Elongase Activity Research Articles

Abstract 4128491: Dietary N-3 Very-Long-Chain Polyunsaturated Fatty Acids Improve Retinal Function And Reduce Aortic Atherosclerosis In ApoE-Deficient Mice

Introduction: N-3 very-long-chain polyunsaturated fatty acids (VLCPUFA; C≥24), which are found primarily in retina and a few other select tissues, are known to play critical roles in specific biological systems. Although n-3 PUFA, such as eicosapentanoic acid (EPA, C20:5 n-3) and docosahexaenoic acid (DHA, C22:6 n-3), may confer cardiovascular benefits, they did not improve age-related macular degeneration (AMD), a leading cause of blindness worldwide, in clinical trials. The activity of ELOVL fatty acid elongase 2 (ELOVL2), an enzyme that converts EPA into tetracosapentaenoic acid (TPA, C24:5 n-3), is known to decrease in the retina with age due to promoter methylation. Hypothesis: We hypothesized that dietary VLCPUFA may delay or prevent AMD, by bypassing the ELOVL2-mediated lipid elongation step. We also hypothesize that VLCPUFA may benefit cardiometabolic health like shorter-chain n-3 PUFA through similar mechanisms. Aims: We aimed to investigate the effect of dietary VLCPUFA on retinal function and cardiometabolic risk factors in mice. Methods: We have produced a new fish oil that contains ~40% (w/w) of C24-C28-rich VLCPUFA. We fed 9-month-old ApoE -/- mice with normal or VLCPUFA fortified diet (1% or 3% (w/w)) for 8 weeks, and age-matched C57BL/6J mice were used as control. We conducted electroretinography (ERG) and cognitive ability tests at the end of feeding period. In in vitro studies, we performed PPAR reporter assay and investigated the anti-inflammatory effects of TPA in lipopolysaccharide-stimulated RAW264.7 cells. Results: Supplementation of VLCPUFA showed a significant and dose-dependent improvement in ERG response. Like EPA and DHA, we also observed favorable cardiometabolic changes and decreased atherosclerotic plaque area due to dietary VLCPUFA. Intriguingly, VLCPUFA supplemented aging mice exhibit better cognitive performance compared with control. Transcriptome analysis revealed that VLCPUFA-enriched fish oil favorably regulated genes involved in nuclear receptor signaling pathways, lipid metabolism and inflammation. Furthermore, purified TPA potently activates PPARs, and suppressed inflammation in macrophage cells. Conclusions: Overall, our studies revealed for the first time several potential health benefits for our new VLCPUFA-enriched fish oil in several age-related diseases and support its future development as a new dietary supplement.

Growth performance, carcass characteristics, fatty acid profile, and meat quality of male goat kids supplemented by alternative feed resources: bitter vetch and sorghum grains

Abstract. Bitter vetch and sorghum grains are alternative local feed resources that are underutilized in the southern Mediterranean area. This study aimed to assess the effects of incorporating these grains into the diet of local goat breeds on growth performance, carcass characteristics, and meat quality. Twenty-four goat kids were divided into three groups. The control group received a conventional diet consisting of oat hay, barley, and fava beans. In the first group, fava beans were replaced with bitter vetch, and in the second group, barley was replaced with sorghum. At the end of the trial, the animals were slaughtered and carcass characteristics and meat fatty acid profiles of the longissimus dorsi (LD) muscle were determined. Alternative grain incorporation had no significant effect on the growth parameters. Still, it significantly affected carcass characteristics, especially in the sorghum group compared to the control group, where mesenteric fat was lower (266 vs. 437 g). The back color was lighter (L*=55.1 vs. 59.1) and less yellow (a*=-1.29 vs. 2.22). The diet also influenced the meat's chemical composition, with less protein and ash in the chevrons of animals receiving bitter vetch and sorghum grains, respectively. Regarding the fatty acid (FA) profile, sorghum grains had decreased C18:2 n-6 and polyunsaturated FA (PUFA), whereas bitter vetch grains had increased C18:3 n-3, elongase activity, and nutritive value index (NVI). The control group exhibited intermediate results for C15:0, C16:0, C16:1, C20:3 n-3, n-3, health promoting index (HPI), and thrombogenic index (TI). No significant effects were reported for saturated FA (SFA) and monounsaturated FA (MUFA). Bitter vetch and sorghum grains can be safely incorporated into fattening diets of goat kids.

Associations of the rs12504538 and rs6824447 Polymorphisms of the Elovl6 Gene with Estimated Elongase and Desaturase Activity and Fatty Acid Concentrations in Mexican Women with Gestational Diabetes Mellitus

Background: This study aimed to investigate the possible associations of the rs12504538 and rs6824447 polymorphisms of the Elovl6 gene with estimated elongase and desaturase activity and saturated fatty acid concentrations in Mexican women with Gestational Diabetes Mellitus (GDM). Methods: We recruited 172 women in the second and third trimesters of pregnancy who had undergone an oral glucose tolerance test, including 66 who had diagnosed with GDM according to the 2016 ADA criteria and 106 who had normal glucose tolerance test results, from the General Hospital and Health Centers of the Health Ministry of Guanajuato, México. Participants were matched by gestational week. Data on age, gestational week and anthropometric characteristics were collected. Blood samples were drawn after an overnight fast for the measurement of serum glucose, lipid, NEFA, serum fatty acid and insulin levels; SNP genotyping and quantification of fatty acids was performed and elongase and desaturase activity was estimated. Findings: With the exception of HDL-cholesterol, all variables, including NEFA levels, were significantly greater in the GDM group than in the non-GDM group. The rs6824447 polymorphism of the Elovl6 gene, an age >25 years and HOMA-IR levels were associated with the development of GDM (OR=5.1, 95% CI 1.56-17.1, p=0.006; OR=4.89, 95% CI 1.65-14.4, p=0.003; OR=34.1 95% CI 8.7-133, p<0.000001, respectively). Palmitic acid (OR=1.08; 95% CI: 1.06-1.11; p<0.001) and oleic acid (OR=1.17; 95% CI: 1.14-1.2; p<0.001) concentrations were also associated with the development of GDM. No differences in the estimated elongase and desaturase activity among the non-GDM and GDM groups were found and only the activity of Δ9D SCD18 desaturase was marginally high in GDM patients (p=0.050). Conclusion: The rs6824447Elovl6 polymorphism is associated with the development of GDM, as are high serum palmitic acid, oleic acid and stearic acid concentrations and estimated Δ9D SCD18 desaturase activity.

Metabolic Reprogramming of Phospholipid Fatty Acids as a Signature of Lung Cancer Type.

Background: Lung cancer is one of the leading causes of cancer-related mortality. Non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) differ in aggressiveness, proliferation speed, metastasis propensity, and prognosis. Since tumor cells notably change lipid metabolism, especially phospholipids and fatty acids (FA), this study aimed to identify FA alterations in lung cancer tissues. Methods: Our study included patients with newly diagnosed, histologically confirmed SCLC (n = 27) and NSCLC (n = 37). Samples were collected from both malignant and healthy tissues from each patient, providing they were within subject design. Results: In both NSCLC and SCLC tumor tissues, FA contents were shifted toward pro-inflammatory profiles, with increased levels of some individual n-6 polyunsaturated FA (PUFA), particularly arachidonic acid, and elevated activity of Δ6 desaturase. Compared to healthy counterparts, lower levels of alpha-linolenic acid (18:3n-3) and total saturated FA (SFA) were found in NSCLC, while decreased levels of linoleic acid (18:2n-6) and all individual n-3 FA were found in SCLC tissue in comparison to the healthy tissue control. When mutually compared, SCLC tissue had higher levels of total SFA, especially stearic acid, while higher levels of linoleic acid, total PUFA, and n-3 and n-6 PUFA were detected in NSCLC. Estimated activities of Δ6 desaturase and elongase were higher in SCLC than in NSCLC. Conclusions: Our findings indicate a notable impairment of lipid metabolism in two types of lung cancer tissues. These type-specific alterations may be associated with differences in their progression and also point out different therapeutic targets.

Structural and functional analysis of plant ELO-like elongase for fatty acid elongation.

ELO-like elongase is a condensing enzyme elongating long chain fatty acids in eukaryotes. Eranthis hyemalis ELO-like elongase (EhELO1) is the first higher plant ELO-type elongase that is highly active in elongating a wide range of polyunsaturated fatty acids (PUFAs) and some monounsaturated fatty acids (MUFAs). This study attempted using domain swapping and site-directed mutagenesis of EhELO1 and EhELO2, a close homologue of EhELO1 but with no apparent elongase activity, to elucidate the structural determinants critical for catalytic activity and substrate specificity. Domain swapping analysis of the two showed that subdomain B in the C-terminal half of EhELO1 is essential for MUFA elongation while subdomain C in the C-terminal half of EhELO1 is essential for both PUFA and MUFA elongations, implying these regions are critical in defining the architecture of the substrate tunnel for substrate specificity. Site-directed mutagenesis showed that the glycine at position 220 in the subdomain C plays a key role in differentiating the function of the two elongases. In addition, valine at 161 and cysteine at 165 in subdomain A also play critical roles in defining the architecture of the deep substrate tunnel, thereby contributing significantly to the acceptance of, and interaction with primer substrates.

Fish oil replacement with different vegetable oils in Onychostoma macrolepis: Effects on fatty acid metabolism based on whole-body fatty acid balance method and genes expression.

To evaluate the fatty acid (FA) metabolism status and possibility as a DHA source of farmed Onychostoma macrolepis, a total of 168 fish (2.03 ± 0.23 g) were fed four diets supplemented with fish oil (FO), linseed oil (LO), soybean oil (SO), and a mixture of LO and SO oil (MO), respectively, for 70 days. Body FA compositions were modified reflecting dietary FAs. Comparing liver and intestine fatty acids with fish fed four diets, the content of ARA in fish fed SO was significantly higher than others (P < 0.05), but showed no difference in muscle. The tissue FA profile showed that the FO-fed group successfully deposited DHA, while the LO-fed group converted ALA to DHA effectively, as well as the liver and intestine EPA was notably highest in the FO group, whereas no difference between the FO and LO group in the muscle. The FA results showed that the DHA contents in the muscle of Onychostoma macrolepis are at a medium-high level compared with several other fish species with the highest aquaculture yield. Correspondingly, in the fish fed diet with LO, SO, and MO, the genes of most FA biosynthesis, transportation, and transcriptional regulation factors were increased in the liver and muscle, but no significant difference was observed in the gene expression of Elovl4b, FATP1, and FABP10 in the muscle. In addition, the enzyme activity involved in PUFA metabolism was higher in fish fed vegetable oil-based diets, corroborating the results of the gene expression. Increased in vivo elongase and desaturase (Δ5, Δ6, and Δ9) activities were recorded in fish fed fish oil-devoid diets, which resulted in the appearance of products associated with elongase and desaturase activities in fish. Besides, as the specific n-3 PUFA synthesis substrate, the dietary supplementation of ALA not only retains most of the nutrition value but also ensures the muscular texture, such as fiber diameter and density. It is concluded that farmed O. macrolepis owns strong n-3 LC-PUFA biosynthetic capacity and high DHA contents so it can be a good DHA source for the population.

Metabolic Consequences of Anabolic Steroids, Insulin, and Growth Hormone Abuse in Recreational Bodybuilders: Implications for the World Anti-Doping Agency Passport

BackgroundHormonal doping in recreational sports is a public-health concern. The World Anti-Doping Agency (WADA) promoted the creation of the Athlete Biological Passport, aiming to monitor athlete’s biological variables over time to facilitate indirect detection of doping. Detection tests for anabolic androgenic steroids (AAS) and growth hormone (GH) are available while insulin abuse cannot be revealed. We have determined in recreational bodybuilders the metabolic effects associated with different patterns of hormone abuse. All analyses were conducted using Statistical Package for Social Sciences (SPSS) 21.0 software (SPSS Chicago, IL).ResultsWe have assessed plasma concentrations of selected metabolic markers and fatty acid content in erythrocyte membranes of 92 male bodybuilders and in 45 healthy controls. Hormonal abuse was identified by anonymous questionnaires. 43% (%) of recruited bodybuilders regularly abused hormones, i.e., anabolic androgenic steroids (95%) often associated with GH (30%) and/or insulin (38%). HDL-cholesterol was lower in insulin and/or GH abusers. Alanine (ALT) and aspartic (AST) transaminases were greater in hormone abusing bodybuilders than in non-doping bodybuilders and controls. Insulin doping was selectively associated with increased plasma ALT-to-AST ratio. In erythrocyte membranes, elongase activity (i.e., stearic-to-palmitic ratio) was lower in insulin and/or growth hormone doping, whereas increased Δ-9 desaturase activity (i.e., palmitoleic-to-palmitic ratio) was selectively associated with insulin doping.ConclusionsIn conclusion, our study demonstrates that insulin and GH abuse are characterized by multiple alterations of specific metabolic markers. Although further studies are needed to test whether longitudinal monitoring of selected metabolic marker such as muscle contraction time, HDL levels, ALT-AST ratio as well as the activities of selected enzymes (e.g. Δ-9 desaturase and elongase), could contribute to the detection of insulin and GH abuse in sport.

Catalytic mechanism of trans-2-enoyl-CoA reductases in the fatty acid elongation cycle and its cooperative action with fatty acid elongases

The fatty acid (FA) elongation cycle produces very-long-chain FAs with ≥C21, which have unique physiological functions. Trans-2-enoyl-CoA reductases (yeast, Tsc13; mammals, TECR) catalyze the reduction reactions in the fourth step of the FA elongation cycle and in the sphingosine degradation pathway. However, their catalytic residues and coordinated action in the FA elongation cycle complex are unknown. To reveal these, we generated and analyzed Ala-substituted mutants of 15 residues of Tsc13. An in vitro FA elongation assay showed that nine of these mutants were less active than WT protein, with E91A and Y256A being the least active. Growth complementation analysis, measurement of ceramide levels, and deuterium-sphingosine labeling revealed that the function of the E91A mutant was substantially impaired in vivo. In addition, we found that the activity of FA elongases, which catalyze the first step of the FA elongation cycle, were reduced in the absence of Tsc13. Similar results were observed in Tsc13 E91A-expressing cells, which is attributable to reduced interaction between the Tsc13 E91A mutant and the FA elongases Elo2/Elo3. Finally, we found that E94A and Y248A mutants of human TECR, which correspond to E91A and Y256A mutants of Tsc13, showed reduced and almost no activity, respectively. Based on these results and the predicted three-dimensional structure of Tsc13, we speculate that Tyr256/Tyr248 of Tsc13/TECR is the catalytic residue that supplies a proton to trans-2-enoyl-CoAs. Our findings provide a clue concerning the catalytic mechanism of Tsc13/TECR and the coordinated action in the FA elongation cycle complex.

Capability of DHA biosynthesis in a marine teleost, Pacific saury Cololabis saira: functional characterization of two paralogous Fads2 desaturases and Elovl5 elongase

The Pacific saury Cololabis saira is an important fishery resource in the Far East, where it is appreciated for its high lipid content, which includes long-chain polyunsaturated fatty acids (LC-PUFAs) such as docosahexaenoic acid (DHA). Although it has been hypothesized that these fatty acids are derived from their prey items, this study focused on evaluating the capacity of saury for endogenous production of LC-PUFAs. To describe its LC-PUFA biosynthetic pathway, we characterized fatty acid desaturase 2 (Fads2) and elongation of very long-chain fatty acid protein 5 (Elovl5) in Pacific saury. Two paralogous fads2 genes, namely fads2a and fads2b, were isolated from the saury and their recombinant protein showed ∆6∆8 and ∆4∆5 desaturase activities, respectively. Meanwhile, saury Elovl5 had elongase activity toward C18 and C20 PUFA. These three enzyme genes were expressed in the brain and liver, although fads2a was absent in the latter. Our results suggest that the saury has sufficient enzymatic functions, particularly in its brain, for DHA biosynthesis through the ∆4 pathway even from α-linolenic acid. This information provides novel insights into the origin of LC-PUFAs in Pacific saury and the future perspective for its potential as a source of such vital fatty acids for human consumption.

Using mass spectrometry imaging to map fluxes quantitatively in the tumor ecosystem

Tumors are comprised of a multitude of cell types spanning different microenvironments. Mass spectrometry imaging (MSI) has the potential to identify metabolic patterns within the tumor ecosystem and surrounding tissues, but conventional workflows have not yet fully integrated the breadth of experimental techniques in metabolomics. Here, we combine MSI, stable isotope labeling, and a spatial variant of Isotopologue Spectral Analysis to map distributions of metabolite abundances, nutrient contributions, and metabolic turnover fluxes across the brains of mice harboring GL261 glioma, a widely used model for glioblastoma. When integrated with MSI, the combination of ion mobility, desorption electrospray ionization, and matrix assisted laser desorption ionization reveals alterations in multiple anabolic pathways. De novo fatty acid synthesis flux is increased by approximately 3-fold in glioma relative to surrounding healthy tissue. Fatty acid elongation flux is elevated even higher at 8-fold relative to surrounding healthy tissue and highlights the importance of elongase activity in glioma.

Potential of Mortierellaceae for polyunsaturated fatty acids production: mini review.

The health benefits of polyunsaturated fatty acids (PUFAs) have encouraged the search for rich sources of these compounds. However, the supply chain of PUFAs from animals and plants presents environmental concerns, such as water pollution, deforestation, animal exploitation and interference in the trophic chain. In this way, a viable alternative has been found in microbial sources, mainly in single cell oil (SCO) production by yeast and filamentous fungi. Mortierellaceae is a filamentous fungal family world-renowned for PUFA-producing strains. For example, Mortierella alpina can be highlighted due to be industrially applied to produce arachidonic acid (20:4 n6), an important component of infant supplement formulas. Thus, the state of the art of strategies to increase PUFAs production by Mortierellaceae strains is presented in this review. Firstly, we have discussed main phylogenetic and biochemical characteristics of these strains for lipid production. Next, strategies based on physiological manipulation, using different carbon and nitrogen sources, temperature, pH and cultivation methods, which can increase PUFA production by optimizing process parameters are presented. Furthermore, it is possible to use metabolic engineering tools, controlling the supply of NADPH and co-factors, and directing the activity of desaturases and elongase to the target PUFA. Thus, this review aims to discuss the functionality and applicability of each of these strategies, in order to support future research for PUFA production by Mortierellaceae species.

63 Fatty Acid Profile of Beef from Feedlot Young Bulls of Two Genetic Groups

Abstract The fatty acid profile of the longissimus thoracis (LT) muscle and the activity of Δ9 desaturase6, Δ9 desaturase8, and elongase enzymes of beef from feedlot cattle of 2 genetic groups were evaluated. Fifty long-yearling young bulls were divided into two groups following their breed composition: Nellore (n = 25) and Angus × Nellore crossbred (n = 25), were randomly assigned into 4 pens (12 or 13 animals/pen) following a completely randomized design. Animals were sourced from the same breeding season and endured a grazing growing phase in Megathyrsus maximus cv. Mombaça pasture, with protein and energy supplement offered at 0.2% of body weight (BW). The feedlot phase comprehended 105 days of feed, and the diet (80% concentrate) was formulated to meet or safely exceed the beef cattle requirements to target an average daily gain (ADG) of 1.6 kg/day, in which major ingredients were represented by (% DM basis): sorghum silage (20%), ground corn (57.6%), ground soybean seed as the lipid source (20.4%), and a mineral/vitamin premix (2%). Samples of the LT muscle (between the 12th and 13th ribs) were taken right after slaughter to determine the profile of intramuscular fat. Lipids were extracted (2:1 chloroform/methanol), and 5 mL of the lipid extract was used for saponification followed by methylation and submitted for analysis using gas chromatography. The activities of Δ9 desaturase6, Δ9 desaturase8, and elongase enzymes were determined through mathematical indexes, in which their respective saturated and monounsaturated fatty acids were used. Data were analyzed using R (R CORE TEAM, 2021), and the effect of breed on the fatty acid profile was evaluated using the completely randomized design one-way, in which animal was used as the experimental unit. The sum of saturated fatty acids and unsaturated fatty acids was not affected (P ≥ 0.12) by genetic groups. Within FA profiles, crossbred bulls had greater (P = 0.05) concentration of monounsaturated fatty acids (49.7 vs. 52.4%), while beef of Nellore cattle showed greater (P ≤ 0.02) concentration of polyunsaturated fatty acids (6.71 vs. 7.67%) and n-3 (0.53 vs. 0.68%). A tendency (P = 0.07) was observed for the sum of n-6 and n-6/n-3 ratio, in which Nellore cattle had numerically greater values (6.63 vs. 4.89%, and 9.75 vs. 9.22, respectively). The activity of Δ9 desaturase6 and Δ9 desaturase8 was not affected (P ≥ 0.14) by genetic groups, while crossbred animals had greater (P = 0.03) activity of elongase (67.8 vs. 65.6%). Although the overall sum of mono and polyunsaturated fatty acids seems not to be affected, the FA profile and unsaturation/elongation enzymatic activity of beef was influenced by the genetic groups evaluated, in which both Nellore and their F-1 crossbreed counterparts had attractive responses.

Determination of dietary essential fatty acids in a deep-sea fish, the splendid alfonsino Beryx splendens: functional characterization of enzymes involved in long-chain polyunsaturated fatty acid biosynthesis

The splendid alfonsino Beryx splendens is a commercially important deep-sea fish in East Asian countries. Because the wild stock of this species has been declining, there is an urgent need to develop aquaculture systems. In the present study, we investigated the long-chain polyunsaturated fatty acid (LC-PUFA) requirements of B. splendens, which are known as essential dietary components in many carnivorous marine fish species. The fatty acid profiles of the muscles, liver, and stomach contents of B. splendens suggested that it acquires substantial levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from its natural diet. The functional characterization of a fatty acid desaturase (Fads2) and three elongases (Elovl5, Elovl4a, and Elovl4b) from B. splendens confirmed their enzymatic capabilities in LC-PUFA biosynthesis. Fads2 showed Δ6 and Δ8 bifunctional desaturase activities. Elovl5 showed preferential elongase activities toward C18 and C20 PUFA substrates, whereas Elovl4a and Elovl4b showed activities toward various C18-22 substrates. Given that Fads2 showed no Δ5 desaturase activity and no other fads-like sequence was found in the B. splendens genome, EPA and arachidonic acid cannot be synthesized from C18 precursors; hence, they can be categorized as dietary essential fatty acids in B. splendens. EPA can be converted into DHA in B. splendens via the so-called Sprecher pathway. However, given that fads2 is only expressed in the brain, it is unlikely that the capacity of B. splendens to biosynthesize DHA from EPA can fulfill its physiological requirements. These results will be useful to researchers developing B. splendens aquaculture methods.

Essential Fatty Acid Deficiency Associates with Growth Faltering and Environmental Enteric Dysfunction in Children.

Environmental enteric dysfunction (EED) is characterized by intestinal inflammation, malabsorption and growth-faltering in children with heightened exposure to gut pathogens. The aim of this study was to characterize serum non-esterified fatty acids (NEFA), in association with childhood undernutrition and EED, as potential biomarkers to predict growth outcomes. The study comprised a cohort of undernourished rural Pakistani infants (n = 365) and age-matched controls followed prospectively up to 24 months of age. Serum NEFA were quantified at ages 3-6 and 9 months and correlated with growth outcomes, serum bile acids and EED histopathological biomarkers. Serum NEFA correlated with linear growth-faltering and systemic and gut biomarkers of EED. Undernourished children exhibited essential fatty acid deficiency (EFAD), with low levels of linoleic acid and total n-6 polyunsaturated fatty acids, compensated by increased levels of oleic acid and increased elongase and desaturase activities. EFAD correlated with reduced anthropometric Z scores at 3-6 and 9 months of age. Serum NEFA also correlated with elevated BA and liver dysfunction. Essential fatty acid depletion and altered NEFA metabolism were highly prevalent and associated with acute and chronic growth-faltering in EED. The finding suggests that targeting early interventions to correct EFAD and promote FA absorption in children with EED may facilitate childhood growth in high-risk settings.

Skeletal muscle gene expression and meat quality of F1 Angus–Nellore young steers and bulls feedlot finished

This study investigated the effects of castration on skeletal muscle gene expression and beef quality. Six-hundred and forty F1 Angus–Nellore steers and bulls (initial body weight of 299 and 297 ± 4.1 kg, respectively) feedlot finished were used. Gene expression revealed that steers showed up-regulation (P<0.05) of acetyl-CoA carboxylase alpha, fatty acid-binding protein, fatty acid synthase, peroxisome proliferator activated receptor (PPAR)-gamma and stearoyl-coa desaturase, while bulls shown higher expression of PPAR-alpha and sterol regulatory element-binding protein 1. Consequently, steers had greater (P<0.01) intramuscular fat (IMF) in longissimus muscle compared to bulls (5.59 vs. 2.07%). Greater concentration of monounsaturated fatty acids was observed in beef loins of steers (P<0.01), while bulls trend to shown higher (P = 0.08) polyunsaturated fatty acids and higher elongase activity (P<0.05). Thus, differences in gene expression were associated with differences in IMF deposition (marbling). Even after 180 days on feed, crossbred young bulls does not produce meat with adequate IMF and better fatty acid profile than steers.

Physicochemical Composition and Fatty Acid Profile of Goat Kids' Meat Fed Ground-Corn-Grain Silage Rehydrated with Different Additives.

The effects of the replacement of dry ground corn (GC) with corn-grain silage rehydrated with water (RCSwater), cactus pear mucilage (RCSmucilage), and whey (RCSwhey) on the growth, physicochemical composition, and fatty acid profile of goat kids’ meat were investigated. Thirty-two crossbred goat kids (16.4 ± 2.50 kg initial weight) were assigned in a randomized block design with four treatments and eight repetitions. The NDF intake of goat kids fed with RCSmucilage was higher in comparison to RCSwater and RCSwhey (p = 0.0009). The dietary replacement of GC by RCSmucilage increased the final weight (p = 0.033) and meat-cooking losses (p = 0.0001) of kids. The concentrations of oleic (p = 0.046), 11,14-eicosadienoic (p = 0.033), and EPA (p = 0.010) were higher in the meat of kids fed with RCSmucilage and RCSwhey, and the α-linolenic concentration was higher (p = 0.019) for animals feeding with RCSmucilage. Meat from kids fed with RCSwhey presented the lowest ∑SFA and the highest ∑MUFA. In contrast, the ∑PUFA (p < 0.012) was higher for goats fed with RCSwater. The ∑ω3 (p < 0.0001) was higher in animals fed with RCSmucilage and RCSwhey. Desirable fatty acids were higher (p = 0.044) in animals fed with RCSmucilage and RCSwhey, and the atherogenicity (p = 0.044) and thrombogenicity (p < 0.0001) indexes were lower for goats fed the RCSwhey diet. The enzymatic activities of Δ9desaturase (C16) were higher (p = 0.027) in goat kids fed with GC and RCSmucilage, and Δ9desaturase (C18) was higher (p = 0.0497) when goats were fed with RCSmucilage and RCSwhey. Elongase activities were higher (p = 0.045) in goat kids fed with GC and RCSwater. The total replacement of GC by RCSmucilage is recommended in the diet of goat kids due to improvements in the weight gain and proportion of desirable fatty acids in the meat. In addition, RCSmucilage promoted better conservation of the silage at a lower cost when compared to commercial additives.

Dominant Elongase Activity of Elovl5a but Higher Expression of Elovl5b in Common Carp (Cyprinus carpio).

Most diploid freshwater and marine fish encode one elovl5 elongase, having substrate specificity and activities towards C18, C20 and C22 polyunsaturated fatty acids (PUFAs). The allo-tetraploid common carp is hypothesized to encode two duplicated elovl5 genes. How these two elovl5 genes adapt to coordinate the PUFA biosynthesis through elongase function and expression divergence requires elucidation. In this study, we obtained the full-length cDNA sequences of two elovl5 genes in common carp, named as elovl5a and elovl5b. Functional characterization showed that both enzymes had elongase activity towards C18, C20 and C22 PUFAs. Especially, the activities of these two enzymes towards C22 PUFAs ranged from 3.87% to 8.24%, higher than those in most freshwater and marine fish. The Elovl5a had higher elongase activities than Elovl5b towards seven substrates. The spatial-temporal expression showed that both genes co-transcribed in all tissues and development stages. However, the expression levels of elovl5b were significantly higher than those of elovl5a in all examined conditions, suggesting that elovl5b would be the dominantly expressed gene. These two genes had different potential transcriptional binding sites. These results revealed the complicated roles of elovl5 on PUFA synthesis in common carp. The data also increased the knowledge of co-ordination between two homoeologs of the polyploid fish through function and expression divergence.

Alteration of Fatty Acid Profile in Fragile X Syndrome.

Fragile X Syndrome (FXS) is the most prevalent monogenic cause of Autism Spectrum Disorders (ASDs). Despite a common genetic etiology, the affected individuals display heterogenous metabolic abnormalities including hypocholesterolemia. Although changes in the metabolism of fatty acids (FAs) have been reported in various neuropsychiatric disorders, it has not been explored in humans with FXS. In this study, we investigated the FA profiles of two different groups: (1) an Argentinian group, including FXS individuals and age- and sex-matched controls, and (2) a French-Canadian group, including FXS individuals and their age- and sex-matched controls. Since phospholipid FAs are an indicator of medium-term diet and endogenous metabolism, we quantified the FA profile in plasma phospholipids using gas chromatography. Our results showed significantly lower levels in various plasma FAs including saturated, monosaturated, ω-6 polyunsaturated, and ω-3 polyunsaturated FAs in FXS individuals compared to the controls. A decrease in the EPA/ALA (eicosapentaenoic acid/alpha linoleic acid) ratio and an increase in the DPA/EPA (docosapentaenoic acid/eicosapentaenoic acid) ratio suggest an alteration associated with desaturase and elongase activity, respectively. We conclude that FXS individuals present an abnormal profile of FAs, specifically FAs belonging to the ω-3 family, that might open new avenues of treatment to improve core symptoms of the disorder.

Changes in plasma free fatty acids in obese patients before and after bariatric surgery highlight alterations in lipid metabolism

Obesity is a complex disease that increases an individual’s risk of developing other diseases and health-related problems. A common feature is dyslipidemia characterized by increased levels of plasma lipids, which include non-esterified fatty acids (NEFAs). The role of NEFAs in obesity-related morbidity is interesting as NEFAs constitute a reservoir of metabolic energy, are principal components of cell membranes and are precursors for signalling molecules. Bariatric surgery promotes sustained weight loss in severely obese patients, reducing the incidence and severity of co-morbidities. In this study we measure changes in circulating NEFA species in plasma samples taken from 25 obese individuals before and 9 months after Roux-en-Y gastric bypass surgery. The mean weight of the cohort reduced by 29.2% from 149.0 ± 25.1 kg pre-surgery to 105.5 ± 19.8 kg post-surgery and the BMI by 28.2% from 51.8 ± 6.3 kg/m2 pre-surgery to 37.2 ± 5.4 kg/m2. Mean glycated haemoglobin (HbA1c) reduced from 6.5 ± 1.3 to 5.5 ± 0.5%, consistent with the intervention leading to improved glycaemic control, particularly in those who were dysglycemic prior to surgery. Total and LDL cholesterol concentrations were markedly reduced following surgery. Concentrations of seven NEFAs were found to decrease 9 months after surgery compared to pre-surgery levels: myristate, palmitoleate, palmitate, linoleate, oleate, stearate and arachidonate. Bariatric surgery led to increased lipogenesis and elongase activity and decreased stearoyl-CoA desaturase 1 activity. This study therefore highlights metabolic changes that take place following gastric bypass surgery in severely obese patients.

Maternal training during lactation modifies breast milk fatty acid composition and male offspring glucose homeostasis in rat

The perinatal exposome can modify offspring metabolism and health later in life. Within this concept, maternal exercise during gestation has been reported modifying offspring glucose sensing and homeostasis, while the impact of such exercise during lactation is little-known. We thus aimed at evaluating short- and long-term effects of it on offspring pancreatic function, assuming a link with changes in breast milk composition. Fifteen-week-old primiparous female Wistar rats exercised during lactation at a constant submaximal intensity (TR) or remained sedentary (CT). Male offspring were studied at weaning and at 7 months of age for growth, pancreas weight, glycemia and insulin responses. Milk protein content was determined by the bicinchoninic acid assay (BCA colorimetric method), and lipid content and fatty acid composition by gas chromatography. Mature milk from TR rats contained significantly less saturated (−7 %) and more monounsaturated (+18 %) and polyunsaturated (PUFA +12 %) fatty acids compared to CT rats, with no difference in total lipid and protein concentrations. In offspring from TR vs CT mothers, fasting glycemia was lower, pancreas weight was higher with a lower insulin content (−37 %) at weaning. Such outcomes were correlated with milk PUFA levels and indices of desaturase or elongase activities. These effects were no longer present at 7 months, whereas a more efficient muscle insulin sensitivity was observed. Maternal training during lactation led to a specific milk phenotype that was associated with a short-term impact on glucose homeostasis and pancreatic function of the male offspring.