McNiven M A
Br J Nutr. 1984 Mar;51(2):297-304. doi: 10.1079/bjn19840034.
The effect of body fatness on the fasting heat production and energetic efficiency of adult sheep was studied. Energy balance and heat production were determined in adult wether sheep at three fatness levels given a diet of grass hay and maize at four feeding levels, including fasting, in open-circuit respiration chambers. The sheep weighted approximately 60 kg at the start and were fed over a period of 4-7 months to obtain one of three levels of body fatness: fat 90 kg, medium 70 kg and thin 55 kg. Neither the digestibility nor the metabolizability of the diet was affected by body fatness or feeding level. Average fasting heat production was 6.47, 7.00 and 8.20 MJ/d for the thin, medium and fat sheep respectively, but when expressed as a multiple of metabolic body size (kg W0.75) remained constant at 0.31 MJ/kg W0.75. At each level of feeding the fat sheep produced most heat, but when heat production was expressed as a multiple of fasting heat production or metabolic body size, the differences due to level of fatness disappeared. Heat increment was not affected by fatness and there was no suggestion that energy utilization was improved by loss of condition. It is concluded that white adipose tissue is highly active and contributes significantly to the maintenance energy requirements of adult sheep. Metabolic body size is a good unit of reference for comparison of energy metabolism in adult animals of the same species but varying in body size.
研究了体脂对成年绵羊空腹产热和能量效率的影响。在开路呼吸室中，给处于三种体脂水平的成年阉羊提供四种饲喂水平（包括禁食）的禾本科干草和玉米日粮，测定其能量平衡和产热情况。实验开始时绵羊体重约60千克，经过4至7个月的饲喂，使其达到三种体脂水平之一：肥胖型90千克、中等型70千克和消瘦型55千克。日粮的消化率和代谢率均不受体脂水平或饲喂水平的影响。消瘦、中等和肥胖绵羊的平均空腹产热分别为6.47、7.00和8.20兆焦/天，但以代谢体重（千克W0.75）的倍数表示时，保持恒定在0.31兆焦/千克W0.75。在每个饲喂水平下，肥胖绵羊产热最多，但当产热以空腹产热或代谢体重的倍数表示时，因体脂水平导致的差异消失。热增量不受体脂影响，也没有迹象表明体重减轻会提高能量利用效率。得出的结论是，白色脂肪组织高度活跃，对成年绵羊维持能量需求有显著贡献。代谢体重是比较同一物种但体型不同的成年动物能量代谢的良好参考单位。
