Forsøksdyr: Pivotal clinical efficacy and duration of efficacy of lufenuron (Imvixa) administered in feed prior to transfer to small-scale sea cages at IMR Austevoll Havbruksstasjon.

Godkjenningsdato 19.03.2020

Godkjenningsperiode 19.03.2020-28.02.2021

The purpose of the present trial is to gain further knowledge of a new potential veterinary pharmaceutical product for the Norwegian market that provides a new tool in the fight against sea lice. In particular, the present study will provide data on efficacy, duration of efficacy and clinical safety of this product. These data are pivotal for the future granting of a Norwegian marketing authorization for the product.
In this study, a maximum of 6,000 juvenile Atlantic salmon will be administered the product as an in-feed treatment at the hatchery, and kept at the hatchery for at least one week post-treatment. Treated fish will then be transferred to the marine farm site at IMR Austevoll Havbruksstasjon and stocked in at least 3 parallels/cages. At the same time an equivalent number of untreated fish will also be transferred to IMR Austevoll Havbruksstasjon and stocked in at least 3 parallels/cages at the same site as controls. At IMR they will be evaluated under the study for up to approximately nine months. The number of animals to be treated has been determined based on the capacity of the facilities at the study site and power analysis. By selecting this number of fish, we expect to replicate, under controlled conditions, the husbandry conditions under which these fish will be reared in farming conditions..
Every week, starting 14 days after transfer to sea, approximately 20 fish per cage will be euthanized, sea lice will be removed, counted and fully differentiated in stages by trained personnel. This will continue weekly until the time point where one or more of the efficacy criteria are not met in two consecutive timepoints. Each month a number of 12 fish per treatment group, of the fish used for sea lice counting, will be kept in case of residue analysis.
Distress in the study is anticipated to be mild with measures taken to minimize distress prior to study-related assessments. The fish will be euthanized for fillet sample collection at the fresh water site and also for sea lice counting at the sea water site. Euthanasia will be performed by trained staff using a recognized method. Based on experience from previous trials both in Norway and abroad, no adverse effects are expected from the treatment. Although adverse events are not expected, study animals will be observed on a daily basis for signs of ill-health. If signs of ill-health are detected, the animals will be assessed and/or treated under the care of a fish health professional and may be humanely euthanized. As the procedure of both sea lice counting and differentiation, and bioanalysis sampling, will be performed after the fish are euthanized, there is no additional requirement to administer analgesia/pain relief to the fish in this study.
Live animals are required for this study. In order to conduct a thorough differentiation of all sea lice stages and residue sampling, the fish will be sacrificed. Regarding the residue sampling there is no in vitro alternative for the evaluation of residue levels in the fish.