吡喹酮对鲤鱼感染台湾棘带吸虫后期囊幼虫的防治效果

目的]探讨3种不同药物处理方式对台湾棘带吸虫引起的鲤鱼幼鱼急性鱼鳃传染病(开放性鳃病)的防治效果.方法]在试验初期,将1620条鲤鱼幼鱼(70日龄)鱼鳃自然感染台湾棘带吸虫,随后分成4组,分别采用CuSO4、福尔马林和吡喹酮不同方式处理6周,与对照(自然喂食、不使用任何化学药剂)比较防治鲤鱼幼鱼急性鳃传染病的效果.结果]感染台湾棘带吸虫的幼鱼生长缓慢,其身长和体重增长均较慢.施药后,幼鱼台湾棘带吸虫后期囊幼虫感染强度减少.在每千克饲料中分别添加50和75 mg吡喹酮喂食幼鱼5d,可以杀死鱼鳃中所有的台湾棘带吸虫后期囊幼虫,且鱼鳃恢复正常;面使用25 mg吡喹酮,仅有35%的后期囊幼虫死亡.所有不同浓度CuSO4处理(0.3、0.4和0.5mg/kg冲洗浸泡24 h及以3.0、4.0和5.0 mg/kg冲洗浸泡10m)和福尔马林处理(20、25和30 mg/kg冲洗浸泡及200、250和300 mg/kg短时间冲洗浸泡)均不能杀死台湾棘带吸虫后期囊幼虫.结论]经普通化学药剂CuSO4或福尔马林冲洗浸泡,不能防治由台湾棘带吸虫后期囊幼虫引起的鲤鱼开放性鳃病,但50~75 mg吡喹酮/kg饲料可以在5d内治疗该病.

Efficacy of praziquantel against Centrocestus formosanus metacercariae infections in common carp(Cyprinus carpio Linnaeus)

Objective]Three treatment regimes were tested for controlling acute gill infections(open gill disease) caused by Centrocestus formosanus in juvenile common carp.Method]A total of 1620 common carp juveniles(70 days old) naturally infected with C.formosanus in the gills at the start of the experiment.The carp fishes were collected and treated with CuSO4,formalin and praziquantel,and compared to controls(kept on a normal diet and without exposure to chemicals) for 6 weeks.Result]Infected fishes exhibited a lower growth rate,both with regard to length and weight.The intensity of metacercarial infections of C.formosanus was reduced throughout the experiment.Praziquantel(50 and 75 mg/kg supplied with feed for 5 days) killed all metacercariae in carp gills.Treated juveniles recovered from the opened gill disease.At the dosage of 25 mg/kg,only 35% of the parasites became inactivated.Immersion and bath in CuSO4 and formalin at all concentrations did not inactivate any metacercariae.Snail-borne trematode diseases should preferentially be controlled by controlling snails and improving hygienic measures.Conclusion]The opened gill disease of common carp due to metacercariae of C.formosanus could not be successfully treated by using normal chemicals(CuSO4 or formaline) applied through bathing or immersing methods.However,it can be treated by praziquantel(50-75 mg of praziquantel per kg of feed) administered through feed for 5 days.