Genetic analysis of resistance to infectious pancreatic necrosis in Atlantic salmon (Salmo salar L.)

The aim of this study was to estimate genetic parameters for resistance to infectious pancreatic necrosis (IPN) in Atlantic salmon and to evaluate the correlation between survival in challenge tests and survival in field outbreaks of IPN. The analyses were based on challenge test data from four sub-populations of fish. Challenge testing for resistance to IPN has been a part of Aqua Gen's breeding programme since 1997. Data from 8 years was included in the study, and a total of 271,366 fish were tested. Moreover, data from two field outbreaks were analysed. The heritabilities were found to be in the range 0.17-0.45 for each year analysed separately. All years analysed together gave an overall estimate of the heritability of 0.31. The genetic correlations between IPN challenge tests and IPN field outbreaks were found to be in the range 0.78-0.83. The results confirm that there is genetic variation for resistance against IPN in Atlantic salmon, and that a strong positive genetic correlation between IPN challenge tests and IPN field outbreaks exists.