Globally increasing levels of artificial light at night (ALAN) are associated with shifts in circadian rhythms of behaviour in many wild species. However, it is still unclear whether changes in behavioural timing are underlined by parallel shifts in the molecular clock, and whether such internal shifts may differ between different tissues and physiological pathways, which could highlight circadian disruption. We tackled these questions in a comprehensive study that integrated behavioural, gene expression and metabolomic analyses. We exposed captive male great tits (Parus major) to three ALAN intensities or to dark nights, recorded their activity rhythms and obtained mid-day and midnight samples of brain, liver, spleen and blood. ALAN advanced wake-up time, and this shift was paralleled by an advance in the expression of the clock gene BMAL1 in all tissues, suggesting close links of brain and peripheral clock gene expression with activity rhythms. However, several metabolic and immune genes were desynchronised the shifted BMAL1 expression, suggesting circadian disruption of behaviour and physiology. This result was reinforced by untargeted metabolomic profiling, which showed that only 9.7% of the 755 analysed metabolites followed the behavioural shift. We suggest circadian as a key mediator of the health impacts of ALAN on wild animals.

中文翻译：

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夜间的人造光会导致鸣禽的昼夜节律紊乱：来自行为，基因组和代谢组学数据的综合证据

全球夜间人工光（ALAN）水平的提高与许多野生物种行为的昼夜节律变化有关。然而，尚不清楚行为时机的变化是否由分子钟中的平行移位所强调，以及这种内部移位是否在不同组织和生理途径之间可能不同，从而可能突出昼夜节律。我们在综合了行为，基因表达和代谢组学分析的综合研究中解决了这些问题。我们将圈养的雄性大山雀（Parus major）暴露于三种ALAN强度或漆黑的夜晚，记录它们的活动节律，并获得大脑，肝脏，脾脏和血液的昼夜采样。ALAN先进的唤醒时间，并且这种变化与所有组织中时钟基因BMAL1的表达水平提高同时出现，表明大脑和外周时钟基因表达与活动节奏密切相关。但是，一些代谢和免疫基因使移位的BMAL1表达失同步，提示其行为和生理的昼夜节律紊乱。非靶向代谢组学分析进一步证实了这一结果，该分析表明，在755种分析代谢物中，只有9.7％遵循了行为转变。我们建议将昼夜节律作为ALAN对野生动物健康影响的关键介质。非靶向代谢组学分析进一步证实了这一结果，该分析表明，在755种分析代谢物中，只有9.7％遵循了行为转变。我们建议将昼夜节律作为ALAN对野生动物健康影响的关键介质。非靶向代谢组学分析进一步证实了这一结果，该分析表明，在755种分析代谢物中，只有9.7％遵循了行为转变。我们建议将昼夜节律作为ALAN对野生动物健康影响的关键介质。