Persistence Assessment of Febantel and its Effects on Blood Profile in Juvenile Japanese Amberjack <i>Seriola quinqueradiata</i>

Abstract

In vertebrates, FBT is metabolized to the active anthelminthic compounds fenbendazole (FBZ), oxfendazole (OXF), and oxfendazolesulfone (OXF-SO 2 ) (Treves-Brown, 2000). Since FBT has already been approved in Japan for aquaculture usage against Heterobothrium okamotoi in Tetraodontiformes, its pharmacokinetics in Takifugu rubripes has been studied. T. rubripes received 50 mg/kg FBT for 5 day; plasma FBZ concentration reached peak by 4 day and were become no longer detectable 1 wk after the administration (Kimura et al., 2007). In rainbow trout Oncorhynchus mykiss, however, a small trace of FBZ was detected even at 27 day after a single administration of 50 mg/kg (Soukupova-Markova et al., 2015). Although temperature may have affected metabolic rate, the persistence of the drug may vary between fish species. To date, no information is available on the persistence of FBT in Seriola fish; therefore, the first aim of the present study was to obtain the basic persistence profile of FBT and its metabolites in S. quinqueradiata.While FBT and FBZ are considered relatively safe anthelminthic options, their toxicities have been reported in some animals, as for other benzimidazoles (e.g. albendazole and mebendazole) (Carlsson et al., 2013;Fuhr et al., 2012;Nwani et al., 2016). Our previous study indicated lethal and sub-clinical toxicity of FBT on S. quinqueradiata when doses over 20 mg/kg body weight per day (mg/kg/d) were administered for a prolonged period (i.e. for several weeks) (Shirakashi et al., 2021). Oral administration of FBT of 3 mg/kg/d for more than 3 day was experimentally shown to be effective in treating beko disease; therefore, the normal usage of FBT should not have considerable adverse effects on Seriola fish (Kawakami et al., 2021;Shirakashi et al., 2021;Yanagi et al., 2021). However, the precise effects of the drug on fish health should be clarified. The second aim of this study was to assess potential effects of FBT at realistic or slightly higher doses (10 or 20 mg/kg for 5 day) on juvenile S. quinqueradiata by checking their blood profiles.

Efficacy of Febantel Against Gill Monogeneans of Amberjacks I: Laboratory Assessment for Effective Dose and Administration Period

“…The FBT treatment at the same dose (10 mg/kg BW/d for 5 days) has been shown to be safe in Seriola spp. in other studies (Kawakami et al, 2021;Shirakashi et al, 2021aShirakashi et al, , 2021b. Therefore, this treatment regimen likely induces no or very minor, if any, toxicity to S. dumerili and S. quinqueradiata.…”

Evaluations of Lethal and Sub-lethal Toxicity of Febantel in the Juvenile Japanese Amberjack <i>Seriola quinqueradiata</i>

“…Analyses on blood smear samples and hematocrit values showed no apparent drug effect on blood cell and hematopoietic function. More detail analyses on blood profile were performed in separate study (Shirakashi et al, 2021).…”