GENETIC VARIATION, GWAS, AND PREDICTABILITY FOR SURVIVAL AGAINST IPNV STRAINS IN RAINBOW TROUT

Contagious diseases are a major threat in aquaculture due to losses caused by high mortalities and the reduced growth  of surviving fish. Infectious pancreatic necrosis (IPN) is one of the highly contagious diseases of farmed salmonid fish caused by Aquabirnavirus. The disease often causes high levels of morbidity and mortality (30–80%, [1]), and ultimately huge economic loses. Juvenile fish and post-smolts during the months following seawater transfer appear to be the most susceptible phases of production cycle. The clinical symptoms of disease outbreak include swollen abdomen and eyes, 
darkening of the skin, necrosis of the pancreas and spiral swimming [2]. The survivors can become healthy carriers that may infect susceptible animals either by vertical and/or horizontal means. Although a large proportion of rainbow trout are vaccinated against IPN-virus, the protective effect is uncertain. Host genetic make-up plays significant role for survival 
against infectious pancreatic necrosis virus (IPNV) with some families survive better than the others. Genetically improved resistance against IPNV is a highly valuable tool to improve survival and to reduce losses due to IPN. The aim of current study was to compute genetic variation for survival against IPNV, further look into the genomic architecture of the trait and 
explore potential for marker assisted and/or genomic selection.