Important Polyunsaturated Fatty Acids Research Articles

A Narrative Review of the Published Pre-Clinical Evaluations: Multiple Effects of Arachidonic Acid, its Metabolic Enzymes and Metabolites in Epilepsy.

Arachidonic acid (AA), an important polyunsaturated fatty acid in the brain, is hydrolyzed by a direct action of phospholipase A2(PLA2) or through the combined action of phospholipase C and diacylglycerol lipase, and released into the cytoplasm. Various derivatives of AA can be synthesized mainly through the cyclooxygenase (COX), lipoxygenase (LOX) and cytochrome P450 (P450) enzyme pathways. AA and its metabolic enzymes and metabolites play important roles in a variety of neurophysiological activities. The abnormal metabolites and their catalytic enzymes in the AA cascade are related to the pathogenesis of various central nervous system (CNS) diseases, including epilepsy. Here, we systematically reviewed literatures in PubMed about the latest randomized controlled trials, animal studies and clinical studies concerning the known features of AA, its metabolic enzymes and metabolites, and their roles in epilepsy. The exclusion criteria include non-original studies and articles not in English.

Fermented Products Enriched with Polyunsaturated Fatty Acids in Broiler Chicken Nutrition and Fat Quality of Produced Meat

Broiler chicken meat is the preferred meat among the human population. Broiler meat contains high-quality protein and a low-fat content, alongside a desirable fatty acid profile. A frequent problem in human nutrition is an insufficient PUFA intake in the diet. One possible strategy to increase the dietary intake of polyunsaturated fatty acids (PUFA) in humans is to produce, and thereby enrich, broiler chicken meat with sufficient amounts of essential PUFA. A method to increase the proportion of essential fatty acids in chicken meat is by changing the fatty acid composition of the feed. Feed production via solid-state fermentation using lower filamentous fungi can be used to prepare valuable feed from cereal by-products enriched with important PUFA and pigments and can thus be included as a suitable feed ingredient in the diet of chickens. From previously published studies, it can be concluded that the application of 3–10% of the prepared fermented products to the diet of broiler chickens increased the proportion of essential fatty acids in the fat of the chicken meat and had a beneficial effect on the growth parameters of chickens.

Trophic stability and change across a sea ice cover gradient on the western Antarctic Peninsula

The western Antarctic Peninsula (AP) is experiencing significant changes to sea ice cover, altering the macroalgal cover and potentially affecting the foundation of benthic food webs. We used fatty acid signatures as dietary and physiological trophic biomarkers to test the hypothesis that a gradient of 36-88% mean annual ice cover would affect the trophic ecology of fleshy macroalgae and diverse benthic invertebrate consumers along the western AP. We used SCUBA to collect organisms from benthic rocky nearshore habitats, 5-35 m depth, at 15 study sites during April-May of 2019. There were no consistent ecosystem-scale differences in the nutritionally important polyunsaturated fatty acids or other univariate fatty acid summary categories in either the seaweeds or invertebrates across the ice gradient, but we did find site-level differences in the multivariate fatty acid signatures of all seaweeds and invertebrates. Ice cover was a significant driver of the fatty acid signatures of 5 invertebrates, including 3 sessile (an anemone, a sponge, and a tunicate) and 2 mobile consumers (a sea star and a sea urchin). The multivariate fatty acid signatures of 2 other sea stars and a limpet were not affected by the ice gradient. These results indicate that the trophic ecology and resource assimilation of sessile consumers that are more connected to the macroalgal-derived food web will be more sensitive than mobile consumers to impending changes to annual ice and macroalgal cover along the western AP.

Iodine values, peroxide values and acid values of Bohai algae oil compared with other oils during the cooking

ObjectiveBohai algae oil contains polyunsaturated fatty acids, such as EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), which are the very important polyunsaturated fatty acids for the human body. In Traditional Chinese Cooking, all cooking methods cannot do without oils. However, the heat of cooking may always lead to formation of large amounts of decomposition products that affect the sensory, nutritional and functional quality of the oils to be unhealthy and the products being cooked, especially the food or edible oil rich in polyunsaturated fatty acids. Therefore, the objective of this study was to research the effect and change of heating on the quality characteristics of Bohai algae oil comparison with soybean oil and olive oil. MethodQuality characteristics such as the iodine values (IVs), peroxide values (POVs) and acid values (AVs) of Bohai algae oil, soybean oil and olive oil were measured, cooking conditions as factors of the study. ResultThe POVs percentage changes of Bohai algae oil were larger than the IVs and AVs percentage changes. Bohai algae oil was better heated in a microwave oven at microwave P-20 within 3min, microwave P-60 and P–H1 within 2min, or in induction cooker at 1500w within 1min, or on electric stove (direct heated) within 2min. ConclusionBohai algae oil was suitable used for low-temperature and short-time cooking or for salad. This study has important significance for promoting the commercial value and extensive application of Bohai algae oil in daily cooking. It plays a theoretical significance role in Bohai algae oil's better processing and traditional chinese cooking. It can improve product quality to further expand the food processing research scope of Bohai algae oil and increase the richness, diversity and universality of edible methods of Bohai algae oil.

Investigation of Phospholipid Differences in Valproic Acid-Induced Autistic Mouse Model Brain Using Mass Spectrometry Imaging

Autism is a neurodevelopmental disorder for which the cause and treatment have yet not been determined. The polyunsaturated fatty acid (PUFA) levels change rapidly in the blood or cerebrospinal fluid of autistic children and PUFAs are closely related to autism spectrum disorder (ASD). This finding suggests that changes in lipid metabolism are associated with ASD and result in an altered distribution of phospholipids in cell membranes. To further understand ASD, it is necessary to analyze phospholipids in organs consisting of nerve cells, such as the brain. In this study, we investigated the phospholipid distribution in the brain tissue of valproic acid-induced autistic mice using matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI). Phospholipids including phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine were identified in each brain region and exhibited differences between the ASD and control groups. These phospholipids contain docosahexaenoic acid and arachidonic acid, which are important PUFAs for cell signaling and brain growth. We expect that the differences in phospholipids identified in the brain tissue of the ASD model with MALDI-MSI, in conjunction with conventional biological fluid analysis, will help to better understand changes in lipid metabolism in ASD.

Metal Exposure and Sex Shape the Fatty Acid Profile of Midges and Reduce the Aquatic Subsidy to Terrestrial Food Webs.

Aquatic micropollutants can be transported to terrestrial systems and their consumers by emergent aquatic insects. However, micropollutants, such as metals, may also affect the flux of physiologically important polyunsaturated fatty acids (PUFAs). As certain PUFAs have been linked to physiological fitness and breeding success of terrestrial consumers, reduced fluxes from aquatic systems could affect terrestrial populations and food webs. We chronically exposed larvae of the aquatic insect Chironomus riparius to a range of environmentally relevant sediment contents of cadmium (Cd) or copper (Cu) in a 28-day microcosm study. Since elevated water temperatures can enhance metals' toxic effects, we used two temperature regimes, control and periodically elevated temperatures (heat waves) reflecting an aspect of climate change. Cd and Cu significantly reduced adult emergence by up to 95% and 45%, respectively, while elevated temperatures had negligible effects. Both metal contents were strongly reduced (∼90%) during metamorphosis. Furthermore, the chironomid FA profile was significantly altered during metamorphosis with the factors sex and metal exposure being relevant predictors. Consequently, fluxes of physiologically important PUFAs by emergent adults were reduced by up to ∼80%. Our results suggest that considering fluxes of physiologically important compounds, such as PUFAs, by emergent aquatic insects is important to understand the implications of aquatic micropollutants on aquatic-terrestrial meta-ecosystems.

Elemental composition, total fatty acids, soluble sugar content and essential oils of flowers and leaves of Moringa oleifera cultivated in Southern Portugal

The evaluation of the elemental content of moringa leaves and flowers by Energy Dispersive X-Ray Fluorescence Spectrometry revealed that the leaves are a good source of some macro (Ca and K) and micronutrients (Mn) beyond the presence of important polyunsaturated fatty acids (PUFAs), essential in human nutrition. Total soluble sugars prevail in the flowers which may be linked to insect attraction and the pollination process. M. oleifera leaves, flowers and seeds essential oils (EOs) were isolated by hydrodistillation. Gas chromatography and gas chromatography-mass spectrometry analysis (GC-MS) showed EOs dominated by alkanes and fatty acids in diverse ratios in the analyzed plant parts. The nutritional characterization of M. oleifera cultivated in Portugal showed some important nutrients to human physiology. Further studies will allow determining if its consumption may overcome the nutritional imbalances of daily modern households, preventing the emergence of hypertension and diabetes.

Investigation of the Role of PUFA Metabolism in Breast Cancer Using a Rank-Based Random Forest Algorithm.

Simple SummaryPolyunsaturated fatty acids (PUFAs) and their derivatives, oxylipins, are a constant focus of cancer research due to the relationship between cancer and processes of energy metabolism and inflammation, where a PUFA system is an active player. Only recently have methods been developed that allow for studying such complex systems. Using the Rank-based Random Forest (RF) model, we show that PUFA metabolism genes are critical for the pathogenesis of breast cancer (BC); BC subtypes differ in PUFA metabolism gene expression. The enrichment of BC subtypes with various genes associated with oxylipin signaling pathways indicates a different contribution of these compounds to the biology of subtypes.Polyunsaturated fatty acid (PUFA) metabolism is currently a focus in cancer research due to PUFAs functioning as structural components of the membrane matrix, as fuel sources for energy production, and as sources of secondary messengers, so called oxylipins, important players of inflammatory processes. Although breast cancer (BC) is the leading cause of cancer death among women worldwide, no systematic study of PUFA metabolism as a system of interrelated processes in this disease has been carried out. Here, we implemented a Boruta-based feature selection algorithm to determine the list of most important PUFA metabolism genes altered in breast cancer tissues compared with in normal tissues. A rank-based Random Forest (RF) model was built on the selected gene list (33 genes) and applied to predict the cancer phenotype to ascertain the PUFA genes involved in cancerogenesis. It showed high-performance of dichotomic classification (balanced accuracy of 0.94, ROC AUC 0.99) We also retrieved a list of the important PUFA genes (46 genes) that differed between molecular subtypes at the level of breast cancer molecular subtypes. The balanced accuracy of the classification model built on the specified genes was 0.82, while the ROC AUC for the sensitivity analysis was 0.85. Specific patterns of PUFA metabolic changes were obtained for each molecular subtype of breast cancer. These results show evidence that (1) PUFA metabolism genes are critical for the pathogenesis of breast cancer; (2) BC subtypes differ in PUFA metabolism genes expression; and (3) the lists of genes selected in the models are enriched with genes involved in the metabolism of signaling lipids.

Novel UV-Releaser of Arachidonic Acid Based on Nitrophenyl-type Photoremovable Protecting Group

Arachidonic acid (AA) is one of the most important polyunsaturated fatty acids. It is the precursor to a wide range of eicosanoids, which are involved in many signaling cascades in the body. The conversion of arachidonic acid to eicosanoids starts with its liberation from membrane phospholipids by a dedicated enzyme. Here we present photolabile “caged” analog of AA, capable of liberation of the free acid under ultraviolet (UV) light with ~340–365 nm wavelength. This can be used in cell culture studies to mimic the first step in the biosynthesis of eicosanoids. We directly confirm the production of AA using high-performance liquid chromatography (HPLC). Furthermore, we found that novel compound yields 4-times more AA in comparison with previously published alternative. Our results demonstrate that the use of the caged compounds can be used to control the release of AA with UV light. The described caged analogs of AA are likely to be anchored in the membrane and enable light-triggered liberation of the free acid to the cytoplasm. This would be superior to the usual approach using the external addition of AA to cells, which suffers from poor solubility of the acid in culture medium and uncontrolled passage through membrane .

Analysis of Fatty Acids of Some Hyoscyamus, Datura, and Atropa Species from Azerbaijan.

Datura stramonium L., D. stramonium var. tatula (L.) Torr., Hyoscyamus reticulatus L., H. niger L., and Atropa caucasica Kreyer naturally found in Azerbaijan and their seeds possess 17-35% of oils. This study aims to evaluate and determine fatty acids of these plants special to Azerbaijan climate and geography. The presented study is the first to research into fatty acids of A. caucasica, which is an endemic species of Caucasus. Fatty acid seed oils were derivatized to methyl esters and analyzed by gas chromatography equipped with a flame ionization detector, compared with a standard mixture of 37 fatty acid methyl esters. Linoleic (55-79%), oleic (11-26%), palmitic (4-12%), and stearic (2-3%) acids compose 97% of total fatty acids. Other minor compounds, including two trans-fatty acids, were determined in the samples. Significantly high concentration of a medicinally important polyunsaturated fatty acid, e.g. linoleic acid, was observed in all samples. The results of this study showed that these oils are particularly valuable sources of linoleic and oleic acids, which have beneficial effects on cardiovascular diseases and are important compounds for the pharmaceutical and cosmetic industries in the manufacture of liposomes, nano- and microemulsions, soaps, etc.

DETERMINATION OF THE CONTENT OF FATTY ACIDSIN FLAX SEEDS

This article presents studies on the fatty acid composition of flax seeds grown in the Republic of Kazakhstan.Omega-3 fatty acids are involved in the construction of cells in many tissues of our body. Their positive impact on human health is very great. Polyunsaturated fatty acids are precursors of local hormones of cellular regulation, which influence the processes of inflammation, immunoregulation, regulation of blood flow, etc. The most important polyunsaturated fatty acids are eicosapentaenoic (EPA), docosahexaenoic (DHA), arachidonic (AA). They are synthesized in the human body from linolenic and linoleic acids, which are rich in vegetable oils. But since the human body produces a small amount of eicosapentaenoic and docosagensaenoic acids, it is important to get them with food in the required amount.We have studied the ratio of Omega-6 to Omega-3 in flax seeds. Proportions are just as important as the origin (animal, vegetable) or the quality of fats. As we know, with an imbalance, that is, an excessive intake of Omega-6 into the human body, substances begin to compete for desaturase enzymes. As a result of a study to determine the content of fatty acid in flax seeds, it was found that the content of Omega-3 in the test sample is 68% higher than Omega-6, which indicates the usefulness of using flax seeds in the food industry.

Effects of Structural and Compositional Changes of Nanochloropsis oceania after Enzyme Treatment on EPA-Rich Lipids Extraction.

Improved methods for the extraction of eicosapentaenoic acid (EPA), an essential and economically important polyunsaturated fatty acid, are urgently required. However, lipid extraction rates using food-grade solvents such as ethanol are usually low. To improve the ethanol-based extraction rate, and to elucidate the relevant mechanisms, we used cellulase and laccase to treat powdered Nannochloropsis, one of the most promising microalgal sources of EPA. Cellulase and laccase synergistically increased lipid yields by 69.31% and lipid EPA content by 42.63%, by degrading the amorphous hemicellulose and cellulose, improving crystallinity, and promoting the release and extraction of lysodiacylglyceryltrimethylhomoserine. Scanning electron microscopy showed that cell morphology was substantially altered, with cell-wall rupture, loss of cell boundaries, and the release of intracellular substances. In conclusion, Nannochloropsis lipid yields may be directly linked to cell-wall hemicellulose structure, and enzymatic treatment to alter this may improve lipid yields.

Effect of Sea Salt and Taro Waste on Fungal Mortierella alpina Cultivation for Arachidonic Acid-Rich Lipid Production

Arachidonic acid (ARA), an important polyunsaturated fatty acid (PUFA), acts as a precursor for eicosanoid hormones, such as prostaglandins, leukotrienes and other biological substances in human and animal bodies. Mortierella alpina is considered to be a potential strain for ARA production. Using agricultural waste as a substrate for microbial fermentation could achieve biorefinery concepts, and sea water utilization of the cultivation process could help to conserve fresh water resources. The objectives of this study were to find a potential M. alpina strain for ARA production, to investigate the tolerance of salinity and to evaluate the feasibility of the taro waste hydrolysate for M. alpina cultivation. The result showed that M. alpina FU30797 had the highest lipid content (25.97%) and ARA ratio (34.60%) among three strains. Furthermore, there was no significant difference between 0 and 10 g/L of sea salt solution on the biomass concentration and lipid content of M. alpina FU30797. The acidic hydrolysate and enzymatic hydrolysate of taro peel waste (TPW) were both utilized as culture substrates by M. alpina FU30797; however, the substrate up-take rate and lipid content in the TPW enzymatic hydrolysate cultivation were 292.33 mg/L-h and 30.68%, respectively, which are higher than those in acidic hydrolysate cultivation, and the ARA ratio was 33.05% in the enzymatic hydrolysate cultivation. From fed-batch cultivation in the bioreactor, the lipid content and ARA ratio reached 36.97% and 46.04%, respectively. In summary, the results from this project could potentially provide useful information for developing the PUFA-ARA bioprocess by using M. alpina.

Lipid Indexes and Quality Evaluation of Omega-3 Rich Oil from the Waste of Japanese Spanish Mackerel Extracted by Supercritical CO2.

Japanese Spanish mackerel (JSM) (Scomberomorus niphonius) is a marine fish species containing health-beneficial polyunsaturated fatty acids (PUFAs). In the present study, the quality of JSM by-products oils extracted by supercritical CO2 (SC-CO2) and organic solvent extraction was compared in terms of physico-chemical properties of the oils. Eicosapentaenoic acid (EPA) is one of the important polyunsaturated fatty acids present in SC-CO2-extracted skin and muscle oil 5.81 ± 0.69% and 4.93 ± 0.06%, respectively. The amount of docosahexaenoic acid (DHA) in SC-CO2-extracted skin and muscle oil was 12.56 ± 0.38% and 15.01 ± 0.28%, respectively. EPA and DHA are considered as important PUFAs for the development of brain function and the prevention of coronary heart diseases. Extracted oils showed considerable antioxidant activity. In the obtained oils, atherogenic index (AI) values varied from 0.72 to 0.93 and thrombogenic index (TI) ranged from 0.75 to 0.92, which is considered an acceptable level. Fatty acid composition, bio potentiality, thermogravimetric, and vitamin D analysis showed that oils extracted from JSM by-products can be a good source of oil for application in food, pharmaceutical and cosmetic industries. Therefore, the present research revealed the potentiality of green valorisation of S. niphonius by-products as a possible sustainable approach for targeting the era of zero waste.

Isolation of oleaginous fungi from natural sources, and fatty acid profile of Cunninghamella echinulata

Oleaginous microorganisms accumulate 20% or more of their dry weight as lipid. In the present study, 247 fungal isolates were obtained from different types of soil, marine water, and food, and screened for their ability to accumulate considerable amounts of lipid. A primary screening with Nile red staining was followed by sulfo-phosphovanillin reaction. The most potent isolate was identified employing both morphological and molecular methods as the Zygomycetous fungus, Cunninghamella echinulata AUMC14396. The lipid of this fungus was extracted, transesterified, and analyzed via GC-MS to elucidate the fatty acid (FA) composition. The fatty acid profile revealed the presence of various fatty acids with different concentrations. Of the total fatty acids, saturated FAs comprised 44.49%, while monounsaturated FAs were 19.91%, and polyunsaturated fatty acids (PUFAs) were 35.61%. The most predominant species was linoleic acid (13.79%) followed by stearic (12.78%) and oleic (12.50%) acids. The polyunsaturated fatty acid, gamma linolenic acid was present in a considerable amount (8.02%). Other important PUFAs were also found in the fatty acid profile such as arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid. The results of this study were discussed in respect to the important applications in the context of production of pharmaceuticals and nutraceuticals.

Assessment of Arabian Gulf Seaweeds from Kuwait as Sources of Nutritionally Important Polyunsaturated Fatty Acids (PUFAs).

The fatty acid (FA) compositions of ten seaweeds representative of Chlorophyta, Rhodophyta, and Ochrophyta from Kuwait in the Arabian Gulf region were determined and are discussed in the context of their potential nutritional perspectives for seaweed valorization. All the seaweeds had higher saturated fatty acid (SFA) and lower monounsaturated (MUFA) and polyunsaturated fatty acid (PUFA) contents than those typical of tropical environments. Palmitic, myristic, stearic, oleic, linoleic, α-linolenic, and stearidonic acids were the major FAs detected. Arachidonic, eicosapentaenoic, and docosahexaenoic acids were detected in minor amounts. Conserved fatty acid patterns revealed phylogenetic relationships among phyla, classes, and orders matching the molecular phylogenies at higher taxonomic ranks. Hierarchical clustering analyses clearly segregated different seaweeds (except Codium papillatum and Iyengaria stellata) into distinct groups based on their FA signatures. All but one species (Chondria sp.) had health-beneficial n6/n3 PUFAs (0.33:1–2.94:1) and atherogenic (0.80–2.52) and thrombogenic indices (0.61–5.17). However, low PUFA/SFA contents in most of the species (except Ulva spp.) may limit their utilization in the formulation of PUFA-rich functional foods. Ulva spp. had substantially high PUFAs with PUFA/SFA > 0.4, n6/n3 (0.33–0.66) and atherogenic (0.80–1.15) and thrombogenic indices (0.49–0.72), providing substantial potential for their utilization in food and feed applications.

Taxonomic composition and lake bathymetry influence fatty acid export via emergent insects

Abstract The ecological role of emergent aquatic insects from lakes in exporting dietary polyunsaturated fatty acids (PUFA) across the freshwater‐land interface is still poorly understood. In this field study, we explored the seasonal biomass export of emergent insects from three subalpine lakes and investigated how lipids of emergent insects were related to lake bathymetry, lipids of organic matter in lake sediments (i.e., basal resources), and the taxonomic composition of insects. The total lipid and PUFA fluxes of emergent insects were strongly related to taxonomy and lake bathymetry, but weakly associated with the PUFA content of the uppermost lake sediment layers. PUFA flux estimates of the dominant taxon, Chironomidae, from the shallowest lake (3 m depth; 125 g PUFA m−2 season−1) were considerably higher than those from the deepest lake (33 m depth; 56 g PUFA m−2 season−1), due to the higher per area biomass of emergent insects from this shallow lake. Insect taxonomy also affected the composition of PUFA transfer to land: Chironomidae were richer in ω‐6 PUFA, such as linoleic acid (18:2n‐6) and arachidonic acid (20:4n‐6), whereas Ephemeroptera and Trichoptera contained more ω‐3 PUFA, especially α‐linolenic acid (18:3n‐3) and eicosapentaenoic acid (20:5n‐3). Our findings suggest that taxon‐specific differences in PUFA content and lake bathymetry jointly shape PUFA fluxes and thus the provisioning of emergent insects as dietary sources of physiologically important PUFA for riparian consumers.

Warming Decreases Bioconversion of Polyunsaturated Fatty Acids in Chironomid Larvae Maintained on Cyanobacterium Microcystis.

Cyanobacteria dominance and warming have been suggested to decrease the production of polyunsaturated fatty acids (PUFA) in freshwater ecosystems. Physiological adaptations of poikilothermic animals to higher temperatures may further decrease PUFA levels in aquatic food webs. We conducted diet manipulation experiments to investigate the combined effects of dietary PUFA and warming on the proportions of eicosapentaenoic acid (EPA) and arachidonic acid (ARA) in Chironomus riparius. The experimental diet consisted of a nontoxic cyanobacterium Microcystis, which contained C20 PUFA: 20:3n-3, 20:4n-3, and 20:3n-6, but no EPA or ARA. Additionally, we used TetraMin® fish flakes as a control treatment. A temperature increase from 20 °C to 25 °C decreased the proportion of n-3 C20 PUFA and the n-3/n-6 ratio in Microcystis. Diet manipulation experiments indicated that Chironomus desaturated dietary C20 precursors to EPA and ARA, but warming decreased this bioconversion and resulted in lower levels of EPA and ARA in Chironomus. Warming did not alter the proportions of EPA and ARA in Chironomus larvae if these PUFA were readily available in the diet (TetraMin® control treatment). In conclusion, warming and cyanobacteria dominance may decrease the production and trophic transfer of physiologically important PUFA in freshwaters by (1) decreasing the n-3/n-6 ratio and the abundance of n-3 C20 precursors in Microcystis, and (2) decreasing the bioconversion of n-3 and n-6 C20 precursors to EPA and ARA in chironomids. These changes may have cascading effects throughout the food web and decrease the content of EPA in fish, potentially affecting its availability to humans.

Parasites and their freshwater snail hosts maintain their nutritional value for essential fatty acids despite altered algal diets.

Despite their ubiquity and considerable biomass, the roles played by parasites in aquatic food webs are still not well understood, especially those of their free-living infectious stages. For instance, cercariae, the motile larvae of parasitic flukes (trematodes) may be a key source of nutrients and energy for consumers. As cercariae clonally reproduce within the digestive-gonadal gland complex of gastropod intermediate hosts that acquire nutritionally important polyunsaturated fatty acids (PUFA) mainly from their diets (e.g., by grazing on primary producers), cercariae could transfer snail-derived PUFA if consumed. Through fatty acid (FA) analysis, we explored whether a change in the diet of parasitized hosts altered the FA profiles of both snail-only and trematode-containing snail tissue, thereby affecting their nutritional values. Freshwater snails (Stagnicola elodes) infected with Plagiorchis sp. were fed three different diets (cyanobacteria, green algae, and diatoms) that differed in nutritional quality with respect to FA profiles. While diet influenced the overall FA composition of both snail-only tissue and snail tissue containing trematodes, levels of certain PUFA (mainly omega-3) were largely unaffected. Trematode-containing snail tissue also generally contained more PUFA relative to snail-only tissue. Notably, both tissue types had far higher levels of PUFA than found in their diets. Our results suggest that freshwater snail hosts, and possibly their associated trematode parasites, could be trophic upgraders of key PUFA despite anthropogenically induced changes in algal communities that may lead to overall diminished PUFA contents. As such, cercariae-mediated trophic transfers of PUFA may play important roles in aquatic food webs.

Overconsumption of Omega-6 Polyunsaturated Fatty Acids (PUFAs) versus Deficiency of Omega-3 PUFAs in Modern-Day Diets: The Disturbing Factor for Their "Balanced Antagonistic Metabolic Functions" in the Human Body.

Polyunsaturated fatty acids (PUFAs) contain ≥2 double-bond desaturations within the acyl chain. Omega-3 (n-3) and Omega-6 (n-6) PUFAs are the two known important families in human health and nutrition. In both Omega families, many forms of PUFAs exist: α-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) from the n-3 family and linoleic acid (LA), dihomo-γ-linolenic acid (DGLA), and arachidonic acid (AA) from the n-6 family are the important PUFAs for human health. Omega-3 and Omega-6 PUFAs are competitively metabolized by the same set of desaturation, elongation, and oxygenase enzymes. The lipid mediators produced from their oxidative metabolism perform opposing (antagonistic) functions in the human body. Except for DGLA, n-6 PUFA-derived lipid mediators enhance inflammation, platelet aggregation, and vasoconstriction, while those of n-3 inhibit inflammation and platelet aggregation and enhance vasodilation. Overconsumption of n-6 PUFAs with low intake of n-3 PUFAs is highly associated with the pathogenesis of many modern diet-related chronic diseases. The volume of n-6 PUFAs is largely exceeding the volume of n-3PUFAs. The current n-6/n-3 ratio is 20-50/1. Due to higher ratios of n-6/n-3 in modern diets, larger quantities of LA- and AA-derived lipid mediators are produced, becoming the main causes of the formation of thrombus and atheroma, the allergic and inflammatory disorders, and the proliferation of cells, as well as the hyperactive endocannabinoid system. Therefore, in order to reduce all of these risks which are due to overconsumption of n-6 PUFAs, individuals are required to take both PUFAs in the highly recommended n-6/n-3 ratio which is 4-5/1.