Limits to sustained energy intake.: X.: Effects of fur removal on reproductive performance in laboratory mice
Limits to sustained energy intake.: X.: Effects of fur removal on reproductive performance in laboratory mice
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DOI：
10.1242/jeb.009779
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发表时间：
2007-12-01
影响因子：
2.8
通讯作者：
Speakman, John R.
中科院分区：
文献类型：
--
作者：
Krol, Elzbieta;Murphy, Michelle;Speakman, John R.
最大持续能量摄入率（SusEI）可能会限制生殖努力和动物性能的其他方面。我们以前曾提出，哺乳期小鼠不受消化道的中枢限制或乳腺的外周限制，但对SusEI的限制是由动物耗散作为加工食物和产奶副产品产生的体热的能力所施加的。为了探索SusEI限制的性质，我们在21 ℃下饲养了MF 1实验室小鼠，然后对哺乳期雌性小鼠进行背部剃毛，以减少其外部绝缘，从而提高其散热能力。这些小鼠的食物摄入量增加了12.0%，平均吸收30.9 kJ天（-1）比未剃毛的动物多的能量。在平均窝仔数几乎相同的情况下（剃毛小鼠为11.4只幼崽，未剃毛小鼠为11.3只幼崽），剃毛小鼠的母亲以乳汁形式输出的能量比对照个体多15.2%（22.0 kJ天（-1））。剃毛小鼠的产奶量增加，使它们能够断奶的窝仔比未剃毛小鼠产生的后代重15.4%（12.2 g）。我们的研究结果反对中央，外周或外在限制SusEI在哺乳高峰期，并提供了强有力的支持散热极限假说。更一般地说，我们看到许多情况下，散热可能是一个以前未被认识到的因素，限制了吸热动物的进化-例如，纬度和海拔的趋势，在离合器和窝仔的大小和鸟类的迁移模式。
The maximum rate of sustained energy intake (SusEI) may limit reproductive effort and other aspects of animal performance. We have previously suggested that lactating mice are not limited centrally by the alimentary tract or peripherally by the mammary glands, but that the limits to SusEI are imposed by the capacity of the animal to dissipate body heat generated as a by-product of processing food and producing milk. To explore the nature of the limits to SusEI, we bred MF1 laboratory mice at 21 C and then dorsally shaved lactating females to reduce their external insulation and thereby elevate their capacity to dissipate body heat. These mice increased their food intake by 12.0% and assimilated on average 30.9 kJ day(-1) more energy than unshaved animals. With nearly identical mean litter sizes (11.4 pups for shaved and 11.3 pups for unshaved mice), shaved mothers exported 15.2% (22.0 kJ day(-1)) more energy as milk than control individuals. The elevated milk production of shaved mice enabled them to wean litters that were 15.4% (12.2 g) heavier than offspring produced by unshaved mice. Our results argue against central, peripheral or extrinsic limits to SusEI at peak lactation and provide strong support for the heat dissipation limit hypothesis. More generally, we see many situations where heat dissipation may be a previously unrecognised factor constraining the evolution of endothermic animals - for example, the latitudinal and altitudinal trends in clutch and litter sizes and the migration patterns of birds.