Oral sea lice vaccine feeds hope

AN oral vaccine for sea lice is being developed by a team of Scottish and international aquaculture experts.

The aim of the project is to produce a vaccine that can be delivered through feed, following recent advances in the understanding of fish immune systems.

With funding provided through the Scottish Aquaculture Innovation Centre (SAIC), partners include Stirling‘s Institute of Aquaculture, BioMar; the nanoparticle company SiSaf; and experts in vaccinology, Tethys Aquaculture.

The consortium also draws on the expertise of vaccinologists at the Moredun Research Institute and academic fish immunologists from the University of Maine in the United States.

The cost of sea lice to the Atlantic salmon production industry is estimated to exceed £50 million per year in Scotland alone.

The parasites are currently managed using integrated pest control measures, including medicines, physical and biological tools, and good husbandry on farms.

Despite existing research and prior testing of injectable vaccines, success has so far been limited, with no commercial solution currently being available.

Veterinary medicines continue to be employed for control, but sea lice are becoming increasingly resistant to treatment.

The new approach to oral vaccination will deliver the vaccine via specially developed feeds that aim to improve fish resistance to parasites using advanced nanoparticle technology.

Innovative bio-engineering tools will also target sea lice by triggering strong immune responses in the skin of fish, rather than delivering it through the bloodstream alone.

Sharing approaches employed to control ticks in agriculture, the new vaccine aims to directly target the proteins important for the parasite’s survival.

Dr Sean Monaghan, from the Institute of Aquaculture, said: ‘Reducing the impact of sea lice is a major concern for salmon producers around the globe and we are making headway towards finding an effective method for vaccinating fish against this parasite.

‘There is strong evidence to support the use of an oral vaccination approach, using nanoparticles in feed for vaccine delivery in order to trigger the desired antibody response.

‘Despite the range of treatment and management tools already in use, sea lice remain a challenge to the industry and increased parasite resistance to drug treatment is reducing the effectiveness of these methods.

‘Development of a vaccine would represent a significant advance in sea lice control, providing a practical, eco-friendly tool for use in an integrated sea lice control strategy.’

Polly Douglas, aquaculture innovation manager at SAIC, added: ‘Addressing environmental and health challenges, including sea lice, is one of SAIC’s priority innovation areas and a crucial concern for the global aquaculture industry.

‘The work of this project correlates directly with the Scottish government’s 10-year Farmed Fish Health Framework, aiming to improve fish health, protect the marine environment, and ensure Scotland’s main food export grows sustainably.’