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Appears in Collections:Aquaculture Journal Articles
Peer Review Status: Refereed
Title: Effect of dietary digestible energy content on expression of genes of lipid metabolism and LC-PUFA biosynthesis in liver of Atlantic salmon (Salmo salar L.)
Author(s): Martinez-Rubio, Laura
Wadsworth, Simon
Vecino, Jose L G
Bell, J Gordon
Tocher, Douglas R
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Keywords: Digestible energy
Atlantic salmon
Lipid metabolism
Dietary lipid content
Issue Date: 25-Mar-2013
Date Deposited: 5-Apr-2013
Citation: Martinez-Rubio L, Wadsworth S, Vecino JLG, Bell JG & Tocher DR (2013) Effect of dietary digestible energy content on expression of genes of lipid metabolism and LC-PUFA biosynthesis in liver of Atlantic salmon (Salmo salar L.). Aquaculture, 384-387, pp. 94-103.
Abstract: The relationship between lipid and digestible energy content of the feed and growth performance has been exploited with great effect in Atlantic salmon (Salmo salar). The precise metabolic consequences of so-called "high-energy" feeds have not been fully defined, but increased and altered tissue lipid deposition patterns impacting on carcass and product quality have been reported. Recent studies on global gene expression have shown that dietary lipid and digestible energy content can have significant effects on gene expression in salmonids. In addition, we recently showed that functional feeds with reduced digestible energy significantly improved outcomes in response to inflammatory disease in salmon. The present study aimed to elucidate and clarify the effects of dietary digestible energy content (22, 20 and 18 MJ/kg; HE, ME and LE diets, respectively) on lipid and fatty acid metabolism in salmon fed diets containing graded amounts of lipid. Specifically the effects on liver lipid and fatty acid compositions, and on the hepatic expression of genes of lipid and fatty acid metabolism were determined. Final weight and weight gain were significantly higher, and FCR lower, in fish fed the HE diet. Crude lipid content was significantly lower in fish fed the LE diet compared to fish fed the two higher energy contents. Significantly lower total lipid and triacylglycerol levels were recorded in liver of fish fed the LE diet compared to fish fed the higher energy diets. Liver lipids in salmon fed the LE diet had generally significantly higher proportions of saturated fatty acids and long-chain polyunsaturated fatty acids (LC-PUFA), and lower monounsaturated fatty acids, C18 and n - 6 PUFA. Consistent with this, salmon fed the LE diet showed increased liver expression of both Δ6 and Δ5 fatty acyl desaturases in comparison to fish fed the diets with higher energy levels. Fatty acid synthase expression showed a clear upward trend as dietary energy decreased, and sterol regulatory element binding protein 2 and liver X receptor showed reciprocal trends that were consistent with the level of dietary cholesterol that reflects digestible energy content. Although not statistically significant, these trends were biologically logical, significant and relevant. Expression of genes of fatty acid oxidation was less consistent. Overall, reduced dietary digestible energy/lipid content alone, without major changes in dietary fatty acid composition, altered the expression of key genes of lipid and fatty acid metabolism resulting in general up-regulation of biosynthetic pathways.
DOI Link: 10.1016/j.aquaculture.2012.12.010
Rights: Published in Aquaculture by Elsevier; Elsevier believes that individual authors should be able to distribute their accepted author manuscripts for their personal voluntary needs and interests, e.g. posting to their websites or their institution’s repository, e-mailing to colleagues. The Elsevier Policy is as follows: Authors retain the right to use the accepted author manuscript for personal use, internal institutional use and for permitted scholarly posting provided that these are not for purposes of commercial use or systematic distribution. An "accepted author manuscript" is the author’s version of the manuscript of an article that has been accepted for publication and which may include any author-incorporated changes suggested through the processes of submission processing, peer review, and editor-author communications.

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