Professor Johan Glette was an important initiator of the present study. To our great bereavement Professor Glette passed away in January 2006, and has thus not been a part of the finalization of the manuscript.
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The effect of hyperoxygenation and reduced flow in fresh water and subsequent infectious pancreatic necrosis virus challenge in sea water, on the intestinal barrier integrity in Atlantic salmon, Salmo salar L.
Article first published online: 4 JUN 2009
DOI: 10.1111/j.1365-2761.2009.01047.x
© 2009 The Authors. Journal compilation © 2009 Blackwell Publishing Ltd
Additional Information
How to Cite
Sundh, H., Olsen, R.-E., Fridell, F., Gadan, K., Evensen, Ø., Glette, J., Taranger, G.-L., Myklebust, R. and Sundell, K. (2009), The effect of hyperoxygenation and reduced flow in fresh water and subsequent infectious pancreatic necrosis virus challenge in sea water, on the intestinal barrier integrity in Atlantic salmon, Salmo salar L.Journal of Fish Diseases, 32: 687–698. doi: 10.1111/j.1365-2761.2009.01047.x
Publication History
- Issue published online: 16 JUL 2009
- Article first published online: 4 JUN 2009
- Received: 20 October 2008 Revision received: 18 December 2008 Accepted: 22 December 2008
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Keywords:
- Atlantic salmon;
- fish;
- intestine;
- infectious pancreatic necrosis virus;
- smoltification;
- stress
Abstract
In high intensive fish production systems, hyperoxygenation and reduced flow are often used to save water and increase the holding capacity. This commonly used husbandry practice has been shown to be stressful to fish and increase mortality after infectious pancreatic necrosis virus (IPNV) challenge, but the cause and effect relationship is not known. Salmonids are particularly sensitive to stress during smoltification and the first weeks after seawater (SW) transfer. This work aimed at investigating the impact of hyperoxygenation combined with reduced flow in fresh water (FW), on the intestinal barrier in FW as well as during later life stages in SW. It further aims at investigating the role of the intestinal barrier during IPNV challenge and possible secondary infections. Hyperoxygenation in FW acted as a stressor as shown by significantly elevated plasma cortisol levels. This stressful husbandry condition tended to increase paracellular permeability (Papp) as well as translocation of Aeromonas salmonicida in the posterior intestine of Atlantic salmon. After transfer to SW and subsequent IPNV challenge, intestinal permeability, as shown by Papp, and translocation rate of A. salmonicida increased in the anterior intestine, concomitant with further elevation in plasma cortisol levels. In the anterior intestine, four of five fish displayed alterations in intestinal appearance. In two of five fish, IPNV caused massive necrosis with significant loss of cell material and in a further two fish, IPNV caused increased infiltration of lymphocytes into the epithelium and granulocytes in the lamina propria. Hyperoxygenation and reduced flow in the FW stage may serve as stressors with impact mainly during later stages of development. Fish with an early history of hyperoxygenation showed a higher stress response concomitant with a disturbed intestinal barrier function, which may be a cause for the increased susceptibility to IPNV infection and increased susceptibility to secondary infections.