The Effect of an Attenuated Live Vaccine against Salmonid Rickettsial Septicemia in Atlantic Salmon () Is Highly Dependent on Water Temperature during Immunization.

Salmonid Rickettsial Septicemia (SRS), caused by the bacterium , is the main reason for antibiotic usage in the Chilean aquaculture industry. In 2016, a live attenuated vaccine (ALPHA JECT LiVac SRS, PHARMAQ AS) was licensed in Chile and has been widely used in farmed salmonids since then. In experimental injection and cohabitation laboratory challenge models, we found that the vaccine is effective in protecting Atlantic salmon () for at least 15 months against -induced mortality.

Modulation of innate immune responses in Atlantic salmon by chronic hypoxia-induced stress.

Atlantic salmon post-smolts were exposed to either chronic hypoxic (Hy) or normal oxygen (No) conditions in seawater tanks for 58 days, mimicking conditions typical of sea cages for farmed salmon at some periods of the year. By day 29 head kidney macrophages were isolated and subjected to in vitro poly I:C stimulation to simulate viral infection, and samples were collected over 48 h. By day 58 fish were subjected to in vivo stimulation using poly I:C or a Vibrio water-based vaccine to simulate viral or bacterial infection, respectively.