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HAVBRUK2-Stort program for havbruksforskning

Genetics of multi-pathogen resistance in Atlantic salmon

Alternative title: Genetikk for multipatogenresistens hos atlantisk laks

Awarded: NOK 12.0 mill.

Project Number:

334333

Application Type:

Project Period:

2023 - 2028

Partner countries:

Fish health in aquaculture is fundamental for both economical and animal welfare considerations. In a typical salmon breeding program, the genetic merits of breeding candidates with respect to disease resistance are evaluated based on performance data from sibs who have been exposed to specific disease agents. However, when there is an outbreak in the field, it is common for fish to be exposed and infected by more than one pathogen simultaneously. Selective breeding to increase host resistance to multiple disease pathogens in interaction with each other will be very important for mitigating the impact of diseases. The current proposal will study the genetics and genomics of coinfection resistance in Atlantic salmon and determine both specific resistance to one disease when other pathogens are present and the general coping of each fish with a complex pathogen load. This paves the way for the development of coinfection-resistant fish through genetic improvement. This proposal also aims at developing a mixed disease challenging test model for four economically important model pathogens selected in this project (i.e., CMS, PD, AGD, and Sea lice). The proposed combined challenge test may replace the currently used specific pathogen challenge tests and reduce the number of routinely required disease challenge tests for the breeding work. This will improve the sustainability of Atlantic salmon production and reduce the number of animals sacrificed through routine challenge testing for breeding work.

In aquaculture, disease resistance plays an important role in the overall sustainability and profitability of the industry. Resistance to specific diseases, evaluated based on survival under a challenge test with a specific pathogen, is part of the breeding objectives for many Atlantic salmon breeding programs. However, when there is an outbreak, it is common for fish to be infected by multiple pathogens simultaneously, and genetic correlations of resistance to different diseases are low to none. Selective breeding to increase host resistance to multiple disease pathogens in interaction with each other will be very important for mitigating the impact of diseases. Furthermore, the current disease challenge models are designed with a high dose of pathogens to achieve at least a 50% mortality rate. This is far from what the fish experience in the production environment. The project will develop and optimize a multi-pathogen challenge test for CMS, PD, AGD, and Sea lice. Further, the proposal will study the genetics of multiple disease resistance in salmon and determine both specific resistance to one disease when other pathogens are present and the general coping of each fish with a complex pathogen load. This paves the way for the development of coinfection-resistant fish through genetic improvement. The mechanisms and gene markers of resistance to multiple infections will be studied by gene expression analyses. The ethical and social implications of establishing and implementing a multi-pathogen challenge test will be determined through a dynamic RRI (responsible research and innovation) process. The project will create a knowledge base and example for the industry regarding mitigation of the impact of disease through genetic improvement for coinfection resistance, this will greatly improve the bio-economy and welfare of Atlantic salmon production.

Funding scheme:

HAVBRUK2-Stort program for havbruksforskning