Application potential of albendazole as an aquatic animal drug based on its safety, efficacy, and residue profiles

The number of available drugs for treating aquatic animals is insufficient, given the occurrence of a variety of parasites and difficulties in developing appropriate treatments, such as vaccines or immunostimulants. Consequently, repurposing livestock drugs for treating aquatic animals is a viable alternative. Several studies have demonstrated that albendazole (ABZ) is a good anthelmintic for humans and animals such as ruminants, poultry, and honeybees. Therefore, we investigated the toxicological studies, metabolic and residue depletion studies, and efficacy trials of ABZ in aquatic animals to identify its application potential as a drug for aquatic animals. ABZ was depleted within 24 h in the muscle tissues of hybrid striped bass, rainbow trout, and tilapia. In muscle tissue with adhering skin obtained from tilapia and largemouth bass, a significant quantity of the amino-sulfone metabolite of ABZ (ABZ-SO₂NH₂) was present, while no ABZ-SO₂NH₂ was detected in hybrid striped bass, channel catfish, and patinga. Fish exposed only to high doses of ABZ showed reduced red blood cell counts and hemoglobin levels and increased lymphocytes. Such signs of toxicity have also been observed in human patients and animal studies. At a dose of 100 mg/L, ABZ showed 100% efficacy in eels. In addition, albendazole sulfoxide (ABZSO) demonstrated efficacies of 96.1% and 100% in pirapatinga and ray-finned fish, respectively, at a dose 500 mg/L. ABZ was also highly effective in treating an intracellular parasite E. hepatopenaei in white shrimp. The application of ABZ in aquatic animals under the low-dose and short-term conditions is considered a reasonable solution to manage parasite infections. The types and residual periods of degradation products differed among fish species, suggesting dissimilar metabolic pathways. With a high demand for new alternative veterinary drugs in aquaculture by fish farmers, this review offers important evidence for considering the use of ABZ in Korean farmed fish, taking food safety issues into account.