Safety of fluralaner oral solution, a novel systemic antiparasitic treatment for chickens, in laying hens after oral administration via drinking water

Abstract

BackgroundPoultry mites are the most significant pest affecting production systems in the egg-laying industry. Fluralaner is a novel systemic insecticide and acaricide that is effective against poultry mites (Dermanyssus gallinae, Ornithonyssus sylviarum) in chickens after oral administration. This study investigated the safety of oral administration of a 1% solution of fluralaner in drinking water to laying hens at the recommended treatment dose and at multiples of this dose.MethodsOne hundred-twenty healthy 28-week-old laying hens, weighing 1.4–2.1 kg at first administration, were included in the study, and allocated to 4 treatment groups of 30 hens each receiving daily doses of 0, 0.5, 1.5 and 2.5 mg fluralaner/kg body weight, equivalent to 0, 1, 3, and 5 times the recommended dose of fluralaner. The product was administered via drinking water on a total of six occasions, as 3-day treatment periods twice with an interval of 4 days with no treatment (treatment on days 1, 2, 3 and 8, 9, 10), representing 3 times the recommended number of administrations. Hens supplied with non-medicated drinking water served as controls.During the study, all hens were clinically observed, and their health was carefully monitored including body weight, food and water consumption, hematology, clinical chemistry, and withdrawal reflex test. Eggs laid over the study were evaluated for main characteristics (e.g. weight, shape, strength, shell thickness and soundness, albumen height, yolk color, Haugh unit and presence of blood and/or meat spots). Following euthanasia of the hens at the end of the second treatment period (day 11) or 18 days later (day 29), complete gross post-mortem examination, including organ weight determination, and histopathological examination of multiple tissues were conducted.ResultsThere were no clinical findings related to fluralaner treatment. Statistically significant differences between the treated groups and the control group were observed for some clinical pathology parameters; none of these findings were considered to be of clinical nor zootechnical relevance. Organ weights, gross post mortem and histopathological examinations did not reveal any finding associated with treatment with fluralaner.ConclusionsOral administration of fluralaner via drinking water at the recommended treatment dose (0.5 mg/kg body weight twice at 1-week interval), is well tolerated and has a high safety margin up to an overall dose of 15 times the recommended one (5 times the daily dose given 3 times the number of days) in healthy adult laying hens. Based on the present results, the use of the new mite treatment based on fluralaner administered via drinking water is expected to be safe for laying hens under industrial conditions, and to have no negative impact on their egg quality and production.

Safety of fluralaner oral solution, a novel systemic poultry red mite treatment, for chicken breeders’ reproductive performances

“…Water consumption was not affected by fluralaner administrations (ANCOVA: F (1,13.2) = 0.00, P = 0.9622). This is consistent with the results of Prohaczik et al [ 7 ] where no effect on water consumption was detected up to 5× the recommended dose. Fluralaner administrations had no detectable effect on feed consumption.…”

“…The recommended treatment dosage of fluralaner oral solution for chicken is two administrations of 0.5 mg/kg body weight, given at 7 days interval. The general safety of such fluralaner treatment has been investigated in laying hen by Prohaczik et al [ 7 ]. The authors have shown that fluralaner is well tolerated in poultry, with a high margin of safety.…”

Effect of oral afoxolaner on naturally occurring infestations of peacocks by the louse Goniodes pavonis

“…Prior evidence that the isoxazolines would be effective against lice was reported in a study of dogs naturally infested with the sucking louse Linognathus setosus . Several prior studies that used isoxazolines in poultry also supported the potential efficacy and safety of an isoxazoline against ectoparasites on birds …”

“…The mechanism of action of the isoxazolines is inhibition of chloride channels dependent on glutamate and gamma‐aminobutyric acid (GABA) . Drugs in this class have been used successfully in exotic animals for the treatment of a variety of insect and mite infestations . In poultry, isoxazolines have been well‐tolerated and shown to have a high margin of safety for oral dosing .…”

“…Drugs in this class have been used successfully in exotic animals for the treatment of a variety of insect and mite infestations . In poultry, isoxazolines have been well‐tolerated and shown to have a high margin of safety for oral dosing . There are no reports of the use of afoxolaner in exotic or ornamental birds.…”