Albendazole and praziquantel for the control of Neoechinorhynchus buttnerae in tambaqui (Colossoma macropomum)

The increase in the production and commercialization of aquatic organisms in Brazil is partly due to the growth of native species such as tambaqui. The intensification of fish farming systems has led to an increased occurrence of parasitic diseases, and this has become a serious issue, especially in fish farms in northern Brazil. The present study evaluated the use of albendazole and praziquantel in the control of Neoechinorhynchus buttnerae in tambaqui, in two separate trials. In the first experiment, six concentrations of albendazole (0, 100, 200, 300, 400, and 500 mg kg−1 diet) were evaluated, in triplicate, with 12 fish per tank, for 21 days. In the second experiment, using the same experimental design, fish were given five different doses of praziquantel (0, 4, 6, 8, and 10 g kg−1 diet). In both trials, control group were fed with commercial feed not medicated. Also, fish from each treatment (n=9) of both experiments were sampled and subjected to parasitological and hematological tests to determine the efficacy of the drugs. The prevalence of the acanthocephalans in fish was 100% in the albendazole trial, with no efficacy observed in 21 days. Prevalence of N. buttnerae in the praziquantel trial ranged from 66.7 to 77.8%, and efficacy varied from 0 (doses < 6 g kg−1 diet) to 59.01% (8 g kg−1 diet, respectively). There was no significant difference between treatments in both trials regarding hematological parameters. Further studies to determine the best treatment route, optimum dose, toxicity to fish, palatability, and any potential side effects are thus needed.