This study aimed to assess the toxicity of the anthelmintic drug praziquantel in the early life stages of grass carp (Ctenopharyngodon idella). The toxicity was evaluated based on mortality, early ontogeny development, growth, oxidative stress biomarkers, antioxidant enzymes and histopathology. Praziquantel at all tested concentrations (1, 2, 4 and 6 mg/l) showed no significant adverse effects on the hatching of grass carp. Concentrations of 2, 4 and 6 mg/l praziquantel caused significantly (P < 0.01) higher mortality and slower growth compared with controls. Praziquantel at concentrations (4 and 6 mg/l) showed a significant (P < 0.01) delay of early ontogeny of grass carp. Concentration of 2 mg/l praziquantel caused significantly (P < 0.01) higher GST activity than controls. Among the groups, no histological changes were detected in tissues. For the early life of grass carp, praziquantel is safe at concentrations ≤1 mg/l.

• Klíčová slova
• antioxidant biomarkers, antiparasitic drug, carp, fish, histopathology,
• Publikační typ
• časopisecké články MeSH

The study aimed to evaluate and compare the routes and rates of the depletion of the antiparasitic praziquantel (PZQ), a derivative of pyrazinoisoquinoline, following its oral administration in grass carp (Ctenopharyngodon idella). We focused on the depletion of PZQ and its major metabolites - cis-hydroxy praziquantel (CPZQ) and trans-hydroxy praziquantel (TPZQ), in water, the plasma, hepatopancreas, kidney, muscle, and skin, following a single oral administration of PZQ in a concentration of 50 mg/kg. Fish were sampled before the drug administration and then eight times in the course of the 30-day-long experiment. Our results indicate the rapid absorption and elimination of PZQ and its metabolites in all the analysed matrices. The most PZQ-burdened tissue was the hepatopancreas, the gill and the skin. In all the samples, the concentration of the drug and its metabolites consistently declined over time. The residue of the parent compound was detected for the longest time in all the tissues. During the study, a significant (P < 0.01) correlation was found within the concentration of PZQ, CPZQ, and TPZQ in the water and all the biological matrices. It was also found that the PZQ residue was not detected below the maximum residue levels (i.e., 20 μg/kg) until 16 days after exposure in the muscle and skin.

• Klíčová slova
• fish, food safety, health, parasites,
• Publikační typ
• časopisecké články MeSH