Forsøksdyr: In vivo disease challenge to measure susceptibility of rainbow trout fry to infection by Flavobacterium psychrophilum.

Godkjenningsdato 14.04.2020

Godkjenningsperiode 15.04.2020-31.10.2021

In this study, the genetic resistance to F. psychrophilum will be tested in 350 families of Rainbow trout with different genotypes.
Up to a total of 3516 fry will be used in this study.
The 3Rs:
Replacement: It is not possible to replace with another species or to use an in vitro alternative to determine virulence or to test susceptibility.
Reduction: Minimum fish numbers for statistical considerations will be used. A further reduction is not recommended based on the applicant’s prior experiences and ‘best practices’ in animal breeding and genomics; a reduction would lead to a reduction in power, which would limit the downstream utility of the data. Fish numbers have also been discussed with, and approved by husbandry experts to ensure optimal stocking densities for the welfare of this species.
Small numbers of fish will be used in the challenge dose and isolate selection and the study will only be taken forward if morbidity is achieved.
Refinement: Fish will be monitored at least twice daily with increased monitoring at critical periods (post challenge and at onset of signs of disease). During critical periods, fish will be checked at least every 12 hours, and more frequently during the working day. The frequency will be increased for the passage test where very high pathogen doses are used.
Fish that are moribund will be taken out of the trial and registered as dead in accordance with humane endpoint.
The results will be of scientific and long-term social value. Methods to prevent RTFS is required.