Updated documentation, per July 2015
Cardiomyopathy syndrome (CMS), is a heart disease affecting salmon that is caused by Piscine myocarditis virus (PMCV). CMS often occurs late in the seawater phase affecting large fish and has become an increasing problem for the Norwegian aquaculture industry since 2010, with 107 cases registered in 2014. The use of QTL eggs that are selected for resistance to CMS is documented to provide significantly improved heart health that contributes to a more robust salmon.
Development and results of QTL-innOva® CMS
Based on data and tissue samples from a field outbreak of CMS in 2008, there was found to be a very good correlation between virus level in the heart, heart tissue damage and mortality. The fish in the study were genotyped and a strong QTL was found that related to virus level in the heart. Effect of the QTL was subsequently tested and confirmed in both a field outbreak and a controlled disease challenge test. In one field outbreak in 2011 around 20% reduced mortality was recorded for fish with the CMS-QTL and an economic analysis showed that as little as 1% CMS related mortality was enough to justify the investment in CMS-QTL.
It was in 2012 that the offspring of the CMS resistant families from the CMS outbreak in 2008 were subjected to an infection challenge with PCMV in the laboratory. Heart damage was assessed using histopathology and once again there was significantly reduced damage in fish that had the CMS-QTL (Figure 1).
Field experience with QTL-innOva® CMS
Autumn 2014 was the first time that S0 smolt were transferred of QTL-innOva® IPN/PD/CMS and QTL-innOva® IPN/PD in two locations that had a history of CMS outbreaks. Until now, CMS has not been recorded in any of the fish groups in these locations.
Following 8.5 months in the sea, at location A, good growth was recorded for all fish groups. At location B there is a tendency for better growth of fish type QTL-innOva® IPN/PD/CMS. On both locations there is on average a lower mortality rate for fish of QTL-innOva® IPN/PD/CMS (Figure 2).
Better heart health gives more robust salmon
In QTL-innova® CMS the most CMS sensitive individuals (qq) are eliminated from the population. This will result in an increased barrier to the introduction and spreading of PMCV in the population, which will therefore be more robust to stress like lice treatment, transport and storage in stand by cages.
Products with CMS protection:
- AquaGen® Atlantic QTL-innOva® IPN/CMS
- AquaGen® Atlantic QTL-innOva® IPN/PD/CMS
- AquaGen® Atlantic QTL-innOva® IPN/CMS/RED
- AquaGen® Atlantic QTL-innOva® IPN/PD/CMS/RED
Benefits of QTL-innOva® CMS:
- Reduced virus levels in the heart, reduced heart damage and lower mortality from CMS outbreak
- Higher degree of herd immunity by the elimination of the most susceptible individuals
- Robust fish that withstand transport and handling better in the final phase of production