ABSTRACT: A total of 24 drugs were evaluated as regards their efficacy for oral treatment of gyrodactylosis in rainbow trout Oncorhynchus mykiss. In preliminary trials, all drugs were supplied to infected fish at 40 g per kg of feed for 10 d. Twenty-two of the drugs tested (aminosidine, amprolium, benznidazole, bithionol, chloroquine, diethylcarbamazine, flubendazole, levamisole, mebendazole, metronidazole, niclosamide, nitroxynil, oxibendazole, parbendazole, piperazine, praziquantel, ronidazole, secnidazole, tetramisole, thiophanate, toltrazuril and trichlorfon) were ineffective. Triclabendazole and nitroscanate completely eliminated the infection. Triclabendazole was effective only at the screening dosage (40 g per kg of feed for 10 d), while nitroscanate was effective at dosages as low as 0.6 g per kg of feed for 1 d.

KEY WORDS: Gyrodactylosis · Rainbow trout · Treatment · Drugs

Published in DAO Vol. 33, No. 3 (1998) on July 30
ISSN: 0177-5103. Copyright © Inter-Research, Oldendorf/Luhe, 1998