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

Praziquantel (PZQ) is a drug effective against several parasitic diseases of fish caused by Platyhelminthes. The study assesses the efficacy of selected in-feed PZQ doses in eliminating metacercariae Diplostomum pseudospathaceum in grass carp. The fish were infected with D. pseudospathaceum in laboratory conditions and subsequently treated with PZQ at daily doses of 30 (PZQ1), 50 (PZQ2), and 100 (PZQ3) mg/kg bw for seven days. The treatment trial was followed by a 23-day observation period during which the fish were parasitologically examined on days 0, 2, 8 and 23. Smaller fish were infected with a significantly higher (P < 0.05) number of metacercariae than bigger fish among three weight groups as follows: up to 7 g > 7 to 12 g > 12 g. The in-feed PZQ at doses of 30, 50 and 100 mg/kg bw for seven days was 47%, 84% and 88% effective against metacercariae D. pseudospathaceum, respectively. A significant decrease (P < 0.01) in moving and an increase (P < 0.01) in the immotile metacercariae in the eye's lens were recorded in all the trial groups on each sampling day. An increasing proportion of motile metacercariae in the post-treatment observation period was seen in PZQ2 and PZQ3, indicating a decreasing trend in the actual efficacy in an environment with no reinfection possibility.

• Klíčová slova
• Diplostomum pseudospathaceum, anthelmintic, diplostomosis, fish, medicated feed,
• Publikační typ
• časopisecké články MeSH

This study aimed to assess the toxicity of praziquantel (anthelmintic drug) in different developmental stages of common carp (Cyprinus carpio) based on mortality, early ontogeny, growth, oxidative stress, antioxidant enzymes, histology and behaviour. Praziquantel at all tested concentrations ranging from 1 to 4 mg/L showed no significant adverse effects on mortality, the early ontogeny and behaviour locomotory (activity, moved distance and velocity) of carp after 35-day exposure. Concentrations of 3 and 4 mg/L caused significantly (P < 0.01) lower growth, total superoxide dismutase and catalase activities compared with controls. Praziquantel is safe for the early life of carp in concentrations ≤ 2 mg/L.

• MeSH
• antioxidancia farmakologie   MeSH
• chemické látky znečišťující vodu * toxicita   MeSH
• embryo nesavčí MeSH
• kapři * MeSH
• katalasa farmakologie   MeSH
• larva MeSH
• praziquantel farmakologie   MeSH
• superoxiddismutasa farmakologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antioxidancia MeSH
• chemické látky znečišťující vodu * MeSH
• katalasa MeSH
• praziquantel MeSH
• superoxiddismutasa MeSH

This study evaluated the toxicity of the pyrazino isoquinoline anthelmintic praziquantel (PZQ) to the Danio rerio zebrafish and Daphnia magna water flea. The estimated 24 h and 96 h LC50 of PZQ to the zebrafish was 39.9 mg/l and 30.4 mg/l, respectively. The highest 24 h and 96 h non-lethal concentration (LC0) was 21.7 mg/l and 21.2 mg/l, respectively. The mobility inhibition test of the juvenile Daphnia magna revealed a 48 h EC50 of 42.7 mg/l.

• Klíčová slova
• 96 h LC50, antiparasitic, bath treatment, water flea, zebrafish,
• Publikační typ
• časopisecké články MeSH