Fipronil is a phenylpyrazole insecticide widely used to control pests in agriculture even though evidence of harmful side effects in non-target species has been reported. A comprehensive study on the effects of dietary administration of Regent®800WG (80 % fipronil) in European sea bass juveniles was carried out under two temperature regimes: a) natural conditions, and b) 3 °C above the natural temperature (an increase predicted for the NW Mediterranean by the end of this century). Fipronil was added to the fish food (10 mg fipronil /Kg feed) and the effects were studied at several time points including right before administration, 7 and 14 days after daily fipronil feed and one-week after the insecticide withdrawal from the diet (depuration period). A wide array of physiological and metabolic biomarkers including feeding rate, general condition indices, plasma and epidermal mucus metabolites, immune response, osmoregulation, detoxification and oxidative-stress markers and digestive enzymes were assessed. General linear models and principal component analyses indicated that regardless of water temperature, fipronil resulted in a significant alteration of several of the above listed biomarkers. Among them, glucose and lactate levels increased in plasma and decreased in epidermal mucus as indicators of a stress response. Similarly, a depletion in catalase activity and higher lipid peroxidation in liver of fipronil-exposed fish were also indicative of an oxidative-stress condition. Fipronil induced a time dependent inhibition of Cytochrome P450-related activities and an increase of phase II glutathione-S-transferase. Moreover, fipronil administration was able to reduce the hypo-osmoregulatory capability as shown by the increase of plasmatic osmolality and altered several digestive enzymes including trypsin, lipase, alpha amylase and maltase. Finally, analyses in bile and muscle confirmed the rapid clearance of fipronil but the persistence of the metabolite fipronil-sulfone in bile even after the 7-day depuration period. Altogether, the results reveal a notable impact of this compound on the physiological condition of the European sea bass. The results should be considered in future environmental risk assessment studies since fipronil could be hazardous to fish species, particularly those inhabiting estuarine ecosystems exposed to the discharge of agriculture runoffs where this pesticide is mainly used.

中文翻译：

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在两种温度条件下鱼类多肉鱼的氟虫腈暴露的多生物标志物方法。

尽管已经报道了非目标物种有害副作用的证据，但Fipronil是一种广泛用于控制农业害虫的苯基吡唑杀虫剂。在两种温度范围内，对Regent®800WG（80％氟虫腈）在欧洲鲈鱼幼鱼中饮食管理的影响进行了全面研究：a）自然条件，b）自然温度以上3°C（预计增加）到本世纪末地中海西北地区）。在鱼饲料中添加氟虫腈（10 mg氟虫腈/ Kg饲料），并在多个时间点研究了其作用，包括给药前，每日氟虫腈饲料后7和14天以及从饮食中撤除杀虫剂一周后（净化）时期）。多种生理和代谢生物标志物，包括进食速度，评估了一般状况指标，血浆和表皮粘液代谢物，免疫反应，渗透压，排毒和氧化应激标志物和消化酶。一般线性模型和主成分分析表明，不管水温如何，氟虫腈都会导致上述几种生物标志物的显着变化。其中，血浆中的葡萄糖和乳酸水平升高，而表皮粘液中的葡萄糖和乳酸水平降低，这是应激反应的指标。同样，暴露于氟虫腈的鱼的过氧化氢酶活性下降和肝脏中较高的脂质过氧化也表明存在氧化应激状态。Fipronil诱导细胞色素P450相关活性的时间依赖性抑制和II期谷胱甘肽-S-转移酶的增加。而且，如血浆渗透压的增加所显示的那样，氟虫腈的施用能够降低低渗调节功能，并改变了几种消化酶，包括胰蛋白酶，脂肪酶，α淀粉酶和麦芽糖酶。最后，在胆汁和肌肉中的分析证实了氟虫腈的快速清除，但是即使在净化7天后，代谢产物氟虫腈-砜仍在胆汁中持续存在。总之，结果表明该化合物对欧洲鲈鱼的生理状况具有显着影响。由于氟虫腈可能对鱼类特别是那些栖息在河口生态系统中且暴露于主要使用该农药的农业径流的环境中的鱼类，因此在未来的环境风险评估研究中应考虑该结果。