IPN (infectious pancreatic necrosis) is a viral disease in salmon and rainbow trout that a few decades ago caused major losses for the Norwegian aquaculture industry. Outbreaks of IPN can occur in fry in the hatchery phase, and for a period in smolts post transfer.
There is variation in the genetic resistance to the disease in salmon, and in 2009 AquaGen used genetic markers in the breeding work against IPN. This has made salmon more resistant to the IPN virus, and since then the number of outbreaks of the disease has decreased by more than 90%.
Robust genetics ensures good survival
IPN is a serious disease that AquaGen monitors continuously. We constantly collect data and review the current & future potential challenges the fish farmers face, to make sure that the genetic basis of the salmon provides it with the very best conditions for performing to its maximum ability throughout its life cycle.
Over the past few years, the Norwegian Veterinary Institute’s work on the characterization of viral strains has shown some cases of a new variant of the IPN virus. Naturally, this creates some uncertainty among breeders. Can the new virus variant break through salmon defense mechanisms and in turn lead to disease and high mortality? To answer this, AquaGen has conducted several infection trials with traditional and the new IPN variant. Several thousand salmon have been studied in the experiments, which have been carried out in controlled environmental conditions at VESO Vikan over a period of 40-50 days.
As expected, the results showed that protection against the traditional virus variant continues to provide over 95% survival in AquaGen salmon during the exposure period. The new virus variant showed a gradual increase in mortality throughout the experiment and overall survival was around 70%.
– The results are confirmed through two independent trials with similar data; no acute mortality, but a gradual development in which 70% of the fish survived the infection. This shows that the AquaGen strain is equipped to meet the new IPN variant in the field, where the infection pressure is significantly lower than in an infection trial, says Vibeke Emilsen, Product Manager at AquaGen.
AquaGen will continue to monitor the situation, but our impression expert view is that the new variant so far has limited scope and significance. We welcome feedback from our customers who experience challenges so that together we can share experience and knowledge and keep the IPN virus at bay also in the future.