Gene discovery to tackle trout disease

GENE markers to improve the resistance of rainbow trout to a major disease will be available in the UK, Norway and Chile in early 2017.

Identified by AquaGen, the genetic markers (QTLs) have significant correlation to flavobacteriosis resistance. Also known as Rainbow Trout Fry Syndrome (RTFS), it is a major problem in rainbow trout production worldwide.

It is widespread, occurs frequently, and can cause high mortality and wounds in fry and larger fish in freshwater hatcheries and on-growing sites. Antibiotics are often used to treat stock.

AquaGen has identified and implemented several gene markers for disease resistance in Atlantic salmon.

They are currently employed to produce salmon with increased resistance to the viral diseases IPN, PD and CMS.

Gene markers for resistance to the bacterial disease SRS and to sea lice have also been identified and put to use.

In rainbow trout, AquaGen has found gene markers for IPN - and now flavobacteriosis resistance.

AquaGen has implemented a genomic tool that uses thousands of markers in order to select for disease resistance in rainbow trout.

In collaboration with Affymetrix and the US Department of Agriculture (USDA), a high density SNP-chip capable of genotyping 55,000 SNP markers from one individual fish in one analysis has been developed.

It is through the use of this SNP-chip that gene markers for IPN and flavobacteriosis resistance could be identified.

In 2014, AquaGen started its work on resistance to flavobacteriosis. A crucial part of this work was the availability of an experimental challenge model developed by a group of scientists at the University of Stirling.

Selection for improved resistance to flavobacteriosis is of relevance to all the major markets for AquaGen rainbow trout. Andrew Reeve, AquaGen sales manager UK/Ireland, said: ‘The new product for significantly increased resistance to RTFS will deliver value by reducing the economic impact for the farmer.’