Submitted to: Book of Abstracts Aquaculture America
Publication Type: Abstract only
Publication Acceptance Date: 11/17/2006
Publication Date: 2/26/2007
Citation: Mitchell, A.J., Hobbs, M. 2007. Acute toxicity of praziquantel (an anthelmintic) to grass carp and golden shiners [abstract]. Book of Abstracts Aquaculture America. p. 619. Interpretive Summary:
Technical Abstract: Praziquantel is an anthelmintic that can be applied to the water to kill tapeworm and trematode parasites in fish. Effective praziquantel treatment rates have been determined but there is little information on the toxicity of this chemical to fish hosts of the parasites. Acute praziquantel toxicity and no observable effect concentrations (NOEC) were determined in the laboratory for grass carp and golden shiners, two commercially raised cyprinids known to harbor the Asian tapeworm Bothriocephalus acheilognathi. The 24- and 96-h LC50 values for golden shiners (1.3 g) were 55.1 and 49.7 mg/L and for grass carp (9.1 g) were 63.4 and 60.6 mg/L, respectively. The 24- and 96-h NOEC for the survival of golden shiners were 50 and 45.0 mg/L and for grass carp were 60.0 and 60.0 mg/L, respectively. In preliminary 24-h trials, grass carp and golden shiners appeared somewhat lethargic after about 2-h of exposure to 20 and 30 mg/L praziquantel and were observed to lose equilibrium at 40 mg/L. In previous studies, praziquantel at 0.5 mg/L for 24-h exposure significantly reduced Asian tapeworm numbers in fish and tapeworm eradication was reported at 1.5 mg/l for a 24-h exposure. With a treatment concentration of 1.5 mg/L, a 30X safety margin is present between effectiveness and an acutely toxic dose, and about 13 X safety margin from the earliest signs (lethargy) of effect on the fish used in the present study.