Monooxygenase mediated pyrethroid detoxification in sea lice (Lepeophtheirus salmonis)

TitleMonooxygenase mediated pyrethroid detoxification in sea lice (Lepeophtheirus salmonis)
AuthorsSevatdal S, Fallang A, Ingebrigtsen K, Horsberg TE
TypeComparative Study
Media TitlePest management science
CitationSevatdal S, Fallang A, Ingebrigtsen K, Horsberg TE. Monooxygenase mediated pyrethroid detoxification in sea lice (Lepeophtheirus salmonis). Pest management science. 2005 Aug; 61(8):772-8.


The role of monooxygenases in detoxification of the pyrethroids cypermethrin and deltamethrin was examined. Four strains of sea lice (Lepeophtheirus salmonis Krøyer) with normal or moderately reduced sensitivity towards the pyrethroids were tested in bioassays by exposure to the pyrethroid alone and in combination with an oxygenase inhibitor, piperonyl butoxide (PBO). The normal (baseline) sensitivity was considered as the sensitivity range for the two most sensitive strains. Pre-treatment with PBO elevated the sensitivity (P < 0.01) compared with groups exposed to the pyrethroid only. A positive, but not statistically significant, correlation between the activity of haem peroxidases and the pyrethroid concentration immobilizing 50% of the parasites was demonstrated (rho = 0.500 for deltamethrin and rho = 0.310 for cypermethrin). The results indicate that cytochrome P450 monooxygenases are involved in detoxification of pyrethroids in sea lice. 14C-Deltamethrin was absorbed in a lesser amount in a group of sea lice exposed to a mixture of the compound and PBO than in a group exposed to 14C-deltamethrin alone. A significant difference could be demonstrated both immediately after exposure (P < 0.01) and 24 h after exposure (P < 0.05). No significant differences were found between groups pre-treated with PBO and groups exposed to 14C-deltamethrin only. 14C-Deltamethrin was taken up mainly through the cuticle, especially the cuticle on the extremities of the ventral surface, and subsequently distributed throughout the body of the parasite.

Author Details
Additional information about authors:
1Sigmund Sevatdal
2Anders Fallang
3Kristian Ingebrigtsen
4Tor Einar Horsberg
Additional details for this publication include:
Property NameValue
Publication ModelPrint
Publication Date2005 Aug
Journal AbbreviationPest Manag. Sci.
Copyright2005 Society of Chemical Industry
Language Abbreng
Publication TypeComparative Study
Journal CountryUnited States
Publication TypeJournal Article
Publication TypeResearch Support, Non-U.S. Gov't
Cross References
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PMID: PMID:15880646