DEVELOPMENT OF NOVEL ORAL VACCINATION STRATEGIES FOR ATLANTIC SALMON.

Development of novel oral vaccination s;trategies for Atlantic salmon

"Farmed salmon is Scotland's number one food export with a retail value >£1billion worldwide, and Scottish salmon is
exported to over 60 countries. The Salmon aquaculture industry employs over 2,200 people and has invested over
£205million between 2006 and 2011, making this industry a major player in Scotland's economy. The world's increasing
demand for animal protein has pushed the consumption of farmed fish from 9% of total fish consumed in the early 80's to
nearly 50% at present, and this is likely to increase further in the coming decades. Producing enough farmed fish to supply
this demand will only be possible if the major bottlenecks to increased production are reduced or removed, and this includes
the control of infectious diseases. Salmon are fish that require a high quality environment for optimal growth but even when
this is provided, occasionally diseases will arise and thousands of pounds can be lost due to fish mortality and quality
depreciation. Fortunately in the late 1980's a strategy for disease prevention was established: fish vaccination. This
strategy has been so successful that the use of antibiotics in aquaculture has almost disappeared and all the salmon that
are farmed in Scotland will have been vaccinated at least once in their life. Although very successful this strategy has two
main drawbacks: the need for individual fish vaccination and the side-effects of adjuvants included in the vaccine
formulations. In 2011 nearly 50 million fish were vaccinated in Scotland alone. This is a very costly process and in addition
causes a significant amount of stress that makes fish susceptible to other diseases and can only be employed before they
are moved to sea. The side-effects from oil-based adjuvants usually include localized inflammation within the peritoneal
cavity, which can compromise growth and depreciate the fillet value. To overcome this problem we propose to undertake
research to allow development of oral vaccination for salmon. This will include testing of a novel oral vaccine delivery
technology based on nanoparticles. Oral vaccination has several advantages in comparison to injection: 1) the vaccine
would be formulated into the feed, making it easy to administer, 2) the stress of handling the fish is thus avoided and the
need for chemical treatments post-vaccination, to prevent opportunistic pathogens, is avoided, 3) extra doses can be given
after fish have been moved to sea. Therefore this technology will help make salmon farming more efficient,
sustainable, and reduce the cost of disease prevention. To achieve this goal we will start the project with basic research
on how foreign molecules are recognized and presented to immune cells in the gut of salmon, key knowledge required to
understand oral vaccine efficacy. We will then elucidate some gene markers of vaccine effectiveness using existing
commercial vaccines that use mucosal delivery, either by immersion of fish in the vaccine solution as a primary
vaccination, or given as oral boosters. Lastly we will evaluate the use of a novel technology, silicon based nanoparticles,
to deliver vaccines against two commercially relevant diseases for Atlantic salmon: Furunculosis and Pancreas Disease.
With the completion of the salmon genome we know more about fish immunity than ever before. This project will use this
knowledge to undertake ground breaking research on several aspects of gut immunity and oral vaccination, helping the
UK's aquaculture industry to remain sustainable and to continue to grow over the coming years."