Long chain polyunsaturated fatty acid synthesis in a marine vertebrate: Ontogenetic and nutritional regulation of a fatty acyl desaturase with 螖4 activity

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• 作者：Sofia Morais^a ; ^{sofia.morais@irta.cat} ; Filipa Castanheira^b ; ^{mcastanheira@ualg.pt} ; Laura Martinez-Rubio^c ; ^{laura.martinez@stir.ac.uk} ; Luis E.C. Conceiç ; ã ; o^b ; ^{lconcei@ualg.pt} ; Douglas R. Tocher^c ; ^{d.r.tocher@stir.ac.uk}
• 关键词：ALA ; 伪-linolenic acid ; ARA ; arachidonic acid ; DAH ; days after hatching ; DHA ; docosahexaenoic acid ; DPA ; docosapentaenoic acid ; EFA ; essential fatty acid ; EPA ; eicosapentaenoic acid ; FA ; fatty acid ; FAME ; Fatty acid methyl esters ; LC-PUFA ; long-chain poly
• 刊名：Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids
• 出版年：2012
• 期刊代码：18_13881981
• 类别：bio
• 出版时间：April, 2012
• 卷：1821
• 期：4
• 页码：660-671
• 文件大小：2695 K

摘要

Solea senegalensis is an unusual marine teleost as it has very low dietary requirement for long-chain polyunsaturated fatty acids (LC-PUFA) during early development. Aquaculture is rapidly becoming the main source of health-beneficial fish products for human consumption. This, associated with limited supply of LC-PUFA-rich ingredients for fish feeds, render S. senegalensis a highly interesting species in which to study the LC-PUFA biosynthesis pathway. We have cloned and functionally characterized fatty acyl desaturase and elongase cDNAs corresponding to 螖4fad (with some 螖5 activity for the n 鈭?#xA0;3 series) and elovl5 with the potential to catalyze docosahexaenoic acid (DHA) biosynthesis from eicosapentaenoic acid (EPA). Changes in expression of both transcripts were determined during embryonic and early larval development, and transcriptional regulation in response to higher or lower dietary n 鈭?#xA0;3 LC-PUFA was assessed during larval and post-larval stages. There was a marked pattern of regulation during early ontogenesis, with both transcripts showing peak expression coinciding with the start of exogenous feeding. Although elovl5 transcripts were present in fertilized eggs, 螖4fad only appeared at hatching. However, eggs have high proportions of DHA (~ 20%) and high DHA/EPA ratio (~ 11) to meet the high demands for early embryonic development. The fatty acid profile of larvae after the start of exogenous feeding closely reflected dietary composition. Nonetheless, 螖4fad was significantly up-regulated in response to LC-PUFA-poor diets, which may suggest biological relevance of this pathway in reducing LC-PUFA dietary requirements in this species, compared to other marine teleosts. These results indicate that sole is capable of synthesizing DHA from EPA through a Sprecher-independent pathway.