorus (NPP): 0.45%, 0.40%, 0.35% and 0.30%), higher-nitrogen-lower-phosphorus group (HL group, CP: 22.70%, 21.60%, 19.50% and 17.50%; NPP: 0.30%, 0.25%, 0.20% and 0.15%), lower-nitrogen-higher-phosphorus group (LH group, CP: 20.70%, 19.70%, 17.70% and 15.70%; NPP: 0.45%, 0.40%, 0.35% and 0.30%) and lower-nitrogen-lower- phosphorus group (LL group, CP: 20.70%, 19.70%, 17.70% and 15.70%; NPP: 0.30%, 0.25%, 0.20% and 0.15%), and HL group and LL group were supplemented with 500, 1 000, 1 500 and 2 000 U/kg thermostable phytase (TP), respectively. The results showed as follows:1) at 1 to 35 days of age, the 35-day-old average body weight (ABW) of HH group and HL group was significantly higher than that of LH group (P<0.01) and LL group (P<0.05). The average daily gain (ADG) of HH group and HL group was significantly higher than that of LH group (P<0.05). The feed to gain ratio (F/G) of HL group was significantly lower than that of LH group and LL group (P<0.05). The average daily feed intake (ADFI) of HH group was significantly higher than that of LH group (P<0.01) and LH group (P<0.05); at 1 to 40 days of age, the 40-day-old ABW of HH group was significantly higher than that of LH group (P<0.05). The ADG and ADFI of HH group were significantly higher than those of LH group (P<0.05). There was no significant difference in the other indexes among groups (P>0.05). 2) The activity of serum alkaline phosphatase of HH group and LH group was significantly higher than that of LL group (P<0.01) and HL group (P<0.05). The content of serum uric acid of HH group was significantly higher than that of LH group (P<0.01) and LL group (P<0.05), and that of HL group was significantly higher than that of LH group (P<0.05). There were no significant differences in the other serum biochemical indexes and carcass traits (P>0.05). The results indicate that, at 1 to 35 days of age, the HL group (CP: 22.70%, 21.60%, 19.50% and 17.50%; NPP: 0.30%, 0.25%, 0.20% and 0.15%; TP: 500, 1 000, 1 500 and 2 000 U/kg) for Ross 308 broilers obtains the best body weight gain and economical profit; at 1 to 40 days of age, the LL group (CP: 20.70%, 19.70%, 17.70% and 15.70%; NPP: 0.30%, 0.25%, 0.20% and 0.15%; TP: 500, 1 000, 1 500 and 2 000 U/kg) obtains the best economical and exobiology profit.