Blount Jonathan D, Metcalfe Neil B, Arnold Kathryn E, Surai Peter F, Devevey Godefroy L, Monaghan Pat
Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
Proc Biol Sci. 2003 Aug 22;270(1525):1691-6. doi: 10.1098/rspb.2003.2411.
Early nutrition has recently been shown to have pervasive, downstream effects on adult life-history parameters including lifespan, but the underlying mechanisms remain poorly understood. Damage to biomolecules caused by oxidants, such as free radicals generated during metabolic processes, is widely recognized as a key contributor to somatic degeneration and the rate of ageing. Lipophilic antioxidants (carotenoids, vitamins A and E) are an important component of vertebrate defences against such damage. By using an avian model, we show here that independent of later nutrition, individuals experiencing a short period of low-quality nutrition during the nestling period had a twofold reduction in plasma levels of these antioxidants at adulthood. We found no effects on adult external morphology or sexual attractiveness: in mate-choice trials females did not discriminate between adult males that had received standard- or lower-quality diet as neonates. Our results suggest low-quality neonatal nutrition resulted in a long-term impairment in the capacity to assimilate dietary antioxidants, thereby setting up a need to trade off the requirement for antioxidant activity against the need to maintain morphological development and sexual attractiveness. Such state-dependent trade-offs could underpin the link between early nutrition and senescence.
近期研究表明，早期营养对包括寿命在内的成年生活史参数具有广泛的下游影响，但其潜在机制仍知之甚少。代谢过程中产生的自由基等氧化剂对生物分子造成的损伤，被广泛认为是体细胞退化和衰老速度的关键因素。亲脂性抗氧化剂（类胡萝卜素、维生素A和E）是脊椎动物抵御此类损伤的重要组成部分。通过使用鸟类模型，我们在此表明，与后期营养无关，雏鸟期经历短时间低质量营养的个体在成年期血浆中这些抗氧化剂的水平降低了两倍。我们发现这对成年期的外部形态或性吸引力没有影响：在择偶试验中，雌性并未区分在幼年期接受标准或低质量饮食的成年雄性。我们的结果表明，低质量的新生儿营养导致同化膳食抗氧化剂的能力长期受损，从而需要在对抗氧化活性的需求与维持形态发育和性吸引力的需求之间进行权衡。这种状态依赖性的权衡可能是早期营养与衰老之间联系的基础。
