Having it all: historical energy intakes do not generate the anticipated trade-offs in fecundity
Having it all: historical energy intakes do not generate the anticipated trade-offs in fecundity
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DOI：
10.1098/rspb.2005.3456
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发表时间：
2006-06-07
影响因子：
4.7
通讯作者：
Speakman, J. R.
中科院分区：
文献类型：
--
作者：
Johnston, S. L.;Grune, T.;Speakman, J. R.
生命史理论的一个公理，也是我们理解衰老的基础，是动物必须权衡它们的资源分配，因为能量和营养是有限的。因此，动物不可能“拥有一切”--联合收割机既有高繁殖率，又有延长的寿命。生命史权衡的想法最近受到了一个发现的挑战，即衰老可能是由一小部分独立于适应性的分子过程控制的。我们通过检查C57 BL/6 J小鼠的生殖力来测试“权衡”和“拥有一切”理论，这些小鼠被置于四种不同的饮食治疗中，产生的热量摄入量为对照组的-21%至+8.6%。我们预测身体脂肪的沉积与热量的摄入有关。众所周知，过多的身体脂肪会导致缩短寿命的并发症，而热量限制则会增强身体保护并延长寿命。权衡模型预测，增加的脂肪是可以容忍的，因为生殖增益抵消了缩短的寿命，而限制摄入量的动物将牺牲生殖来延长寿命。体脂对治疗的反应符合我们的预期，然而，生殖性能（繁殖力，窝质量）和历史摄入量/体脂之间存在负相关。我们的饮食限制动物具有较低的蛋白质氧化损伤，并且似乎能够以与传统预期相反的方式将联合收割机生活史特征结合起来，即具有增加繁殖力和延长寿命的潜力。
axiom of life-history theory, and fundamental to our understanding of ageing, is that animals must trade-off their allocation of resources since energy and nutrients are limited. Therefore, animals cannot 'have it all'-combine high rates of fecundity with extended lifespans. The idea of life-history trade-offs was recently challenged by the discovery that ageing may be governed by a small subset of molecular processes independent of fitness. We tested the 'trade-off' and 'having it all' theories by examining the fecundities of C57BL/6J mice placed onto four different dietary treatments that generated caloric intakes from -21 to +8.6% of controls. We predicted body fat would be deposited in relation to caloric intake. Excessive body fat is known to cause co-morbidities that shorten lifespan, while caloric restriction enhances somatic protection and increases longevity. The trade-off model predicts that increased fat would be tolerated because reproductive gain offsets shortened longevity, while animals on a restricted intake would sacrifice reproduction for lifespan extension. The responses of body fat to treatments followed our expectations, however, there was a negative relationship between reproductive performance (fecundity, litter mass) and historical intake/body fat. Our dietary restricted animals had lower protein oxidative damage and appeared able to combine life-history traits in a manner contrary to traditional expectations by having increased fecundity with the potential to have extended lifespans.