Studies on a New Nitrofuran Deviative Nifurprazine(HB-115) in Ayu Fish, Plecoglossus altivelis

Abstract

The toxicity, therapeutic effect and distribution of 1-(5-nitro-2-furyl)-2-(6-amino-3-pyridazyl)-ethylene hydrochloride(nifurprazine hydrochloride, HB-115 HCl)were investigated in ayu, a salmonoid fish. The results were as follows.1. Ayu frys were immersed in the water containing various concentrations of HB-115 HCl at various temperatures(11-26°C)for 6 hrs., and then transferred into clean water.Mortalities were checked 3 days later. Minimum lethal concentrations were 1.6, 4.1, 6.0, 6.0 ppm at 26, 22, 16, 11°C, respectively.2. When immersing periods were prolonged 1.5 times, toxicities were enhanced apProximately 2 times.3. Cunative effects of HB-115 HCl on the infection caused by intramuscular injection of Vibrio anguillarum in ayu fish were diminished by increasing the inoculum size.4. Good therapeutic effects by bathing were achieved by the suitable combination of concentration and immersing period (e. g. 10 ppm-20 mins., 3 ppm-45 mins., 1 ppm-360 mins.).5. Effects of water temperatures on the therapeutic effects of HB-115 were not noticed.6. When ayu fishes were immersed in the water containing 2-30 ppm of HB-115 HCl was detected in serum and skin, but not in muscle and viscera.