“Significant breakthrough” with genetic discovery in fight against fish disease

News
0

A team of international aquaculture researchers has identified two new genetic markers that indicate greater resistance to a bacterial infection in Atlantic salmon.

In a project backed by the Sustainable Aquaculture Innovation Centre (SAIC), a consortium has been exploring the genetics that determine whether fish are resistant to Flavobacterium psychrophilum. This is bacteria that can lead to health issues in salmon fry.

The project was led by AquaGen Scotland, as well as the University of Stirling’s Institute of Aquaculture, DawnFresh Farming and Cooke Aquaculture Scotland.

In the press release, SAIC writes that the scientific milestone is expected to pave the way for selective breeding programmes, which could boost the health and welfare of farmed Scottish salmon by breeding new fish from parents that possess the genetic resistance markers and are, therefore, expected to display increased resistance to the bacteria.

Flavobacteriosis, the disease caused by the bacteria, can be a particular threat to smaller, juvenile fish and is a widespread challenge for the aquaculture sector, with infections also reported in Chile, Norway and Canada. However, current prevention and treatment programmes are limited, vaccination by injection cannot be used due to the size of the fish and, as the sector continues to move away from antibiotic treatments, a genetic breakthrough could hold the key.

AquaGen Managing director Andrew Reeve said that “genetic markers for disease resistance, such as those discovered through this SAIC funded project, are valuable tools that can and will be immediately employed in breeding work.”

To identify the two genetic markers, more than 4,000 fish from breeding company AquaGen were tested for more than 70,000 genetic markers using a specially designed lab-based model, which mimics the natural infection route. The next stage of the research programme is to conduct field trials at one of Cooke Aquaculture’s sites using salmon eggs specifically selected by AquaGen. It is hoped that in the event of a natural outbreak of the bacterial disease being detected, these fish can be tested to validate the effect of the genetic markers.

Research fellow at the Institute of Aquaculture Dr Rowena Hoare said that “flavobacteriosis is known to be problematic for salmonid culture in freshwater globally for decades”.

“This project has shown how fruitful it can be to combine the expertise of academic and industry researchers to address a complex and economically important disease,” she added.