Olomu J M, Offiong S A
Poult Sci. 1980 Apr;59(4):828-35. doi: 10.3382/ps.0590828.
Three experiments were conducted to determine the optimum protein and energy levels for starting and finishing broiler chickens and the optimum time of change from broiler starter rations to broiler chicken finisher rations. We tested four protein levels (17, 20, 23, and 26%), each fed at three energy levels (2800, 3000, and 3200 kcal/kg diet). For starting chickens, maximum weight gains, feed efficiency, and lowest feed cost per kilogram live weight gain were obtained on the rations containing 23 or 26% protein. Differences in dietary energy levels did not significantly affect weight gain and feed consumption. Feed efficiency improved with increase in dietary energy levels although the differences in feed efficiency between any two consecutive groups were not significant. Feed cost tended to increase nonsignificantly with increase in energy level. For finishing broiler chickens, dietary protein level did not have any significant effects on weight gains. The poorest weight gain, feed efficiency, and feed cost per kilogram gain were obtained on the rations containing 17% protein. The differences in feed efficiency between protein levels of 20, 23, and 26% were not significant while no two consecutive protein levels among the 20, 23, and 26% protein diets gave feed cost per kilogram gain that was significantly different from each other. Weight gain, feed consumption, and feed cost per kilogram gain were not significantly affected by dietary energy levels. Efficiency of feed conversion tended to improve with increase in dietary energy levels, although differences in feed efficiency between 3000 and 3200 kcal/kg diet were not significant. Performances of birds fed the starter ration for 0, 1, 2, 3, or 4 weeks before changing to the finisher ration were not as good as those fed the starter ration for 5 or 6 weeks before being change) to the finisher ration or those fed the starter ration for the 9 weeks experimental period. The results of the present work indicate that a protein level of 23% and energy level of 2800 to 3000 kcal/kg diet may be recommended for starting broiler chicks raised in Nigeria. For finishing broiler chickens, a protein level of 20% and energy level of 3000 kcal/kg diet may be recommended. The optimum time of change from broiler starter to broiler finisher may be recommended at 5 or 6 weeks of age.
进行了三项试验，以确定肉仔鸡育雏期和育肥期的最佳蛋白质和能量水平，以及从肉仔鸡育雏日粮转换为肉仔鸡育肥日粮的最佳时间。我们测试了四种蛋白质水平（17%、20%、23%和26%），每种蛋白质水平分别饲喂三种能量水平（2800、3000和3200千卡/千克日粮）。对于育雏期肉仔鸡，在含23%或26%蛋白质的日粮上可获得最大体重增加、饲料效率以及每千克体重增加的最低饲料成本。日粮能量水平的差异对体重增加和采食量没有显著影响。随着日粮能量水平的提高，饲料效率有所改善，尽管任意两个连续组之间的饲料效率差异不显著。饲料成本倾向于随着能量水平的提高而无显著增加。对于育肥期肉仔鸡，日粮蛋白质水平对体重增加没有任何显著影响。在含17%蛋白质的日粮上获得的体重增加、饲料效率和每千克增重的饲料成本最差。20%、23%和26%蛋白质水平之间的饲料效率差异不显著，而在20%、23%和26%蛋白质日粮中，任意两个连续蛋白质水平之间每千克增重的饲料成本彼此之间没有显著差异。体重增加、采食量和每千克增重的饲料成本不受日粮能量水平的显著影响。随着日粮能量水平的提高，饲料转化率倾向于提高，尽管3000千卡/千克日粮和3200千卡/千克日粮之间的饲料效率差异不显著。在转换为育肥日粮之前，饲喂育雏日粮0、1、2、3或4周的肉仔鸡的性能不如在转换为育肥日粮之前饲喂育雏日粮5或6周的肉仔鸡，也不如在9周试验期内一直饲喂育雏日粮的肉仔鸡。本研究结果表明，对于在尼日利亚饲养的肉仔鸡雏鸡，建议日粮蛋白质水平为23%，能量水平为2800至3000千卡/千克日粮。对于育肥期肉仔鸡，建议日粮蛋白质水平为20%，能量水平为3000千卡/千克日粮。从肉仔鸡育雏日粮转换为育肥日粮的最佳时间可能建议为5或6周龄。
