Genetic analysis of disease resistance to Vibrio harveyi by challenge test in Chinese tongue sole (Cynoglossus semilaevis).

Abstract Recently, Vibrio harveyi has emerged as an important pathogenic disease with a high mortality rate (50%–70%) in Chinese tongue sole. The aim of this study was to estimate genetic parameters for resistance to V. harveyi in Chinese tongue sole and to evaluate the genetic correlation between resistance and growth traits (i.e. body weight and total length) (involving 50 full-sib families and 8547 individuals). Longitudinal linear models and cross-sectional threshold models were fitted by using different trait definitions (binary and categorical). After a 14-day test, the overall challenge test survival was 57.86% (ranging from 9.30% to 94.30% in families). The heritabilities of survival were ranging from 0.11 to 0.28, estimates obtained by linear models were higher than threshold models. The genetic correlations between resistance (binary and categorical traits) and two growth traits were moderately positive (0.27–0.51). Very high Pearson and Spearman correlations (0.99 to 1) of full-sib family EBVs between different models were all close to unity which might reveal the similar predictive ability of the four models. The favourable heritabilities and moderate positive genetic correlations indicate that joint genetic improvement of vibriosis resistance and growth performance would be feasible. Statement of relevance This paper offers guidelines to disease-resistance selective breeding strategies in Chinese tongue sole. Highlights • Genetic variation for disease resistance traits were evaluated by challenge test with Vibrio harveyi in Chinese tongue sole. • Two types of models (cross-sectional and longitudinal models) were used for genetic analyses based on different trait definitions (i.e., binary test survival and categorical test day survival). • Low to moderate heritabilities for V. harveyi resistance traits were estimated, indicating that resistance could be genetically improved by selective breeding. • Genetic correlations between disease resistance traits and growth traits were moderately positive (ranging from 0.27 to 0.51) and significantly different from zero. • Estimated breeding values (EBVs) of the four models showed high and positive correlations (0.99–1), which meant that these models demonstrated similar utility for predicting breeding value. [ABSTRACT FROM AUTHOR]