Polyunsaturated Fatty Acid Composition Research Articles

Gender Differences in the Associations of Plasma Pyridoxal 5'-Phosphate with Plasma Polyunsaturated Fatty Acids among US Young and Middle-Aged Adults: NHANES 2003-2004.

Vitamin B6-restricted diets and low plasma pyridoxal 5′-phosphate (PLP) status altered plasma polyunsaturated fatty acids (PUFA) compositions. Evidence suggests the role of gender in the metabolism of vitamin B6 and PUFA. However, no epidemiologic study examined the impact of gender on the relationship between vitamin B6 and PUFA status in adults. Thus, we investigated whether there were gender differences in the association of vitamin B6 intake and plasma PLP concentration with plasma PUFA concentrations and ratios (eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), arachidonic acid (AA), EPA + DHA, EPA/AA, (EPA + DHA)/AA) in US young/middle-aged adults. In total, 864 participants (20–59 years; 484 men, 380 women) from the National Health and Nutrition Examination Survey (NHANES) 2003–2004 were used for this cross-sectional study. Nutrient intakes were estimated from two 24 h recalls and supplement questionnaires; plasma PLP and PUFA were measured. Multivariate linear regression was utilized to obtain unstandardized (b) and standardized (β) coefficients. Covariates included demographic, socioeconomic, dietary variables, physical activity level, cigarette smoking status, alcohol consumption, prescription medication use, and BMI. There were significant interactions between gender and PLP on EPA (P-interaction = 0.004), DHA (P-interaction = 0.020), EPA + DHA (P-interaction = 0.010), EPA/AA (P-interaction = 0.002), (EPA + DHA)/AA (P-interaction = 0.004), whereas no interaction between gender and B6 intake existed. In gender-stratified analyses, in men, PLP was positively associated with EPA (β = 0.138, b = 0.104, p = 0.0004), DHA (β = 0.101, b = 0.058, p = 0.036), EPA + DHA (β = 0.125, b = 0.073, p = 0.005), EPA/AA (β = 0.144, b = 0.099, p = 0.0002), (EPA + DHA)/AA (β = 0.123, b = 0.068, p = 0.005). However, no associations between PLP and PUFA existed in women. In conclusion, gender differences were found in the relationships between plasma PLP and plasma EPA, DHA, EPA + DHA, EPA/AA, and (EPA + DHA)/AA, with significant direct associations in men only among US young/middle-aged adults.

Improvement of Microalga Biodiesel Production Capacity

This research is directed at developing renewable fuel sources, which are not only environmentally friendly, but also more importantly harvested faster and not competitive with agricultural land. For this reason, the potential oil-producing microalgae need to be explored, because it has fast growth and its cultivation development will not compete in land use with food agriculture. This study aims specifically to determine the types of microalgae producing biodiesel oil that can be isolated from the natural Wallacea in NTB waters, to determine light spectrum treatment and N elimination in microalgae culture which significantly increases the productivity and quality of the biodiesel it produces. Based on the distribution map of potential biofuel-producing microalgae types in NTB waters, samples will be collected from several NTB waters, then the target types of microalgae are isolated and cultured in two systems: a closed system (bioreactor) and an open system (raceway pool) with light spectrum variation treatment and elimination of N in microalgae culture nutrients to increase the productivity and quality of the biodiesel oil produced. Biomass was harvested every 48 hours from the bioreactor and every 4 weeks from the experimental pond. Microalgae biomass was extracted with hexane to produce primary oil. This primary oil usually still has a relatively high viscosity compared to petrodiesel, so it is then trans-esterified with methanol and an acid catalyst to increase the fire point and reduce its viscosity. Oil fractionation is also carried out to sort and determine the composition of saturated, mono-unsaturated and poly-unsaturated fatty acids which greatly determine the biodeasel quality of these microalgae. The biodiesel quality variables to be measured are density, viscosity, flash point, freezing point, solubility in water, vapor pressure, reactivity, physical appearance, odor and toxicity. The result showed that, in the community of marine microalgae from Lombok and Sumbawa Islands consist of 62 species of potential producing-oil microalgae were dominated by Bacteriastrum delicatulum, B. variance, Chaetoceros amini, C. affinis, C. liciniosum, C. lorenzianum, Gyrosigma sp., Nannochloropsis oculata, Nitzchia spp., Oscillatoria sp., Pseudonitzschia spp., and Thalassionema nitzschicoides. Types of oil-producing freshwater microalgae in Lombok Island consist of 19 species of potential producing-oil microalgae, identified with high abundance and dominance, covering Microcystis aeruginosa, M. incerta, Nostoc sp., and Pediastrum boryanum. The oil content of the three species of microalgae, namely Chaetoceros amini, Nannochloropsis oculata, and Nitzchia spp which had been cultured by trietmant were 34, 68, and 46% dry weight, respectively.

Study of Polyunsaturated Fatty Acids in Cheeses Using Near-Infrared Spectroscopy: Influence of Milk from Different Ruminant Species

This study has examined the polyunsaturated fatty acid composition of 224 cheeses with variable percentages (0–100%) of milk from different species (cow, ewe’s, and goat) during 6 months of ripening. We analyzed the concentration of ω3 (Σ C20:5 + C22:6 + C18:3), ω6 (ΣC20:4 + C18:2), Σ isomers of the conjugated linoleic acid (CLA), the total of polyunsaturated fatty acids (ω3 + ω6 + CLA), and the ω6/ω3 nutritional relationship of the cheeses. The importance of the animal species, the seasonality, the ripening time, and its influence on the composition of polyunsaturated fatty acids (PUFAs) has been studied. Concerning the species, sheep show a higher concentration of CLA levels and ω6. The seasonality affects above all the levels of CLA and ω3, while ripening only affects the CLA levels. The capacity of NIR technology to predict the concentration of PUFA in cheese by direct application to cheese slices was also assessed. The docosahexaenoic acid relationship (C22:6 ω-3) and the ω6/ω3 relationship presented the most accurate prediction equation (RSQ > 0.7).

EXTRACTION AND EVALUATION OF EDIBLE OIL FROM SCHIZOCHYTRIUM SP. USING AN AQUEOUS ENZYMATIC METHOD

<List> <ListItem><ItemContent> • Aqueous enzymatic extraction (AEE) is performed for oil extraction from <i>Schizochytrium</i> sp. </ItemContent></ListItem> <ListItem><ItemContent> • AEE process is optimized by response surface methodology. </ItemContent></ListItem> <ListItem><ItemContent> • Microalgal oil extracted by AEE has high contents of PUFA, tocopherols and phenolics. </ItemContent></ListItem> <ListItem><ItemContent> • AEEO exhibits considerable antioxidant activity as compared with SEO. </ItemContent></ListItem></List> <i>Schizochytrium</i> sp., a marine microalga, is a potential source of edible oil due to its short growth cycle and rapid lipid accumulation, especially of docosahexaenoic acid. An approach to isolate edible microalgal oil from <i>Schizochytrium</i> sp. using aqueous enzymatic extraction (AEE) was developed. Parameters were optimized by single-factor experiments followed by Box-Behnken design. Proteases were effective in extracting oil. The maximum free oil recovery (49.7%±0.58%) and total oil recovery (68.1%±0.94%) were obtained under optimum conditions of liquid-to-solid ratio of 4.8:1, a 2.5% enzyme concentration of papain and an extraction time of 2.2 h. There was a significant difference (<i>P</i><0.05) in polyunsaturated fatty acid composition between microalgal oil obtained by AEE and by Soxhlet extraction, with the former having superior physiochemical properties and higher concentrations of bioactive components including total phenolic compounds and total tocopherols. These findings indicate a potential application of AEE for extraction of oil from <i>Schizochytrium</i> sp.

Immobilized MAS1 Lipase-catalyzed Synthesis of n-3 PUFA-rich Triacylglycerols in Deep Eutectic Solvents.

n-3 polyunsaturated fatty acids (PUFA)-rich triacylglycerols (TAG) with many beneficial effects are still difficult to be synthesized efficiently and rapidly by current synthetic techniques. This study reports the fatty acid specificity of immobilized MAS1 lipase and its efficient synthesis of n-3 PUFA-rich TAG by esterification of glycerol with n-3 PUFA in natural deep eutectic solvents (NADES) systems. Immobilized MAS1 lipase showed the highest preference for capric acid [C10:0, the highest specificity constant (1/α)=1] whereas it discriminated strongly against docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) due to their lowest specificity constants (1/α=0.19 and 0.2). Moreover, the highest n-3 PUFA-rich TAG content (55.8%) with similar n-3 PUFA composition to the substrate was obtained in choline chloride/glycerol (CG) system. There was a 1.38-fold increase of TAG content in CG system compared with that in the solvent-free system. Interestingly, immobilized MAS1 lipase exhibited no regiospecificity in the solvent-free and various NADES systems. Besides, the potential reaction mechanism of immobilized MAS1 lipase-catalyzed esterification of glycerol with n-3 PUFA in NADES systems was described. It was found that the use of NADES as solvents could greatly enhance TAG content, and make it easy to separate the product. These results indicated that immobilized MAS1 lipase is a promising biocatalyst for the efficient synthesis of n-3 PUFA-rich TAG by esterification of glycerol with n-3 PUFA in NADES systems.

The ultimate peanut butter on crackers for Hyalella: diatoms on macrophytes rather than bacteria and fungi on conditioned terrestrial leaf litter

Abstract It is well established that terrestrial and aquatic ecosystems are interlinked in a myriad of ways, yet understanding of the role terrestrial particulate organic matter (OM) plays in supporting aquatic macroinvertebrate production is still incomplete and debated. We investigated the role of terrestrial particulate OM (leaf litter) and autochthonous OM (macrophytes) with and without biofilm as food sources for the model benthic macroinvertebrate Hyalella (Amphipoda). We hypothesised that biofilm (algae, fungi, bacteria) associated with terrestrial and aquatic plants is the main food source for benthic primary consumers. First, we microbially conditioned the leaf litter insitu for 10‐weeks. Then, we performed a laboratory feeding experiment with nine treatments: no food, conditioned leaf litter from two native terrestrial plants, non‐conditioned leaf litter from these plants, two freshly collected macrophyte species with periphyton, and these macrophytes without periphyton. We measured the growth and analysed the fatty acid (FA) composition of field‐collected and experimental amphipods reared on these diets. We found that amphipods fed food sources without biofilm grew poorly and had a FA content and composition resembling that of starved animals. The same was observed for amphipods fed one leaf litter type with biofilm. However, animals fed the other leaf litter type with biofilm grew during the feeding experiment and showed a characteristic FA composition linked to the higher fungal biomass in this food source. We showed that amphipods fed macrophytes with biofilm resembled field‐collected animals regarding FA amounts and composition; monounsaturated FA representing &gt;40% of total FA, with 16:1n‐7 (palmitoleic acid) and 18:1n‐9 (oleic acid) being the most abundant, and polyunsaturated FA representing 30% of total FA. The FA data indicated algae, particularly diatoms, as evidenced by large quantities of its biomarker 16:1n‐7, were the main food for the amphipods. We conclude diatoms were the peanut butter on crackers for the amphipods, and diatom consumption supported its somatic growth and polyunsaturated FA composition. In contrast, bacteria and fungi on conditioned leaf litter were lower quality food sources because they do not provide essential FA for macroinvertebrates growth and physiology. These results have important ecological implications from a food web perspective.

Properties of immobilized MAS1-H108A lipase and its application in the efficient synthesis of n-3 PUFA-rich triacylglycerols.

This study reports the properties of immobilized MAS1-H108A lipase from marine Streptomyces sp. strain W007 on XAD1180 resin and its application in the synthesis of n-3 polyunsaturated fatty acids (PUFA)-rich triacylglycerols (TAG) for the first time. It was found that the optimal temperature and pH for both immobilized MAS1-H108A lipase and free lipase MAS1-H108A were 70°C and 7.0, respectively. However, immobilized MAS1-H108A lipase exhibited higher thermostability when compared with free lipase MAS1-H108A. It was also interesting that both immobilized MAS1-H108A lipase and free lipase MAS1-H108A showed no regiospecificity in the hydrolysis of triolein. Subsequently, immobilized MAS1-H108A lipase and free lipase MAS1-H108A were employed to catalyze glycerolysis of n-3 PUFA-rich ethyl esters (EE) and esterification of n-3 PUFA with glycerol under vacuum in the solvent-free system. The results showed that n-3 PUFA-rich TAG were synthesized efficiently by non-regiospecific immobilized MAS1-H108A lipase and TAG contents separately reached 92.07% and 76.13% during the esterification and glycerolysis reactions, which were significantly higher than those (71.82% and 39.62%, respectively) obtained by free lipase MAS1-H108A. Besides, TAG exhibited similar n-3 PUFA composition to the substrate. These findings indicated that non-regiospecific immobilized MAS1-H108A lipase is a promising and efficient biocatalyst for the industrial synthesis of n-3 PUFA-rich TAG.

Oxidative Stress in Endurance Cycling Is Reduced Dose-Dependently after One Month of Re-Esterified DHA Supplementation.

Docosahexaenoic acid (DHA) supplementation can reduce exercise-induced oxidative stress generated during long aerobic exercise, with the minimum dose yet to be elucidated for physically active subjects. In this study, we performed a dose finding with re-esterified DHA in triglyceride form in a randomized double-blind parallel trial at different doses (350, 1050, 1750, and 2450 mg a day) for 4 weeks in males engaged in regular cycling (n = 100, 7.6 ± 3.7 h/week). The endogenous antioxidant capacity of DHA was quantified as a reduction in the levels of the oxidative stress marker 8-hydroxy-2′-deoxyguanosine (8-OHdG) recollected in 24-h urine samples after 90 min of constant load cycling before and after intervention. To ascertain incorporation of DHA, erythrocyte polyunsaturated fatty acid (PUFA) composition was compared along groups. We found a dose-dependent antioxidant capacity of DHA from 1050 mg with a trend to neutralization for the highest dose of 2450 mg (placebo: n = 13, F = 0.041; 350 mg: n = 10, F = 0.268; 1050 mg: n = 11, F = 7.112; 1750 mg: n = 12, F = 9.681; 2450 mg: n = 10, F = 15.230). In the erythrocyte membrane, the re-esterified DHA increased DHA and omega-3 percentage and decreased omega 6 and the omega-6 to omega-3 ratio, while Eicosapentaenoic acid (EPA) and PUFA remained unchanged. Supplementation of re-esterified DHA exerts a dose-dependent endogenous antioxidant property against moderate-intensity long-duration aerobic exercise in physically active subjects when provided at least 1050 mg a day for 4 weeks.

Polyunsaturated fatty acids in fish tissues more closely resemble algal than terrestrial diet sources

The River Continuum Concept implies that consumers in headwater streams have greater dietary access to terrestrial basal resources, but recent studies have highlighted the dietary importance of high-quality algae. Algae provide consumers with physiologically important omega-3 (n-3) polyunsaturated fatty acids (PUFA), particularly eicosapentaenoic acid (EPA). However, terrestrial plants and most benthic stream algae lack the long-chain (LC) n-3 PUFA docosahexaenoic acid (DHA, 22:6n-3), which is essential for neural development in fish and other vertebrates. We sampled subalpine streams to investigate how the PUFA composition of neural (brain and eyes), muscle, and liver tissues of freshwater fish is related to their potential diets (macroinvertebrates, epilithon, fresh and conditioned terrestrial leaves). The PUFA composition of consumers was more similar to epilithon than to terrestrial leaves. Storage lipids of eyes most closely resembled dietary PUFA (aquatic invertebrates and algae). However, DHA and arachidonic acid (ARA, 20:4n-6) were not directly available in the diet but abundant in organs. This implies that algal PUFA were selectively retained or were produced internally via enzymatic PUFA conversion by aquatic consumers. This field study demonstrates the nutritional importance of algal PUFA for neural organs in aquatic consumers of headwater regions.

Dietary phytanic acid-induced changes in tissue fatty acid profiles in mice.

The aims of this research communication were to investigate the in vivo tissue accumulation of phytanic acid (PA) and any changes in the tissue fatty acid profiles in mice. Previous in vitro studies have demonstrated that PA is a milk component with the potential to cause both beneficial effects on lipid and glucose metabolism and detrimental effects on neuronal cells. However, there is limited information about its in vivo actions. In this study, mice were fed diets containing either 0.00 or 0.05% 3RS, 7R, 11R-PA, which is the isomer found in milk and the human body. After 4 weeks, adipose tissue, liver and brain were harvested and their fatty acid profiles were determined by gas chromatographic analysis. The results showed that PA and its metabolite pristanic acid accumulated in the adipose tissue of PA-fed mice, and that dietary PA decreased the hepatic compositions of several saturated fatty acids such as palmitic acid while increasing the compositions of polyunsaturated fatty acids including linoleic acid and docosahexaenoic acid. However, dietary PA neither accumulated nor had a high impact on the fatty acid profile in the brain. These results suggested that dietary PA could exert its biological activities in adipose tissue and liver, although the brain is relatively less affected by dietary PA. These data provide a basis for understanding the in vivo physiological actions of PA.

Effects of a 6-month dietary-induced weight loss on erythrocyte membrane omega-3 fatty acids and hepatic status of subjects with nonalcoholic fatty liver disease: The Fatty Liver in Obesity study

Omega-3 polyunsaturated fatty acids (PUFAs) have been suggested as important biomolecules in the management of nonalcoholic fatty liver disease (NAFLD). This study aimed to evaluate the effect of 6-month weight loss diets on erythrocyte membrane omega-3 PUFA composition of NAFLD adults, and to evaluate the potential relationship between erythrocyte membrane omega-3 PUFAs and hepatic health markers. In this secondary analysis of the Fatty Liver in Obesity study, erythrocyte membranes were analyzed by gas chromatography in 54 subjects with liver steatosis detected by ultrasonography who achieved a weight loss >5% after the follow-up. Baseline and 6-month evaluation included hepatic acoustic radiation force impulse elastography and magnetic resonance imaging, anthropometry, body composition, and biochemical determinations. After the follow-up, α-linolenic acid (ALA) proportion significantly increased in erythrocyte membranes, whereas eicosapentaenoic acid (EPA) showed no statistical difference and docosapentaenoic acid decreased. Both the changes in erythrocyte membrane ALA and EPA were positively associated with dietary ALA. Regression analyses evidenced that the changes in erythrocyte membrane ALA and EPA were inversely associated with the changes in liver stiffness and liver iron content, respectively. The adherence to weight loss strategies for 6months led to changes in erythrocyte membrane omega-3 PUFA composition, which in turn were associated with changes in hepatic markers, suggesting that these fatty acids accompany the improvements in the liver during a dietary treatment. These findings show that beyond weight loss, the composition of the diet has an important role in the management of NAFLD.

Hepatic Levels of DHA-Containing Phospholipids Instruct SREBP1-Mediated Synthesis and Systemic Delivery of Polyunsaturated Fatty Acids.

SummaryPolyunsaturated fatty acids (PUFAs), such as docosahexaenoic acid (DHA) and arachidonic acid (ARA), play fundamental roles in mammalian physiology. Although PUFA imbalance causes various disorders, mechanisms of the regulation of their systemic levels are poorly understood. Here, we report that hepatic DHA-containing phospholipids (DHA-PLs) determine the systemic levels of PUFAs through the SREBP1-mediated transcriptional program. We demonstrated that liver-specific deletion of Agpat3 leads to a decrease of DHA-PLs and a compensatory increase of ARA-PLs not only in the liver but also in other tissues including the brain. Together with recent findings that plasma lysophosphatidylcholine (lysoPC) is the major source of brain DHA, our results indicate that hepatic AGPAT3 contributes to brain DHA accumulation by supplying DHA-PLs as precursors of DHA-lysoPC. Furthermore, dietary fish oil-mediated suppression of hepatic PUFA biosynthetic program was blunted in liver-specific Agpat3 deletion. Our findings highlight the central role of hepatic DHA-PLs as the molecular rheostat for systemic homeostasis of PUFAs.

Alteration of Serum Phospholipid n-6 Polyunsaturated Fatty Acid Compositions in Nonalcoholic Fatty Liver Disease in the Japanese Population: A Cross-Sectional Study.

We performed a cross-sectional study on 215 Japanese employees aged 20-68 years to investigate the association between NAFLD and serum phospholipid fatty acid composition. NAFLD was diagnosed by ultrasonography. The fatty acid composition between the control and NAFLD groups was compared, and the inverse probability of treatment weighting (IPTW) was performed to eliminate each confounding effect of sex, smoking status, BMI, insulin resistance, dietary cholesterol, and salt intake. A receiver operating characteristic (ROC) curve analysis was performed to evaluate the NAFLD prediction accuracy of fatty acids. Seventy-one subjects were diagnosed with NAFLD. Their serum phospholipid dihomo-γ-linolenic acid (DGLA) level was significantly higher after adjusting for each variable using IPTW. In the ROC analysis, the ratio of ARA to DGLA had an area under the curve (AUC) of 0.763. By combining the ratio of ARA to DGLA with the ratio of AST to ALT, AUC increased to 0.871. In conclusion, NAFLD subjects in a Japanese working population have higher serum phospholipid DGLA. Results of the IPTW and ROC analysis indicated that serum PL DGLA and the ratio of ARA to DGLA provide diagnosis information on the fatty liver that is different to AST and ALT and improve the accuracy of fatty liver prediction, owning potential value as serum biomarkers.

Genetic variants in FADS1 and ELOVL2 increase level of arachidonic acid and the risk of Alzheimer's disease in the Tunisian population

Polyunsaturated fatty acids (PUFAs) are closely related to various physiological conditions. In several age-related diseases including Alzheimer's disease (AD) altered PUFAs metabolism has been reported. However, the mechanism behind PUFAs impairment and AD developpement remains unclear. In humans, PUFAs biosynthesis requires delta-5 desaturase (D5D), delta-6 desaturase (D6D) and elongase 2 activities; which are encoded by fatty acid desaturase 1 (FADS1), fatty acid desaturase 2 (FADS2), and elongation of very-long-chain fatty acids-like 2 (ELOVL2) genes, respectively. In the present work, we aim to assess whether genetic variants in FADS1, FADS2 and ELOVL2 genes influence plasma and erythrocyte PUFA composition and AD risk. A case-control study was carried out in 113 AD patients and 161 healthy controls.Rs174556, rs174617, and rs3756963 of FADS1, FADS2, and ELOVL2 genes, respectively were genotyped using PCR-RFLP. PUFA levels were quantified using Gas Chromatography. Genotype distributions of rs174556 (FADS1) and rs3756963 (ELOVL2) were different between case and control groups. The genotype TT of rs174556 and rs3756963 single nucleotide polymorphism (SNP) increases significantly the risk of AD in our population. PUFA analysis showed higher plasma and erythrocyte arachidonic acid (AA) level in patients with AD, whereas only plasma docosahexaenoic acid (DHA) was significantly decreased in AD patients. The indexes AA/Dihomo-gamma-linolenic acid (DGLA) and C24:4n-6/Adrenic acid (AdA) were both higher in the AD group. Interestingly, patients with TT genotype of rs174556 presented higher AA level and AA/DGLA index in both plasma and erythrocyte. In addition, higher AA and AA/DGLA index were observed in erythrocyte of TT genotype ofrs3756963 carrier's patients. Along with, positive correlation between AA/DGLA index, age or Gamma-linolenic acid (GLA)/ Linoleic acid (LA) index was seen in erythrocyte and /or plasma of AD patients. After adjustment for confounding factors, the genotype TT of rs174556, erythrocyte AA and AA/DGLA index were found to be predictive risk factors for AD while plasma DHA was found associated with lower AD risk. Both rs174556 and rs3756963 influence AD risk in the Tunisian population and they are likely associated with high AA level. The combination of the two variants increases further the susceptibility to AD. We suggest that FADS1 and ELOVL2 variants could likely regulate the efficiency of AA biosynthesis which could be at the origin of inflammatory derivate.

Performance of the African edible bush‐cricket, Ruspolia differens, on single and mixed diets containing inflorescences of their host plant species

AbstractThe African edible bush‐cricket, Ruspolia differens (Serville) (Orthoptera: Tettigoniidae), is an economically valuable insect in sub‐Saharan Africa. For its mass‐rearing, suitable diets that can sustain its performance need to be identified. This study aimed at finding inflorescence diets of 10 host plant species and their mixtures that result in the highest R. differens production. We reared newly hatched nymphs to adults on inflorescences of single host species, and also on a gradient of five diversifying dietary mixtures consisting of one and mixtures of two, three, five, and seven host plant species. For the single host‐plant diets, the developmental time was shortest on Pennisetum purpureum, Chloris gayana, and Brachiaria ruziziensis (approximately 63 days), whereas the fresh weight was highest on B. ruziziensis and P. purpureum (approximately 0.383 g). Survival was highest (&gt;65%) on C. gayana, P. purpureum, B. ruziziensis, Setaria sphacelata, and Sporobolus pyramidalis, and lowest on Panicum maximum, Hyparrhenia rufa, Cynodon dactylon, and Paspalum scrobiculatum (&lt;40%). With respect to diet mixtures, the developmental time was significantly shorter (on average 16 days shorter), and survival was higher, in the most diversified diets compared to the least diversified diets. The contents of polyunsaturated fatty acids and fatty acid composition did not differ significantly among the diets. However, the content of monounsaturated fatty acids differed significantly among the diets and there was a significant diet*sex interaction. From the applied point of view, based on our results, for maximal weight and survival plus fast development, we recommend rearing on P. purpureum, C. gayana, B. ruziziensis, and S. sphacelata, and on dietary mixtures of inflorescences. These findings are important in designing large‐scale rearing programs for this species.

Aryl Hydrocarbon Receptor-Dependent inductions of omega-3 and omega-6 polyunsaturated fatty acid metabolism act inversely on tumor progression

The Western diet contains a high ratio of omega-6 (ω6) to omega-3 (ω3) polyunsaturated fatty acids (PUFA). The prototypical aryl hydrocarbon receptor (AHR) ligand, 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), induces CYP1 family enzymes, which can metabolize PUFA to epoxides. Mice fed ω3-rich or ω6-rich diets were treated with TCDD and injected subcutaneously with AHR-competent Hepa1-GFP hepatoma cells or AHR-deficient LLC lung cancer cells. TCDD reduced the growth rates of the resulting tumors in ω3-fed mice and inhibited their metastasis to the liver and/or lung, but had the opposite effects in mice fed ω6 PUFA. These responses were likely attributable to the corresponding PUFA epoxides generated in tumor cells and/or host, since many depended upon co-administration of a soluble epoxide hydrolase (EPHX2) inhibitor in males, and/or were associated with increases in epoxide levels in tumors and sites of metastasis. Equivalent effects occurred in females in the absence of EPHX2 inhibition, probably because this sex expressed reduced levels of EPHX2. The responses elicited by TCDD were associated with effects on tumor vascularity, tumor cell proliferation and/or apoptosis. Thus environmental AHR agonists, and potentially also endogenous, nutritional, and microbiome-derived agonists, may reduce or enhance cancer progression depending on the composition of dietary PUFA, particularly in females.

Polyunsaturated fatty acids-enriched lipid from reduced sugar alcohol mannitol by marine yeast Rhodosporidiobolus fluvialis Y2

Brown macroalgae is a promising marine biomass for the production of bioethanol and biodiesel fuels. Here we investigate the biochemical processes used by marine oleaginous yeast for assimilating the major carbohydrate found in brown macroalgae. Briefly, yeast Rhodosporidiobolus fluvialis strain Y2 was isolated from seawater and grown in minimal medium containing reduced sugar alcohol mannitol as the sole carbon source with a salinity comparable to seawater. Conditions limiting nitrogen were used to facilitate lipid synthesis. R. fluvialis Y2 yielded 55.1% (w/w) and 39.1% (w/w) of lipids, per dry cell weight, from mannitol in the absence and presence of salinity, respectively. Furthermore, mannitol, as a sugar source, led to an increase in the composition of polyunsaturated fatty acids, linoleic acid (C18:2) and linolenic acid (C18:3), compared to glucose. This suggests that oxidation of mannitol leads to the activation of NADH-dependent fatty acid desaturases in R. fluvialis Y2. Such fatty acid composition may contribute to the cold-flow properties of biodiesel fuels. Our results identified a salt-tolerant oleaginous yeast species with unique metabolic traits, demonstrating a key role as a decomposer in the global carbon cycle through marine ecosystems. This is the first study on mannitol-induced synthesis of lipids enriched with polyunsaturated fatty acids by marine yeast.

Spleen Oxylipin and Polyunsaturated Fatty Acid Profiles are Altered by Dietary Source of Polyunsaturated Fatty Acid and by Sex.

As the largest secondary lymphoid organ, the spleen plays an important role in immune responses. The role of arachidonic acid (ARA) and its 20-carbon eicosanoids in modulating immune function has long been of interest. However, recent advances have enabled the identification of numerous other n-6 and n-3 polyunsaturated fatty acid (PUFA)-derived oxylipins. Here, we investigate the effects of diet and sex on the spleen nonesterified oxylipin profiles and phospholipid and neutral lipid PUFA composition in Sprague-Dawley rats supplemented with oils rich in α-linolenic acid (ALA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), or linoleic acid. Dietary ALA, EPA, and DHA resulted in lower levels of ARA and ARA oxylipins. Oxylipins derived from other n-6 PUFA were also reduced despite no or opposite effect on their PUFA levels. Each diet also resulted in higher levels of oxylipins almost exclusively derived from the supplemented PUFA, despite PUFA in the same biosynthetic pathway also often being increased. Further, while oxylipin differences often reflected changes to phospholipid PUFA, there were instances where they corresponded more closely to changes in neutral lipid PUFA. With respect to sex effects, >50% of lipoxygenase ARA-derived oxylipins were higher in males in at least one diet group, while multiple DHA oxylipins were lower in males only in rats provided the DHA diet. This fundamental description of oxylipin composition in the spleen, including the influence of diet and sex and the relationship to PUFA composition, will help inform future studies examining the functions of these oxylipins under physiological and pathological conditions.

The relationship between acrosome reaction and polyunsaturated fatty acid composition in boar sperm.

This study investigated the relationship between acrosome reactions and fatty acid composition with respect to fertility in boar sperm. The acrosome reaction was induced more than 85% by 60mM methyl-beta-cyclodextrin (MBCD), and plasma membrane integrity was significantly reduced dependent on the MBCD level in boar sperm (p<.05). The acrosome-reacted sperm exhibited significantly higher saturated fatty acids (SFAs) and lower polyunsaturated fatty acids (PUFAs) composition compared to the non-acrosome reaction group (p<.0001). In addition, the PUFAs, C22:5n-6 (docosapentaenoic acid [DPA]; p<.01) and C22:6n-3 (docosahexaenoic acid [DHA]; p<.0001) were significantly decreased, and cleavage and blastocyst formation of oocytes were significantly (p<.0001) decreased in acrosome-reacted sperm relative to non-acrosome-reacted sperm. Moreover, acrosome reaction was positively correlated with SFAs, whereas negatively correlated with PUFAs, of the PUFAs, the DPA (p=.0005) and DHA (p=<.0001) were negatively correlated with the acrosome reaction. Therefore, these results suggest that the PUFAs composition of sperm is closely involved in acrosome reaction in pigs.

Polyunsaturated Fatty Acid Composition of Cerebrospinal Fluid Fractions Shows Their Contribution to Cognitive Resilience of a Pre-symptomatic Alzheimer's Disease Cohort.

Alzheimer’s disease (AD) pathology is characterized by an early and prolonged decrease in the amyloid peptide (Aβ) levels concomitant with a later increase in phospho-tau concentrations in cerebrospinal fluid (CSF). We propose that changes in lipid metabolism can contribute to the abnormal processing of Aβ42 in AD. Our aim was to determine if polyunsaturated fatty acid (PUFA) metabolism can differentiate pre-symptomatic AD from normal aging and symptomatic AD. Using neuropsychology measures and Aβ42/T-tau in cerebrospinal fluid (CSF), we classify three groups of elderly study participants: cognitively healthy with normal Aβ42/T-tau (CH-NAT), cognitively healthy with pathological Aβ42/T-tau (CH-PAT), and AD individuals. We determined the size distribution and the concentration of CSF particles using light scattering and quantified PUFA composition in the nanoparticulate (NP) fraction, supernatant fluid (SF), and unesterified PUFA levels using gas chromatography combined with mass spectrometry. Four PUFAs (C20:2n-6, C20:3n-3, C22:4n-6, C22:5n-3) were enriched in NP of AD compared with CH-NAT. C20:3n-3 levels were higher in the NP fraction from AD compared with CH-PAT. When normalized to the number of NPs in CSF, PUFA levels were significantly higher in CH-NAT and CH-PAT compared with AD. In the SF fractions, only the levels of docosahexaenoic acid (DHA, C22:6n-3) differentiated all three clinical groups. Unesterified DHA was also higher in CH-NAT compared with the other clinical groups. Our studies also show that NP PUFAs in CH participants negatively correlate with CSF Aβ42 while C20:4n-6, DHA, and n-3 PUFAs in the SF fraction positively correlate with T-tau. The profile of PUFAs in different CSF fractions that correlate with Aβ42 or with T-tau are different for CH-NAT compared with CH-PAT. These studies show that PUFA metabolism is associated with amyloid and tau processing. Importantly, higher PUFA levels in the cognitively healthy study participants with abnormal Aβ42/T-tau suggest that PUFA enhances the cognitive resilience of the pre-symptomatic AD population. We propose that interventions that prevent PUFA depletion in the brain may prevent AD pathology by stabilizing Aβ42 and tau metabolism. Further studies to determine changes in PUFA composition during the progression from pre-symptomatic to AD should reveal novel biomarkers and potential preventive approaches.