Forsøksdyr: Efficacy of novel vaccines towards Tenacibaculum maritimum when administered to Atlantic salmon (Salmo salar) by injection.

Godkjenningsdato 01.07.2020

Godkjenningsperiode 10.08.2020-10.08.2022

Mouthrot is a major health and welfare problem in farmed Atlantic salmon in Western Canada, especially during the first few months following transfer into saltwater. This disease, associated with the bacterium Tenacibaculum maritimum, is the main reason the Atlantic salmon farming industry in this region continues to use antibiotics. Currently, no commercial vaccine is available against the bacterium. There is therefore an urgent need for developing mitigation tools such as vaccines targeting this bacterium.
The purpose of the experiment is to test novel vaccines to prevent infections with Tenacibaculum maritimum. Previous fish experiments have shown that the disease can be replicated in lab conditions with certain isolates of T. maritimum using a bath infection cohabitation model. This experiment aims to use this bath infection model to test the efficacy of novel vaccines targeting this bacterium.
A total of 700 Atlantic salmon will be a part of the experiment. 80 fish will be used in an integrated pre-experiment /freshwater treatment experiment to confirm the infection protocol and to evaluate the effect of freshwater treatment against T. maritimum. 32 fish will be used to test antibody levels pre-immunization. 428 fish will be immunized either with a control vaccine or with a novel vaccine against T. maritimum. At 600 degree-days post immunization, 60 vaccinated fish will be sampled to measure antibody levels. For the bath challenge, 160 unvaccinated fish will be challenged and serve as shedders in the cohabitation challenge model. 24 hours post shedder infection, 352 vaccinated cohabitant fish will be transferred into tanks containing the infected shedders.
Some fish will experience disease. To reduce their suffering and discomfort to a minimum strict surveillance of humane endpoints will be enforced. The objectives of the experiment cannot be carried out without the use of laboratory fish. The number of fish is reduced to a minimum for what is necessary to provide sufficient quality data.