Gut microbiota in Atlantic salmon: Role for production biology

Farmed salmon have experienced rapid domestication and face extraordinarily intensive production environments. Salmon still occasionally show unacceptably high mortality rates during the seawater production phase, with sudden stress-related mortalities in large preharvest fish being an increasing problem. Safeguarding fish welfare throughout the production cycle, as well as understanding biological constraints has become a priority. The differing abilities of individual fish to adapt to and cope with changing production environments is the focus. In addition to genetics, one of the ways that individual variation could be conferred is via the gut microbiota. Bacteria in gut have been shown to influence host physiology and vice versa. The current project will study how the gut microbiota might play a role in shaping different phenotypes of fish that have different coping strategies for responding to stress. Additionally the role of social stress in shaping the gut microbiota will also investigated. Salmon from both farms and laboratory experiments will be used. Close monitoring of behavioural, microbiological, and physiological phenotypes will be employed to facilitate the identification mechanisms underlying variable ability to adapt to new, potentially stressful environments. Probiotics and pathogens in fish with different coping strategies will be measured using real time PCR. Additionally feed will be supplemented with probiotics to see if underperforming fish can be rescued and turned into a marketable product. Based on differences in gut microbiota observed in mammals exposed to social stressors further investigation into gut microbiota in cultured Atlantic salmon could prove useful to the industry in helping address the problem of stress, acute mortality and production loss.