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Docosahexaenoic acid biosynthesis via fatty acyl elongase and Δ4-desaturase and its modulation by dietary lipid level and fatty acid composition in a marine vertebrate.
Biochim Biophys Acta 2015; 1851(5):588-97BB

Abstract

The present study presents the first "in vivo" evidence of enzymatic activity and nutritional regulation of a Δ4-desaturase-dependent DHA synthesis pathway in the teleost Solea senegalensis. Juvenile fish were fed diets containing 2 lipid levels (8 and 18%, LL and HL) with either 100% fish oil (FO) or 75% of the FO replaced by vegetable oils (VOs). Fatty acyl elongation (Elovl5) and desaturation (Δ4Fad) activities were measured in isolated enterocytes and hepatocytes incubated with radiolabeled α-linolenic acid (ALA; 18:3n-3) and eicosapentaenoic acid (EPA; 20:5n-3). Tissue distributions of elovl5 and Δ4fad transcripts were also determined, and the transcriptional regulation of these genes in liver and intestine was assessed at fasting and postprandially. DHA biosynthesis from EPA occurred in both cell types, although Elovl5 and Δ4Fad activities tended to be higher in hepatocytes. In contrast, no Δ6Fad activity was detected on (14)C-ALA, which was only elongated to 20:3n-3. Enzymatic activities and gene transcription were modulated by dietary lipid level (LL>HL) and fatty acid (FA) composition (VO>FO), more significantly in the liver than in the intestine, which was reflected in tissue FA compositions. Dietary VO induced a significant up-regulation of Δ4fad transcripts in the liver 6h after feeding, whereas in fasting conditions the effect of lipid level possibly prevailed over or interacted with FA composition in regulating the expression of elovl5 and Δ4fad, which were down-regulated in the liver of fish fed the HL diets. Results indicated functionality and biological relevance of the Δ4 LC-PUFA biosynthesis pathway in S. senegalensis.

Authors+Show Affiliations

IRTA, Ctra. Poble Nou Km 5.5, 43540 Sant Carles de la Rápita, Spain. Electronic address: sofia.morais@irta.cat.Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, 11510 Puerto Real, Cádiz, Spain. Electronic address: gabriel.mourente@uca.es.IRTA, Ctra. Poble Nou Km 5.5, 43540 Sant Carles de la Rápita, Spain. Electronic address: almudena.martinez@irta.cat.IRTA, Ctra. Poble Nou Km 5.5, 43540 Sant Carles de la Rápita, Spain. Electronic address: noelia.gras@irta.cat.Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK. Electronic address: d.r.tocher@stir.ac.uk.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

25660580

Citation

Morais, Sofia, et al. "Docosahexaenoic Acid Biosynthesis Via Fatty Acyl Elongase and Δ4-desaturase and Its Modulation By Dietary Lipid Level and Fatty Acid Composition in a Marine Vertebrate." Biochimica Et Biophysica Acta, vol. 1851, no. 5, 2015, pp. 588-97.
Morais S, Mourente G, Martínez A, et al. Docosahexaenoic acid biosynthesis via fatty acyl elongase and Δ4-desaturase and its modulation by dietary lipid level and fatty acid composition in a marine vertebrate. Biochim Biophys Acta. 2015;1851(5):588-97.
Morais, S., Mourente, G., Martínez, A., Gras, N., & Tocher, D. R. (2015). Docosahexaenoic acid biosynthesis via fatty acyl elongase and Δ4-desaturase and its modulation by dietary lipid level and fatty acid composition in a marine vertebrate. Biochimica Et Biophysica Acta, 1851(5), pp. 588-97. doi:10.1016/j.bbalip.2015.01.014.
Morais S, et al. Docosahexaenoic Acid Biosynthesis Via Fatty Acyl Elongase and Δ4-desaturase and Its Modulation By Dietary Lipid Level and Fatty Acid Composition in a Marine Vertebrate. Biochim Biophys Acta. 2015;1851(5):588-97. PubMed PMID: 25660580.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Docosahexaenoic acid biosynthesis via fatty acyl elongase and Δ4-desaturase and its modulation by dietary lipid level and fatty acid composition in a marine vertebrate. AU - Morais,Sofia, AU - Mourente,Gabriel, AU - Martínez,Almudena, AU - Gras,Noélia, AU - Tocher,Douglas R, Y1 - 2015/02/04/ PY - 2014/10/27/received PY - 2015/01/18/revised PY - 2015/01/27/accepted PY - 2015/2/10/entrez PY - 2015/2/11/pubmed PY - 2015/8/26/medline KW - DHA KW - Desaturation and elongation activity KW - Dietary lipid level KW - Fatty acid composition KW - Nutritional regulation KW - Polyunsaturated fatty acid synthesis SP - 588 EP - 97 JF - Biochimica et biophysica acta JO - Biochim. Biophys. Acta VL - 1851 IS - 5 N2 - The present study presents the first "in vivo" evidence of enzymatic activity and nutritional regulation of a Δ4-desaturase-dependent DHA synthesis pathway in the teleost Solea senegalensis. Juvenile fish were fed diets containing 2 lipid levels (8 and 18%, LL and HL) with either 100% fish oil (FO) or 75% of the FO replaced by vegetable oils (VOs). Fatty acyl elongation (Elovl5) and desaturation (Δ4Fad) activities were measured in isolated enterocytes and hepatocytes incubated with radiolabeled α-linolenic acid (ALA; 18:3n-3) and eicosapentaenoic acid (EPA; 20:5n-3). Tissue distributions of elovl5 and Δ4fad transcripts were also determined, and the transcriptional regulation of these genes in liver and intestine was assessed at fasting and postprandially. DHA biosynthesis from EPA occurred in both cell types, although Elovl5 and Δ4Fad activities tended to be higher in hepatocytes. In contrast, no Δ6Fad activity was detected on (14)C-ALA, which was only elongated to 20:3n-3. Enzymatic activities and gene transcription were modulated by dietary lipid level (LL>HL) and fatty acid (FA) composition (VO>FO), more significantly in the liver than in the intestine, which was reflected in tissue FA compositions. Dietary VO induced a significant up-regulation of Δ4fad transcripts in the liver 6h after feeding, whereas in fasting conditions the effect of lipid level possibly prevailed over or interacted with FA composition in regulating the expression of elovl5 and Δ4fad, which were down-regulated in the liver of fish fed the HL diets. Results indicated functionality and biological relevance of the Δ4 LC-PUFA biosynthesis pathway in S. senegalensis. SN - 0006-3002 UR - https://www.unboundmedicine.com/medline/citation/25660580/Docosahexaenoic_acid_biosynthesis_via_fatty_acyl_elongase_and_Δ4_desaturase_and_its_modulation_by_dietary_lipid_level_and_fatty_acid_composition_in_a_marine_vertebrate_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S1388-1981(15)00047-5 DB - PRIME DP - Unbound Medicine ER -