In-feed Praziquantel treatment ofgrass carp (Ctenopharyngodon idella) infected with eye flukes.

Abstract

Praziquantel (PZQ) isadrug effective against several parasitic diseases offish caused byPlatyhelminthes. The study assesses the efficacy ofselected in-feed PZQ doses ineliminating metacercariae Diplostomum pseudospathaceum ingrass carp. The fish were infected with D.pseudospathaceum inlaboratory conditions and subsequently treated with PZQ atdaily doses of30 (PZQ1), 50 (PZQ2), and 100 (PZQ3) mg/kgbwfor seven days. The treatment trial was followed bya23-day observation period during which the fish were parasitologically examined ondays0, 2, 8 and 23. Smaller fish were infected with asignificantly higher (P < 0.05) number ofmetacercariae than bigger fish among three weight groups asfollows: upto7 g > 7 to12 g > 12 g. The in-feed PZQ atdoses of30, 50 and 100mg/kgbwfor seven days was 47%, 84% and 88% effective against metacercariae D.pseudospathaceum, respectively. Asignificant decrease (P < 0.01) inmoving and anincrease (P < 0.01) intheimmotile metacercariae inthe eye's lens were recorded inall the trial groups oneach sampling day. Anincreasing proportion ofmotile metacercariae inthe post-treatment observation period was seen inPZQ2 and PZQ3, indicating adecreasing trend inthe actual efficacy inanenvironment with noreinfection possibility.