title: Effect of ration size on fillet fatty acid composition, phospholipid allostasis and mRNA expression patterns of lipid regulatory genes in gilthead sea bream (Sparus aurata).
abstract: The effect of ration size on muscle fatty acid (FA) composition and mRNA expression levels of key regulatory enzymes of lipid and lipoprotein metabolism have been addressed in juveniles of gilthead sea bream fed a practical diet over the course of an 11-week trial. The experimental setup included three feeding levels: (i) full ration until visual satiety, (ii) 70 % of satiation and (iii) 70 % of satiation with the last 2 weeks at the maintenance ration. Feed restriction reduced lipid content of whole body by 30 % and that of fillet by 50 %. In this scenario, the FA composition of fillet TAG was not altered by ration size, whereas that of phospholipids was largely modified with a higher retention of arachidonic acid and DHA. The mRNA transcript levels of lysophosphatidylcholine acyltransferases, phosphatidylethanolamine N-methyltransferase and FA desaturase 2 were not regulated by ration size in the present experimental model. In contrast, mRNA levels of stearoyl-CoA desaturases were markedly down-regulated by feed restriction. An opposite trend was found for a muscle-specific lipoprotein lipase, which is exclusive of fish lineage. Several upstream regulatory transcriptions were also assessed, although nutritionally mediated changes in mRNA transcripts were almost reduced to PPARα and β, which might act in a counter-regulatory way on lipolysis and lipogenic pathways. This gene expression pattern contributes to the construction of a panel of biomarkers to direct marine fish production towards muscle lean phenotypes with increased retentions of long-chain PUFA.
authors.affiliation: Nutrigenomics and Fish Growth Endocrinology, Instituto de Acuicultura Torre de la Sal, IATS-CSIC, Castellón, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Benedito-Palos
authors.forename: Josep A
authors.initials: JA
authors.lastname: Calduch-Giner
authors.forename: Gabriel F
authors.initials: GF
authors.lastname: Ballester-Lozano
authors.forename: Jaume
authors.initials: J
authors.lastname: Pérez-Sánchez
mesh_terms: D052636:Allostasis; D000818:Animals; D017756:Aquaculture; D001267:Atlantic Ocean; D015415:Biomarkers / Q000378:metabolism; D031204:Caloric Restriction / Q000662:veterinary*; D015536:Down-Regulation; D004790:Enzyme Induction; D005231:Fatty Acids, Unsaturated / Q000032:analysis / Q000096:biosynthesis*; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D008071:Lipoprotein Lipase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000254:growth & development / Q000378:metabolism; D010743:Phospholipids / Q000032:analysis / Q000096:biosynthesis* / Q000737:chemistry; D010802:Phylogeny; D012333:RNA, Messenger / Q000378:metabolism; D021541:Sea Bream / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D017747:Seafood / Q000032:analysis*; D013030:Spain; D013230:Stearoyl-CoA Desaturase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015430:Weight Gain
chemical_list: D015415:Biomarkers; D005231:Fatty Acids, Unsaturated; D029941:Fish Proteins; D010743:Phospholipids; D012333:RNA, Messenger; D013230:Stearoyl-CoA Desaturase; D008071:Lipoprotein Lipase