Research Institute of Fish Culture and Hydrobiology, University of South Bohemia in Ceské Budejovice, Faculty of Fisheries Protection of Water, Zatisi 728/II, Vodnany 38925, Czech Republic.
Parasitol Res. 2010 Jan;106(2):539-42. doi: 10.1007/s00436-009-1666-8. Epub 2009 Nov 10.
The parasitic ciliate Ichthyophthirius multifiliis infests all species of freshwater fish and can cause severe economic losses in fish breeding. The most effective treatment, malachite green, has been banned in Europe and North America for use in food fish production. Peracetic acid (PAA) was found to be toxic to I. multifiliis theronts at low concentrations. I. multifiliis-infested carp were exposed to 1 mg/l PAA in a dynamic exposure by means of peristaltic pumps. Five days after infestation, gills, tail fins, and skin below the dorsal fin were observed microscopically for I. multifiliis abundance. After PAA exposure, PAA-treated fish showed lower infestation of I. multifiliis in all investigated tissues than the unexposed control fish. The infestation increased in the control group whereas the infestation in the PAA-exposed groups significantly decreased (p = 0.0083, Bonferroni correction). The fish in the two exposure groups showed a slight reinfestation with I. multifiliis. This might be caused by a peroxide degradation (hydrolysis) and/or reduction of the delivered PAA concentration. Thus, PAA concentrations were possibly too low to be effective on the released trophonts and/or the infective theronts. This hypothesis is corroborated by the fact that the I. multifiliis in the gills, skin, and fins of the PAA-exposed carp were in an early developmental stage.
多子小瓜虫寄生在所有淡水鱼类中，会给鱼类养殖带来严重的经济损失。最有效的治疗药物孔雀石绿已在欧洲和北美被禁止用于食用鱼生产。研究发现，低浓度的过氧乙酸（PAA）对小瓜虫的滋养体有毒。通过蠕动泵以动态暴露的方式，将受多子小瓜虫感染的鲤鱼暴露于 1mg/L 的 PAA 中。感染后 5 天，通过显微镜观察鱼的鳃、尾鳍和背鳍下方的皮肤，评估小瓜虫的丰度。与未暴露的对照组相比，PAA 处理过的鱼在所有研究组织中的小瓜虫感染程度较低。对照组的感染程度增加，而 PAA 暴露组的感染程度显著降低（p=0.0083，Bonferroni 校正）。两组暴露组的鱼再次受到小瓜虫的轻微感染。这可能是由于过氧化物的降解（水解）和/或输送的 PAA 浓度降低所致。因此，释放的滋养体和/或感染性滋养体的 PAA 浓度可能太低而无法有效作用。这一假设得到了以下事实的证实：PAA 处理过的鲤鱼的鳃、皮肤和鳍中的小瓜虫处于早期发育阶段。
