There are two likely interpretations of these data:
1. Smoltification-associated immune-reprogramming is a natural, adaptive response, possibly to avoid overstimulation of the immune system upon seaward migration
2. Aquaculture methods stimulate an abnormal immunosuppressive response to photoperiod-driven smoltification
As a part of ASTI theme 2 (‘comparative seasonal chronobiology’), we seek to test this second interpretation. Aquaculture lighting regimes use several weeks of constant light exposure. A choice which increases growth rate, but which in mammals, disrupts the circadian clock – bringing serious negative consequences for health and the immune system. Using complementary in vitro and in vivo techniques, we will test the role of the circadian clock in the salmon immune response and contrast ‘chronodisruptive’ standard aquaculture lighting profiles with our own ‘chronosympathetic’ designs.
This project also operates within ASTI theme 3 (‘one health’). More than 50 million farmed salmonids died upon transfer to sea cages last year in Norway alone. Better understanding of the interaction between aquaculture lighting regimes, the salmonid circadian clock, and their immune system could dramatically improve this statistic, with clear benefits for both animal welfare and food production efficiency.