Promising disease research on salmon in RAS facilities

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By Milthon Lujan

A new research facility for infection studies in Recirculating Aquaculture Systems (RAS) provides more relevant research for the RAS industry. Preliminary results also show that infection trials in RAS facilities can be conducted faster than in flow-through systems.

Infection models are important tools in fish health research and must resemble real conditions in aquaculture operations as much as possible. Nofima has many years of experience in establishing and using infection models in flow-through systems. Currently, RAS facilities dominate salmon production, and infection models must be reassessed and adapted to RAS.

In collaboration with Tromsø Aquaculture Research Station and UiT – The Arctic University of Norway, Nofima has established brand new RAS facilities. Recently, the first infection trials were carried out there by Nofima. The conclusion after the first experiments is that the infection models worked very well and that the RAS trials can be carried out in less time compared to trials conducted in flow-through systems.

New protocols

Disinfection strategies have played a key role in the trials that have taken place so far. It is crucial to establish protocols for the disinfection of RAS facilities, and for how any disease outbreak should be managed.

“In the RAS trials, we have simulated, among other things, how pathogenic bacteria get into the RAS facilities. This allows us to study how disease develops in the fish, while at the same time we can investigate how and where the pathogens establish themselves and spread throughout the system”, says Carlo C. Lazado, senior scientist at Nofima.

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In previous reports, Nofima has pointed out that many RAS facilities in Norway and North America have disinfection protocols, but it is uncertain how effective these are if pathogens such as viruses and bacteria enter the system.

“Several trials conducted in the new RAS facility will provide us with knowledge about critical areas in the system where the pathogens potentially thrive. This knowledge will be crucial for us in developing risk assessment protocols in RAS, but even more importantly, in developing disinfection protocols that are effective following a disease outbreak”, says Lazado.

A more rapid course of disease

The RAS facility in Tromsø is the first of its kind where it has been reported that this type of controlled bacterial infection trial on salmon has been carried out.

“When we recently conducted a trial with the pathogen Yersinia ruckeri, we saw that disease developed faster than in flow-through systems. The fish were also susceptible to experimental infection at a different stage in the production cycle compared to what we have observed before. This provides more flexibility in infection trials. In addition, we will test virus infection in the system to see if the same tendencies are observed”, says Lill-Heidi Johansen, a fish health scientist at Nofima.

Contact person
Lill Heidi Johansen
Phone: +47 908 82 677

Carlo C. Lazado
Senior Scientist
Phone: +47 930 27 905

Source: Nofima

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