海水鱼蛭阿鲁加姆锡兰蛭(Zeylanicobdella arugamensis)的在体感染与生活史观察

In vivo infestation and life cycle observation of marine leech Zeylanicobdella arugamensis

中文关键词: 鱼蛭  在体感染  生活史  棘颊雀鲷  白条双锯鱼

英文关键词: Fish leech (Zeylanicobdella arugamensis)  In vivo Infestation  Life cycle  Spinecheek anemonefish (Premnas biaculeatus)  Tomato anemonefish (Amphiprion frenatus)

中文摘要:

      阿鲁加姆锡兰蛭(Zeylanicobdella arugamensis)是重要的鱼类体外寄生虫，可感染30余种海水鱼类。阿鲁加姆锡兰蛭病在我国和东南亚多个国家的海水养殖鱼类中流行，严重时可导致鱼类大量死亡。为持续、稳定、足量地获得活体寄生虫，供防治鱼蛭病研究使用，本研究通过鱼蛭在体感染实验，建立了阿鲁加姆锡兰蛭的传代培养体系。研究结果证实，2种海水观赏鱼[棘颊雀鲷(Premnas biaculeatus)和白条双锯鱼(Amphiprion frenatus)]可作为宿主鱼，用于该鱼蛭的传代培养，且传9代后产生的子代仍具有很强的感染力。鱼蛭的生活史观察显示，该鱼蛭的生活史可分为卵茧孵化和幼蛭发育2个阶段。在水温为26℃、盐度为30的条件下，鱼蛭最短20 d即可完成其生活史。其中，卵茧孵化为幼蛭需要9 d，孵化率高达83.8%；幼蛭感染宿主、发育成熟并开始产卵茧最短需要11 d。本研究可为海水鱼蛭的生物学和鱼蛭病的防治研究提供技术支撑。

英文摘要:

      Zeylanicobdella arugamensis is an important ectoparasitic leech that can infest more than 30 species of marine fish. Diseases associated with Z. arugamensis are prevalent in China and many countries of Southeast Asia, and frequently cause the death of cultured marine fishes. In order to continually and steadily provide sufficient live leeches and cocoons for the research of the prevention and treatment of Z. arugamensis, this study established a propagation method for Z. arugamensis through in vivo infestation experiments, and proved that two ornamental fish species, spinecheek anemonefish (Premnas biaculeatus) and tomato anemonefish (Amphiprion frenatus), were suitable for use as fish hosts. The parasite descendants generated by the in vivo propagation method are still very transmittable after nine generations. This study also used micrography to observe cocoons and the life cycle of propagated fish leeches. The results showed that the average cocoon size of Z. arugamensis was (0.66±0.06) mm, and there was only one fertilized egg in each cocoon. The life cycle of Z. arugamensis can be divided into two stages: The cocoon hatching stage and the juvenile development stage. Under a seawater temperature of 26℃ and salinity of 30, Z. arugamensis can complete its life cycle in as short as 20 days. The cocoons of Z. arugamensis developed into juvenile leeches in nine days, with a hatching rate as high as 83.8%. The juvenile leeches subsequently infected the host fish, grew to mature adults, and produced new cocoons in 11 days. This article confirmed for the first time that P. biaculeatus and A. frenatus were both susceptible hosts for Z. arugamensis. This study not only established an in vivo propagation method for Z. arugamensis, but also provided technical support for research on the pathogen, pathology, pathogenic mechanism, detection, and prevention of leech diseases related to Z. arugamensis.