Data from: Meta-analysis indicates that oxidative stress is both a constraint on and a cost of growth

Oxidative stress (OS) as a proximate mechanism for life-history trade-offs is widespread in the literature. One such resource allocation trade-off involves growth rate, and theory suggests that OS might act as both a constraint on and a cost of growth, yet studies investigating this have produced conflicting results. Here, we use meta-analysis to investigate whether increased OS levels impact on growth (OS as a constraint on growth) and whether greater growth rates can increase OS (OS as a cost of growth). The role of OS as a constraint on growth was supported by the meta-analysis. Greater OS, in terms of either increased damage or reduced levels of antioxidants, was associated with reduced growth although the effect depended on the experimental manipulation used. Our results also support an oxidative cost of growth, at least in terms of increased oxidative damage, although faster growth was not associated with a change in antioxidant levels. These findings that OS can act as a constraint on growth support theoretical links between OS and animal life histories and provide evidence for a growth–self-maintenance trade-off. Furthermore, the apparent oxidative costs of growth imply individuals cannot alter this trade-off when faced with enhanced growth. We offer a starting platform for future research and recommend the use of oxidative damage biomarkers in nonlethal tissue to investigate the growth–OS relationship further.

氧化应激（Oxidative Stress，OS）作为生活史权衡（life-history trade-offs）的近因机制，在相关学术文献中已有大量研究报道。其中一类典型的资源分配权衡（resource allocation trade-off）与生长速率相关，现有理论指出，氧化应激既可能对生长构成约束，也可能成为生长的代价，但相关实证研究得出的结论却相互矛盾。本研究通过元分析（meta-analysis），探讨了氧化应激水平升高是否会对生长产生抑制作用（即氧化应激作为生长的约束），以及更高的生长速率是否会提升氧化应激水平（即氧化应激作为生长的代价）。
元分析结果支持了氧化应激对生长的约束作用：无论是氧化损伤加剧还是抗氧化剂水平降低所导致的氧化应激升高，均与生长速率下降相关，但该效应因所采用的实验操控方式而异。本研究结果同时证实了生长的氧化代价，至少在氧化损伤加剧层面如此——尽管生长速率加快并未对抗氧化剂水平产生显著影响。
上述关于氧化应激可对生长构成约束的发现，佐证了氧化应激与动物生活史之间的理论关联，并为生长-自我维持权衡（growth–self-maintenance trade-off）提供了实证依据。此外，生长所伴随的氧化代价表明，当个体面临加速生长的情境时，无法改变这一权衡关系。
本研究为未来相关研究提供了基础框架，并建议通过非致死组织中的氧化损伤生物标志物（oxidative damage biomarkers），进一步探究生长与氧化应激之间的关联。