Dietary alpha-linolenic acid does not enhance accumulation of omega-3 long-chain polyunsaturated fatty acids in barramundi (Lates calcarifer)
Files
(Submitted version)
Date
2013
Authors
Tu, W.
Muhlhausler, B.
James, M.
Stone, D.
Gibson, R.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Journal article
Citation
Comparative Biochemistry and Physiology B: Biochemistry and Molecular Biology, 2013; 164(1):29-37
Statement of Responsibility
Wei-Chun Tu, Beverly S. Mühlhäusler, Michael J. James, David A.J. Stone, Robert A. Gibson
Conference Name
Abstract
This study examined the effects of substituting fish oil and fish meal with a blend of alpha-linolenic acid (ALA, 18:3 n-3) rich vegetable oils (14%, w/w) and defatted poultry meal (34%, w/w) in a formulated diet, on growth and tissue fatty acid profiles in barramundi fingerlings. Results indicated that on average, while the ALA levels of the barramundi liver and fillet increased with increasing dietary ALA, there was no corresponding increase in the levels of the omega-3 (n-3) long chain polyunsaturated fatty acid (LCPUFA). Compared to fish consuming a commercial feed, which contained fish meal and fish oil, fish on the ALA diets grew slower, had a lower feed intake and lower n-3 LCPUFA levels in the tissues. Hepatic mRNA expression of Δ6 desaturase (FADS2) and elongase (ELOVL5/2) was ~10 fold and ~3 fold higher, respectively, in all the ALA dietary groups, relative to those fed the commercial feed. However, the level of expression of the two genes was not different between fish fed differing ALA levels. These data demonstrate that increasing the ALA level of the diet is not an appropriate strategy for replacing marine sources of n-3 LCPUFA in barramundi. It was also noted, however, that within the different ALA dietary groups there was a large amount of variation between individual fish in their tissue DHA levels, suggesting a significant heterogeneity in their capacity for conversion of ALA and/or retention of n-3 LCPUFA. When dietary ALA intakes were greater than 0.8% en, tissue DHA levels were inversely related to ALA intake, suggesting that high intake of dietary ALA may inhibit DHA synthesis.
School/Discipline
Dissertation Note
Provenance
Description
Access Status
Rights
© 2012 Elsevier Inc. All rights reserved.