579. Genetic parameters and genome-wide association study of resistance to acute hyperthermia in rainbow trout

Abstract

Selective breeding is a promising solution to reduce fish farms vulnerability to heat peaks. Objectives of this study were to give a new insight on the genetic architecture of resistance to acute hyperthermia stress in rainbow trout. At 275 days post-fertilization, 1,384 fish were phenotyped for acute hyperthermia resistance and body weight. Challenged fish were genotyped for 57K SNP and their genotypes were imputed at high-density thanks to their parents being genotyped on a 665K SNP array. Heritability estimate of resistance to acute hyperthermia was 0.32 ± 0.04. This trait was genetically negatively correlated with body weight (-0.58 ± 0.17). The genome-wide association study revealed that resistance to acute hyperthermia is highly polygenic as altogether the 5 detected QTLs explained less than 5% of the genetic variance. The main QTL region explained 3% of the genetic variance and contained two candidate genes previously described to be associated with temperature resistance.