0～4周龄怀乡鸡饲粮中非植酸磷的适宜水平

Dietary Optimum Level of Non-Phytate Phosphorous for Huaixiang Broilers Aged from 0 to 4 Weeks

本试验旨在通过研究饲粮非植酸磷(NPP)水平对0~4周龄怀乡鸡生长性能、胫骨特 性、钙与磷代谢率及血清生化指标的影响,确定其饲粮中 NPP 的适宜水平。 采用单因子完全随 机设计,选用健康、体重相近的 1 日龄怀乡鸡 300 只,随机分为 5 组,每组 6 个重复,每个重复 10 只鸡。 5 组试鸡分别饲喂 NPP 水平为 0.32%、0.39%、0.46%、0.53%、0.60%的玉米-豆粕型试 验饲粮,试验期28d。 结果显示:1)饲粮NPP水平对怀乡鸡的平均日采食量没有显著影响(P> 0.05),但对末重、平均日增重和料重比有显著影响(P<0.05),其与饲粮 NPP 水平的最佳拟合曲 线分别为二次折线(R^2=0.8520)、线性折线(R^2=0.8541)和二次曲线(R^2=0.9001)。 2)饲粮 NPP水平对怀乡鸡的胫骨抗压强度及灰分、钙含量有显著影响(P<0.05),其与饲粮 NPP 水平的 最佳拟合曲线分别为二次曲线(R^2=0.8872)、二次折线(R^2=0.9043)、线性折线(R^2= 0.900 7)。 3)怀乡鸡的粗灰分、钙、磷代谢率也随饲粮 NPP 水平的增加发生显著变化(P< 0.05),其与饲粮NPP水平的最佳拟合曲线分别为线性折线(R^2=0.9643)、线性折线(R^2= 0.8762)、二次曲线(R^2=0.9411)。 4)饲粮NPP水平对怀乡鸡的血清磷含量有显著影响(P< 0.05),其与饲粮NPP水平的最佳拟合曲线为线性折线(R^2=0.9463)。 综上可知,料重比、胫骨 灰分和钙含量、粗灰分和磷代谢率及血清磷含量可敏感反映0~4周龄怀乡鸡体内磷营养状况, 通过这 6 个敏感指标的拟合方程求得饲粮 NPP 适宜水平分别为 0.47%、0.46%、0.46%、0.46%、 0.49%、0.45%,因此建议0~4周龄怀乡鸡饲粮中NPP的适宜水平为0.45%~0.49%,仅满足怀 乡鸡生长的 NPP 需要量为 0.39%,而满足其骨骼发育的 NPP 需要量为 0.46%。

In this experiment,the effects of dietary non-phytate phosphorous(NPP)level on growth performance,tibia characteristics,the metabolism rates of calcium and phosphorous and serum bio-chemical indices were investigated to determine the dietary optimum level of NPP for Huaixiang broilers aged from 0 to 4 weeks.A total of 300 one-day-old healthy Huaixiang broilers with the similar body weight were assigned to 5 groups with 6 replicates of 10 birds each using a completely randomized design.Broilers in the 5 groups were fed a corn-soybean meal type experimental diets containing 0.32%,0.39%,0.46%,0.53%and 0.60%NPP for 28 days,respectively.The results showed that the dietary NPP level did not significantly affect average daily feed intake(P>0.05),but significantly affected final weight,average daily gain and feed/gain(P<0.05).The best fitted curves of the final weight,average daily gain and feed/gain with dietary NPP level were quadratic broken line(R^2=0.852 0),linear broken line(R^2=0.854 1)and quadratic curve(R^2=0.900 1),respectively.2)Dietary NPP level had significant effects on tibia broken strength,tibia ash content,tibia bone calcium content(P<0.05).The best fitted curves of the tibia broken strength,tibia ash content,tibia bone calcium content with dietary NPP level were quadratic curve(R^2=0.887 2),quadratic broken line(R^2=0.904 3)and linear broken line(R^2=0.900 7),respectively.3)The metabolic rates of ash,calcium and phosphorous were significantly changed with the dietary NPP level increasing(P<0.05).The best fitted curves of the metabolic rates of ash,calcium and phosphorous with dietary NPP level were linear broken line(R^2=0.964 3),linear broken line(R^2=0.876 2)and quadratic curve(R^2=0.941 1),respectively.4)Dietary NPP level had significant effect on serum phosphorous content(P<0.05),and the serum phosphorous content showed a linear broken line(R^2=0.964 3)with the dietary NPP level.In conclusion,feed/gain,tibia ash content,tibia calcium content,the metabolic rates of ash and phosphorous and serum phosphorous content are sensitive indicators for estimating phosphorous nutrient status of Huaixiang broilers.Based on the fitted equations of the 6 sensitive indicators,the estimated NPP optimum levels are 0.47%,0.46%,0.46%,0.46%,0.49%and 0.45%,respectively.So,the recommended dietary NPP optimum level for Huaixiang broilers aged from 0 to 4 weeks is in the range of 0.45%to 0.49%.The NPP requirement for optimum growth can set to be 0.39%,while the NPP requirement for optimum bone development seems to be 0.46%.