title: Characterization of the fatty acyl elongase (elovl) gene family, and hepatic elovl and delta-6 fatty acyl desaturase transcript expression and fatty acid responses to diets containing camelina oil in Atlantic cod (Gadus morhua).
abstract: For aquaculture to become sustainable, there is a need to substitute fish oil [FO, rich in ω3 long chain polyunsaturated fatty acids (LC-PUFA) such as 20:5ω3 (EPA) and 22:6ω3 (DHA)] in aquafeed with plant oils such as camelina oil [CO, rich in C18 PUFA such as 18:3ω3 (ALA) and 18:2ω6 (LNA)]. The LC-PUFA are essential components in fish diets for maintaining optimal health, physiology and growth. However, most marine fish including Atlantic cod are inefficient at producing LC-PUFA from shorter chain precursors. Since elovl genes encode enzymes that play key roles in fatty acid biosynthesis, we hypothesized that they may be involved in Atlantic cod responses to diets rich in 18:3ω3 and 18:2ω6. Ten members of the cod elovl gene family were characterized at the mRNA level. RT-PCR was used to study constitutive expression of elovl transcripts in fifteen tissues. Some transcripts (e.g. elovl5) were ubiquitously expressed, while others had tissue-specific expression (e.g. elovl4a in brain and eye). Cod fed a CO-containing diet (100% CO replacement of FO and including solvent-extracted fish meal) had significantly lower weight gain, with significant up-regulation of elovl5 and fadsd6 transcripts in the liver as shown by QPCR analysis, compared with cod on a FO control diet after a 13-week trial. Multivariate statistical analyses (SIMPER and PCA) indicated that high 18:3ω3 and/or low ω3 LC-PUFA levels in the liver were associated with the up-regulation of elovl5 and fadsd6, which are involved in LC-PUFA biosynthesis in cod.
authors: Department of Ocean Sciences, Memorial University of Newfoundland, 1 Marine Lab Road, St. John's, NL A1C 5S7, Canada.
authors: Xi
authors: X
authors: Xue
authors: Department of Ocean Sciences, Memorial University of Newfoundland, 1 Marine Lab Road, St. John's, NL A1C 5S7, Canada.
authors: Charles Y
authors: CY
authors: Feng
authors: Department of Ocean Sciences, Memorial University of Newfoundland, 1 Marine Lab Road, St. John's, NL A1C 5S7, Canada.
authors: Stefanie M
authors: SM
authors: Hixson
authors: Genome Atlantic, 1344 Summer Street, Halifax, NS B3H 0A8, Canada.
authors: Kim
authors: K
authors: Johnstone
authors: Department of Plant and Animal Sciences, Faculty of Agriculture, Dalhousie University, Truro, NS B2N 5E3, Canada.
authors: Derek M
authors: DM
authors: Anderson
authors: Department of Ocean Sciences, Memorial University of Newfoundland, 1 Marine Lab Road, St. John's, NL A1C 5S7, Canada.
authors: Christopher C
authors: CC
authors: Parrish
authors: Department of Ocean Sciences, Memorial University of Newfoundland, 1 Marine Lab Road, St. John's, NL A1C 5S7, Canada. Electronic address: mrise@mun.ca.
authors: Matthew L
authors: ML
authors: Rise
mesh_terms: D000123:Acetyltransferases / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D019607:Brassicaceae / Q000737:chemistry; D004032:Diet; D000081031:Fatty Acid Elongases; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis / Q000378:metabolism*; D048389:Gadus morhua / Q000254:growth & development / Q000378:metabolism*; D015870:Gene Expression; D050602:Linoleoyl-CoA Desaturase / Q000378:metabolism; D008099:Liver / Q000201:enzymology / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D010938:Plant Oils; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D005231:Fatty Acids, Unsaturated; D010938:Plant Oils; D012333:RNA, Messenger; D050602:Linoleoyl-CoA Desaturase; D000123:Acetyltransferases; D000081031:Fatty Acid Elongases
keywords: Atlantic cod; Camelina oil (CO); Delta-6 fatty acyl desaturase (fadsd6); Fatty acyl elongase (elovl); Liver gene expression