立达霉对七彩神仙鱼卵水霉病的防治效果

Control effect of Ridomil on saprolegniasis infected Discus fish(Symphysodon aequifasciatus) zygotes

【目的】探讨分析立达霉对七彩神仙鱼(Symphysodon aequfasciatus)受精卵水霉病的防治效果及其安全性,为鱼类人工孵化过程中水霉病的防治提供参考依据。【方法】采用倍比稀释法验证立达霉对水霉菌的体外抑菌效果,并利用水浴染毒法使七彩神仙鱼卵感染水霉菌,然后将其浸泡在不同浓度的立达霉溶液中,以孔雀石绿、无菌水为阳性对照和空白对照,观察不同药物处理对鱼卵发育的影响。【结果】8.0 mg/L立达霉和0.10 mg/L孔雀石绿即可明显抑制水霉菌丝生长。以8.0 mg/L立达霉分别浸泡受精36 h后和受精3 h内的七彩神仙鱼卵,鱼卵的水霉菌感染率和死亡率极显著(P<0.01)或显著(P<0.05)降低,而孵化率明显提高。鱼卵组织切片观察发现,空白对照组的鱼卵结构较紧密,0.10 mg/L孔雀石绿组的鱼卵内部结构疏松、组织溶解破碎,8.0 mg/L立达霉组的鱼卵内部结构未发生明显变化。【结论】立达霉可有效防治观赏鱼类的水霉病,且不会对鱼卵产生明显毒害作用,生产推荐使用浓度为8.0 mg/L。

[Objective]The present experiment was conducted to study safety and control effect of Ridomil on saprolegniasis of Symphysodon aequfasciatus zygote, in order to provide scientific basis for prevention and treatment of saprolegniasis during artificial incubation of fish. [ Method]The antibacterial effect of Ridomil on saprolegniasis in vitro was verified by using multiple proportion dilution. By means of water bath, S. aequfasciatus zygote was infected by Saprolegnia. Then the infected zygotes were exposed to different concentrations of Ridomil, malachite green of 0.1 mg/L （positive control） and water （blank control ）, respectively. The zygote develgpment of different drug treatments were observed to calculate zygote mortality, hatchability and infection rate of Saprolegnia. [Result]The results showed that, Ridomil（8.0 mg/L） and malachite green（0.10 mg/L） could significantly inhibit the hypha growth of Saprolegnia. Both the zygotes fertilized after 36 h and the zygotes fertilized within 3 h were soaked in 8.0 mg/L Ridomil, the infection rate of Saprolegnia and zygote mortality were found to be extremely significantly reduced （P〈0.01） or significantly reduced （P〈0.05）, while hatchability of zygote was found to be significantly increased. The tissue section of zygote showed that the compact structure of fish zygote was found out from blank control group. While the internal structure of zygote in positive control group was loose, dissolved and broken. As for Ridomil group of 8.0 mg/L, its internal structure of zygote did not change obviously. [Conclusion]Ridomil can prevent and treat saprolegniasis of fancy fish, which have not toxic effect on fish zygote. The recommendation concentration of Ridomil is 8.0 mg/L in the production.