Differential effects of krill oil and fish oil on the hepatic transcriptome in mice
ABSTRACT: Dietary supplementation with ω-3 polyunsaturated fatty acids (ω-3 PUFAs), specifically the fatty acids docosahexaenoic acid (DHA; 22:6 ω-3) and eicosapentaenoic acid (EPA; 20:5 ω-3), is known to have beneficial health effects including improvements in glucose and lipid homeostasis and modulation of inflammation. To evaluate the efficacy of two different sources of ω-3 PUFAs, we performed gene expression profiling in the liver of mice fed diets supplemented with either fish oil or krill oil. We found that ω-3 PUFA supplements derived from a phospholipid krill fraction (krill oil) downregulated the activity of pathways involved in hepatic glucose production as well as lipid and cholesterol synthesis. The data also suggested that krill oil-supplementation increases the activity of the mitochondrial respiratory chain. Surprisingly, an equimolar dose of EPA and DHA derived from fish oil modulated fewer pathways than a krill oil-supplemented diet and did not modulate key metabolic pathways regulated by krill oil, including glucose metabolism, lipid metabolism and the mitochondrial respiratory chain. Moreover, fish oil upregulated the cholesterol synthesis pathway, which was the opposite effect of krill supplementation. Neither diet elicited changes in plasma levels of lipids, glucose or insulin, probably because the mice used in this study were young and were fed a low fat diet. Further studies of krill oil supplementation using animal models of metabolic disorders and/or diets with a higher level of fat may be required to observe these effects. Twenty-one microarrays: three diets (CO, FO, KO) x seven mice per diet x one microarray per mouse
Project description:Since the liver is the central organ of metabolism, changes in diet have a great impact on this organ and overall on health with aging. It is well known that dietary fat source strongly influences many parameters of the hepatic mitochondria. These changes includes modification of lipid composition of mitochondrial membrane, affecting the mtETC functions, oxidative stress and mtDNA alterations. We used microarrays to detail the changes in gene expression provides by feeding lifelong on different dietary fat sources, and identified distinct classes of up and down-regulated genes during aging under different dietary conditions. Rats were fed lifelong on a normolipidic diet (4% w/w) with virgin olive, sunflower or fish oil as dietary fat source. At 6 and 24 months, animals were killed and liver were removed for RNA extraction and hybridization on Affymetrix microarrays. We sought to obtain changes in gene expression due to both aging and dietary conditions. There were 6 experimental groups (virgin olive oil at 6 months, sunflower oil at 6 months, fish oil at 6 months, virgin olive oil at 24 months, sunflower oil at 24 months and fish oil at 24 months. 3 animals were studied of each experimental group, so a total of 18 samples were analyzed.
Project description:Transcriptional profiling of adipose tissue comparing three diets with different levels of replacement of fish oil for vegetable oils. Juvenile gilthead sea bream (Sparus aurata L.) of 16 g initial mean body weight were distributed into 9 fibreglass tanks (500 l) in groups of 60 fish at the research experimental facilities of IATS. Each group received (from May 23rd to September 19th) one of the three experimental diets nominally CTRL, 66VO and VO. All diets were based on plant proteins and dietary oil was either Scandinavian FO (CTRL diet) or a blend of vegetable oils, replacing the 66% (66VO diet) and 100% (VO diet) of FO. Four samples, using a control diet (CTRL) as reference and double color hybridization and dye swap with the other two (66VO, VO)
Project description:New de novo sources of omega 3 (n-3) long chain polyunsaturated fatty acids (LC-PUFA) are required as alternatives to fish oil in aquafeeds in order to maintain adequate levels of the beneficial fatty acids, eicosapentaenoic and docosahexaenoic (EPA and DHA, respectively). The present study investigated the use of an EPA+DHA oil derived from a transgenic Camelina sativa in feeds for Atlantic salmon (Salmo salar) containing low levels of fishmeal (35 %) and fish oil (10 %), reflecting current commercial formulations, to determine the impacts on intestinal transcriptome, tissue fatty acid profile and health of farmed salmon. Post-smolt Atlantic salmon were fed for 12-weeks with one of three experimental diets containing either a blend of fish oil/rapeseed oil (FO), wild-type camelina oil (WCO) or transgenic camelina oil (DCO) as added lipid source. The DCO diet did not affect any of the fish performance or health parameters studied. Analyses of the mid and hindgut transcriptomes showed only mild effects on metabolism. Flesh of fish fed the DCO diet accumulated almost double the amount of n-3 LC-PUFA than fish fed the FO or WCO diets, indicating that these oils from transgenic oilseeds offer the opportunity to increase the n-3 LC-PUFA in farmed fish to levels comparable to those found twelve years ago.
Project description:Vegetable oils (VO) are possible substitutes for fish oil in aquafeeds but are limited by their lack of omega-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFA). However, oilseed crops can be modified to produce n-3 LC-PUFA such as eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids, representing a potential option to fill the gap between supply and demand of these important nutrients. Camelina sativa was metabolically engineered to produce a seed oil with around 15 % total n-3 LC-PUFA to potentially substitute for fish oil in salmon feeds. Post-smolt Atlantic salmon (Salmo salar) were fed for 11-weeks with one of three experimental diets containing either fish oil (FO), wild-type Camelina oil (WCO) or transgenic Camelina oil (DCO) as added lipid source to evaluate fish performance, nutrient digestibility, tissue n-3 LC-PUFA, and metabolic impact determined by liver transcriptome analysis. The DCO diet did not affect any of the performance or health parameters studied and enhanced apparent digestibility of EPA and DHA compared to the WCO diet. The level of total n-3 LC-PUFA was higher in all the tissues of DCO-fed fish than in WCO-fed fish with levels in liver similar to those in fish fed FO. Endogenous LC-PUFA biosynthetic activity was observed in fish fed both the Camelina oil diets as indicated by the liver transcriptome and levels of intermediate metabolites such as docosapentaenoic acid, with data suggesting that the dietary combination of EPA and DHA inhibited desaturation and elongation activities. Expression of genes involved in phospholipid and triacylglycerol metabolism followed a similar pattern in fish fed DCO and WCO despite the difference in n-3 LC-PUFA contents.
Project description:The effect of different diets (i.e. fish oil based vs vegetable oil based) on liver transcription profiles over the life history stages (freshwater and marine phases) of cultured Atlantic salmon (Salmo salar) were explored. Two groups of fish were raised from first feeding on different lipid containing diets; a) the standard 100% fish oil based diet, the other enriched with a blend of vegetable oils (75%) + fish oil (25%). Liver samples were taken from fish at four time points: two freshwater phase (as parr 36 weeks post hatch (wph); as pre-smolts, 52 wph) and two marine phase ( as post-smolts 55 wph; and as adult fish , 86 wph). A total of 96 cDNA microarray hybridisations - TRAITS / SGP Atlantic salmon 17k feature cDNA microarray - were performed ( 2 diets x 4 time points x 6 biological replicates x 2 -dye swap) using a comon pooled reference contol design.
Project description:in the present study, we evaluated whether microbiota modulation is able to restore hepatic steatosis induced by n-3 PUFA depletion in mice. For this purpose, mice were fed during three months with a n-3 PUFA-depleted diet (presenting a high n-6/n-3 PUFA ratio), and then supplemented with fructooligosaccharides (FOS, 0.25g/day/mice), a prebiotic, during the last ten days of the experiment (DEF/FOS). In the same time, some n-3 PUFA-depleted mice were returned on a control diet during the last 10 days of treatment (DEF/CT) to compare the effect of FOS supplementation to a restored intake in n-3 PUFA. Microarray analyses were performed to identify the molecular targets modified by FOS supplementation in the liver of n-3 PUFA depleted mice. These mice were compared to control mice (fed a control diet during the 112 days of experiment) and to n-3 PUFA-depleted mice (fed a n-3 PUFA-depleted diet during the 112 days of experiment) for which the results have been previously published (Pachikian B.D. et al. PLoS One. 2011;6(8):e23365, accession number GSE26986) Male C57Bl/6J mice (9 weeks old; Charles River, Brussels, Belgium) were housed in groups of 4 mice per cage at 22°C in a 12 h light/dark cycle and given free access to diet and water. After an acclimatisation period of 1 week, mice were fed a control (CT) (D08041805, Research Diets, New Brunswick, USA) or an n-3 PUFA-depleted diet (DEF) (D08041806, Research Diets, New Brunswick, USA) for 112 days ad libitum. The CT diet contained the following (percent w/w): casein 20, total carbohydrate 72.4 (including corn starch 44.2, sucrose 10, maltodextrin 13.2, cellulose 5), soybean oil 5, mineral mix 3.5 and vitamin mix 1. The depletion was induced by replacing the soybean oil with sunflower oil, which exhibited a higher n-6/n-3 PUFA ratio. The n-6/n-3 PUFA ratio was 6.9 and 127.2 for the CT diet and the DEF diet, respectively. Ten days before the end of the experiment, DEF mice were divided into three groups: DEF, DEF/FOS and DEF/CT mice. The DEF mice were still fed with the n-3 PUFA depleted diet (DEF). The DEF/FOS mice were still fed the DEF diet and were supplemented for 10 days with fructooligosaccharides (DEF/FOS). FOS (Beneo P95 gift from Orafti; Tienen, Belgium) was added to tap water in a concentration adequate to reach an intake of 0.25g of FOS per day. For DEF/CT mice, the DEF diet was replaced by the CT diet during the last 10 days of treatment. At the end of the study period, mice fed the CT (n=4), DEF (n=7), DEF/CT (n=8) or DEF/FOS diet (n=8) were anaesthetised (ketamine/xylazine i.p., 100 and 10 mg/kg of body weight, respectively). The liver tissue was immediately clamped in liquid N2 and kept at -80°C until analysis. All mice experiments were approved by the local animal ethics committee and the housing conditions were as specified by the Belgian Law of April 6, 2010 on the protection of laboratory animals (agreement n° LA 1230314).
Project description:Weanling rats fed a choline-deficient diet develop acute renal failure (ARF) after 6-7 days of receiving the experimental diet. Its pathogenesis is controversial. Menhaden oil has a protective effect in this experimental model. The aim of this study is to describe both the genetic profile and its changes when vegetable oils are replaced by menhaden oil. Wistar, weanling rats from the Animal Facility of the Centre of Experimental and Applied Pathology were divided into 4 groups and fed with the following diets: 1- Choline-deficient diet with vegetable oils as lipids (corn and hydrogenated oils); 2- Choline-supplemented diet with vegetable oils as lipids; 3- Choline-deficient diet with menhaden oil as lipid; and 4- Choline supplemented diet with menhaden oil as lipid. Animals were sacrificed after 6 days of receiving the experimental diets. The right kidney was cryopreserved. In this assay biological duplicated samples were used. In order to evaluate changes in gene expression WT Expression Kit (Ambion, USA) over the platform GeneChip® Gene 1.0 ST Rat Genome Array (Affymetrix Inc, USA) was used. Fluorescent distribution in the array was obtained using the language R (www-r-project.org), in house own algorithms and other formsbioconductor tools http://www.bioconductor.org/. We analyzed the differential gene expression, using as cut value p<0.01 with fdr control & |log FC|>1.5, in all groups. Rats fed with diets 2, 3 and 4 have similar genetic profiles. However, the comparison between rats fed with diets 2 and 4 showed 35 genes with diferential expression. As these rats did not have renal necrosis, we can hypothesize that the differential expression is due to the menhaden oil of the diet. In short, the massive analysis of genetic expression allowed to confirm that menhaden oil has a protective effect in this experimental model and to identify 35 genes that could be responsible of that protection. Twenty eight animals were sacrificed after 6 days of receiving the experimental diets. The right kidney was cryopreserved for microarray analysis. Cryopreserved kidney was pulverized under liquid-nitrogen conditions. Total RNA was purified from 30 mg of frozen rat kidney tissue. Each sample represents a pool of 3 animals (except CD+AM SN with 2 animals/pool), to reduce biological variation. In this assay biological duplicated samples were used.
Project description:We used DNA microarrays to identify discriminative gene signatures for the purpose of classifying n-3 PUFA-fed, carcinogen injected Sprague Dawley rats at the initiation and progression stages. Animals were assigned to three dietary treatments differeing only in the type of fat (corn oi/n-6 PUFA, fish oil/n-3 PUFA, or olive oli/n-9 monounsaturated fatty acid). The effects of diet on colonic mucosal gene expression signatures during tumor initiation with the progression of colon cancer. Each dietary lipid source exhibited its own unique transcriptional profile, as assessed by linear discriminant analysis. Applying this novel approach we identified the single genes and the two- to three-gene combinations that best distinguished the dietary treatment groups. For the chemoprotective fish oil diet, mediators of stem cell homeostasis, e.g., ephrin B1 and bone morphogenic protein 4, were the top-permorming gene classifiers. keywords: diet analysis 29 samples were analyzed. 10 samples had repeat arrays. No control or reference samples were included.
Project description:Elevated circulating triglycerides, which are considered a risk factor for cardiovascular disease, can be targeted by treatment with fenofibrate or fish oil. To gain insight into underlying mechanisms, we carried out a comparative transcriptomics and metabolomics analysis of the effect of 2 week treatment withfenofibrate and fish oil in mice. Plasma triglycerides were significantly decreased byfenofibrate (-49.1%) and fish oil (-21.8%), whereas plasma cholesterol was increased by fenofibrate (+29.9%) and decreased by fish oil (-32.8%). Levels of various phospholipid species were specifically decreased by fish oil, while levels of Krebs cycle intermediates were increased specifically by fenofibrate. Plasma levels of many amino acids were altered by fenofibrate and to a lesser extent by fish oil. Both fenofibrate and fish oil upregulated genes involved in fatty acid metabolism, and downregulated genes involved in blood coagulation and fibrinolysis. Significant overlap in gene regulation by fenofibrate and fish oil was observed, reflecting their property as high or low affinity agonist for PPARα, respectively. Fenofibrate specifically downregulated genes involved in complement cascade and inflammatory response. Fish oil specifically downregulated genes involved in cholesterol and fatty acid biosynthesis, and upregulated genes involved in amino acid and arachidonic acid metabolism. Taken together, the data indicate that despite being similarly potent towards modulating plasma free fatty acids, cholesterol and triglyceride levels, fish oil causes modest changes in gene expression likely via activation of multiple mechanistic pathways, whereas fenofibrate causes pronounced gene expression changes via a single pathway, reflecting the key difference between nutritional and pharmacological intervention. Expression profiling of liver from mice fed control diet, fish oil or fenofibrate for 2 weeks.
Project description:Dietary n-3 polyunsaturated fatty acids can reduce inflammation via a range of mechanisms. This study tested the effect of dietary eicosapentaenoic acid (EPA) on intestinal inflammation using interleukin-10 gene-deficient (Il10-/-) mice. Methods: At 35 days of age, 12 weaned Il10-/- and 12 C57 mice were randomly assigned to one of two modified AIN-76A diets, supplemented with 3.7% purified ethyl esters of either EPA (n-3) or oleic acid (OA, control). To identify genes relevant to colon inflammation, transcription profiling (microarrays and qRT-PCR) and bioinformatic analyses were used. Results: In this study, dietary EPA reversed the decrease in colon fatty acid β-oxidation gene expression observed in OA-fed Il10-/- compared to C57 mice. Il10-/- mice fed the OA diet showed decreased expression of antioxidant enzyme genes, as well as those involved in detoxification of xenobiotics, compared to C57 mice on the same diet. In contrast, dietary EPA increased the expression of these genes in Il10-/- mice. Conclusions: These data indicate that dietary EPA induced endogenous lipid oxidation which might have a potential anti-inflammatory effect on colon tissue. This is supported by the activation of the Ppara gene that regulates the expression of pro-inflammatory and immunomodulatory genes and proteins. Experiment Overall Design: The diet abbreviations EPA, OA, AA and CO used in the sample records Experiment Overall Design: refer to the following : Experiment Overall Design: CO : AIN-76A (control) Experiment Overall Design: OA : AIN-76A (fat-free) + 1% corn oil + 3.7% oleic acid Experiment Overall Design: EPA : AIN-76A (fat-free) + 1% corn oil + 3.7% eicosapentaenoic acid Experiment Overall Design: AA : AIN-76A (fat-free) + 1% corn oil + 3.7% arachidonic acid Experiment Overall Design: Corn oil was supplemented with purified linoleic and alpha-linolenic acid to meet the nutritional requirements of mice for these essential fatty acids. Diets fed for 6 weeks.