Selecting broodstocks resistant to infectious diseases is a proven, sustainable, and effective method to prevent mortalities and outbreaks as well as enhance fish health and productivity. The selection of lumpfish families resistant to bacterial infectious diseases has not been reported. In this study, we describe the development of a selection program for lumpfish resistant to Vibrio anguillarum infection and study the Major Histocompatibility Complex (MHC) gene exons for polymorphism. Following quarantine, lumpfish that survived the intraperitoneal challenge with V. anguillarum were raised until sexual maturity. A resistant ♂ was crossed with a resistant ♀ and a domestic ♀. Similarly, a resistant ♀ was crossed with a domestic ♂, and a domestic ♀ was crossed with a domestic ♂. After the First Filial (F1) generation reached 70–100 g, they were bath challenged with V. anguillarum O2 (2 ×104 CFU/mL) for 30 min. At 42 days post-challenge, the relative percentage survival (RPS) of the resistant crosses (resistant ♀ and resistant ♂) was 43.05%. In contrast, the resistant ♀ crossed with a domestic ♂, and the resistant ♂ with a domestic ♀ showed an RPS of 6.77 and 0%, respectively. Additionally, there was no significant association between MHC genotype and resistance to V. anguillarum . Here, we demonstrated that resistance to V. anguillarum in lumpfish has a genetic basis, highlighting the need for further research to better characterize this trait and support its integration into future selective breeding and improvement programs. • We developed a method to select for lumpfish resistant to V. anguillarum infection. • The resistant group showed 44% survival while the crosses groups showed only 1–5% survival. • A significant association between MHC genotype and resistance to V. anguillarum was not observed .
Onireti et al. (Tue,) studied this question.