Bacteriophages can fight diseases in aquaculture.

Bacteriophages would be a good tool in aquaculture facilities, say scientists in Finland, after discovering that the viruses survive up to 21 days in recirculating aquaculture systems and could be a long-term solution against bacterial diseases.

Theoretically, recirculating aquaculture systems could be an ideal environment for bacteriophages, viruses that only infect bacteria, as phages can remain in the system for long periods and are small enough to pass through filters and other barriers.

This could mean an extension of the efficacy of phage therapy without affecting the biofilter bacteria due to the high specificity of phages.

The researchers said they wanted to find out if the use of bacteriophages would cause the subjects to change in such a way that they could infect bacteria that initially became immune.

“This is something that is documented in open systems,” they said.

They used a type of bacteriophage that infects the wound bacterium Flavobacterium columnare. The bacterium causes infections that lead to ulcers in the skin, rot, and dead gill tissue in rainbow trout.

The study results show that the bacteriophages were still present in water samples, fish mucus, and the biofilter after 21 days.

Three-week survival rate

“We have shown that bacteriophages can survive in a RAS facility three weeks after their initial addition. The concentration of phages was higher in the biofilter, suggesting that the biofilm can be a site where the subjects are enriched,” the researchers said.

The researchers explained that it is the biofilter and fish mucus that are most likely to contribute to the survival of phages in RAS. This is because these act as a repository that releases the viruses over a longer period.

“This can help delay the outbreak of bacterial diseases by keeping bacterial numbers low due to bacteriophage infections,” they explained.

They add that the presence of bacteriophages does not alter water quality and causes no mortality.

Translation of the source: https://www.fishfarmingexpert.com/article/study-bacteria-eating-bugs-can-fight-disease-in-ras-facilities/

What are bacteriophages?

Bacteriophages (or phages) efficiently destroy specific bacteria and are completely harmless to plants, animals, and humans. They are the most numerous organisms on the planet; for example, it is estimated that there are 100 times as many phages as human cells in the human body.

Phages are much more specific than chemical antibiotics and can only eliminate pathogenic bacteria while leaving the rest of the ecosystem intact.

Source: Fixed-Phage, West of Scotland Science Park, Glasgow.