Sibbald I R, Wolynetz M S
Poult Sci. 1984 Apr;63(4):691-702. doi: 10.3382/ps.0630691.
An experiment was conducted in which the energy and nitrogen voided by cockerels during the final 48 hr of each of 14 72-hr fasts, 28 days apart, were measured. There were 12 Single Comb White Leghorn cockerels of each of two strains aged 150 days at the time of the first excreta collection and 12 birds from each of two meat-type strains aged 268 days at the first collection. Birds that died during the experiment were replaced by similar birds maintained under comparable conditions. Both excreta energy (FE + UE) and excreta nitrogen (FN + UN) varied among time periods and among birds and appeared to be related to metabolic body size. Similar patterns were observed when the FE + UE data were corrected to zero nitrogen balance (FEn + UEn ). There was a significant (P less than .01) quadratic relationship between ambient temperature and FE + UE, FN + UN, and FEn + UEn with higher excreta outputs being associated with either low or high temperatures. Frequently, but not inevitably, higher FE + UE and FN + UN were observed prior to death. The FE + UE was significantly (P less than .01) correlated with FN + UN. In general, the estimated regression coefficient relating energy to nitrogen output was similar to the value, based upon the energy content of chicken urine, used to correct FE + UE to FEn + UEn . However, the analyses indicated that the correction factor may vary among birds or over time and may be related to metabolic body weight. To what extent this variability can be defined and incorporated into metabolic energy assays requires further investigation.
进行了一项实验，测量了14只公鸡在每28天一次、每次为期72小时禁食的最后48小时内排出的能量和氮。在第一次收集排泄物时，两个品系的12只单冠白来航公鸡年龄均为150天，两个肉用型品系的12只公鸡在第一次收集时年龄为268天。实验期间死亡的鸡被处于类似条件下饲养的相似鸡只替代。排泄物能量（FE + UE）和排泄物氮（FN + UN）在不同时间段和不同鸡只之间存在差异，并且似乎与代谢体重有关。当将FE + UE数据校正为零氮平衡（FEn + UEn）时，观察到了类似的模式。环境温度与FE + UE、FN + UN和FEn + UEn之间存在显著（P小于0.01）的二次关系，较高的排泄物输出与低温或高温相关。在死亡前，经常（但并非必然）观察到较高的FE + UE和FN + UN。FE + UE与FN + UN显著（P小于0.01）相关。一般来说，将能量与氮输出相关的估计回归系数与基于鸡尿液能量含量用于将FE + UE校正为FEn + UEn的值相似。然而，分析表明校正因子可能因鸡只或时间而异，并且可能与代谢体重有关。这种变异性在多大程度上可以被定义并纳入代谢能测定中需要进一步研究。
