Optimisation of dietary n-3 and n-6 fatty acids for a robust Atlantic salmon (Salmo salar)
An optimal diet for Atlantic salmon (Salmo salar) should promote a healthy fish that is robust to changes in its environmental conditions and can withstand the handling it will encounter under farming conditions, all while promoting good and rapid growth. The plant ingredients commonly used in aquaf...
Published in: | Metabolites |
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Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
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The University of Bergen
2022
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Online Access: | https://hdl.handle.net/11250/2999623 |
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Open Polar |
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University of Bergen: Bergen Open Research Archive (BORA-UiB) |
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ftunivbergen |
language |
English |
description |
An optimal diet for Atlantic salmon (Salmo salar) should promote a healthy fish that is robust to changes in its environmental conditions and can withstand the handling it will encounter under farming conditions, all while promoting good and rapid growth. The plant ingredients commonly used in aquafeeds do not have an ideal FA composition for salmon. In particular, they are lacking the n-3 fatty acids (FA) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are essential nutrients for salmon. Further, they are rich in the n-s6 FA linoleic acid (LA) and the n-9 FA oleic acid (OA), which are not common in the natural diet of salmon. The exact requirement of EPA and DHA for Atlantic salmon is, however, still not known. There are also indications that a higher inclusion of dietary n-6 FA can increase the requirement for EPA and DHA. Many previous trials investigating these nutrients have been short-term, land-based trials where the fish have been shielded from difficult situations. Though such trials can define minimum requirements, the practical requirements need to be determined in a challenging environment. The focus of this thesis has been to investigate the effect of dietary EPA, DHA and n-6 FA on the robustness of Atlantic salmon exposed to challenging environmental conditions. It has been suspected that dietary n-6 can affect the requirement of EPA and DHA, and that it may have an effect on the response to chronic and acute stress. To investigate this, a feeding experiment was conducted with three diets containing equal absolute amounts of n-3 FA and increasing n-6 FA (n-6/n-3 ratios of 1, 2 and 6), as well as a final diet with double absolute n-3 FA content and an n-6/n-3 ratio of 1. This allowed for a separation between effects of ratio and absolute amounts on tissue FA levels. These diets were used in a 13-week growth trial and a 4-week stress trial. In the stress trial, half the fish were exposed to a repeated stressor (hypoxia) three times weekly, while the other half were undisturbed ... |
author2 |
orcid:0000-0002-0408-7532 |
format |
Doctoral or Postdoctoral Thesis |
author |
Hundal, Bjørg Kristine |
spellingShingle |
Hundal, Bjørg Kristine Optimisation of dietary n-3 and n-6 fatty acids for a robust Atlantic salmon (Salmo salar) |
author_facet |
Hundal, Bjørg Kristine |
author_sort |
Hundal, Bjørg Kristine |
title |
Optimisation of dietary n-3 and n-6 fatty acids for a robust Atlantic salmon (Salmo salar) |
title_short |
Optimisation of dietary n-3 and n-6 fatty acids for a robust Atlantic salmon (Salmo salar) |
title_full |
Optimisation of dietary n-3 and n-6 fatty acids for a robust Atlantic salmon (Salmo salar) |
title_fullStr |
Optimisation of dietary n-3 and n-6 fatty acids for a robust Atlantic salmon (Salmo salar) |
title_full_unstemmed |
Optimisation of dietary n-3 and n-6 fatty acids for a robust Atlantic salmon (Salmo salar) |
title_sort |
optimisation of dietary n-3 and n-6 fatty acids for a robust atlantic salmon (salmo salar) |
publisher |
The University of Bergen |
publishDate |
2022 |
url |
https://hdl.handle.net/11250/2999623 |
genre |
Atlantic salmon Salmo salar |
genre_facet |
Atlantic salmon Salmo salar |
op_relation |
Paper I: Hundal BK, Liland NS, Rosenlund G, Bou M, Stubhaug I & Sissener NH. (2021a) Increasing dietary n-6 fatty acids while keeping n-3 fatty acids stable decreases EPA in polar lipids of farmed Atlantic salmon (Salmo salar). British Journal of Nutrition, vol. 125, issue 1, pp. 10-25. The article is available in the thesis file. The article is also available at: https://doi.org/10.1017/S0007114520002494 Paper II: Hundal BK, Liland NS, Rosenlund G, Höglund E, Araujo P, Stubhaug I & Sissener NH. (2021b). Increasing the dietary n-6/n-3 ratio alters the hepatic eicosanoid production after acute stress in Atlantic salmon (Salmo salar). Aquaculture, vol. 534, article number 736272. The article is available in the thesis file. The article is also available at: https://doi.org/10.1016/j.aquaculture.2020.736272 Paper III: Hundal BK, Lutfi E, Sigholt T, Rosenlund G, Liland NS, Glencross B, Sissener NH. (2022). A Piece of the Puzzle—Possible mechanisms for why low dietary EPA and DHA cause hepatic lipid accumulation in Atlantic salmon (Salmo salar). Metabolites, 12, issue 2, article number 159. The article is available in the thesis file. The article is also available at: https://doi.org/10.3390/metabo12020159 container/e0/9c/bf/3c/e09cbf3c-7286-4879-ae12-ed6860b60f65 urn:isbn:9788230844533 urn:isbn:9788230849873 https://hdl.handle.net/11250/2999623 |
op_rights |
Attribution (CC BY). This item's rights statement or license does not apply to the included articles in the thesis. https://creativecommons.org/licenses/by/4.0/ Copyright the Author. |
op_doi |
https://doi.org/10.3390/metabo12020159 |
container_title |
Metabolites |
container_volume |
12 |
container_issue |
2 |
container_start_page |
159 |
_version_ |
1766361366219718656 |
spelling |
ftunivbergen:oai:bora.uib.no:11250/2999623 2023-05-15T15:30:54+02:00 Optimisation of dietary n-3 and n-6 fatty acids for a robust Atlantic salmon (Salmo salar) Hundal, Bjørg Kristine orcid:0000-0002-0408-7532 2022-06-07T07:13:37.953Z application/pdf https://hdl.handle.net/11250/2999623 eng eng The University of Bergen Paper I: Hundal BK, Liland NS, Rosenlund G, Bou M, Stubhaug I & Sissener NH. (2021a) Increasing dietary n-6 fatty acids while keeping n-3 fatty acids stable decreases EPA in polar lipids of farmed Atlantic salmon (Salmo salar). British Journal of Nutrition, vol. 125, issue 1, pp. 10-25. The article is available in the thesis file. The article is also available at: https://doi.org/10.1017/S0007114520002494 Paper II: Hundal BK, Liland NS, Rosenlund G, Höglund E, Araujo P, Stubhaug I & Sissener NH. (2021b). Increasing the dietary n-6/n-3 ratio alters the hepatic eicosanoid production after acute stress in Atlantic salmon (Salmo salar). Aquaculture, vol. 534, article number 736272. The article is available in the thesis file. The article is also available at: https://doi.org/10.1016/j.aquaculture.2020.736272 Paper III: Hundal BK, Lutfi E, Sigholt T, Rosenlund G, Liland NS, Glencross B, Sissener NH. (2022). A Piece of the Puzzle—Possible mechanisms for why low dietary EPA and DHA cause hepatic lipid accumulation in Atlantic salmon (Salmo salar). Metabolites, 12, issue 2, article number 159. The article is available in the thesis file. The article is also available at: https://doi.org/10.3390/metabo12020159 container/e0/9c/bf/3c/e09cbf3c-7286-4879-ae12-ed6860b60f65 urn:isbn:9788230844533 urn:isbn:9788230849873 https://hdl.handle.net/11250/2999623 Attribution (CC BY). This item's rights statement or license does not apply to the included articles in the thesis. https://creativecommons.org/licenses/by/4.0/ Copyright the Author. Doctoral thesis 2022 ftunivbergen https://doi.org/10.3390/metabo12020159 2023-03-14T17:42:32Z An optimal diet for Atlantic salmon (Salmo salar) should promote a healthy fish that is robust to changes in its environmental conditions and can withstand the handling it will encounter under farming conditions, all while promoting good and rapid growth. The plant ingredients commonly used in aquafeeds do not have an ideal FA composition for salmon. In particular, they are lacking the n-3 fatty acids (FA) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are essential nutrients for salmon. Further, they are rich in the n-s6 FA linoleic acid (LA) and the n-9 FA oleic acid (OA), which are not common in the natural diet of salmon. The exact requirement of EPA and DHA for Atlantic salmon is, however, still not known. There are also indications that a higher inclusion of dietary n-6 FA can increase the requirement for EPA and DHA. Many previous trials investigating these nutrients have been short-term, land-based trials where the fish have been shielded from difficult situations. Though such trials can define minimum requirements, the practical requirements need to be determined in a challenging environment. The focus of this thesis has been to investigate the effect of dietary EPA, DHA and n-6 FA on the robustness of Atlantic salmon exposed to challenging environmental conditions. It has been suspected that dietary n-6 can affect the requirement of EPA and DHA, and that it may have an effect on the response to chronic and acute stress. To investigate this, a feeding experiment was conducted with three diets containing equal absolute amounts of n-3 FA and increasing n-6 FA (n-6/n-3 ratios of 1, 2 and 6), as well as a final diet with double absolute n-3 FA content and an n-6/n-3 ratio of 1. This allowed for a separation between effects of ratio and absolute amounts on tissue FA levels. These diets were used in a 13-week growth trial and a 4-week stress trial. In the stress trial, half the fish were exposed to a repeated stressor (hypoxia) three times weekly, while the other half were undisturbed ... Doctoral or Postdoctoral Thesis Atlantic salmon Salmo salar University of Bergen: Bergen Open Research Archive (BORA-UiB) Metabolites 12 2 159 |