The objective of this study was to determine if temporal variations in tissue metal concentrations are related to biomarkers of retinoid metabolism and oxidative stress responses in juvenile yellow perch (Perca flavescens). To this end, kidney metal (Cd, Cu and Zn) concentrations were measured in fish sampled in spring and fall 2012 in four lakes representing a wide range of water and sediment metal contamination in the Rouyn-Noranda (Quebec) region. Lakes Opasatica and Hélène were considered as reference lakes while lakes Dufault and Marlon were metal-contaminated. Kidney concentrations of Cd, Cu and Zn varied widely between spring and fall in fish from both clean and metal-contaminated lakes. An inter-lake difference in renal metal concentrations was only observed for Cd, with fish from Lake Marlon consistently displaying higher concentrations. In the spring, the concentrations of liver dehydroretinol, dehydroretinyl palmitate and total vitamin A esters were higher in fish sampled in the most contaminated lake. Strong temporal variations in the concentrations of these metabolites, as well as in the percentage of liver free dehydroretinol and the epidermal retinol dehydrogenase 2 transcription levels, were observed in fish living in the most metal-impacted lake, with generally higher values in the spring. In contrast to liver, in muscle, no clear seasonal variations in the concentrations of dehydroretinol, dehydroretinyl stearate or in the percentage of free dehydroretinol were observed in fish captured in the most contaminated lake. Temporal variations of traditional biomarkers of oxidative stress response were also observed in the most metal-impacted lake. For example, the transcription level of the gene encoding Cu/Zn superoxide dismutase-1 in liver and muscle catalase activity of perch sampled in the most contaminated lake were higher in spring than in fall. Positive relationships were found between kidney Cd concentrations and the transcription level of the gene encoding glucose 6-phosphate dehydrogenase, and all forms of retinoid concentrations in liver in spring, except with the percentage of free dehydroretinol where the correlation was negative. Our results translate to a state of stress caused by Cd and illustrate that temporal variations in tissue metal concentrations affect retinoid metabolism and antioxidant capacities in juvenile wild yellow perch. Overall this study contributes to highlight the importance of considering temporal variations when investigating the consequences of metal contamination on the physiology of wild fish.

这项研究的目的是确定组织金属浓度的时间变化是否与幼年黄鲈（Perca flavescens）中的类维生素A代谢和氧化应激反应的生物标志物有关）。为此，2012年春季和秋季在四个湖泊中对鱼中的肾脏金属（镉，铜和锌）浓度进行了测量，这些湖泊代表了鲁恩-诺兰达（魁北克）地区广泛的水和沉积物金属污染。Opasatica湖和Hélène湖被视为参考湖，而Dufault湖和Marlon湖则被金属污染。从春季到秋季，来自清洁湖泊和金属污染湖泊的鱼类肾脏中镉，铜和锌的浓度差异很大。仅在镉中观察到了湖间肾金属浓度的差异，来自马龙湖的鱼始终显示出较高的浓度。在春季，在污染最严重的湖泊中采样的鱼中肝脏脱氢视黄醇，棕榈酸脱氢视黄基酯和总维生素A酯的浓度更高。在生活在受金属影响最严重的湖泊中的鱼类中，观察到这些代谢物的浓度以及肝脏游离脱氢视黄醇和表皮视黄醇脱氢酶2转录水平的强烈时间变化，春季通常更高。与肝脏相反，在肌肉中，在污染最严重的湖泊中捕获的鱼中没有观察到明显的季节性变化，如脱氢视黄醇，脱氢视黄醇硬脂酸酯或游离脱氢视黄醇的百分比。在受金属影响最大的湖泊中也观察到了传统生物标志物的氧化应激反应的时间变化。例如，春季污染最严重的湖中鲈鱼肝脏和肌肉过氧化氢酶活性中编码Cu / Zn超氧化物歧化酶-1的基因的转录水平在春季高于秋季。在春季，肾脏中的镉浓度与6-葡萄糖葡萄糖脱氢酶编码基因的转录水平以及肝脏中所有​​形式的类维生素A浓度之间存在正相关关系，但游离脱氢视黄醇的百分数呈负相关。我们的结果转化为Cd引起的压力状态，并说明组织金属浓度的时间变化会影响幼年野生黄鲈的类维生素A代谢和抗氧化能力。