【摘要】 采用分组饲养试验、氮平衡试验和屠宰试验等方法 ,测定生长期绍鸭不同周龄 (0～ 4、5～8、9～ 16、17～ 2 0 )阶段、不同粗蛋白水平的等能日粮对氮利用率、日增重的影响 .用析因法推测单位增重及羽毛生长的蛋白质需要 .结果为 :(1)氮利用率受日粮蛋白质水平的影响 ,蛋白质水平越高 ,氮存留率越低 ,但这种影响不显著 .氮存留率与周龄有一定的相关性 ,0～ 8周的存留率显著高于 9～ 16周 ;(2 ) 0～ 4周增重速度最快 ,且受日粮蛋白质水平的影响显著 ,蛋白质越高 ,增重越快 ,5～ 8周增重有所减慢 ,9周后增重显著减慢 ,2 0周后体重变化不大 ;(3)单位增重的氮需要量随周龄增加而增大 ,增重效率随周龄增加而减小 ,0～ 4周为 50 mg/ g,4 6 .3% ;4～ 8周为 10 0 mg/ g,2 6 .0 % ;8周以后为 140 mg/ g,2 0 .5% .更多还原

【Abstract】 A grouped feeding trial,nitrogen(N) balance trial and slaughter tests were conducted to determine the effect of isoenergetic diets with different crude protein(CP)level sequences on feed protein utilization and bodyweight gain in Shaoxing Ma ducks at different periods (0-4,5-8,9-16 and17-20 weeks).Factorial method was used to calculate requirements for weight gain and feather growth. Bodyweight gain was significantly affected by the dietaly CP level during the first 4 weeks of age. The ratio of N retention to N intake tended to decrease with increasing dietary protein level in 0-8 weeks old, while there was no significant difference between CP levels( P >0.05). The ratio was also influenced by weeks of age ,with significantly higher value in 0-8 weeks than that in 9-16 weeks. The N requirement for weight gain increased and feed efficiency decreased with the age of weeks.更多还原