Efficacy of Orally Administered Febantel against Monogenean Heterobothrium okamotoi infection of Cultured Tiger Puffer Takifugu rubripes

Abstract

ABSTRACT-We examined the efficacy of febantel against the infection of the diclidophorid monogenean Heterobothrium okamotoi in cultured tiger puffer Takifugu rubripes. Febantel is a prodrug of fenbendazole, a benzimidazole drug, which is widely used in the field of veterinary medicine. Febantel was metabolized to fenbendazole in tiger puffer just like veterinary animals for oral administration. At the doses of 12.5 mg/kg and 25 mg/kg for 5 days, and 50 mg/kg for 3 days, 88%, 96% and 94%, respectively, of mature worms, and 97%, 95% and 97%, respectively, of immature worms were eradicated at 22-23∞C. These results suggest that febantel has high anti-H. okamotoi activity.

Field Trials of Febantel against Gill Fluke Disease Caused by the Monogenean Heterobothrium okamotoi in Cultured Tiger Puffer Takifugu rubripes

“…Low dose administration in this trial was less effective than high dose administration. However, worm eradication rates were lower than those obtained in a previous experiment using land based tanks and the individual difference in the number of parasites was larger than in our previous study (Kimura et al, 2006).…”

“…The efficacy of febantel against mature of H. okamotoi was demonstrated in this field trial, confirming the results obtained using tiger puffers raised in land based tanks (Kimura et al, 2006). Low dose administration in this trial was less effective than high dose administration.…”

“…The present results were in good accordance with those in the previous experiment, in which 50 mg/kg of febantel was administered to tiger puffers in land base tanks (Kinmura et al, 2007). Furthermore, the blood concentration of fenbendazole, metabolized from febantel, was essentially zero 3 days after the end of administration (Kimura et al, 2007). Therefore, febantel was thought to be safe for use in the field.…”

“…The numbers of mature and immature H. okamotoi worms were counted using the method described by Anshary et al (2001), with some modifications (Kimura et al, 2006). The statistical significance level of the data was judged using Mann-Whitney's U-test (p< 0.05) by comparing the number of H. okamotoi detected between the same dosage groups before and after administration.…”

“…Febantel is a pro-drug of fenbendazole and widely used in veterinary medicine. We investigated whether febantel is effective against this gill fluke disease in a previous study (Kimura et al, 2006). Febantel is metabolized to fenbendazole in tiger puffer in the same manner as in other animals given the drug orally, and the effective dose against H. okamotoi in fish is 12.5 or 25 mg/kg body weight with daily administration for 5 days (Kimura et al, 2006).…”