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Gill disease in Atlantic salmon – studies of multiple factors in challenge models

Project number: NFR/233858

Sound gill health is a key-factor for fish growth and welfare. Gill disease contributes with a significant part of disease-related losses in marine farming of Atlantic salmon in Norway. A better understanding of gill diseases, their etiology, pathogenesis and pathophysiology, is needed to develop more effective disease prophylaxis and treatment. The gills are multifunctional organs, involved in respiration, osmoregulation, acid-base and nitrogen excretion in fish. A number of infectious and non-infectious factors are linked to gill diseases, and the etiology seems to be of multifactorial origin.

The aim of the project is to study the significance and interaction of different factors associated with gill disease, by means of challenge models with live fish. Standardized challenge models will be developed with viral, bacterial, parasitic agents with expected importance for gill disease, as well as with planktonic agents like algae and diatoms, and zooplankton (such as jellyfish and siphonophores). The agents to be involved in these trials include the amoeba Paramoeba perurans, the bacterium Branchiomonas cysticola, and poxvirus. Cultivation of these agents in vitro for challenge purposes will be emphasized, and they will also be subjected to more detailed genetic characterization. Potentially harmful phytoplankters will be included, such as Chaetoceros sp. and Alexandrium sp., or jellyfish like Aurelia auritaor Periphylla periphylla.

The effects of challenge will be studied in trials with one agent alone, or more agents in combination. Parameters to be measured include respiratory and cardiovascular responses, and effects on blood chemistry, acid-base balance and electrolyte levels. Histopathological changes will be evaluated by implementing a new gill scoring system based on a totality of cellular and epithelial abnormalities. The detection of relevant gill associated microbial agents will be included.


Project leader for the Norwegian Veterinary Institute
Anne-Gerd Gjevre

Professor Mark Powell, Norwegian Institute for Water Research (NIVA)
Dr. Nina Blöcher, SINFEF
Dr. Matthew Cook, University of Tasmania

Duration: 01.04.2014 - 31.03.2017


Gjevre Anne-Gerd

Fagansvarlig fiskehelse

Colquhoun Duncan

Senior Researcher

Hansen Haakon


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