Project description:The natural food for Atlantic salmon (Salmo salar) in freshwater has relatively lower levels of omega-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFA) than found in prey for post-smolt salmon in seawater. Land-locked salmon such as the Gullspång population feed exclusively on freshwater type lipids during its entire life cycle, a successful adaptation derived from divergent evolution. Studying land-locked populations may provide insights into the molecular and genetic control mechanisms that determine and regulate n-3 LC-PUFA biosynthesis and retention in Atlantic salmon. A two factorial study was performed comparing land-locked and farmed salmon parr fed diets formulated with fish or rapeseed oil for 8 weeks. The land-locked parr had higher capacity to synthesise n-3 LC-PUFA as indicated by higher expression and activity of desaturase and elongase enzymes. The data suggested that the land-locked salmon had reduced sensitivity to dietary fatty acid composition and that dietary docosahexaenoic acid (DHA) did not appear to suppress expression of LC-PUFA biosynthetic genes or activity of the biosynthesis pathway, probably an evolutionary adaptation to a natural diet lower in DHA. Increased biosynthetic activity did not translate to enhanced n-3 LC-PUFA contents in the flesh and diet was the only factor affecting this parameter. Additionally, high lipogenic and glycolytic potentials were found in land-locked salmon, together with decreased lipolysis which in turn could indicate increased use of carbohydrates as an energy source and a sparing of lipid.
Project description:We studied genes that are related to atopic diseases [i.e., atopic eczema (AE)]. Immunological factors and principal genes involved in the biosynthesis of polyunsaturated fatty acids were included. We analyzed whether expression of genes encoding key enzymes of LC-PUFA synthesis (FADS1, FADS2 and ELOVL5) is associated with circulating LC-PUFA levels and risk of AE in 4-year-old children. AE (n=20) and non-AE (n=104) children participating in the Sabadell cohort within the INfancia y Medio Ambiente (INMA) Project were included in the present study. RT-PCR with TaqMan Low-Density Array cards was used to measure the expression of these genes.
Project description:Liver transcriptomes of Atlantic salmon families with contrasting flesh n-3 LC-PUFA profiles, and all fed the same 100% vegetable oil replacement diet, were compared by microarray analysis (Agilent oligoarray platform). The objective was to identify gene pathways and molecular mechanisms which might explain differences in flesh n-3 LC-PUFA content, independent of total lipid deposition, when salmon families are fed the same LC-PUFA deficient diet. A factorial design was chosen in which families containing higher and lower n-3 LC-PUFA relative levels were compared at similar total lipid percentages in flesh.
Project description:We studied genes that are related to atopic diseases [i.e., atopic eczema (AE)]. Immunological factors and principal genes involved in the biosynthesis of polyunsaturated fatty acids were included. We analyzed whether expression of genes encoding key enzymes of LC-PUFA synthesis (FADS1, FADS2 and ELOVL5) is associated with circulating LC-PUFA levels and risk of AE in 4-year-old children. AE (n=20) and non-AE (n=104) children participating in the Sabadell cohort within the INfancia y Medio Ambiente (INMA) Project were included in the present study. RT-PCR with TaqMan Low-Density Array cards was used to measure the expression of these genes. RT-PCR gene expression profile. The samples are described in the sumary. Each sample was measured in duplicate in the same TLDA card and we present the average of each sample.
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 use of high levels of marine fish oil in aquafeeds is a non-sustainable practice. However, more sustainable oils sources from terrestrial plants do not contain long-chain polyunsaturated fatty acids (LC-PUFA). Consequently, feeds based on conventional vegetable oils reduce n-3 LC-PUFA levels in farmed fish. Therefore, the aquaculture industry desperately requires new, sustainable oil sources that contain high levels of n-3 LC-PUFA in order to supply the increasing demand for fish and seafood while maintaining the high nutritional quality of the farmed product. One approach to the renewable supply of n-3 LC-PUFA is metabolic engineering oilseed crops with the capacity to synthesize these essential fatty acids in seeds. In the present study, the oilseed Camelina sativa has been transformed with algal genes encoding the n-3 biosynthetic pathway and expression restricted to the seeds via seed-specific promoters to produce an oil containing > 20% eicosapentaenoic acid (EPA). This oil was investigated as a replacement for marine fish oil in feeds for post-smolt Atlantic salmon. In addition, this study with EPA-rich oil will contribute to our understanding of the biochemical and molecular mechanisms involved in the control and regulation of docosahexaenoic acid (DHA) production from EPA, and will thus better inform our understanding of this key part of the LC-PUFA biosynthetic pathway.
Project description:Currently, the only sustainable alternatives for dietary fish oil (FO) in aquafeeds are vegetable oils (VO) that are devoid of omega-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFA). Entirely new sources of n-3 LC-PUFA such as eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids through de novo production is a potential solution to fill the gap between supply and demand of these important nutrients. Camelina sativa,was metabolically engineered to produce a seed oil (ECO) with > 20 % EPA and its potential to substitute for FO in Atlantic salmon feeds was tested. Fish were fed one of three experimental diets containing FO, wild-type camelina oil (WCO) or ECO as the sole lipid sources for 7-weeks. Inclusion of ECO did not affect any of the performance parameters studied and enhanced apparent digestibility of individual n-6 and n-3 PUFA compared to dietary WCO. High levels of EPA were maintained in brain, liver and intestine (pyloric caeca), and levels of DPA and DHA were increased in liver and intestine of fish fed ECO compared to fish fed WCO likely due to increased LC-PUFA biosynthesis based on up-regulation of the genes. Fish fed WCO and ECO showed slight lipid accumulation within hepatocytes similar to that with WCO, although not significantly different to fish fed FO. The regulation of a small number of genes could be attributed to the specific effect of ECO (311 features) with metabolism being the most affected category. The EPA oil from transgenic Camelina (ECO) could be used as a substitute for FO, however it is a hybrid oil containing both FO (EPA) and VO (18:2n-6) fatty acid signatures that resulted in similarly mixed metabolic and physiological responses.
Project description:Gene expresion profiles from the scAT following 6 week LC n-3 PUFA and 6 week placebo supplementation were compared Women with PCOS were supplemented with 4g n-3 PUFA (containing 1.8g EPA and DHA) daily for 6 weeks and changes in subcutaneous adipose tissue gene expression was compared with 6 week placebo supplementation.
Project description:Impaired resistance to insulin, the key defect in type 2 diabetes (T2D), is associated with a low capacity to adapt fuel oxidation to fuel availability, i.e., metabolic inflexibility. The hampered metabolic adaptability triggers a further damage of insulin signaling. Since skeletal muscle is the main site of glucose uptake, effectiveness of T2D treatment depends in large on the improvement of insulin sensitivity and metabolic adaptability of the muscle. We have shown previously in mice fed an obesogenic high-fat diet that a combination treatment using n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) and thiazolidinedione (TZD) anti-diabetic drugs preserved metabolic health and synergistically improved muscle insulin sensitivity. We investigated here whether TZD rosiglitazone could elicit the additive beneficial effects on metabolic flexibility when combined with n-3 LC-PUFA. Adult male C57BL/6J mice were fed an obesogenic corn oil-based high-fat diet (cHF) for 8 weeks, or randomly assigned to various dietary treatments: (i) cHF+F, cHF with n-3 LC-PUFA concentrate replacing 15% of dietary lipids; (ii) cHF+ROSI, cHF with 10 mg rosiglitazone/kg diet; and (iii) cHF+F+ROSI, or chow-fed. Indirect calorimetry demonstrated superior preservation of metabolic flexibility to carbohydrates in response to the combination treatment. Metabolomic and gene expression analyses in the muscle suggested distinct and complementary effects of the single treatments, with rosiglitazone augmenting insulin sensitivity by the modulation of branched-chain amino acid metabolism, and n-3 LC PUFA supporting complete oxidation of fatty acids in mitochondria. These beneficial metabolic effects were associated with the activation of the switch between glycolytic and oxidative muscle fibers, especially in the cHF+F+ROSI mice. Our results further support the idea that the combination treatment using n-3 LC-PUFA and TZDs could improve the efficacy of the treatment of obese and diabetic patients.
Project description:Impaired resistance to insulin, the key defect in type 2 diabetes (T2D), is associated with a low capacity to adapt fuel oxidation to fuel availability, i.e., metabolic inflexibility. The hampered metabolic adaptability triggers a further damage of insulin signaling. Since skeletal muscle is the main site of glucose uptake, effectiveness of T2D treatment depends in large on the improvement of insulin sensitivity and metabolic adaptability of the muscle. We have shown previously in mice fed an obesogenic high-fat diet that a combination treatment using n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) and thiazolidinedione (TZD) anti-diabetic drugs preserved metabolic health and synergistically improved muscle insulin sensitivity. We investigated here whether TZD rosiglitazone could elicit the additive beneficial effects on metabolic flexibility when combined with n-3 LC-PUFA. Adult male C57BL/6N mice were fed an obesogenic corn oil-based high-fat diet (cHF) for 8 weeks, or randomly assigned to various dietary treatments: (i) cHF+F, cHF with n-3 LC-PUFA concentrate replacing 15% of dietary lipids; (ii) cHF+ROSI, cHF with 10 mg rosiglitazone/kg diet; and (iii) cHF+F+ROSI, or chow-fed. Indirect calorimetry demonstrated superior preservation of metabolic flexibility to carbohydrates in response to the combination treatment. Metabolomic and gene expression analyses in the muscle suggested distinct and complementary effects of the single treatments, with rosiglitazone augmenting insulin sensitivity by the modulation of branched-chain amino acid metabolism, and n-3 LC PUFA supporting complete oxidation of fatty acids in mitochondria. These beneficial metabolic effects were associated with the activation of the switch between glycolytic and oxidative muscle fibers, especially in the cHF+F+ROSI mice. Our results further support the idea that the combination treatment using n-3 LC-PUFA and TZDs could improve the efficacy of the treatment of obese and diabetic patients.