title: Effects of dietary carbohydrate on hepatic de novo lipogenesis in European seabass (Dicentrarchus labrax L.).
abstract: Farmed seabass have higher adiposity than their wild counterparts and this is often attributed to carbohydrate (CHO) feeding. Whether this reflects a reduction in fat oxidation, increased de novo lipogenesis (DNL), or both, is not known. To study the effects of high CHO diets on hepatic TG biosynthesis, hepatic TG deuterium ((2)H) enrichment was determined following 6 days in (2)H-enriched tank water for fish fed with a no-CHO control diet (CTRL), and diets with digestible starch (DS) and raw starch (RS). Hepatic fractional synthetic rates (FSRs, percent per day(-1)) were calculated for hepatic TG-glyceryl and FA moieties through (2)H NMR analysis. Glyceryl FSRs exceeded FA FSRs in all cases, indicating active cycling. DS fish did not show increased lipogenic potential compared to CTRL. RS fish had lower glyceryl FSRs compared with the other diets and negligible levels of FA FSRs despite similar hepatic TG levels to CTRL. DS-fed fish showed higher activity for enzymes that can provide NADPH for lipogenesis, relative to CTRL in the case of glucose-6-phosphate dehydrogenase (G6PDH) and relative to RS for both G6PDH and 6-phosphogluconate dehydrogenase. This approach indicated that elevated hepatic adiposity from DS feeding was not attributable to increased DNL.
authors.affiliation: Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal Center for Functional Ecology, Department Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal iviegas@ci.uc.pt.
authors.forename: Ivan
authors.identifier: 0000-0003-2589-2212
authors.initials: I
authors.lastname: Viegas
authors.affiliation: Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal.
authors.forename: Ivana
authors.initials: I
authors.lastname: Jarak
authors.affiliation: Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal Center for Functional Ecology, Department Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal.
authors.forename: João
authors.initials: J
authors.lastname: Rito
authors.affiliation: Center for Functional Ecology, Department Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal.
authors.forename: Rui A
authors.initials: RA
authors.lastname: Carvalho
authors.affiliation: Secció de Bioquímica i Biologia Molecular, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia, Universitat de Barcelona, 08028 Barcelona, Spain.
authors.forename: Isidoro
authors.initials: I
authors.lastname: Metón
authors.affiliation: Center for Functional Ecology, Department Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Pardal
authors.affiliation: Secció de Bioquímica i Biologia Molecular, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia, Universitat de Barcelona, 08028 Barcelona, Spain.
authors.forename: Isabel V
authors.initials: IV
authors.lastname: Baanante
authors.affiliation: Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal.
authors.forename: John G
authors.initials: JG
authors.lastname: Jones
mesh_terms: D000818:Animals; D001492:Bass / Q000378:metabolism*; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D050155:Lipogenesis / Q000187:drug effects / Q000502:physiology*; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D014280:Triglycerides / Q000378:metabolism*
chemical_list: D004040:Dietary Carbohydrates; D004041:Dietary Fats; D014280:Triglycerides
keywords: carbohydrate metabolism; dehydrogenases; deuterated water; fish aquaculture; lipolysis and fatty acid metabolism; liver; nuclear magnetic resonance; nutrition/carbohydrate