The importance of genetics in fish health and -wellbeing is growing in the field of aquaculture. AquaGen has, from an early stage, incorporated new technology into fish breeding, and has, over the past five years put great efforts in to mapping out which diseases are most suitable for resistance breeding.
When the “Frisk Fisk”-conference started in Tromsø 3rd March 2015, four of AquaGen’s scientists were there to speak.
Amoebic Gill Disease (AGD) is an disease which has increased in recent years in Ireland, Scotland and Norway. In 2014 there were 69 new registered outbreaks across Norway. Breeding for increased resistance against AGD is already being used on Tasmanian salmon. Recently completed trials and experiences show that the potential for such breeding work is also big in Norway. AquaGen has gathered data from infection experiments carried out at VESO Vikan, as well as from outbreaks in the field. The results show that 55% of the variation in mortality rates with AGD is attributable to genetics. Scientist Vibeke Emilsen said that eggs selected for AGD-resistance will be made available in 2016, or perhaps even this year.
Mechanisms for IPN resistance
Selection for IPN resistance in salmon has been a great success, and QTL-IPN eggs have become standard for the field of aquaculture. Over the course of five years, the number of IPN cases in salmon in Norway has decreased by 83%, from 223 (2009) to 38 (2014). The gene marker for IPN resistance in salmon has shown significant positive effects, and many have wondered whether it is possible to determine what mechanism lies behind the success. Senior scientist, Jacob Seilø Torgersen, showed in his presentation that an IPN resistant fish shuts the virus out from its cells because the “ lock” has been changed and the virus no longer has the right “key” to get in.
CMS is a serious disease as it affects large fish just before harvesting, and because there is no treatment or preventive measures available. AquaGen has identified a genetic marker (QTL) for CMS resistance, and in 2014 launched eggs selected for CMS resistance. Senior scientist Sissel Kjøglum presented documentation showing reduced mortality rates and less internal organ damage in salmon selected for CMS-resistence. Calculations indicate that eggs based on QTL selection will pay off in the event of a CMS outbreak with a mortality rate greater than 1%.
IPN resistance in rainbow trout
Rainbow trout is an important species in Norway, and across the world, and we also see issues with IPN outbreaks with this species. AquaGen, together with Norwegian and international collaborators, has developed powerful genotyping tools for rainbow trout. Through genotyping of families of fish infected with IPN in controlled experiments, a strong marker has been identified for IPN resistance in rainbow trout. The marker was implemented in egg production in 2015, and senior scientist Thomas Moen, said there are high expectations that these eggs will have the same value as QTL eggs for IPN resistance in salmon.