INRA - UMR Pegase Saint-Gilles, France ; Agrocampus Ouest - UMR Pegase Rennes, France.
Front Physiol. 2013 Jun 19;4:146. doi: 10.3389/fphys.2013.00146. eCollection 2013.
In growing pigs, the feed cost accounts for more than 60% of total production costs. The determination of efficiency of energy utilization through calorimetry measurements is of importance to sustain suitable feeding practice. The objective of this paper is to describe a methodology to correct daily heat production (HP) obtained from measurements in respiration chamber for the difference in energy expenditure related to physical activity between animals. The calculation is based on a preliminary published approach for partitioning HP between HP due to physical activity (AHP), thermic effect of feeding (TEF) and basal metabolic rate (fasting HP; FHP). Measurements with male growing pigs [mean body weight (BW): 115 kg] which were surgically castrated (SC), castrated through immunization against GnRH (IC), or kept as entire male (EM) were used as an example. Animals were fed the same diet ad-libitum and were housed individually in two 12-m(3) open-circuit respiration chambers during 6 days when fed ad-libitum and one supplementary day when fasted. Physical activity was recorded through interruption of an infrared beam to detect standing and lying positions and with force transducers that recorded the mechanical force the animal exerted on the floor of the cage. Corrected AHP (AHPc), TEF (TEFc), and HP (HPc) were calculated to standardize the level of AHP between animals, assuming that the ratio between AHPc and ME intake should be constant. Inefficiency of energy utilization (sum of AHPc and TEFc) was lower than the inefficiency estimated from the slope of the classical relationship between HPc and ME intake but was associated with higher requirements for maintenance. Results indicate that EM pigs had higher FHP but lower TEFc than IC and SC pigs. These results agree with the higher contents in viscera of EM pigs that stimulate their basal metabolic rate and with the reduced utilization of dietary protein to provide energy for maintenance energy requirements and fat deposition (FD).
在生长猪中，饲料成本占总生产成本的 60%以上。通过量热法测量来确定能量利用效率对于维持适宜的饲养实践非常重要。本文的目的是描述一种方法，用于校正通过呼吸室测量得到的每日产热量（HP），以消除动物之间与体力活动相关的能量消耗差异。该计算基于先前发表的一种方法，即将 HP 分为体力活动相关 HP（AHP）、饲料热效应（TEF）和基础代谢率（空腹 HP；FHP）。以雄性生长猪（平均体重（BW）：115 公斤）为例，这些猪接受了手术去势（SC）、通过 GnRH 免疫去势（IC）或保持完整雄性（EM）。动物自由采食相同的饮食，并在 6 天自由采食期间单独饲养在两个 12 立方米的开路呼吸室内，然后在禁食的一天进行补充。通过中断红外光束来检测站立和躺卧姿势来记录体力活动，并用力传感器记录动物对笼子地板施加的机械力。校正后的 AHP（AHPc）、TEF（TEFc）和 HP（HPc）被计算出来，以标准化动物之间的 AHP 水平，假设 AHPc 和 ME 摄入之间的比例应该是恒定的。能量利用效率（AHPc 和 TEFc 的总和）低于从 HPc 和 ME 摄入的经典关系斜率估计的效率，但与更高的维持需求有关。结果表明，EM 猪的 FHP 较高，但 TEFc 比 IC 和 SC 猪低。这些结果与 EM 猪内脏含量较高的情况一致，内脏会刺激其基础代谢率，并且用于满足维持能量需求和脂肪沉积（FD）的能量的饲料蛋白质利用率降低。
