Estimation of genetic parameters for resistance to Vibrio alginolyticus infection in the Pacific oyster (Crassostrea gigas)

The Pacific oyster (Crassostrea gigas) is one of the most important aquaculture species in the world, while its industry has been hampered by mass summer mortality caused by pathogenic factors including Vibrio bacteria. Selective breeding of oyster strains with high resistance to Vibrio bacteria would be an effective and sustainable approach to prevent massive economic loss. Estimation of genetic parameters for disease resistance is the critical step toward selective breeding. In this study, we constructed 52 full-sib families using the C. gigas with diverse genetic backgrounds, and performed an artificial infection experiment to assess disease resistance among families and estimate genetic parameters for resistance to Vibrio alginolyticus infection. The survival rate of the 52 families ranged from 0% to 56.25%, suggesting high levels of phenotypic variation in resistance to V. alginolyticus infection. Genetic parameters for resistance to V. alginolyticus infection estimated using six different models revealed low to moderate heritability, ranging from 0.133 to 0.257. The Pearson and Spearman correlation coefficients among family estimated breeding values (EBVs) were high (correlation coefficients ?0.989), indicating that the predictive ability of different models for family EBVs was consistent. The genetic and phenotypic correlation between resistance to V. alginolyticus and growth traits were low, suggesting the feasibility of simultaneous genetic improvement of both growth and resistance traits. This work reported the first estimation of genetic parameters for resistance to V. alginolyticus and provided valuable information toward genetic improvement of resistance to V. alginolyticus using traditional selection or genomic selection breeding approach.

Automated summary

The Pacific oyster showed high phenotypic variation in resistance to Vibrio alginolyticus infection, with low to moderate heritability estimates for resistance. High correlation coefficients among family estimated breeding values suggest consistent predictive ability of different models for family EBVs. The low genetic and phenotypic correlation with growth traits indicate the feasibility of simultaneous genetic improvement in both growth and resistance traits.