Extermination of the Parasites of Cultured Puffer by Domoic Acid

用添加250 ppm软骨藻酸（DA）的海水（SW）和添加100 ppm DA的淡水（FW）浸泡感染东方鲀（Pf）的养殖河豚5 min和20 min，对皮肤中Pf的去除率（R）分别为80.0%和100%。该值远高于相同浓度的海洋酸和福尔马林的值。在FW洗浴的情况下，在10和50 ppm DA下10-20 min去除超过90%的Pf，5 ppm下20 min去除71%。当使用添加有14-128 ppm红藻氨酸（KA）的FW进行类似实验时，R在超过64 ppm时达到100%，洗浴时间超过15 min。另一方面，从养殖的河豚鱼中，挑选出6只四齿异槽绦虫（Heterobothriumtetrodonis，Ht）幼鱼及其寄生部位（鳃）。其中2条鱼用不含DA的SW浸泡，其余4条鱼用添加100 ppm DA的SW浸泡，结果表明，前2条鱼在鳃上存活时间均超过4小时，后4条鱼在30分钟内从鳃上脱落，用100 ppmDA水溶液浸泡河豚鱼20 min后，血液检测结果均正常，通过HPLC和LC/MS分析，在100 ppm DA或64 ppm KA下FW浸泡20分钟的样本中未检测到DA和KA。从这些结果可以得出结论，DA和KA是针对Pf或Ht非常有效且安全的杀寄生虫剂。

The cultured tiger puffers parasitized by Pseudocaligusfugu (Pf) were bathed for 5 min in the seawater (SW) added with 250 ppm ofdomoic acid (DA), or for 20 min in the freshwater (FW) with 100 ppm DA. The removal rates (R) of Pf from the puffer skin during these bathing experiments were 80.0 and 100 %, respectively, the values being much higher than those of the same concentrations of Marine Sour and formalin. In case of FW bathing, more than 90 % of Pfwere removed at 10 and 50 ppm DA for 10-20 min, and 71 %, at 5 ppm for 20 min. When the similar experiment was performed using FW added with 14-128 ppm of kainic acid (KA),R reached to 100 % at more than 64 ppm with the bathing time of more than 15 min.On the other hand, six juveniles ofHeterobothrium tetrodonis (Ht) were picked out together with their parasitic part (the gills) from cultured puffers. Two of them were bathed in SW without DA, and the rest were in SW added with 100 ppm DA. As the results, both of the former two were alive on the gills for more than 4 hours, while the latter four removed from the gills within 30 min, and died within 4 hours.The results of blood test of the puffer specimens subjected to FW bathing at 100 ppm DA for 20 min showed that they are all normal, and no DA nor KAwas detectable by HPLC and LC/MS analyses from the specimens submitted to FW bathing at 100 ppm DA or 64 ppm KA for 20 min. From these results, it can be concluded that DA and KA are very effective and safe parasiticides against Pf or Ht.