Long-chain Polyunsaturated Fatty Acids Profiles Research Articles

Can Artemia franciscana produce essential fatty acids? Unveiling the capacity of brine shrimp to biosynthesise long-chain polyunsaturated fatty acids

Artemia nauplii are widely used as live preys for feeding early life-cycle stages of marine finfish and shrimp. However, a major drawback associated to using Artemia is their deficient nutritional value for marine larvae that is primarily linked to suboptimal levels of long-chain polyunsaturated fatty acids (LC-PUFA), essential nutrients that guarantee normal growth and development of animals. While common marine hatchery procedures involve enrichment processes to address such nutritional deficiencies, the specific drivers accounting for the naturally occurring variability in LC-PUFA of Artemia are largely unknown. Biosynthesis, along diet, is one of the main factors determining the LC-PUFA profiles in animals and it depends upon the repertoire and function of fatty acyl elongases and desaturases existing in a particular species. The aim of this study was the molecular and functional characterisation of all elongase and desaturase enzymes involved in the LC-PUFA biosynthesis from Artemia franciscana, arguably the most commonly used Artemia species. Seven out of eight elongases (termed “Elo1-8”) found in A. franciscana had distinctive features of LC-PUFA biosynthesising elongases. Consistently, functional assays showed these elongases were able to elongate multiple substrates and thus enabling A. franciscana to perform all elongation reactions of the LC-PUFA biosynthetic pathways. While all seven functionally characterised elongases from A. franciscana showed activity towards multiple substrates including C18 to C22 polyunsaturated fatty acids, particularly high activity was detected for the Elovl8 orthologue (termed herein as “Elo7”). Additionally, A. franciscana was found to have three genes of the so-called “first” desaturases (“Des1-3”), and lack other key LC-PUFA biosynthesising desaturases such as methyl-end and front-end desaturases. Two desaturases have the expected ∆9 desaturase activity, whereas a third one showed ∆12 activity. Neither methyl-end nor front-end desaturases were found in A. franciscana. In conclusion, this study demonstrated that A. franciscana has high elongation capacity but its overall LC-PUFA biosynthesis can be regarded as limited due to the lack of an adequate complement of fatty acyl desaturases in its genome.

Partial fads2 Gene Knockout Diverts LC-PUFA Biosynthesis via an Alternative Δ8 Pathway with an Impact on the Reproduction of Female Zebrafish (Danio rerio).

The zebrafish (Danio rerio) genome contains a single gene fads2 encoding a desaturase (FADS2) with both Δ6 and Δ5 activities, the key player in the endogenous biosynthesis of long-chain polyunsaturated fatty acids (LC-PUFAs), which serve essential functions as membrane components, sources of energy and signaling molecules. LC-PUFAs include the precursors of eicosanoids and are thus predicted to be indispensable molecules for reproductive health in virtually all vertebrates. In mice, an amniotic vertebrate, fads2 deletion mutants, both males and females, have been confirmed to be sterile. In anamniotic vertebrates, such as fish, there is still no information available on the reproductive (in)ability of fads2 mutants, although zebrafish have become an increasingly important model of lipid metabolism, including some aspects of the generation of germ cells and early embryonic development. In the present study, we apply the CRISPR/Cas9 genome editing system to induce mutations in the zebrafish genome and create crispants displaying a degree of fads2 gene editing within the range of 50–80%. Focusing on adult G0 crispant females, we investigated the LC-PUFA profiles of eggs. Our data suggest an impaired pathway of the LC-PUFA biosynthesis of the ω6 and ω3 series in the first-rate limiting steps of the conversion of linoleic acid (LA) into γ-linolenic acid (GLA), and α-linolenic acid (ALA) into stearidonic acid (SDA), respectively, finally resulting in bad-quality eggs. Our data suggest the existence of an alternative Δ8 pathway, which bypasses the first endogenous LC-PUFA biosynthetic step in zebrafish in vivo, and suggest that the zebrafish bifunctional FADS2 enzyme is actually a trifunctional Δ6/Δ5/Δ8 desaturase.

Nutritional Enhancement of Health Beneficial Omega-3 Long-Chain Polyunsaturated Fatty Acids in the Muscle, Liver, Kidney, and Heart of Tattykeel Australian White MARGRA Lambs Fed Pellets Fortified with Omega-3 Oil in a Feedlot System.

Simple SummaryThe problem addressed in this research was the possibility of enhancing the nutritional value and health beneficial omega-3 long-chain fatty acid content of lamb and its edible components. The aims and objectives were to evaluate the omega-3 contents of muscle, liver, kidney, and heart of lot-fed Tattykeel Australian White lambs of the MARGRA brand, in response to dietary supplementation with or without omega-3 oil fortified pellets. The findings demonstrate that the inclusion of omega-3 oil in feedlot diets of lambs enhances the human health beneficial omega-3 long-chain polyunsaturated fatty acid profiles of edible muscle tissue and organs without compromising meat quality or shelf life. These results are valuable to society because of increased functionality, health benefits, micro-marbling, tender, mouth-melting taste, and high-end eating quality experience of MARGRA lamb tissues and organs.The aim of this research was to evaluate the nutritional enhancement of omega-3 long-chain polyunsaturated fatty acid (n-3 LC-PUFA) composition of edible lamb Longissimus thoracis et lumborum muscle, heart, kidney, and liver in response to dietary supplementation of lot-fed lambs with or without omega-3 oil fortified pellets. The hypothesis tested was that fortifying feedlot pellets with omega-3 oil will enhance the human health beneficial n-3 LC-PUFA composition of edible lamb muscle tissue and organs. Seventy-five Tattykeel Australian White lambs exclusive to the MARGRA brand, with an average body weight of 30 kg at six months of age, were randomly assigned to the following three dietary treatments of 25 lambs each, and lot-fed as a cohort for 47 days in a completely randomized experimental design: (1) Control grain pellets without oil plus hay; (2) Omega-3 oil fortified grain pellets plus hay; and (3) Commercial whole grain pellets plus hay. All lambs had ad libitum access to the basal hay diet and water. Post-slaughter fatty acid composition of the Longissimus thoracis et lumborum muscle, liver, kidney, and heart were determined using thee gas chromatography–mass spectrophotometry technique. Results indicated significant variations (p < 0.05) in fatty acid profiles between tissues and organs. Omega-3 oil fortified pellets significantly (p < 0.05) increased ≥C20 n-3 LC-PUFA (C20:5n-3 eicosapentaenoate, EPA + C22:5n3 docosapentaenoate, DPA + C22:6n3 docosahexanoate DHA); C18:3n-3 alpha-linolenate, ALA; C18:2 conjugated linoleic acid, CLA; total monounsaturated fatty acids, MUFA; polyunsaturated fatty acids, PUFA contents; and reduced the ratio of omega-6 to omega-3 fatty acids in all lamb organs and tissues without impacting shelf-life. The findings demonstrate that the inclusion of omega-3 oil in feedlot diets of lambs enhances the human health beneficial omega-3 long-chain polyunsaturated fatty acid profiles of edible muscle tissue and organs without compromising meat quality.

MARGRA Lamb Eating Quality and Human Health-Promoting Omega-3 Long-Chain Polyunsaturated Fatty Acid Profiles of Tattykeel Australian White Sheep: Linebreeding and Gender Effects.

Health-conscious consumers increasingly demand healthier, tastier, and more nutritious meat, hence the continuous need to meet market specifications and demand for high-quality lamb. We evaluated the longissimus dorsi muscle of 147 Tattykeel Australian White (TAW) sheep fed on antioxidant-rich ryegrass pastures exclusive to MAGRA lamb brand for meat eating quality parameters of intramuscular fat (IMF) content, fat melting point (FMP) and omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA). The aim was to assess the impact of linebreeding and gender on pasture-fed lamb eating quality and to test the hypothesis that variation in healthy lamb eating quality is a function of lamb gender and not its antioxidant status or inbreeding coefficient (IC). After solid-phase extraction and purification, phenolics and antioxidant enzyme activities were analysed by high-performance liquid chromatography and mass spectrometry. IMF and fatty acid composition were determined using solvent extraction and gas chromatography, respectively. IC was classified into low (0–5%), medium (6–10%) and high (>10%) and ranged from 0–15.6%. FMP and IMF ranged from 28 to 39 °C and 3.4% to 8.2%, with overall means of 34.6 ± 2.3 °C and 4.4 ± 0.2%, respectively, and n-3 LC-PUFA ranged from “source” to “good source” levels of 33–69 mg/100 g. Ewes had significantly (P ˂ 0.0001) higher IMF, C22:5n-3 (DPA), C22:6n-3 (DHA), C18:3n-6, C20:3, C22:4n-6, C22:5n-6, total monounsaturated (MUFA), PUFA and Σn-3 fatty acids and lower total saturated fatty acids (SFA) and FMP, than rams. As IC increased, there were no differences in FMP and IMF. Folin–Ciocalteu total phenolics, ferric reducing antioxidant power and antioxidant activities of glutathione peroxidase, catalase and superoxide dismutase enzymes did not differ by either gender or IC. This study provides evidence that IC is inconsequential in affecting antioxidant status, IMF, FMP and n-3 LC-PUFA in linebred and pasture-fed TAW sheep because the observed variation in individual fatty acids was mainly driven by gender differences between ewes and rams, hence the need to accept the tested hypothesis. This finding reinforces the consistent healthy eating quality of MARGRA lamb brand from TAW sheep regardless of its linebred origin.

Oil from transgenic Camelina sativa as a source of EPA and DHA in feed for European sea bass (Dicentrarchus labrax L.)

Aquaculture, the fastest growing food production sector cannot continue to rely on finite stocks of marine fish as the primary source of the omega-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFA), eicosapentaenoic acid (EPA; 20:5n3) and docosahexaenoic acid (DHA; 22:6n-3), for feeds. A four-month feeding trial was conducted to investigate the impact of a de novo oil, with high levels of EPA and DHA, obtained from transgenic Camelina sativa on growth performance, tissue fatty acid profiles, and expression of lipid metabolism genes when used as a replacement for fish oil in feed for European seabass (Dicentrachus labrax). Triplicate groups of 50 juvenile fish (initial weight 16.7 ± 0.92 g) per tank were fed for 4 months with one of three isolipidic and isoproteic experimental diets consisting of a standard diet containing a commercial blend of fish oil and rapeseed oil (CFO), a diet containing transgenic Camelina oil (TCO), or a blend of fish oil and rapeseed oil with enhanced levels of EPA and DHA (EFO) formulated to match the n-3 LC-PUFA profile of the TCO feed. Final weight of fish fed the GM-derived oil was not different to fish fed either CFO or EFO. Slight lower growth performance of fish fed TCO at the beginning of the trial was related to transient reduced feed intake, possibly caused by glucosinolates in the raw Camelina sativa oil. The GM-derived oil improved the nutritional quality of the fish fillet by enhancing total n-3 PUFA levels compared to the fish fed the other two feeds, and maintained flesh EPA and DHA at the same levels as in fish fed the diets containing fish oil. The metabolic response in liver and intestine was generally relatively mild although diets TCO and EFO seemed to trigger a metabolic response consisting of an up-regulation of both β-oxidation (cpt1a) and fatty acid transport (fabp1), possibly reflecting higher levels of LC-PUFA. Overall, the present study indicated that an oil of terrestrial origin, Camelina sativa, when engineered to contain high levels of EPA and DHA can replace fish oil in feeds for European seabass with no detrimental impact on growth or feed efficiency, while also maintaining or increasing tissue n-3 LC-PUFA contents.

Effects of Diets Enriched in Linseed and Fish Oil on the Expression Pattern of Toll-Like Receptors 4 and Proinflammatory Cytokines on Gonadal Axis and Reproductive Organs in Rabbit Buck.

Infections of the genital tract can perturb the fertility in humans and animals. Pathogen recognition and activation of innate immunity onset through the pattern recognition receptor activation, such as Toll-like receptor 4 (TLR4), leading to the production of proinflammatory cytokines and mediators. TLR4 is expressed both on leukocytes and nonimmune cells. Rabbit TLR4 shows great similarity to its human counterpart. Moreover, the TLR4 signalling pathway could be modulated by long-chain polyunsaturated fatty acids (LC-PUFA). The objectives of this study were (i) to determine the expression levels of TLR4 and proinflammatory cytokines in the reproductive hypothalamic-gonadal axis of the male rabbit and (ii) to evaluate if the n-3 PUFA-enriched diets can modify their expression levels in the tissues and LC-PUFA profiles in seminal plasma. Fifteen rabbit bucks (n = 5/experimental group) were fed with different diets: commercial standard (group C), rich in extruded linseed (10%, group L), and in fish oil (3%, group FO) for 110 days. TLR4, TNF-α, and IL-1β mRNA were ubiquitously expressed throughout the hypothalamic-gonadal axis. However, TLR4 mRNA expression was lower in the hypothalamus than the epididymis (P < 0.01), seminal vesicles (P < 0.01), and pituitary gland (P < 0.05). Dietary enrichment in PUFA did not modify the gene expression profile nor the histological characteristics of the tissues. Conversely in seminal plasma, rabbits fed with L and FO had lower n-6 (P < 0.05), LC-PUFA n-6 (P < 0.05), and n-6/n-3 ratio (P < 0.05) but higher n-3 (P < 0.001) and LC-PUFA n-3 (P < 0.01) compared to the control group. Our study builds a map of the gene expression of TRL4 and proinflammatory cytokines in the reproductive hypothalamic-gonadal axis of the male rabbit, fundamental step for understanding the immune defence mechanisms. Diets enriched in LC-PUFA did not affect basal gene expression but modulated sperm fatty acid composition. Finally, rabbit may be an excellent animal model to study the relationship between inflammation and infertility, and the nutritional modulation of immune functions.

Long-Chain Polyunsaturated Fatty Acids in the Green Microalga Lobosphaera incisa Contribute to Tolerance to Abiotic Stresses.

Lobosphaera incisa is a green microalga that accumulates high levels of the valuable omega-6 long-chain polyunsaturated fatty acids (LC-PUFA) arachidonic acid (ARA, 20:4n-6) in triacylglycerols (TAG) under nitrogen (N) starvation. LC-PUFA accumulation is a rare trait in photosynthetic microalgae with insufficiently understood physiological significance. In this study, RNAi was attempted, for the first time in L. incisa, to produce knockdown lines for the Δ5 desaturase gene. Two lines, termed modified lines, which were isolated during screening for transgenic events, demonstrated alterations in their LC-PUFA profile, ARA-biosynthesis gene expression and lipid class distribution. In line M5-78, which appeared to carry a mutation in the Δ6 elongase gene, LC-PUFA were substituted by 18:3n-6 in all glycerolipids. Line M2-35, for which the exact genetic background has not been established, displayed a dramatic reduction in 20:4n-6, concomitant with an augmented proportion of 18:1n-9, in particular in the extraplastidial membrane lipids and TAG. The physiological responses of the modified lines to stressful conditions were compared with the wild type and the Δ5 desaturase mutant. In the N-replete cells of modified lines, the frequency of lipid droplets was reduced, while a number of starch grains increased, suggesting altered partitioning of assimilated carbon into reserve products. Furthermore, both lines exhibited reduced ability to accumulate TAG under N deprivation and recover from N starvation. Both lines demonstrated lower photosynthetic pigment contents, impairments in photosynthesis under a range of stressful conditions, and less efficient functioning of photoprotection under optimal conditions. Possible implications of fatty acids modifications in the stress response of L. incisa are addressed.

A specific combined long-chain polyunsaturated fatty acid supplementation reverses fatty acid profile alterations in a mouse model of chronic asthma

BackgroundThe immune-modulating potential of long-chain polyunsaturated fatty acids (LCPUFAs) based on their conversion into lipid mediators in inflammatory situations has been proven by several studies. Respecting the immune-modulative role of lipid mediators in bronchoconstriction, airway inflammation and resolution of inflammatory processes, LCPUFAs play an important role in asthma. To design a disease-specific and most beneficial LCPUFA supplementation strategy, it is essential to understand how asthma alters LCPUFA profiles. Therefore, this study characterizes the alterations of LCPUFA profiles induced by allergic asthma. In addition, this study explores whether a simple eicosapentaenoic acid (EPA) alone or a specific combined LCPUFA supplementation could restore imbalanced LCPUFA profiles.MethodsMice were sensitized with a daily dose of 40 μg house dust mite (HDM)-extract in a recall model and fed with either normal diet, EPA or a specific combined (sc)-LCPUFA supplementation containing EPA, docosahexaenoic acid (DHA), γ -linolenic acid (GLA) and stearidonic acid (SDA) for 24 days. After recall with HDM, mice were sacrificed and blood and lung tissue were collected. Fatty acid profiles were determined in plasma, blood cells and lung cells of asthmatic mice by capillary gas-chromatography.ResultsIn lung cells of asthmatic mice, arachidonic acid (AA, p < 0.001) and DHA (p < 0.01) were increased while dihomo-γ-linolenic acid (DGLA, p < 0.05) was decreased. EPA supplementation increased only EPA (p < 0.001) and docosapentaenoic acid (DPA, p < 0.001), but neither DGLA nor DHA in lung cells of asthmatic mice. In contrast, a specific combined dietary supplementation containing n-3 and n-6 LCPUFAs could decrease AA (p < 0.001), increase EPA (p < 0.001), DPA (p < 0.001) and DHA (p < 0.01) and could reverse the lack of DGLA (p < 0.05).ConclusionsIn summary, allergic asthma alters LCPUFA profiles in blood and lung tissue. In contrast to the EPA supplementation, the distinct combination of n-3 and n-6 LCPUFAs restored the LCPUFA profiles in lung tissue of asthmatic mice completely. Subsequently, sc-LCPUFA supplementation is likely to be highly supportive in limiting and resolving the inflammatory process in asthma.

The mechanism through which dietary supplementation with heated linseed grain increases n-3 long-chain polyunsaturated fatty acid concentration in subcutaneous adipose tissue of cashmere kids.

The aim of this study was to investigate the effects of dietary supplementation with heated linseed on the fatty acid (FA) composition of the plasma, liver, and subcutaneous adipose tissue (SADT) of Albas white cashmere kids, particularly the effect on n-3 long-chain polyunsaturated FA profiles and the mRNA expression of genes related to lipid metabolism in SADT. Sixty 4-month-old castrated male kids (average BW 18.6 ± 0.1 kg) were selected and randomly allocated into three groups in a randomized block design. Three dietary treatments were used: (1) basal diet without supplementation (Control), (2) basal diet supplemented with linseed oil (LSO), and (3) basal diet supplemented with heated linseed grain (HLS). The diets were fed for 104 d, consisting of 14 d for adaptation followed by 90 d of measurement. Different FA profiles were found in SADT between LSO and HLS. Kids fed HLS had more C18:3n3 (P < 0.0001), C22:6n3 (P = 0.007), and n-3 PUFA (P < 0.0001) and a less (P < 0.0001) n-6/n-3 ratio than LSO kids. These FA differences between LSO and HLS kids were due to the increased expression of elongation of very long chain FA protein 5 (P < 0.0001), delta-6 desaturase (P < 0.0001), and peroxisome proliferator-activated receptor α (P = 0.003) in SADT of HLS kids and was also associated with liver fat metabolism. Together, these results suggest that the consumption of HLS leads to more C22:6n3 than LSO in SADT by increasing liver C22:6n3 content and by increasing SADT mRNA expression of ELOVL5 and FADS2 through promoting PPARα expression.

Hydroxytyrosol prevents reduction in liver activity of \u0394-5 and \u0394-6 desaturases, oxidative stress, and depletion in long chain polyunsaturated fatty acid content in different tissues of high-fat diet fed mice

BackgroundEicosapentaenoic acid (EPA, C20:5n-3), docosahexaenoic acid (DHA, C22:6n-3) and arachidonic acid (AA, C20:4n-6) are long-chain polyunsaturated fatty acids (LCPUFAs) with relevant roles in the organism. EPA and DHA are synthesized from the precursor alpha-linolenic acid (ALA, C18:3n-3), whereas AA is produced from linoleic acid (LA, C18:2n-6) through the action of Δ5 and Δ6-desaturases. High-fat diet (HFD) decreases the activity of both desaturases and LCPUFA accretion in liver and other tissues. Hydroxytyrosol (HT), a natural antioxidant, has an important cytoprotective effects in different cells and tissues.MethodsMale mice C57BL/6 J were fed a control diet (CD) (10% fat, 20% protein, 70% carbohydrates) or a HFD (60% fat, 20% protein, 20% carbohydrates) for 12 weeks. Animals were daily supplemented with saline (CD) or 5 mg HT (HFD), and blood and the studied tissues were analyzed after the HT intervention. Parameters studied included liver histology (optical microscopy), activity of hepatic desaturases 5 and 6 (gas-liquid chromatography of methyl esters derivatives) and antioxidant enzymes (catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase by spectrophotometry), oxidative stress indicators (glutathione, thiobarbituric acid reactants, and the antioxidant capacity of plasma), gene expression assays for sterol regulatory element-binding protein 1c (SREBP-1c) (qPCR and ELISA), and LCPUFA profiles in liver, erythrocyte, brain, heart, and testicle (gas-liquid chromatography).ResultsHFD led to insulin resistance and liver steatosis associated with SREBP-1c upregulation, with enhancement in plasma and liver oxidative stress status and diminution in the synthesis and storage of n-6 and n-3 LCPUFAs in the studied tissues, compared to animals given control diet. HT supplementation significantly reduced fat accumulation in liver and plasma as well as tissue metabolic alterations induced by HFD. Furthermore, a normalization of desaturase activities, oxidative stress-related parameters, and tissue n-3 LCPUFA content was observed in HT-treated rats over control animals.ConclusionsHT supplementation prevents metabolic alterations in desaturase activities, oxidative stress status, and n-3 LCPUFA content in the liver and extrahepatic tissues of mice fed HFD.

Synovial fluid and plasma n3 long chain polyunsaturated fatty acids in patients with inflammatory arthritis

Relationships between n-3 long chain polyunsaturated fatty acids (LC-PUFA) in plasma and synovial fluid (SF) were examined in 36 patients with knee effusion within the context of a variety of rheumatic diagnoses and various stated fish oil (FO) intakes (from 0 to 30mL of standard FO daily) of variable duration. In a sub-group of patients, correlations between PUFA in SF mononuclear cells (MNC) and cell-free supernatants of SF and between SF MNC and peripheral blood (PB) MNC were examined. Correlations were also sought between clinical data (stated FO intake, pain score) and n-3 LC-PUFA.Correlations between plasma n-3 LC-PUFA and SF n-3 LC-PUFA were very strong (r2>0.9, p<0.001). The LC-PUFA profiles of SF supernatants differed from those of MNC. PUFA profiles in PB MNC and SF MNC were similar, except for a higher proportion of DHA in the latter. Positive correlations were observed between stated intakes of FO and EPA in plasma and SF (for both r=0.37, p=0.02) and DHA in plasma (r=0.37, p=0.02) and SF (r=0.36, p=0.03). n-3 LC-PUFA in plasma and SF correlated inversely with pain score (plasma r2=0.16, p<0.02; SF r2 0.32, p=0.001).In conclusion, plasma n-3 LC-PUFA is a strong indicator of SF n-3 LC-PUFA status across a broad range of rheumatic diagnoses and FO intakes. Higher n-3 LC-PUFA in plasma and SF were associated with lesser pain experience.

ω-3 Long-Chain Polyunsaturated Fatty Acids and Fatty Acid Desaturase Activity Ratios as Eventual Endophenotypes for ADHD

Objective: Epidemiological studies suggest that long-chain polyunsaturated fatty acids (LC-PUFAs) may be suitable as endophenotypes for ADHD. To be appropriated vulnerability traits, endophenotypes should be altered in unaffected relatives of index cases. Serum profiles of LC-PUFAs in unaffected relatives of ADHD patients remain understudied. The main objective of this study was to compare serum LC-PUFAs in ADHD patients, unaffected relatives of index cases, and general-population unaffected participants. Method: LC-PUFA profiles of 72 participants (27 ADHD patients, 27 unaffected relatives, and 18 general-population participants) were obtained by gas chromatography–mass spectrometry (GC-MS). Groups were compared by parametrical statistics. Results: Unaffected females from the general population presented lower Docosapentaenoic acid (DPA; p = .0012) and a-linolenic acid (ALA; p = .0091) levels compared with ADHD females and unaffected relatives. In addition, docosahexaenoic acid (DHA)/ALA and DHA/DPA ratios, addressing desaturase activity, were significantly lower in ADHD patients and unaffected relatives of ADHD patients in the female-subgroup (p = .022 and .04, respectively). Conclusion: DHA/ALA, DHA/DPA, serum DPA, and serum ALA may be suitable as endophenotypes for ADHD women.

Effects of the total replacement of fish-based diet with plant-based diet on the hepatic transcriptome of two European sea bass (Dicentrarchus labrax) half-sibfamilies showing different growth rates with the plant-based diet

BackgroundEfforts towards utilisation of diets without fish meal (FM) or fish oil (FO) in finfish aquaculture have been being made for more than two decades. Metabolic responses to substitution of fishery products have been shown to impact growth performance and immune system of fish as well as their subsequent nutritional value, particularly in marine fish species, which exhibit low capacity for biosynthesis of long-chain poly-unsaturated fatty acids (LC-PUFA). The main objective of the present study was to analyse the effects of a plant-based diet on the hepatic transcriptome of European sea bass (Dicentrarchus labrax).ResultsWe report the first results obtained using a transcriptomic approach on the liver of two half-sibfamilies of the European sea bass that exhibit similar growth rates when fed a fish-based diet (FD), but significantly different growth rates when fed an all-plant diet (VD). Overall gene expression was analysed using oligo DNA microarrays (GPL9663). Statistical analysis identified 582 unique annotated genes differentially expressed between groups of fish fed the two diets, 199 genes regulated by genetic factors, and 72 genes that exhibited diet-family interactions. The expression of several genes involved in the LC-PUFA and cholesterol biosynthetic pathways was found to be up-regulated in fish fed VD, suggesting a stimulation of the lipogenic pathways. No significant diet-family interaction for the regulation of LC-PUFA biosynthesis pathways could be detected by microarray analysis. This result was in agreement with LC-PUFA profiles, which were found to be similar in the flesh of the two half-sibfamilies. In addition, the combination of our transcriptomic data with an analysis of plasmatic immune parameters revealed a stimulation of complement activity associated with an immunodeficiency in the fish fed VD, and different inflammatory status between the two half-sibfamilies. Biological processes related to protein catabolism, amino acid transaminations, RNA splicing and blood coagulation were also found to be regulated by diet, while the expression of genes involved in protein and ATP synthesis differed between the half-sibfamilies.ConclusionsOverall, the combined gene expression, compositional and biochemical studies demonstrated a large panel of metabolic and physiological effects induced by total substitution of both FM and FO in the diets of European sea bass and revealed physiological characteristics associated with the two half-sibfamilies.

Plasma long-chain fatty acids profile and metabolic outcomes in normolipidaemic obese children after one-year nutritional intervention

To assess the association between changes in plasma long-chain polyunsaturated fatty acids (LCPUFAs) profile and metabolic outcomes after 1-year nutritional intervention in normolipidaemic obese children. Fifty-seven normolipidaemic obese children, aged 8-13 years, were recruited in the study. Body mass index (BMI) z-scores were calculated. Fasting blood samples were analysed for insulin, glucose, lipid profile and fatty acid (FA) levels at baseline and after an 1-year nutritional-behaviour intervention. Insulin resistance was estimated by homeostatic model assessment (HOMA). Fifty-one obese children completed the study. At the end of the intervention, the children showed decreased BMI z-score (mean reduction 0.25; 95% confidence interval [CI], 0.18-0.31), HOMA index (1.6; 0.6-2.5), plasma-saturated FA (1.49; 0.67-2.31 mg/dL), C20:3n-9 (0.05; 0.02-0.07 mg/dL) and increased plasma levels of monounsaturated FA (mean increase 1.35; 0.63-2.07 mg/dL), n-6 PUFA (1.02; 0.08-1.97 mg/dL), n-3 PUFA (0.24; 0.07-0.40 mg/dL), C20:4n-6 (0.37; 0.11-0.63 mg/dL), C18:3n-3 (0.04; 0.01-0.07 mg/dL), C22:6n-3 (0.30; 0.17-0.42 mg/dL) and the C22:6n-3/C20:4n-6 ratio (0.02; 0.01-0.03 mg/dL) ratio. Nutritional interventions may improve plasma LCPUFA profile and metabolic outcomes of normolipidaemic obese children.

Long-chain polyunsaturated fatty acids profile in plasma phospholipids of hyperphenylalaninemic children on unrestricted diet

Introduction The aim of the present study was to examine whether hyperphenylalaninemic children on unrestricted diet (MHP) may exhibit a different LCPUFA profile from PKU or healthy children in plasma phospholipids. Patients and methods Forty-five MHP children (age 9–14 years) were age and sex matched with 45 PKU and 45 healthy children. Fatty acids were determined and expressed as % of total fatty acids. Results MHP children showed docosahexaenoic acid (DHA) levels higher than PKU children (mean difference, 0.2%; 95% confidence interval, 0.02%–0.38%), although difference was not significant after correction for multiple comparisons, and lower levels than healthy children (−0.8%; −1.01% to −0.59%). Concentration of n-3 PUFA was higher in MHP than PKU children (0.6%; 0.4% to 0.8%), Conclusions The results suggest that low DHA levels in plasma phospholipids not only are evident in PKU but also may occur in MHP children, who are on unrestricted diet, as compared to healthy children.

Dietary krill oil increases docosahexaenoic acid and reduces 2-arachidonoylglycerol but not N-acylethanolamine levels in the brain of obese Zucker rats

Evidence suggests that dietary long chain polyunsaturated fatty acids (LCPUFAs), and particularly those belonging to the n-3 family, may influence the brain fatty acid profile and, thereby, the biosynthesis of endocannabinoids in rodents. However, the doses used are usually quite high and not comparable with human intake. Recently, we have shown that relatively low doses of dietary n-3 LCPUFAs (4 weeks), in the form of either fish or krill oil, balanced for EPA and DHA content, and against a control diet with no EPA and DHA and similar contents of oleic, linoleic and α-linolenic acids, lower the concentrations of the endocannabinoids, anandamide (AEA) and 2-arachidonoylglycerol (2-AG), in the visceral adipose tissue, and of AEA in the liver and heart, of obese Zucker rats. This, in turn, is associated with lower levels of arachidonic acid in membrane phospholipids and with amelioration of some metabolic syndrome parameters. We investigated here whether in Zucker rats, under the same conditions, fish and krill oil are also able to influence LCPUFA and endocannabinoid profiles in brain. Only krill oil was able to increase significantly DHA levels in brain phospholipids, with no changes in arachidonic acid. DHA increase was associated with lower levels of 2-AG in the brain, whereas AEA and its congeners, N-palmitoylethanolamine and N-oleoylethanolamine, were unchanged. We conclude that, despite the strong impact of dietary n-3 fatty acid on endocannabinoid levels previously observed in peripheral tissues, in the brain only 2-AG is affected by dietary krill oil, suggesting that the beneficial effect of the latter on the metabolic syndrome is mostly exerted by modifying peripheral endocannabinoids. Nevertheless, possible effects of dietary krill oil in the brain through modification of 2-AG levels deserve further investigation.

Plasma phospholipid fatty acid status and depressive symptoms: Association only present in the clinical range

Background Long-chain polyunsaturated fatty acids (LCPUFA) have been implicated in depression, but their role in mood variability in the general population is still unclear. We investigated the associations between LCPUFA status or fish consumption on the one hand and depressive symptoms and chronicity of depressed mood on the other in a community-based sample. Methods Plasma phospholipid LCPUFA profiles of 241 participants of the Maastricht Aging Study (MAAS) were determined. Depressive symptoms were measured using the CES-D and SCL-90 questionnaires. Using linear regression analyses, associations between the actual level and longitudinal (12-year) variability in depressive symptoms on the one hand and LCPUFA concentrations or fish consumption on the other were examined. Results No linear associations were found in the total sample between depressive symptoms and LCPUFA concentrations or fish consumption. Chronicity of depressed mood was also not related to LCPUFA status or fish consumption. Post-hoc analyses, however, showed a negative correlation between docosahexaenoic acid (DHA, 22:6 n-3) concentration and depressed mood in persons with CES-D scores above the clinical threshold. Regression analysis suggested a non-linear association between depressive symptoms and DHA concentration in the total sample. Limitations The cross-sectional nature of the present study did not allow for inferences about causality. Conclusions This study offers a first indication that a suboptimal LCPUFA status might accompany depressive symptoms primarily within the clinical spectrum.

Evolutionary modifications of human milk composition: evidence from long-chain polyunsaturated fatty acid composition of anthropoid milks

Brain growth in mammals is associated with increased accretion of long-chain polyunsaturated fatty acids (LCPUFA) in brain phospholipids. The period of maximum accumulation is during the brain growth spurt. Humans have a perinatal brain growth spurt, selectively accumulating docosahexaenoic acid (DHA) and other LCPUFA from the third trimester through the second year of life. The emphasis on rapid postnatal brain growth and LCPUFA transfer during lactation has led to the suggestion that human milk LCPUFA composition may be unique. Our study tests this hypothesis by determining fatty acid composition for 11 species of captive anthropoids ( n = 53; Callithrix jacchus, Cebus apella, Gorilla gorilla, Hylobates lar, Leontopithecus rosalia, Macaca mulatta, Pan troglodytes, Pan paniscus, Pongo pygmaeus, Saimiri boliviensis, and Symphalangus syndactylus). Results are compared to previously published data on five species of wild anthropoids ( n = 28; Alouatta paliatta, Callithrix jacchus, Gorilla beringei, Leontopithecus rosalia, and Macaca sinica) and human milk fatty acid profiles. Milk LCPUFA profiles of captive anthropoids (consuming diets with a preformed source of DHA) are similar to milk from women on a Western diet, and those of wild anthropoids are similar to milk from vegan women. Collectively, the range of DHA percent composition values from nonhuman anthropoid milks (0.03–1.1) is nearly identical to that from a cross-cultural analysis of human milk (0.06–1.4). Humans do not appear to be unique in their ability to secrete LCPUFA in milk but may be unique in their access to dietary LCPUFA.

Plasma long‐chain fatty acids and the degree of obesity in Italian children

To examine whether the plasma levels of long-chain polyunsaturated fatty acids (LC-PUFAs) are associated with the degree of obesity in children. Sixty-seven normolipidaemic obese children, aged 8-12 y, and 67 age- and sex-matched normal-weight children were included in the study. Obesity was defined in accordance with the International Obesity Task Force. BMI z-scores were calculated. Fasting blood samples were analysed for insulin, glucose, lipid profile and fatty acid (FA) levels (expressed as % total FA). Insulin resistance was estimated by homeostatic model assessment (HOMA). Compared with normal-weight children, obese children exhibited lower mean plasma total PUFA (37.8% vs 39.7%), omega-6 PUFAs (35.0% vs 36.8%) and C22:6omega-3-to-C18:3omega-3 ratio (5.52 vs 7.61), and higher total monounsaturated FA (26.6% vs 25.0%), C18:3omega-3 (0.28% vs 0.25%) and C20:5omega-3 (0.45% vs 0.39%). In obese children, the BMI z-score was negatively related to plasma PUFA, omega-3 PUFAs, C22:6omega-3, and the C22:6omega-3-to-C20:6omega-6 and C22:6omega-3-to-C18:3omega-3 ratios, and positively with total saturated FA and C20:3omega-9. In obese children, plasma LC-PUFA profile may be associated with the degree of obesity.

Effects of protein-energy malnutrition and human immunodeficiency virus-1 infection on essential fatty acid metabolism in children

This report summarizes data on the availability of essential fatty acids (EFAs) and their long-chain polyunsaturated fatty acid (LCPUFA) metabolites in protein-energy malnutrition (PEM), in human immunodeficiency virus-1 (HIV-1) infection for which less information is available, and the combination of both PEM and HIV-1. The contribution of different EFAs and LCPUFAs to the fatty-acid composition of plasma and erythrocyte membrane lipids was found to be reduced in children with PEM in comparison with well-nourished children. In addition to limited dietary EFA supply, reduced bioconversion of EFAs to their respective LCPUFA metabolites and/or peroxidative degradation of LCPUFAs may contribute to the reduction of LCPUFA status in malnourished children. Restoration of normal energy, protein, and EFA intakes does not appear to readily correct abnormalities of plasma and erythrocyte membrane LCPUFA values. Enhanced dietary supply of LCPUFAs and/or improved supply of antioxidant vitamins may represent novel therapeutic modalities in severe PEM. With and without PEM, HIV infection was related to altered availability of various EFAs and LCPUFAs in HIV-seropositive children. The plasma total lipid fatty-acid profiles seen in well-nourished children with HIV infection were compatible with an HIV infection–related enhancement of the metabolic activity of the conversion of EFAs to their respective LCPUFA metabolites. However, the plasma phospholipid EFA and LCPUFA profiles seen in severely malnourished children with HIV infection more closely resembled those seen in children with PEM but without HIV infection than in those in children with HIV infection but no PEM. Metabolic studies using stable isotope-labeled fatty acids may contribute to better understanding of the HIV-related changes in EFA metabolism and clearly are needed before therapeutic conclusions can be drawn.