title: Effects of dietary plant meal and soya-saponin supplementation on intestinal and hepatic lipid droplet accumulation and lipoprotein and sterol metabolism in Atlantic salmon (Salmo salar L.).
abstract: Altered lipid metabolism has been shown in fish fed plant protein sources. The present study aimed to gain further insights into how intestinal and hepatic lipid absorption and metabolism are modulated by plant meal (PM) and soya-saponin (SA) inclusion in salmon feed. Post-smolt Atlantic salmon were fed for 10 weeks one of four diets based on fishmeal or PM, with or without 10 g/kg SA. PM inclusion resulted in decreased growth performance, excessive lipid droplet accumulation in the pyloric caeca and liver, and reduced plasma cholesterol levels. Intestinal and hepatic gene expression profiling revealed an up-regulation of the expression of genes involved in lipid absorption and lipoprotein (LP) synthesis (apo, fatty acid transporters, microsomal TAG transfer protein, acyl-CoA cholesterol acyltransferase, choline kinase and choline-phosphate cytidylyltransferase A), cholesterol synthesis (3-hydroxy-3-methylglutaryl-CoA reductase) and associated transcription factors (sterol regulatory element-binding protein 2 and PPARγ). SA inclusion resulted in reduced body pools of cholesterol and bile salts. The hepatic gene expression of the rate-limiting enzyme in bile acid biosynthesis (cytochrome P450 7A1 (cyp7a1)) as well as the transcription factor liver X receptor and the bile acid transporter abcb11 (ATP-binding cassette B11) was down-regulated by SA inclusion. A significant interaction was observed between PM inclusion and SA inclusion for plasma cholesterol levels. In conclusion, gene expression profiling suggested that the capacity for LP assembly and cholesterol synthesis was up-regulated by PM exposure, probably as a compensatory mechanism for excessive lipid droplet accumulation and reduced plasma cholesterol levels. SA inclusion had hypocholesterolaemic effects on Atlantic salmon, accompanied by decreased bile salt metabolism.
authors: Department of Basic Science and Aquatic Medicine, Norwegian School of Veterinary Science, Aquaculture Protein Centre (a CoE), PO Box 8146 Dep, NO-0033 Oslo, Norway.
authors: Min
authors: M
authors: Gu
authors: Department of Basic Science and Aquatic Medicine, Norwegian School of Veterinary Science, Aquaculture Protein Centre (a CoE), PO Box 8146 Dep, NO-0033 Oslo, Norway.
authors: Trond M
authors: TM
authors: Kortner
authors: Department of Basic Science and Aquatic Medicine, Norwegian School of Veterinary Science, Aquaculture Protein Centre (a CoE), PO Box 8146 Dep, NO-0033 Oslo, Norway.
authors: Michael
authors: M
authors: Penn
authors: Nofima AS, NO-6600 Sunndalsøra, Norway.
authors: Anne Kristine
authors: AK
authors: Hansen
authors: Department of Basic Science and Aquatic Medicine, Norwegian School of Veterinary Science, Aquaculture Protein Centre (a CoE), PO Box 8146 Dep, NO-0033 Oslo, Norway.
authors: Åshild
authors: Å
authors: Krogdahl
mesh_terms: D000818:Animals; D000924:Anticholesteremic Agents / Q000009:adverse effects / Q000378:metabolism; D001647:Bile Acids and Salts / Q000037:antagonists & inhibitors / Q000378:metabolism; D004032:Diet / Q000009:adverse effects / Q000662:veterinary*; D004044:Dietary Proteins / Q000009:adverse effects / Q000378:metabolism; D002149:Energy Intake; D005234:Fatty Liver / Q000209:etiology / Q000378:metabolism / Q000473:pathology / Q000662:veterinary; D029941:Fish Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D005983:Glutens / Q000009:adverse effects / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000254:growth & development / Q000473:pathology; D050356:Lipid Metabolism; D008074:Lipoproteins / Q000037:antagonists & inhibitors / Q000097:blood / Q000378:metabolism; D008099:Liver / Q000254:growth & development / Q000378:metabolism* / Q000473:pathology; D031297:Lupinus / Q000737:chemistry; D010940:Plant Proteins / Q000009:adverse effects* / Q000378:metabolism; D020317:Salmo salar / Q000097:blood / Q000254:growth & development / Q000378:metabolism*; D012503:Saponins / Q000009:adverse effects* / Q000378:metabolism; D013025:Glycine max / Q000737:chemistry; D013261:Sterols / Q000037:antagonists & inhibitors / Q000097:blood / Q000378:metabolism; D014908:Triticum / Q000737:chemistry; D015430:Weight Gain
chemical_list: D000924:Anticholesteremic Agents; D001647:Bile Acids and Salts; D004044:Dietary Proteins; D029941:Fish Proteins; D008074:Lipoproteins; D010940:Plant Proteins; D012503:Saponins; D013261:Sterols; D005983:Glutens