Macrolide antibiotics (MALs) are widely used for both human and animal health. Most MALs and their metabolites transfer into aquatic organisms and environment resulting in violent consequences. Previous studies show that MALs cause cardiotoxicity in humans and mammals. However, the potential risk of these chemicals in aquatic organisms remains unclear. Here, we used zebrafish embryos as a model to evaluate the toxicity of MALs. Zebrafish embryos were exposed to four typical MALs including azithromycin (AZM), clarithromycin (CLR), tilmicosin (TMS) and tylosin (TYL) to study their cardiotoxicity. The heart rate of zebrafish embryos showed similar biphasic distribution in the presence of four MALs at 2 days post-fertilization (dpf). The heart rate increased significantly at low levels of MALs while decreased obviously at high levels. Subsequently, TMS was chose to study its acute toxicity and developmental toxicity, which caused pericardial edema and spinal curvature in zebrafish embryos at 4 dpf. Furthermore, we found that TMS triggered oxidative stress, with decreased SOD activities and increased MDA contents. Lastly, apoptosis was observed in zebrafish embryos under TMS treatment, with up-regulation of apoptosis associated genes such as p53, bcl 2, bax, caspase 3 and caspase 9, confirmed by increased protein expression based on Western blot analysis. Taken together, these data indicate that MALs can cause serious toxicity in the development of zebrafish. Great caution should be taken due to the huge consumption of MALs for food animal production and treatments with TMS for infections in aquaculture.

大环内酯类抗生素（MALs）被广泛用于人类和动物的健康。大多数MAL及其代谢物转移到水生生物和环境中，导致暴力后果。先前的研究表明，MALs对人类和哺乳动物都有心脏毒性。但是，尚不清楚这些化学物质在水生生物中的潜在风险。在这里，我们使用斑马鱼胚胎作为模型来评估MALs的毒性。斑马鱼的胚胎暴露于四种典型的MAL，包括阿奇霉素（AZM），克拉霉素（CLR），替米考星（TMS）和泰乐菌素（TYL），以研究其心脏毒性。受精后2天（dpf），在有四种MAL的情况下，斑马鱼胚胎的心率显示出相似的双相分布。在低水平的MALs下，心率显着升高，而在高水平的SMA下，心率明显降低。随后，选择TMS研究其急性毒性和发育毒性，这些毒性在4 dpf时引起斑马鱼胚胎的心包水肿和脊柱弯曲。此外，我们发现TMS触发了氧化应激，降低了SOD活性，增加了MDA含量。最后，在TMS处理下在斑马鱼胚胎中观察到凋亡，并且凋亡相关基因例如p53，bcl 2，bax，caspase 3和caspase 9的表达基于蛋白质印迹分析通过蛋白质表达的增加得到证实。综上所述，这些数据表明，MALs可以在斑马鱼的发育中引起严重的毒性。由于在食用动物生产中大量使用MAL以及在水产养殖中使用TMS处理感染，应格外谨慎。