Mechanisms and mode of action for probiotic enhancements in Atlantic salmon

Offentlig prosjektsammendrag

A major challenge in the salmon farming industry is disease and new health managment tools are needed. A good microbiome has a well-known potential to outcompete and inhibit pathogens and represents an untapped potential to sustain fish health. Interventions with probiotic bacteria enhance a healthy microbiome balance, but the specific mechanisms of this are still largely unknown. Fish skin constitutes a mechanical barrier, however, it is a mucosal membrane like gut and other mucosal surfaces of other animals and bacterial uptake occurs over intact skin. Like all other mucosal surfaces of animals, the skin of Atlantic salmon has a resident microbial community. This robustness of this microbiota plays a role in development of host immunity and competes with pathogens for sustenance, which contributes to a healthy host. Atlantic salmon given probiotic baths have a significant uptake of bacteria through the skin, but little is known about where the bacteria are transported and reside after they reach the blood and how the bacteria and host interact. This project will identify activity and interaction between Atlantic salmon and bacteria in various tissues in both in freshwater and saltwater. The location and tissue distribution microbiota in wild salmon and farmed salmon will be determined. Host response (gene expression studies and effector cell responses) will be characterized. Atlantic salmon exposed to a series of probiotic and pathogenic bacteria will be studies over all life stages. We will inform on the correlation of host responses microbiota in lab on field studies on and productive measures of probiotic interventons resulting in improved growth, ulcer development, sea lice infection, amoebic gill disease (AGD), and other production data, all of which lead to increased knowledge for the underlying mechanisms of action of probiotics and their increased application for sustainablility in salmon aquaculture.