贪食迈阿密虫的体外培养及有效抗虫药物筛选

贪食迈阿密虫(Miamiensis avidus)是一种已知的养殖鱼类兼性寄生虫, 可严重危害养殖水产动物的健康并导致死亡. 为了研究有效的贪食迈阿密虫防治方法, 以从虎斑乌贼溃疡病患处分离的一株贪食迈阿密虫(SP-1株)为实验对象, 设计了一种贪食迈阿密虫的体外培养方法, 结果显示在最适生长温度为20℃, 培养至稳定期时虫体密度可达1×105个?mL-1. 采用体外浸浴模型分析了阿苯达唑、盐酸强力霉素、甲硝唑、硫酸奎宁、盐酸左旋咪唑、福尔马林和双氧水等药物对SP-1株的杀灭效果. 结果表明, SP-1株对硫酸奎宁、盐酸左旋咪唑的敏感性较高, 24h浸浴最小致死质量浓度分别为12.5μg?mL-1和25μg?mL-1; 体积浓度为50μL?L-1的福尔马林溶液或双氧水均可在1h内完全杀灭暴露在其中的SP-1株.

In vitro culture of fish pathogen Miamiensis avidus and screening of effective antiprotozoals

Miamiensis avidus is a known facultative fish parasite. This histophagous ciliate has been reported to infest several mariculture fish and cause a high mortality level. In the present study, we successfully cultured a M. avidus strain SP-1 isolated from skin ulcers of a captive Sepia pharaonis. The results of culture experiments showed that the optimal growth temperature was 20℃ and the ciliate was able to grow to 105 cells?mL-1 in the medium. To develop prophylactic strategies for M. avidus infections, seven candidate antiprotozoals were screened for activity against this pathogen in vitro. Five of these were found potent in the antiprotozoal effect measured by quinine sulfate (24-h minimum lethal concentration; MLC-24=12.5mg?L-1), levamisole hydrochloride (MLC-24=25.0mg?L-1), albendazole (MLC-24=100.0mg?L-1), hydrogen peroxide (1-h lethal concentration MLC-1=50.0mg?L-1) and formalin (MLC-1=50.0mg?L-1). Our findings provide supporting evidence about parasitic ciliate infection prevention in aquaculture.