Effects of temperature and feed composition on essential fatty acid (n-3 and n-6) retention in Atlantic salmon (Salmo salar L.) parr
Retentions of total n-3 and n-6 essential fatty acids (EFAs) were assessed in Atlantic salmon (Salmo salar L.) parr held at 8 °C and 2 °C until they increased in weight from ca. 19 g to 38 g. Feeds contained sandeel oil or a rapeseed:linseed oil blend at 21 and 34% dietary fat. EFA retention efficie...
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Published in | Fish physiology and biochemistry Vol. 29; no. 2; pp. 133 - 140 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
Dordrecht
Springer Nature B.V
01.01.2003
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Subjects | |
Online Access | Get full text |
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Summary: | Retentions of total n-3 and n-6 essential fatty acids (EFAs) were assessed in Atlantic salmon (Salmo salar L.) parr held at 8 °C and 2 °C until they increased in weight from ca. 19 g to 38 g. Feeds contained sandeel oil or a rapeseed:linseed oil blend at 21 and 34% dietary fat. EFA retention efficiencies [(g EFA gained g EFA ingested-1) × 100] were estimated by the 'mass balance method' from measurements of feed intake, changes in biomass for each tank of fish, and fatty acid compositions of the feeds and fish. The n-3 EFA retentions were higher (overall mean 71%) across feed treatments and temperatures than the n-6 EFA retentions (overall mean 63%). Retentions of the n-3 fatty acids were higher in the fish given the feeds with the lower fat content (77% vs. 65%), implying improved retention with reduced n-3 EFA availability. n-3 EFA retention tended to be higher at 2 °C than at 8 °C, although this was not consistent across feeds. At low temperature there was very high retention of the n-3 EFAs in feeds containing sandeel oil (80%). Such high retention may represent an adaptation response to low temperature. Lower n-6 EFA retentions imply that more n-6 fatty acids were metabolized than n-3 EFAs. Feed oil influenced retention of the n-6 fatty acids, retention being lower for the salmon parr given the feeds containing sandeel oil (56% vs. 71%). This could indicate a higher tissue deposition of n-6 fatty acids when they are freely available via the diet. Abbreviations: AA – arachidonic acid (C20:4 n-6); DHA – docosahexaenoic acid (C22:6 n-3); EFA – essential fatty acid; EPA – eicosapentaenoic acid (C20:5 n-3); HUFA – highly-unsaturated fatty acid (\ge4 double bonds); MUFA – monounsaturated fatty acid (1 double bond); PL – phospholipid; PUFA – poly-unsaturated fatty acids (\ge2 double bonds); SFA – saturated fatty acid (no double bond); TAG – triacylglycerol. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 0920-1742 1573-5168 |
DOI: | 10.1023/B:FISH.0000035937.68098.83 |