Abstract Parasitic infestations are frequently reported in brackishwater fish. Hence, prevention and control strategy is paramount for successful brackishwater aquaculture. Emamectin benzoate (EMB) is found to be an effective in-feed treatment for controlling several ecto-parasites in fish. The objective of this study was to understand the biosafety, withdrawal and efficacy of EMB for use in brackishwater reared Asian Seabass (Lates calcarifer) under tropical climate. Biosafety was evaluated at doses of 0, 50, 250 and 500 μg kg−1 of fish body weight (BW) day−1 for 21 days. EMB was administered per os through coated pellet feed. Gross, haematological and histopathological observations were made and found that there were no biologically significant adverse changes between control and treated groups. Withdrawal period was estimated with similar experiment with same doses but for seven consecutive days. Samples were collected on 0th, 7th, 14th, 21st and 28th day of post-medication for QTRAP 4000 LC-MS/MS analysis. The data showed that the level of EMB in whole fish treated with 50, 250 and 500 μg kg−1 of fish BW day−1 were 21.0 ± 0.0, 142.4 ± 0.1 and 209.7 ± 0.1 parts per billion (ppb) on 0th day of withdrawal, respectively. These values were found drastically decreased on 7th day of withdrawal and reached undetectable level by 28th day. For assessing the environmental safety, acute immobilization test was conducted using 24 h old daphnid. The EC50 and LC50 values in daphnids were 107 and 160 times higher than the the treatment dose, respectively. Efficacy was tested with the therapeutic dose on Asian Seabass fingerlings infested with naturally sea louse (Caligus minimus). Medicated pellet feed was fed at 4% BW day−1 divided equally between three feedings. Efficacy trial showed that there was significant improvement in survival (92.0 ± 2.3%; P

中文翻译：

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亚洲鲈鱼（Lates calcarifer）抗寄生虫药物苯甲酸阿维菌素的生物安全性、停药和疗效

摘要 在咸水鱼中经常报告寄生虫感染。因此，预防和控制策略对于成功的咸水养殖至关重要。Emamectin benzoate (EMB) 被发现是一种有效的饲料中处理方法，可用于控制鱼类中的几种体外寄生虫。本研究的目的是了解 EMB 在热带气候下用于咸水养殖的亚洲鲈鱼（Lates calcarifer）的生物安全性、撤除和功效。在 0、50、250 和 500 μg kg−1 鱼体重 (BW) day−1 的剂量下评估生物安全性，持续 21 天。EMB 通过包衣颗粒饲料口服给药。进行了大体、血液学和组织病理学观察，发现对照组和治疗组之间没有生物学上显着的不利变化。使用相同剂量但连续 7 天的类似实验估计停药期。在用药后第 0、7、14、21 和 28 天收集样品用于 QTRAP 4000 LC-MS/MS 分析。数据显示，用 50、250 和 500 μg kg-1 的鱼 BW day-1 处理的全鱼的 EMB 水平在第 0 天分别为 21.0 ± 0.0、142.4 ± 0.1 和 209.7 ± 0.1 ppb。分别退出。发现这些值在停药第 7 天急剧下降，并在第 28 天达到检测不到的水平。为了评估环境安全性，使用 24 小时大的水蚤进行了急性固定试验。水蚤的 EC50 和 LC50 值分别比治疗剂量高 107 和 160 倍。用治疗剂量对感染了天然海虱（Caligus minimus）的亚洲鲈鱼鱼种进行了功效测试。第 1 天以 4% BW 喂食含药颗粒饲料，平均分配给三种饲料。疗效试验表明生存率显着提高（92.0±2.3%；P