Sibbald I R, Price K
Poult Sci. 1975 Mar;54(2):448-56. doi: 10.3382/ps.0540448.
Two experiments were conducted to measure the variability of the M.E. values of diets and dietary ingredients fed to adult S.C.W.L. roosters. The first experiment was concerned with the variability between birds and days, the acclimatization to dietary change and the effect of the nitrogen correction. The standard error of the mean dietary M.E. value appropriate to an individual bird on one day was found to be 0.073 kcal./g. Increasing the number of days of excreta collection reduced this value slightly faster than did increasing the number of birds. The results suggest that the dietary acclimatization period should be at least 48 hr. The nitrogen correction was very small and of doubtful value. The second experiment comprised 5 bioassays in each of which 6 different samples of grain were fed at 3 levels of dietary inclusion (25, 50 and 75%) to birds drawn from the population used in the first experiment. The standard error of the mean dietary M.E. value was in agreement with the earlier value. The variance of ingredient M.E. values increased as the level of dietary inclusion decreased. Standard deviations of the mean M.E. value of an ingredient predicted from the data of the first experiment were in agreement with actual values observed in the second experiment. It is concluded that the adult rooster is suitable for use in bioassays designed to measure the M.E. values of diets and ingredients.
进行了两项试验以测定成年单冠白来航公鸡所采食日粮及日粮成分的代谢能值的变异性。第一项试验涉及不同鸡只及不同天数之间的变异性、对日粮变化的适应性以及氮校正的影响。发现某一天适合某只鸡的日粮代谢能值的平均标准误为0.073千卡/克。增加排泄物收集天数比增加鸡只数量能更快地略微降低该值。结果表明日粮适应期应至少为48小时。氮校正量非常小，其价值存疑。第二项试验包括5次生物测定，每次测定中，将6种不同的谷物样品按3种日粮添加水平（25%、50%和75%）喂给取自第一项试验群体的鸡只。日粮代谢能值的平均标准误与先前的值一致。随着日粮添加水平的降低，成分代谢能值的方差增大。根据第一项试验数据预测的成分代谢能值的平均标准差与第二项试验中观察到的实际值一致。得出结论，成年公鸡适用于旨在测定日粮及成分代谢能值的生物测定。
