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The effect of Teflubenzuron on the control of Lernanthropus kroyeri (van Beneden, 1851) (Lernanthropidae) infestations in cultured sea bass, Dicentrarchus labrax (Linnaeus, 1758).
| Content Provider | Semantic Scholar |
|---|---|
| Author | Tokşen, Erol Değirmenci, Ulaş Cankurt, Murat |
| Copyright Year | 2009 |
| Abstract | Two different dose groups were formed to evaluate the efficacy of teflubenzuron as a treatment for Lernanthropus kroyeri (van Beneden, 1851) infestation in cultured sea bass Dicentrarchus labrax (L.). Teflubenzuron, coated on commercial feed pellets was administered orally at doses of 0 (control), 10, 20 mg kg-1 biomass day-1 for 7 consecutive days. Fish were randomly sampled and parasites were counted on days 7, 14, 21 and 28, and comparisons were made to untreated control fish. Seawater temperature was 16-18 oC. Treatment with teflubenzuron was not effective against larval and mature stages of L. kroyeri. No differences were observed in growth between the treatment groups and the control group. No mortality was found and adverse drug reactions or palatability problems were not associated with the treatments during the study (p > 0,05). Introduction Lernanthropus kroyeri (van Beneden, 1851) is a serious copepod pathogen of farmed sea bass (Dicentrarchus labrax L.) in Mediterranean region (Manera & Dezfuli, 2003; Toksen, 2007). The principal chemotherapeutic agents include dichlorvos, azamethiphos, hydrogen peroxide, cypermethrin and deltamethrin, currently are administered as bath treatments to control copepod parasites under commercial conditions in various countries. Emamectin benzoate, diflubenzuron and teflubenzuron are administered orally against to different copepod parasites (Roth, 2000; Toksen et al., 2006). However, reduced sensitivity to several of these products has been reported (Jones et al., 1992; Treasurer et al., 2000). Teflubenzuron is an insect growth regulator of the acylurea group which interferes with the synthesis of chitin in insects (Clark & Jewess, 1990; Ishaaya & Klein, 1990; Ah-Sun, 1991) and sea lice (Grøntvedt, 1996; Branson et al., 2000). The mode of action of the compound led to its consideration as a possible candidate for the control of Lernanthropus kroyeri. Registered as Calicide in the UK (a medicinal premix containing 100% teflubenzuron) and Ektobann in Norway (a medicated feed containing 2 kg teflubenzuron per tonne fish feed), teflubenzuron has been used as a treatment for sea lice infestations in Norway since 1996 and in the UK since 2000 (Branson et al., 2000). Teflubenzuron has been extensively tested as Bull. Eur. Ass. Fish Pathol., 29(6) 2009, 206 a treatment for Lepeophtheirus salmonis and demonstrated that when administered orally at 10 mg kg–1 fish d–1 for 7 consecutive days teflubenzuron was highly effective in trials conducted at water temperatures ranging from 11 to 15°C (Branson et al., 2000). The purpose of the present study was to evaluate the efficacy of teflubenzuron towards infestations of Lernanthropus kroyeri under commercial conditions. Materials and Methods The trials were conducted in March-May of 2006 at a commercial sea bass farm in İzmir, Turkey. Seven pens, each with a volume of 50 m3 (1 control and 6 treatments), were stocked with 1200 sea bass weighing 80-100 g (mean weight: 92 ± 1 g SD) (each pen included 240 fish). Parasite enumeration was performed by removing 20 fish from each group for each counting. During the study, water temperatures were recorded at 2 m depth, daily. Salinity was assumed to remain stable throughout the trial period. Sea bass naturally infected with L. kroyeri were exposed to different dosages of teflubenzuron for 7 days: 0 (as control), 10 and 20 mg kg-1. A commercial sea bass pellet was coated with teflubenzuron. All of the fish were fed this medicated feed for a period of 7 consecutive days (days 0-6) at a rate of 0.8%-1% biomass. On days 0, 7, 14, 21, 28 and 35 of the experiment, fish were sacrificed and weighed, and then parasites on the gills were counted. All attached parasites were removed and fixed in 5% formalin. Fish was examined individually using a low power microscope and the mean quantities of parasites were calculated. In this study negative binomial regression was used since the numbers of parasite are the dependent variable. All the models in the study were subjected to alpha test to see if the NBR is the correct model for the analysis. |
| Starting Page | 205 |
| Ending Page | 209 |
| Page Count | 5 |
| File Format | PDF HTM / HTML |
| Volume Number | 29 |
| Alternate Webpage(s) | https://eafp.org/download/2009-Volume29/Issue%206/Bulletin%20296-4.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
