Abstract Ractopamine, a β-adrenergic receptor agonist, is commonly used as a repartitioning agent and growth promotor in animal agriculture. There is evidence that ractopamine can enter natural water sources from livestock wastes, at concentrations in the low ng/L range. Currently, aquatic toxicity data for ractopamine is scarce. Therefore, in two separate experiments Xenopus laevis tadpoles were exposed to ractopamine in tank water at concentrations ranging from 2 ng/L to 2.2 mg/L for up to 14 d utilizing FETAX methodology. No overt signs of toxicity were identified in measured endpoints including survival, growth, malformation, and developmental stage. Oral ractopamine exposure in mammals and fish is associated with cardiotoxicity, increased mortality, and physiological alterations; however, this study suggests that aqueous ractopamine is not a developmental toxicant or overtly toxic to amphibians at environmentally relevant concentrations. Graphical Abstract

中文翻译：

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低于 0.22 mg/L 的莱克多巴胺水溶液暴露对发育中的非洲爪蟾蝌蚪的死亡率、畸形或生长没有影响

摘要 莱克多巴胺是一种β-肾上腺素能受体激动剂，在畜牧业中常用作再分配剂和生长促进剂。有证据表明，莱克多巴胺可以从牲畜粪便中进​​入天然水源，浓度在低 ng/L 范围内。目前，莱克多巴胺的水生毒性数据很少。因此，在两个独立的实验中，非洲爪蟾蝌蚪暴露于水箱水中的莱克多巴胺，浓度范围为 2 ng/L 至 2.2 mg/L，使用 FETAX 方法长达 14 天。在测量的终点（包括存活、生长、畸形和发育阶段）中没有发现明显的毒性迹象。哺乳动物和鱼类的口服莱克多巴胺暴露与心脏毒性、死亡率增加和生理改变有关；然而，这项研究表明，莱克多巴胺水溶液在环境相关浓度下对两栖动物没有发育毒性或明显毒性。图形概要