Abstract

The purpose of this study was to assess the acute and chronic effects of the macrolide azithromycin (AZI) on the European sea bass (Dicentrarchus labrax) early life stages. Azithromycin is a semi-synthetic antibiotic frequently detected in the aquatic environment, despite this few information about its effects on aquatic organisms were reported. Investigations of AZI acute toxicity on D. labrax early life stages were made using six increasing concentrations (0.625, 1.25, 2.5, 5, 10 and 20 mg/l) during 96 h of exposure. The chronic toxicity was tested at one year old juveniles using two sublethal concentrations (C1 = 0.05 µg/l and C2 = 0.8 µg/l) during 4 and 14 days. Malondialdehyde (MDA), glutathione S-transferase (GST), catalase (CAT) and acetylcholinesterase (AChE) activities were measured in gill and liver tissues of juveniles. The half lethal concentration (LC₅₀), 96 h value of AZI for the European sea bass was determined as 31 mg/l. Results showed that short-time exposure to 20 mg/l of azithromycin induces 18% and 7.5% of larvae mortality and morphological abnormalities, respectively. Azithromycin provoked oxidative stress, peroxidative damage, and neurotoxicity in juveniles D. labrax. Overall, the CAT and AChE activities decreased in gill and liver tissues, while dissimilarity in response in both organs depending on AZI concentrations and time of exposure was observed in MDA and GST levels.

摘要

本研究的目的是评估大环内酯类阿奇霉素 (AZI) 对欧洲鲈鱼 ( Dicentrarchus labrax ) 早期生命阶段的急性和慢性影响。阿奇霉素是一种在水生环境中经常检测到的半合成抗生素，尽管关于其对水生生物影响的报道很少。AZI对D. labrax的急性毒性研究在 96 小时的暴露期间，使用六种递增浓度（0.625、1.25、2.5、5、10 和 20 毫克/升）进行早期生命阶段。在 4 天和 14 天内，使用两种亚致死浓度（C1 = 0.05 µg/l 和 C2 = 0.8 µg/l）对 1 岁的青少年进行了慢性毒性测试。在幼鱼的鳃和肝组织中测量丙二醛 (MDA)、谷胱甘肽 S-转移酶 (GST)、过氧化氢酶 (CAT) 和乙酰胆碱酯酶 (AChE) 的活性。欧洲鲈鱼的 AZI 96 小时半致死浓度 (LC _{50 ) 值为 31 mg/l。}结果表明，短时间暴露于 20 mg/l 阿奇霉素分别导致 18% 和 7.5% 的幼虫死亡率和形态异常。阿奇霉素在青少年中引起氧化应激、过氧化损伤和神经毒性D.拉布拉克斯。总体而言，鳃和肝组织中的 CAT 和 AChE 活性降低，而在 MDA 和 GST 水平中观察到两种器官的反应不同，这取决于 AZI 浓度和暴露时间。