Forsøksdyr: Therapeutic effect of different feed regimes

Godkjenningsdato 24.03.2020

Godkjenningsperiode 13.04.2020-15.09.2021

1 Purpose
To assess duration of protection (efficacy) and safety aspects of a chemotherapeutic agent to control sea lice.

2 rounds of treatment of fish with subsequent transfer to sea with natural sea louse infestation and efficacy assessment.
The first round of treatment will mimic spring transfer of fish. The second round of treatment will mimic Autumn transfer of fish to sea.

2 Distress
Slight/negligible. The main stressor is transportation to sea. No treatment-related harm is expected. Much study data has reported no treatment-related adverse effects following oral administration of the target dose of the active ingredient. Two specific safety studies have further indicated a high safety margin. The product was well tolerated in Atlantic salmon after oral treatment at up to five times the recommended dose and for three times the duration.

3 Expected benefit
Potentially high. Sea lice are one of the major challenges in the Norwegian salmon industry. Major efforts are made to prevent and treat the infestation but more methods are needed. The present trial will generate knowledge of a new potential product for the toolbox in the fight against sea lice.
This data is pivotal for the future granting of a Norwegian marketing authorization for the product.

4 Number of animals, and what kind
In this study, a total of 6000 juvenile Atlantic salmon will be given the product as an in-feed treatment at the hatchery, 3000 fish in 2 different time points, i.e. in Spring and Autumn of 2020. This will amount to totally 6000 treated fish.
In addition we will mock treat the same amount of fish that will serve as control fish.
Thus in total, the trial will be comprised of 12 000 fish transferred from the hatchery to the Marine site.

The fish will later be transferred to a marine farm site where they will continue to grow and be evaluated in the the study until efficacy is lost. Each cage in the marine farm will hold 1000 medicated or control fish. This means that 3000 treated fish and 3000 controls fish will be transferred to the marine site in the spring of 2020 and the same number of fish will be transferred to different cages in the Autumn.

This number of animals to be stocked in each cage at the marine site is chosen so that the number of fish for sampling and minimum density of fish in the cages is representative of the husbandry prectices under which fish are reared in commercial fish farming in Norway.

5 How to adhere to 3R
The number of animals used is considered to be the minimum number needed to recreate a representative commercial fish farm environment with respect to fish density, also after sampling of most fish. The trial requirements to not allow for further replacement or refinement.