Effects of praziquantel on metacercarial cysts of Centrocestus sp. on the gills of goldfish Carassius auratus

Abstract

Effects of praziquantel (a compound for trematode and cestode control in dogs) on metacercarial cysts of Centrocestus sp. (a digenetic trematode: Family Heterophyidae) occurring on the gills of goldfish Carassius auratus were investigated by oral and bath treatments. Praziquantel incorporated to the feed at a dose of 200 ppm for 7 days (feed ration of 3% of the body weight/day) was effective in killing 94% ±3.8 of metacercariae. Bath treatment with 0.75 ppm killed only 49% ± 5.2 of metacercariae; dosages higher than 0.75 ppm stressed the fish. Mortality recorded for the control group of fish over a period of 6 weeks was 89% ± 2.8, while the recorded mortality for fish that received oral and bath treatments over the same period of time was 7.3% ± 0.7 and 22.3% ± 1.7 respectively. Results revealed that oral administration of praziquantel is more effective in killing metacercariae of Centrocestus sp.