New fish vaccines developed at Mowi - MOWI - Scotland

New fish vaccines developed at Mowi

Building on the success of previous collaborations between Ridgeway Biologicals Ltd and Mowi Scotland that have delivered effective vaccinations to protect fish health, the partnership has now developed a new vaccine strategy to safeguard salmon against the bacteria Yersinia ruckeri.

Bacterial infection by the pathogen can lead to a disease known as enteric red mouth disease (ERM), mainly found in salmonid species. The disease has caused clinical outbreaks and mortalities in salmon populations farmed on the west coast of Scotland.

The work to develop an effective vaccine against Yersinia ruckeri was initiated in 2022, with the collection and characterisation of many isolates across Mowi Scotland farms. The vaccine was then tested in controlled conditions in 2023 and will now be implemented fully within Mowi in 2024, with the first commercial batches to be vaccinated in spring 2024 and results expected in 2025. The vaccine strategy includes both a dip vaccination early during fish development in freshwater followed by an intraperitoneal injection prior to transfer to sea.

Past collaborations between the two companies have included a vaccine to protect against Pasteurella skyensis – first tested in 2021 before fully implementing across all Mowi stock in late 2022. No clinical outbreaks of the bacteria have been reported at any Mowi farms since, even though the bacteria has been detected.

Commenting on the benefits of this collaboration, Prof. Herve Migaud, Mowi’s Director of Fish Health, Welfare and Biology, said: “The collaboration has generated a lot of knowledge on the evolution of bacterial communities in farm-raised salmon through the use of biotyping and serotyping technologies at a time when sea waters have reached the highest recorded temperatures on the west coast of Scotland.

“Monitoring and understanding what the threats are is the first line of defence against clinical outbreaks and the collaboration contributed very significantly to improve the health and welfare of Mowi Scotland stocks and reduce the use of antibiotics.”

Over the last three years (2021-2023) the use of antibiotics (active ingredient) by Mowi Scotland has been reduced by 79% which shows how successful prevention through vaccine and biosecurity can be.

This collaboration has also showcased how science can be translated into practical solutions for the salmon farming sector.

The Ridgeway/Mowi success is being recognised at the 2024 Aquaculture Awards, with the pair named as finalists in the ‘Collaboration’ category. Awards winners will be announced on Wednesday May 15th in Aviemore.

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