Imidacloprid (IMI) is an insecticide used worldwide, a neonicotinoid that could cause toxicity in non-target organisms. Zebrafish (Danio rerio) is a model organism widely used in different fields of research such as behavioral studies, biochemical parameters as well as neurotoxicity research. Here, we investigate whether the exposure to three concentrations (0.15, 15, and 45 μg/L) of IMI for 96 h alters responses in zebrafish. Oxidative stress parameters and acetylcholinesterase activity (AChE) as well as the behavioral responses of locomotion were measured. IMI exposure decreased distance traveled in fish exposed to the 45 μg/L. In the exploratory activity, time spent and transitions to the top area of the water column decreased in fish exposed to all concentrations of IMI. In addition, exposures to 45 and 15 μg/L of IMI decreased episodes of erratic movement in the zebrafish. Exposures to IMI at a concentration of 45 μg/L decreased the time spent in erratic movements and increased the time spent with no movement (i.e., “freezing”). Glutathione S-transferase (GST) activity was increased in the brain of zebrafish exposed for 96 h to concentrations of 0.15 and 45 μg/L. Brain AChE activity was reduced and the levels of carbonyl protein (CP) increased in brain of zebrafish at concentrations of 15 and 45 μg/L. Lipid peroxidation measured by TBARS and, also non-protein thiols (NPSH) did not show any variation in the brain of zebrafish exposed to IMI. Changes in the activity of cholinergic neurotransmitters in the brain tissues of zebrafish indicate IMI toxicity. Exposures of fish over 96 h to IMI at a nominal concentration of 45 μg/L caused more extensive sublethal responses in zebrafish, but this concentration is well above those expected in the aquatic environment. Studies are warranted to evaluate the effects on behavior and biomarker responses in fish exposed over longer periods to IMI at environmentally relevant concentrations.

吡虫啉 (IMI) 是一种世界范围内使用的杀虫剂，是一种新烟碱类物质，可能对非目标生物造成毒性。斑马鱼 ( Danio rerio) 是一种模式生物，广泛应用于不同的研究领域，如行为研究、生化参数以及神经毒性研究。在这里，我们调查暴露于三种浓度（0.15、15 和 45 μg/L）的 IMI 96 小时是否会改变斑马鱼的反应。测量氧化应激参数和乙酰胆碱酯酶活性 (AChE) 以及运动的行为反应。IMI 暴露减少了暴露于 45 μg/L 的鱼的行进距离。在探索活动中，暴露于所有 IMI 浓度的鱼所花费的时间和过渡到水柱顶部区域的时间减少。此外，暴露于 45 和 15 μg/L 的 IMI 减少了斑马鱼不稳定运动的发生。暴露于浓度为 45 μg/L 的 IMI 减少了不规律运动所花费的时间并增加了无运动（即“冻结”）所花费的时间。暴露于 0.15 和 45 μg/L 浓度的斑马鱼大脑中的谷胱甘肽 S-转移酶 (GST) 活性增加了 96 小时。当浓度为 15 和 45 μg/L 时，斑马鱼脑中的脑 AChE 活性降低，羰基蛋白 (CP) 水平增加。TBARS 和非蛋白硫醇 (NPSH) 测量的脂质过氧化在暴露于 IMI 的斑马鱼的大脑中没有显示任何变化。斑马鱼脑组织中胆碱能神经递质活性的变化表明 IMI 毒性。将鱼暴露于标称浓度为 45 μg/L 的 IMI 超过 96 小时会导致斑马鱼出现更广泛的亚致死反应，但这种浓度远高于水生环境中的预期浓度。有必要进行研究以评估长期暴露于环境相关浓度的 IMI 对鱼的行为和生物标志物反应的影响。