Publikasjoner

Antagonistic Mechanisms of Probiotic Aliivibrio sp. Strain Vl2 Against Moritella viscosa: Evidence from Co-cultivation and Targeted Transcriptomic Analysis

Winter ulcers, primarily caused by Moritella viscosa, represent a significant challenge for the Norwegian aquaculture industry. Effective control measures are hampered by the lack of effective vaccines and limited use of antibiotics, driven by the global effort to combat antibiotic resistance. Recent studies have shown that probiotic Aliivibrio spp. colonize the skin and ulcers of Atlantic salmon and are linked to a reduced prevalence of winter ulcers. These observations suggest that M. viscosa and Aliivibrio spp. may interact within ulcers in vivo. In this study, we investigated how the probiotic Aliivibrio sp. strain Vl2 (hereafter Aliivibrio Vl2) modulates M. viscosa in vitro, using both co-cultures and cultures within the salmonid cell line CHSE-214. We found that this probiotic strain antagonizes M. viscosa, reducing its growth and its pathogenicity toward the salmonid cells. Targeted transcriptome analysis of Aliivibrio Vl2 during co-culture revealed potential antagonistic mechanisms that impede the growth of this competing pathogen. Together, our findings demonstrate that this probiotic bacterium inhibits M. viscosa growth in vitro. Furthermore, the identified transcriptomic changes suggest potential mechanisms underlying the reduced prevalence of winter ulcers observed in field studies after probiotic administration.

Reduced Infestation Levels of Lepeophtheirus salmonis in Atlantic Salmon

Salmon lice (Lepeophtheirus salmonis) constitute a major challenge during the production of farmed Atlantic salmon in Norway. Preventive measures are considered to have a higher impact on sustainable control than lice treatment.

Enhanced growth and decreased mortality in Atlantic Salmon

Disease in farmed Atlantic salmon occurs in all its life stages. Salmon are particularly vulnerable to infectious diseases at transition from the freshwater stage to the saltwater stage. Our aim in these studies reported was to investigate the possibility that waterborne delivery of a probiotic comprised of naturally occurring marine bacterial species would reduce the mortality and improve the health and growth of farmed Atlantic salmon.

Improved health and better survival of farmed lumpfish (Cyclopterus lumpus) after a probiotic bath with two probiotic strains of Aliivibrio

Cleaner wrasse eat sea lice (Lepeophtheirus salmonis) directly from the skin of the Atlantic salmon (Salmo salar). To reduce harvest from the wild wrasse populations and to increase the quality and availability of cleaner fish, lumpfish (Cyclopterus lumpus) have been increasingly developed as a service industry to the farming of Atlantic salmon in the last few years. Acquired resistance against the de-lousing chemicals is occuring at an increasing speed particularly in mid- and western-Norway has made the farming of lumpfish more important in the control of the sea lice infestations in farmed Atlantic salmon.