The autumn of 2009 Aqua Gen launched salmon eggs from brood fish which were chosen based on use of a genetic marker for IPN resistance. Nearly 50 million of this egg type, called QTL eggs, were delivered to Norwegian and Scottish customers in the course of the egg season 2009/2010. The results of laboratory tests and reports from hatcheries show that the salmon fry have so far been very well protected against IPN.
Documentation of QTL Eggs in the Field
Several of the hatcheries which have staked a lot on QTL eggs are plants which earlier have had serious problems with IPN. Therefore it will be interesting to compare the results from this year’s deliveries of QTL eggs with earlier years experience with IPN in the same facilities.
So far data has been collected up to and including June 2010, but the results are already quite promising for the QTL eggs. Looking specifically at facilities which have earlier had extensive IPN problems, up to June 2009, six IPN outbreaks among the fry were registered. For the same facilities in 2010 there were no IPN outbreaks in the corresponding period.
Documentation of QTL Eggs from Laboratory Tests
In order to test the QTL eggs which were delivered to the hatcheries in the 2009/2010 season, an infection trial was conducted with IPN at Tromsø Aquaculture Research Station under the direction of Nofima Marin. Different groups of start-fed fry were examined: Aqua Gen ® Atlantic R x E QTL (selected with genetic marker) and Aqua Gen ® Atlantic R x E (not selected with genetic marker). In addition there were two experimental control groups with relatively IPN strong and IPN weak fish as well as a group of uninfected fish.
In spite of the fact that the fish in the R x E QTL group were exposed to large quantities of IPN virus, the mortality rate was at the same level of the uninfected control fish. This shows that one can achieve very good IPN resistance using only selection by gene markers, without going via challenge experiments. The frequency of the good IPN marker gene was decided for each group by genotyping, and altogether the trial shows an almost linearrelationship between the overall rate of the good IPN marker gene in the population and survival after infection.
IPN protection from Day One
Selection for IPN resistance through genetic markers provides a protection against IPN which is comparable to the effect of vaccines, but has several additional inherent values. The fish will be protected against IPN from hatching to slaughter, while not requiring resource-intensive procedures during the production to maintain a high degree of protection.
This new approach to better fish health gives obvious advantages to many hatcheries. T his new approach for improved fish health provides obvious benefits for many fish farmers. Aqua Gen sees this as the start of a new era in selective breeding, and a new and better life for salmon farmers who have long struggled with IPN in their fish.
Comprehensive documentation about QTL eggs can be found here:
“Selective breeding resolves the IPN problems in salmon farming”, Fishfarming Xpert nr. 7, 2010