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Faculty of Science / Naturvetenskapliga fakulteten >
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Doctoral Theses / Doktorsavhandlingar >
Chronic stress and intestinal barrier function: Implications for infection and inflammation in intensive salmon aquaculture
Please use this identifier to cite or link to this item:
http://hdl.handle.net/2077/20826
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| Title: | Chronic stress and intestinal barrier function: Implications for infection and inflammation in intensive salmon aquaculture |
| Authors: | Sundh, Henrik |
| Email: | henrik.sundh@zool.gu.se |
| Issue Date: | 2009-10-09 |
| University: | University of Gothenburg. Faculty of Science |
| Department: | Department of Zoology ; Zoologiska institutionen |
| Parts: | 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.) (2009) H.Sundh, R. E. Olsen, F. Fridell, K. Gadan, Ø. Evensen, J. Glette, G. L. Taranger, R. Myklebust and K. Sundell. Journal of Fish Diseases 32:687-698.
VIEW ARTICLE
Disturbed intestinal barrier function in Atlantic salmon (Salmo salar L.) post smolts caused by common sea cage environmental conditions: A possible physiological welfare indicator. H. Sundh, R. E. Olsen, T. Ellis, B. O. Kvamme, F. Fridell, G. L. Taranger and K. Sundell (Under revision for publication in BMC Physiology).
High stocking density and poor water quality disturb physical and immunological barriers in Atlantic salmon (Salmo salar, L.) intestine. H Sundh, T. Ellis, F Fridell, G L Taranger and K Sundell (Submitted for publication in Fish and Shellfish Immunology).
Local innate immune responses in the intestinal mucosa of Atlantic Salmon (Salmo salar) after long term exposure to low oxygen levels and high temperature in the environment. L. Niklasson, H. Sundh, B. O. Kvamme, F. Fridell, G. L. Taranger and K. Sundell (Manuscript)
Translocation of infectious pancreatic necrosis virus across the intestinal epithelium of Atlantic salmon (Salmo salar L.). H. Sundh, S. Calabrese, F. Jutfelt, L. Niklasson, R. E. Olsen and K. Sundell (Submitted for publication in Aquaculture).
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| Date for public defence: | 2009-10-30 |
| Public defence: | Fredagen den 30 oktober 2009, kl. 10.00, i föreläsningssalen, Zoologiska institutionen, Medicinaregatan 18, Göteborg |
| Publication type: | Doctoral Theses |
| Keywords: | Intestinal barrier function
stress
cortisol
Ussing chamber
welfare
health
inflammation
neutrophils
cytokines
chronic stress |
| Abstract: | Aquaculture is a fast growing food-producing sector worldwide. This has increased the awareness among the public as well as governments of the need to secure the welfare and health of farmed fish. Atl... moreantic salmon is, in non-Asian countries, one of the most successful aquacultured species. Despite continuous improvement of husbandry practices and development of new vaccines, both bacterial and viral diseases are main threats to the health of farmed Atlantic salmon. Chronic stress, created by sub- optimal husbandry conditions is believed to be an important factor behind disease outbreaks. The intestinal epithelium of Atlantic salmon is an important organ. Not just in nutrient absorption, but also as a barrier, preventing antigens and pathogens within the intestinal lumen to gain entrance to the host and thereby start an infection. Chronic stress is known to have a negative impact on the intestinal barrier in mammals, a situation that can cause a leaky epithelium and increased bacterial translocation. Stressful husbandry conditions could have a similar effect on the intestine of Atlantic salmon and would thus be a major threat to the welfare of farmed fish.
This thesis aimed at elucidating the importance of the intestinal physical and immunological barrier function in disease susceptibility of farmed Atlantic salmon. It further aimed to reveal the impact of key husbandry conditions in Atlantic salmon aquaculture hypothesized to be potential threats to health and welfare of the fish.
All husbandry conditions examined, i.e. hyperoxygenation combined with low water flow, low levels of dissolved oxygen and high temperature as well as high fish density in combination with poor water quality was concluded stressful to the fish. These common husbandry practises all generated primary and secondary stress responses such as increased plasma cortisol levels, increased cortisol release rate into the water and a decreased function of all intestinal barriers. Decreased physical barrier was evident in the form of increased paracellular permeability. This was accompanied by increased translocation rates of the pathogen bacteria Aeromonas salmonicida, suggesting an increased risk for bacterial infections in fish under chronic stress. Dysfunction of the intestinal immunological barrier was manifested as impaired expression of the pro-inflammatory cytokine IFN-γ. This down regulation could be the result of an immuno suppressive effect of cortisol but could also be an effect of the decreased physical intestinal barrier resulting in increased leakage of luminal antigens. The decreased expression of IFN-γ could be a sign of decreased cellular immunity which would render an intestinal barrier with reduced ability to cope with virus infections like the IPNV. Chronic stress also resulted in increased homing of neutrophils and signs of sever local inflammation. These findings suggest that stressed fish may experience increased disease susceptibility towards viral pathogens like IPNV as well as an increased risk of developing chronic intestinal inflammation.
Intestinal barrier function was further evaluated as a new scientific tool for assessment of potential threats to welfare in aquaculture. The intestine was demonstrated to be a sensitive indicator of stress at times when no or only minor differences in primary stress responses was observed
In conclusion, common husbandry may constitute a threat to health and welfare of farmed fish and intestinal barrier function can serve as a valuable tool for assessing potential stressful husbandry conditions in the future. |
| ISBN: | 978-91-628-7909-9 |
| URI: | http://hdl.handle.net/2077/20826 |
| Appears in Collections: | Doctoral Theses from University of Gothenburg / Doktorsavhandlingar från Göteborgs universitet
Doctoral Theses / Doktorsavhandlingar
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