盐度对寄主暗纹东方鲀(Takifugu obscurus)存活影响及其对车轮虫的杀灭作用

The Effects of Salinity on the Survival of Takifugu obscurus and Annihilation of Its Parasite, Trichodina sp.

中文关键词: 暗纹东方鲀  盐度  车轮虫  灭杀  存活

英文关键词: Takifugu obscurus  Salinity  Trichodina  Kill  Survival

中文摘要:

      为防治河鲀车轮虫病，分别设置0、2.5、5.0、7.5、10.0、12.5、15.0、17.5、20.0、25.0、30.0、35.0和40.0共13个盐度梯度，对暗纹东方鲀进行了浸浴实验。结果显示，盐度为15以下，对暗纹东方鲀的存活没有影响；盐度为0、2.5、5.0时，4 d内车轮虫的数量没有减少反而有增加趋势；盐度7.5作用4 d，盐度10.0作用3.5 d，盐度12.5作用3 d，杀虫率可达95%以上；盐度15.0作用32 h，盐度17.5作用24 h，盐度20.0作用10 h，盐度25.0作用4 h，盐度30.0作用1.5 h，盐度35.0作用1 h，盐度40.0作用0.5 h，对车轮虫的杀虫率均可达100%。应用SPSS软件，对杀虫盐度和时间进行拟合曲线方程分析，其数学模型为对数曲线方程y =34.19−5.55lnx。另外，车轮虫在暗纹东方鲀体表的复活试验显示，用提高盐度的方法杀灭暗纹东方鲀体表车轮虫后，再恢复到正常养殖盐度5.0的情况下，暗纹东方鲀的体表车轮虫病不再复发，说明盐度7.5以上能治疗暗纹东方鲀的车轮虫病。结合提高盐度治疗暗纹东方鲀车轮虫病的生产性试验结果，建议以盐度为7.5–15.0作为治疗暗纹东方鲀体表车轮虫的适宜盐度。

英文摘要:

      Trichodiniasis is a common fish disease and has recently become a serious issue in fugu fish culture in China. In this study we investigated the effects of salinity on the survival of fugu, Takifugu obscurus, and annihilation of the parasites, Trichodina sp., on the fish body surface. We set up 13 salinity gradient groups (0, 2.5, 5.0, 7.5, 10.0, 12.5, 15.0, 17.5, 20.0, 25.0, 30.0, 35.0, and 40.0) for the experiment. The results showed that T. obscurus could survive safely under salinity 15.0. At low salinity (0, 2.5 or 5.0) Trichodina on the body surface was not reduced, and tended to increase in 4 days. However, more than 95% of Trichodina could be killed at the salinity 7.5 for 4 days, 10.0 for 3.5 days, or 12.5 for 3 days. The parasites could be completely killed if treated at salinity 15.0 for 32 h, 17.5 for 24 h, 20.0 for 10 h, 25.0 for 4 h, 30.0 for 1.5 h, 35.0 for 1 h, or 40.0 for 0.5 h. A fitting curve equation of salinity and the killing time for Trichodina was established using the software SPSS, and the logarithmic curve equation was y＝34.19－5.55lnx. Moreover, according to the resurgence test of Trichodina sp. on fish body surface, Trichodiniasis in T. obscurus did not reoccur when the salinity returned back to 5.0 during farming if Trichodina sp. were entirely killed by the raised salinity. Our results suggested that trichodiniasis in T. obscurus could be cured if salinity was maintained higher than 7.5. Salinity between 7.5 and 15.0 could be proper for the treatment of the trichodiniasis in T. obscurus. Our study should provide insights and technical supports for clinical treatment of trichodiniasis in fugu farming.