Genomic selection for visceral white-nodules diseases resistance in large yellow croaker

Large yellow croaker is an important economic fish for marine aquaculture. Visceral white-nodules disease (VWND), usually caused by Pseudomonas plecoglossicida, outbreaks in the season when the seawater temperature is about 15-20 C. With high morbidity and mortality, VWND is one of the most serious problems faced by the large yellow croaker aquaculture industry. Current cold-water disease prevention and control measures may lead to animal welfare burdens and environmental pollution, necessitating alternative strategies. This study aimed to investigate the genetic parameters of resistance to VWND and genomic-based approaches to improve disease resistance by genomic selection (GS). 1163 large yellow croakers were challenged by VWND to construct a reference population, and the distribution of death time showed a normal pattern, suggesting that there may be individual differences in host resistance to VWND. A genotype dataset containing 607 individuals and 46,039 high-quality SNPs was constructed and used for GS analysis. By evaluating different low-density SNP panels and mathematical methods, the most appropriate GS model was established and the genomic estimated breeding value (GEBV) of the candidate population was calculated. The individuals with the highest ranking of GEBV in the candidate population were selected for breeding resistant strains (RS). The challenge experiment showed that the VWND resistance performance of the RS group was significantly better than that of the control group. This study provides a theoretical basis for disease resistance breeding of marine fish, and also provides experimental materials and data support for the upcoming further research on VWND resistance.