The Effect of Emamectin Benzoate in the Control of Lernanthropus kroyeri (van Beneden, 1851) (Lernanthropidae) Infestations in Cultured Sea Bass, Dicentrarchus labrax (Linnaeus, 1758) (original) (raw)
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Sea bass with approximate average weights of 5 and 20 g were treated against Ceratothoa oestroides infection with: (i) medicated pellets of diflubenzuron PC90 at a dosage of 3 mg kg )1 body weight (BW) per day for 14 days. Lice were counted at the beginning of treatment and 19 days after treatment. The drug cleared all lice in the treated group; in the control group, infection remained high 30 days after beginning the experiment. It was concluded that medicated pellets containing 3 mg kg )1 BW diflubenzuron effectively cleared pre-adult and adult stages of the isopod parasite over a 14-day period. No adverse effects were recorded in treated sea bass during the trials and no reinfection occurred 15 days after end of the treatment. (ii) Deltamethrin by means of bath treatments in infected sea bass kept in experimental tanks at 20°C. Before treatment, toxicity on healthy fish was preliminarily assessed by testing five fish from each size group at concentrations of 30, 10, 5, 3, 1, 0.1, 0.05 and 0.01 mg L )1 for 30 min. The therapeutic concentrations tested were: 10, 5, 3, 0.15, 0.1, and 0.05 lg L )1 and assessed at 1, 24 and 48 h. Best results were achieved with the 10 lg L )1 (0.01 mg L )1 ) dose, where prevalence was reduced from 100 to 0% over 24 h in both large and small fish. No parasite recovery was observed at 48 h. The dose of 5 lg L )1 reduced prevalence from 100 to 11.7% and to 0% for small and large fish, respectively. Finally, with the 3 lg L )1 dose, prevalence was reduced from 100 to 37.5% (small fish) and to 13.3% (large fish). Lower doses were ineffective on the parasites at either 24 or 48 h.
Bulletin- European Association of Fish Pathologists
Sea bass, Dicentrarchus labrax naturally infected with L. kroyeri were exposed to dosage of trichlorfon for 7 days: 0 (as control), 50 mg kg-1. On days 0, 7, 14, 21, 28 and 35 of the experiment, fish were randomly sampled and weighed, and then parasites on the gills were counted. Comparisons were made to untreated control fish. Sea water temperature and salinity in the pens were measured as 16.0-16.5 ºC and 35 ppt, respectively. When the study began, all of the examined fish were infected with L. kroyeri. There were no statistical differences (P > 0.05) in terms of mean number of L. kroyeri within each group, including the control. According to the IRR coefficients, 50 mg dose of trichlorfon reduce the males at 98.3%, females at 97.1% and the total 97.1% when compared to the control group. No mortality was found and adverse drug reactions or palatability problems were not associated with the treatments during the study.
Diseases of Aquatic Organisms, 2004
Efficacy of in-feed treatment with emamectin benzoate (Slice) for the control of ectoparasitic Argulus coregoni on rainbow trout Oncorhynchus mykiss was tested under laboratory and field conditions. In both experiments fish were fed with fish feed to deliver a therapeutic dose of 0 (control) or 50 µg emamectin benzoate kg-1 d-1 (treatment) for a period of 7 d. After 3 d of challenge with A. coregoni in the laboratory, the infestation level in treated fish was lower than that observed in the controls (p < 0.001). Efficacy of 100% against newly hatched A. coregoni metanauplii and adults and 80% against juveniles was observed. In the field, trial medication was undertaken at 2 sections on a flow-through canal with 1 wk between treatments. Mean infestations of 100 to 200 A. coregoni per fish with 100% prevalence was recorded prior to medication. Following the treatment, the mean infestation of A. coregoni on fish declined to 31 lice per fish at Section A and 2.5 lice per fish at Section B. Then, after 28 d of treatment, the number of lice per fish was <1 at Section A; in contrast the mean number of A. coregoni per fish at the control section was > 20. The prevalence of A. coregoni remained < 50% over a period of 72 d of treatment, but started to increase again thereafter. This suggests that emamectin benzoate concentration in fish remained at a level high enough to kill A. coregoni over a period of 9 wk. Emamectin benzoate was very effective in the control of A. coregoni infesting trout.
Bulletin of The European Association of Fish Pathologists, 2009
Sea bass, Dicentrarchus labrax naturally infected with L. kroyeri were exposed to dosage of trichlorfon for 7 days: 0 (as control), 50 mg kg-1. On days 0, 7, 14, 21, 28 and 35 of the experiment, fish were randomly sampled and weighed, and then parasites on the gills were counted. Comparisons were made to untreated control fish. Sea water temperature and salinity in the pens were measured as 16.0-16.5 oC and 35 ppt, respectively. When the study began, all of the examined fish were infected with L. kroyeri. There were no statistical differences (P > 0.05) in terms of mean number of L. kroyeri within each group, including the control. According to the IRR coefficients, 50 mg dose of trichlorfon reduce the males at 98.3%, females at 97.1% and the total 97.1% when compared to the control group. No mortality was found and adverse drug reactions or palatability problems were not associated with the treatments during the study. Introduction Lernanthropus is the most common genus of paras...
Journal of Aquatic Animal Health, 2011
The effect of 0.2% emamectin benzoate (SLICE; Intervet/ Schering-Plough Animal Health, Roseland, New Jersey) administered in top-dressed, pelleted commercial fish feed was evaluated for control of freshwater Argulus sp. in goldfish Carassius auratus and koi carp, a variant of common carp Cyprinus carpio, in freshwater aquaria at 24-25 • C. Sixteen individually housed goldfish were each exposed to 37 Argulus. The number of fish lice attached to each fish at the start of the experiment was not determined; however, the total number of motile fish lice in each aquarium (on fish and in the water) was determined at the start and end of each experiment. Eight goldfish were fed the control diet (0 µg · kg fish biomass −1 · d −1 ) and eight were fed the medicated diet (50 µg · kg fish biomass −1 · d −1 ) for seven consecutive days. After treatment, fish louse infestation in controls was 20.5 ± 1.5 (mean ± SE) lice per fish. No Argulus were found on fish in the treated group. In a separate experiment, 10 individually housed koi were each exposed to 128 Argulus. Five koi were fed the control diet and five were fed a low-dose medicated diet (5 µg · kg fish biomass −1 · d −1 ) for 7 d. After treatment, fish louse infestation among the controls was 14.6 ± 3.8 lice per koi. No Argulus were found on koi in the treated group. Hence, a 7-d regimen of oral emamectin benzoate controlled experimental infestation of Argulus when administered to goldfish at 50 µg · kg fish biomass −1 · d −1 and to koi at 5 µg · kg fish biomass −1 · d −1 .
The toxicity of emamectin benzoate, an aquaculture pesticide, to planktonic marine copepods
Aquaculture, 2003
The acute and sublethal toxicity of emamectin benzoate to non-target planktonic marine copepods was determined. Emamectin benzoate is the active ingredient in SliceR, an in-feed pesticide formulation used to control parasitic sea lice in salmon aquaculture. The comparative sensitivity of three life stages (nauplii, copepodites, adults) of four common marine copepods (Acartia clausi, Pseudocalanus elongatus, Temora longicornis and Oithona similis) was assessed in 48-h exposures followed by a recovery period in toxicant-free sea water. The calanoid copepods responded similarly to emamectin benzoate and EC50 values were significantly lower than those for the cyclopoid O. similis. Nauplii and copepodite 48-h EC50 values were generally lower than those for the adults. EC50 values ranged from 0.12 Ag/l (P. elongatus nauplii) to 232 Ag/l (O. similis adults). The primary toxic effect, immobilisation, was generally irreversible. A 7-day sublethal test with adult A. clausi females measured a significant reduction in egg production at higher concentrations. The noobserved-effect-concentration (NOEC) and lowest-observed-effect-concentration (LOEC) values were 0.05 and 0.158 Ag/l, respectively. Concentrations causing toxicity to planktonic copepods were considerably higher than Predicted Environmental Concentrations (PEC) in the vicinity of treated salmon farms and suggest that the use of emamectin benzoate for lice control is unlikely to adversely affect planktonic copepods. D
Diseases of Aquatic Organisms, 2000
Two trials were conducted at commercial salmon farms to evaluate the efficacy of emamectin benzoate (Slicem. 0.2 % aquaculture p r e-M , Schering-Plough Animal Health) as a treatment for sea lice Lepeophthe~rus salmonjs (Krayer) and Caligus elongatus Nordmann infestations in Atlantic salmon Salmo salar L. Tnals were carried out in 15 m2 commercial sea pens, at temperatures of 5.5 to 7.5"C and 10.8 to 13.8"C. Each pen was stocked with 14 000 to 17 500 fish with mean weights of 0.44 to 0.74 and 1.33 to 1.83 kg. Fish were naturally infested with sea hce at the start of each trial. At Day-1, samples of 10 or 15 fish were taken from each pen to determine pre-treatment numbers of lice. Emamectin benzoate was administered in feed, to 4 replicate pens, at a dose of 50 pg kg-' biomass d-' for 7 consecutive days (Days 0 to 6). Sea lice were counted again, between Days 7 and 77, and comparisons made with untreated control fish. Despite adverse weather conditions, wide vanations in fish weights and exposure to new infestations, treatment was effective against challmus and motile stages of L. salmon~s. In the autumn tnal, efficacy at Day 27 was 89%, and lice numbers remained lower on treated fish than on control fish 64 d from the start of treatment. In the winter trial, reductions in lice numbers at low temperatures were slower but good efficacy was achieved by Day 35. Although control fish had to be treated with hydrogen peroxide at Day 21, fish treated only with emamectin benzoate on Days 0 to 6 still had 89% fewer lice than control fish at Day 35. There were very few C. elongatus present, but at the end of both trials numbers were lower on treated fish. No adverse effects were associated with treatment of fish with emamectin benzoate. KEY WORDS: Sea lice. Lepeophtheirus salmonls. Caligus elongatus. Salmo salar. Emamectin benzoate O Inter-Research 2000 Resale of full article not permitted
Aquaculture, 2000
Three field trials were conducted to evaluate the efficacy of emamectin benzoate as a treatment Ž. Ž. for sea lice, Lepeophtheirus salmonis Krøyer and Caligus elongatus Nordmann , infestations on Ž. Atlantic salmon Salmo salar L.. Trials were carried out at sea temperatures of 13.0-15.58C and 7.2-8.58C. Salmon naturally infested with sea lice, with mean weights of 438, 513 and 2662 g, respectively, were held in experimental pens on commercial sites. At day y1 or y2, 20 or 30 fish were sampled from each pen to determine pre-treatment numbers of lice. Emamectin benzoate was administered in-feed at a dose of 50 mg kg y1 biomass day y1 for 7 consecutive days. Sea lice were counted again on days 7, 14 and 21, and comparisons made with untreated control fish. Treatment with emamectin benzoate was effective against chalimus and motile stages of sea lice. In all three trials, treated groups were surrounded by pens of heavily infested fish and L. salmonis numbers increased over time on control fish by 87-284%, whereas over the same period, L. salmonis were reduced on treated fish by 68-98%. In the low temperature trial, reductions were slower but numbers were still 90% lower than on control fish at day 21. At the end of the