DAO 52:69-76 (2002)  -  doi:10.3354/dao052069

Toxicity and pathological effects of orally and intraperitoneally administered ivermectin on sea bass Dicentrarchus labrax

F. Athanassopoulou1,*, V. Ragias2, M. Roth3, N.Liberis4, S. Hatzinikolaou4

1Deptartment of Fish Diseases and Aquaculture, Athens Veterinary Research Center, National Agricultural Research Foundation, 25 Neapoleos Street, Agia Paraskevi, Athens 15341, Greece
2Kavala Fishing Cooperation, Nea Peramos, Kavala, Greece
3Aquaculture Solutions, 499 Clarence Street East, Ottawa, Ontario KIP 5E7, Canada
4Simi Aquaculture Ltd., 43 Meg. Konstantinou Street, Rhodes 85100, Greece

ABSTRACT: The toxicity and histopathology of ivermectin was studied in 3 and 35 g sea bass Dicentrarchus labrax L. following in-feed, oral intubation and injection administration at dose rates ranging from 0.5 to 3.5 mg kg-1. Estimated LD50 values for 3 g fish were 0.335 and 0.106 mg kg-1 following oral intubation and injection administration respectively, for fish reared at 11°C; and 0.839 and 1.023 mg kg-1 following oral intubation and injection administration, respectively for fish reared at 20°C. For 35 g fish reared at 11°C, the estimated LD50 was 0.523 and 0.361 mg kg-1 following oral intubation and injection administration respectively. No signs of toxicity were observed when the compound was administered via the feed at 0.5 and 0.7 mg kg-1. However, toxicity (> 10%) was observed at dose rates of 0.2 mg kg-1 and higher when the compound was administered via oral intubation and at 0.5 mg kg-1 when administered via injection. The compound was significantly more toxic to fish reared at 11°C than at 20°C. Further, ivermectin was more toxic to 3 g than to 35 g sea bass when administered via injection. Histopathological examination of the major organs revealed pathology was largely restricted to gills and intestinal tissue. In 3 g sea bass, lesions were also found in the kidneys.


KEY WORDS: Ivermectin · Sea bass · Dicentrarchus labrax · Toxicity · Histopathology


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