Studies of longevity rely on baseline life expectancy of reference genotypes measured in standardized conditions. Variation among labs, protocols, and genotypes makes longevity intervention studies difficult to compare. Furthermore, extending lifespan under suboptimal conditions or that of a short-lived genotype may be of a lesser theoretical and translational value than extending the maximal possible lifespan. Daphnia is becoming a model organism of choice for longevity research complementing data obtained on traditional models. In this study, we report longevity of several genotypes of a long-lived species D. magna under a variety of protocols, aiming to document the highest lifespan, factors reducing it, and parameters that change with age and correlate with longevity. Combining longevity data from 25 experiments across two labs, we report a strong intraspecific variation, moderate effects of group size and medium composition, and strong genotype-by-environment interactions with respect to food level. Specifically, short-lived genotypes show no caloric restriction (CR) effect, while long-lived ones expand their lifespan even further under CR. We find that the CR non-responsive clones show little correlation between longevity and two measures of lipid peroxidation. In contrast, the long-lived, CR-responsive clones show a positive correlation between longevity and lipid hydroperoxide abundance, and a negative correlation with MDA concentration. This indicates differences among genotypes in age-related accumulation and detoxification of LPO products and their effects on longevity. Our observations support the hypothesis that a long lifespan can be affected by CR and levels of oxidative damage, while genetically determined short lifespan remains short regardless.

长寿研究依赖于在标准化条件下测量的参考基因型的基线预期寿命。实验室、方案和基因型之间的差异使得长寿干预研究难以比较。此外，在次优条件或短寿命基因型条件下延长寿命的理论和转化价值可能低于延长最大可能寿命。水蚤正在成为长寿研究的首选模式生物，补充了在传统模型上获得的数据。在这项研究中，我们报告了在各种方案下长寿物种 D. magna 的几种基因型的寿命，旨在记录最高寿命、降低寿命的因素以及随年龄变化并与寿命相关的参数结合来自两个实验室的 25 个实验的长寿数据，我们报告了强烈的种内变异、群体规模和中等成分的中等影响， 以及与食物水平相关的强烈基因型与环境相互作用。具体来说，短寿命基因型没有显示热量限制 （CR） 效应，而长寿命基因型在 CR 下进一步延长了它们的寿命。我们发现 CR 无反应克隆在寿命与脂质过氧化的两种测量之间几乎没有相关性。相比之下，长寿、CR 反应性克隆显示寿命与脂质氢过氧化物丰度呈正相关，与 MDA 浓度呈负相关。这表明 LPO 产品与年龄相关的积累和解毒及其对长寿的影响的基因型之间存在差异。 我们的观察结果支持这样一个假设，即长寿命会受到 CR 和氧化损伤水平的影响，而遗传决定的短寿命无论如何都很短。