Randomized clinical trial to investigate the effectiveness of teflubenzuron for treating sea lice on Atlantic salmon

Abstract

A double-blind, randomized control clinical trial was performed to investigate the effectiveness of teflubenzuron in controlling sea lice Lepeophtheirus salmonis on farmed Atlantic salmon Salmo salar. A total of 40 sea cages from 3 commercial cage sites in Atlantic Canada were used in this Good Clinical Practice (GCP) trial. The teflubenzuron was administered in the feed at a dosage of 10 mg kg -1 biomass d -1 for 7 d. Medicated and control cages were matched by site, cage size, and pre-treatment mean lice counts using cages as the unit of concern. Post-treatment lice counts and staging of developmental stages were performed at 1 and 2 wk after the end of treatment. Chalimus stages in medicated cages were significantly lower than in control cages at 1 wk (79% reduction in mean lice counts, p < 0.001), and at 2 wk (53% reduction, p < 0.001). Mobile (pre-adult and adult) stages were also significantly reduced in medicated cages at 1 wk (69% reduction, p < 0.01), and at 2 wk (40% reduction, p < 0.01) post-treatment, respectively. Teflubenzuron was proven effective for reducing lice burdens on salmon despite the low parasite levels experienced during the trial and the recruitment of lice from the untreated cages. The use of cage as the unit of concern was an important design component of this trial.

Whole‐animal accumulation, oxidative stress, transcriptomic and metabolomic responses in the pink shrimp (Pandalus montagui) exposed to teflubenzuron

“…Flubenzurons are thought to act by inhibiting the expression of the enzyme chitin synthase, involved in the polymerization process during molting. These compounds are therefore effective against all arthropods undergoing molting, but show low toxicity toward other marine species such as algae, mollusks and fish (Branson, Rønsberg, & Ritchie, 2000;Campbell, Hammell, Dohoo, & Ritchie, 2006a, 2006bMacken, Lillicrap, & Langford, 2015;Ritchie, Ronsberg, Hoff, & Branson, 2002). Few data are available on dose descriptors for flubenzurons, particularly on non-targeted marine crustaceans and after oral administration of the pesticide.…”

The Use of Lufenuron to Treat Fish Lice (Argulus sp) in Koi (Cyprinus carpio)

“…7 The concentration of the teflubenzuron in the medicated feed for the Atlantic salmon was 2 kg per metric ton. 8 To our knowledge, no report exists of a water treatment regimen with this drug class.…”

“…In 1995 it was estimated that infestations caused by another ectoparasite, the sea louse (Lepeophtheirus salmonis), which is a distant relative to Argulus sp, resulted in approximately $20 million in losses to the New Brunswick fishing industry. 8 Fish lice are some of the largest ectoparasites of fish and can be observed with the naked eye. Argulus foliaceus ranges from 5 to 10 mm in length; given the relatively large size, the lice can be easily recognized, as was found in this case.…”

“…Teflubenzuron is approved as an in-feed treatment for sea lice control in Norway, the United Kingdom, and Ireland. 8 Teflubenzuron is part of a group of compounds called the acylureas (benzophenylureas), which act to disrupt the synthesis of chitin, a polysaccharide of particular importance to arthropods. 16 An oral dose of teflubenzuron-10 mg of active ingredient per kilogram of biomass daily for 7 days-was administered to Atlantic salmon (Salmo salar).…”

Toxicological assessment of the anti-salmon lice drug diflubenzuron on Atlantic cod Gadus morhua

“…The consumption of diflubenzuron measured as an active component in Norwegian aquaculture was 1413, 1893, 704 and 1611kg in 2009, 2010, respectively (FHI 2013. Benzamide insecticides act by inhibition of chitin synthesis, and chitin-synthesizing organisms are sensitive to these chemicals during molting (Branson et al 2000, Ritchie et al 2002, Campbell et al 2006a, 2006b, Merzendorfer et al 2012. A portion of the diflubenzuron and teflubenzuron that are administered to fish as well as their metabolites ends up in the environment, and release of such chemicals into the environment has raised considerable concern in recent years (Eisler 1992, Fischer & Hall 1992, Haya et al 2005, Burridge et al 2010.…”