Chain Polyunsaturated Fatty Acids Research Articles

Impact of Long-chain Polyunsaturated Fatty Acids on Hyperoxia-Induced Lung Injury in Neonatal Murine Model

ObjectivesReduced levels of long chain-polyunsaturated fatty acids (LCPUFAs) in preterm infants are associated with several neonatal morbidities, including bronchopulmonary dysplasia (BPD). We hypothesized that LCPUFA supplementation would attenuate hyperoxia-induced lung injury in a neonatal mouse model, and we tested our hypothesis in 40%O2-induced-lung injury in neonatal murine model. MethodsC57BL/6 WT dams were allowed to deliver naturally, and pups were randomized within 12 hours of birth to either hyperoxia (H, 40% O2) or room air (RA) for 10 days. To study the effect of LCPUFAs on hyperoxia-induced lung injury, the pups were randomized to the following groups: 1) RA (vehicle), 2) H (vehicle), 3) H + AA (120mg/kg/day), 4) H + DHA (60mg/kg/day), and 5) H + AA: DHA at 120mg/kg/day and 60mg/kg/day, respectively, maintaining a 2:1 ratio. Mice were gavage fed once daily 50 ul/g body weight from day 1–9. On day 10, the mice were sacrificed, and the lungs were removed for morphometric analyses. Mean Linear Intercept (MLI), Mean Septal Thickness (MST), and Radial Alveolar Count (RAC) were quantified and analyzed using R software and data was shown as mean ± SD. ResultsCompared to RA group, mice in hyperoxia groups showed a significant increase in MLI intercept (RA vs H = 47.75 ± 2.02 vs 56.24 ± 5.54, p < 0.01) and MST (RA vs H = 7.33 ± 0.45 vs 7.88 ± 0.70, p < 0.01), and a significant decrease in RAC (RA vs H = 12.93 ± 0.82 vs 10.26 ± 1, p < 0.01). Compared to H alone, AA: DHA resulted in a significant reduction in hyperoxia-induced MST (H vs H + AA: DHA = 8.70 ± 0.44 vs 6.94 ± 0.74, p < 0.001) and improved hyperoxia-induced reduction in RAC (H vs H + AA: DHA = 9.7 ± 0.9 vs 12.0 ± 1.4, p < 0.001). Noteworthy, while AA decreased hyperoxia-induced MST (H vs H + AA = 8.7 ± 0.4 vs 6.9 ± 0.6, p < 0.001), it significantly increased MLI (H vs H + AA = 58.76 ± 5.9 vs 71.19 ± 6.1, p < 0.001). ConclusionsWe reproduced lung injury in a neonatal murine model using 40% O2 and showed a significant increase in MLI, MST, and decreased RAC. The data also demonstrate that LCPUFAs acts distinctively, and specific fatty acids alone or in combination have contrasting effects. Whether the observed changes are also associated with the inflammatory response needs to be investigated further to better understand the impact of LCPUFAs in hyperoxia-induced lung injury and inflammation. Funding SourcesCharles H. and Judy H. Family Infant Health Research Program.

Differential Incorporation of Alpha-Linolenic Acid Into Phospholipid Classes in H4IIE Cells

Abstract Objectives Alpha-linolenic acid (ALA) is an essential fatty acid found in plant-based oils, with health benefits attributed to its metabolic conversion to very-long chain polyunsaturated fatty acids. Other routes of cellular ALA metabolism exist, but much of our knowledge of ALA metabolism stems from dated analytical techniques. Essential fatty acids are present in cells primarily as fatty acyls, glycerolipids, and glycerophospholipids, but finer details of ALA metabolism remain unexplored. The current study used unbiased metabolomics to profile the ALA metabolites produced in liver cells after treatment with ALA. Methods H4IIE hepatoma cells were incubated with or without 60 μM ALA for 0, 15, 30, 60, 120, 180, 260, 480, and 720 minutes. Samples were extracted and prepared for HPLC/LC-QTOF-MS analysis. MS data acquisitions were completed in both positive and negative modes. Data were analyzed with 2-way ANOVA (ALA and time as factors) followed by Bonferroni FWER corrections for multiple comparisons. Differences with p &amp;lt; 0.05 were considered significant. Results Among the metabolites detected, differences in patterns of ALA-containing phospholipids (PLs) were observed with ALA treatment. Consistent with a high proportion of phosphatidylcholine (PC) in mammalian cell membranes, ALA-containing PCs such as PC(18:3/18:3), PC(18:3/18:4), lysoPC(18:3/0:0), and PC(18:3/18:1) were significantly higher in ALA-treated cells at most time points. In addition, several phosphatidylethanolamine (PE) species with ALA were significantly higher in ALA-treated cells, including PE(18:3/18:3), PE(18:3/18:2), PE(18:3/16:0), PE(18:3/20:5), and PE(18:3/22:6). To a lesser degree, ALA was also found in phosphatidylserine (PS)(18:3/20:5), lysoPS(18:3/0:0), lysophosphatidylglycerol (18:3/0:0) and phosphatidic acid (PA)(18:3/18:2) and PA(18:3/22:6), suggesting that ALA incorporation into PLs is not limited to PC, contrary to the current known pathways of ALA metabolism. Conclusions Based on these results, there appears to be a preference for incorporation of ALA into PC and PE; however, ALA is also incorporated into PS, PG, and PA. Given the role of different PLs, and functionality based on their fatty acyl composition, future studies will explore the functional outcomes of ALA incorporation into different PL classes. Funding Sources NSERC Discovery Grant

Marine Bivalves as a Dietary Source of High-Quality Lipid: A Review with Special Reference to Natural n-3 Long Chain Polyunsaturated Fatty Acids

The most important nutritional feature of mollusks is their lipid composition. Marine bivalves are a good source of high quality lipid, mainly because they concentrate eicosapentaenoic acid and docosahexaenoic acid. Meanwhile, these n-3 Long Chain Polyunsaturated Fatty Acids (LC-PUFAs) are essential in the fight against inflammation, preventing depression, reducing weight and waist size, decreasing liver fat and promoting mental wellbeing. Typically, marine bivalves have a low saturated fatty acid content and a high n-3 LC-PUFA concentration, which is usually absent in most foods. Freshwater bivalves generally contain lower proportions of n-3 PUFA than marine bivalves; the lipid quality also differ in farmed and wild species. The focus of this review is on physiological important n-3 LC-PUFA present in marine bivalves, with an emphasis on the indicators for assessing quality and the effects of heat on bivalve lipid.

Plastidial acyl carrier protein Δ9-desaturase modulates eicosapentaenoic acid biosynthesis and triacylglycerol accumulation in Phaeodactylum tricornutum.

SUMMARYThe unicellular marine diatom Phaeodactylum tricornutum accumulates up to 35% eicosapentaenoic acid (EPA, 20:5n3) and has been used as a model organism to study long chain polyunsaturated fatty acids (LC‐PUFA) biosynthesis due to an excellent annotated genome sequence and established transformation system. In P. tricornutum, the majority of EPA accumulates in polar lipids, particularly in galactolipids such as mono‐ and di‐galactosyldiacylglycerol. LC‐PUFA biosynthesis is considered to start from oleic acid (18:1n9). EPA can be synthesized via a series of desaturation and elongation steps occurring at the endoplasmic reticulum and newly synthesized EPA is then imported into the plastids for incorporation into galactolipids via an unknown route. The basis for the flux of EPA is fundamental to understanding LC‐PUFA biosynthesis in diatoms. We used P. tricornutum to study acyl modifying activities, upstream of 18:1n9, on subsequent LC‐PUFA biosynthesis. We identified the gene coding for the plastidial acyl carrier protein Δ9‐desaturase, a key enzyme in fatty acid modification and analyzed the impact of overexpression and knock out of this gene on glycerolipid metabolism. This revealed a previously unknown role of this soluble desaturase in EPA synthesis and production of triacylglycerol. This study provides further insight into the distinctive nature of lipid metabolism in the marine diatom P. tricornutum and suggests additional approaches for tailoring oil composition in microalgae.

Using C. elegans to Investigate the Effects of Polyunsaturated Fatty Acids and Their Metabolites on Lifespan and Healthspan

Aging is a burdensome process that increases one's susceptibility to disease and disability. Many environmental factors, including diet, have been shown to influence aging outcomes. Specific omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) have been shown to have protective effects against aging-related conditions such as cardiovascular disease, inflammation, and Alzheimer's Disease. However, it is unclear which unsaturated fatty acids are required in the diet and how these molecules and their metabolites affect different health and disease states. This study aims to investigate the physiological roles of individual unsaturated fatty acids in the aging process. Our data will grant us the preliminary knowledge for making dietary and treatment suggestions to ameliorate aging-related conditions and promote healthy aging. This study will utilize the model organism C. elegans because of its short lifespan, its genetic pliability, and its ability to reliably function as a model for human health and disease. Single and multiple genetic knockouts of fatty acid desaturase enzymes will be used to assess the in vivo effects of unsaturated fatty acids on the aging process because these mutants contain different PUFA compositions in vivo. This investigation will lead to the creation of one dataset that includes lifespan and healthspan data for every available desaturase enzyme genetic knockout in the worm. Lifespan assays were used to quantify changes in the lifespans of different genetic knockouts, and thrashing assays were used to assess their physical fitness throughout the aging process, an indicator of healthspan. Additionally, gas chromatography/mass spectrometry fatty acid methyl esters analysis (GC/MS FAME) was used to assess the lipidome of key strains. We hypothesized that certain PUFAs play more important physiological roles than others due to their corresponding downstream metabolites’ role in lipid signaling. Our data confirm this hypothesis and demonstrate that the different desaturase enzyme knockouts vary in lifespan, fitness, and their lipid profile throughout the aging process. All mutants that have genetic disruption of PUFA biosynthesis were observed to have decreased median lifespan. Interestingly, our results from several mutants are different from the published data which involve the use of FuDR, a chemical that prevents the production of progeny. These mutants additionally have poor physical fitness across the first five days of adulthood. Notably, lipidomic analysis of day 1 adult fat-3 knockout worms, which cannot endogenously synthesize long chain PUFAs, revealed that these in vivo observations are associated with an increase in linoleic acid and alpha-linolenic acid and a decrease in other upstream and downstream metabolites. Taken together, our data suggest that altering endogenous levels of PUFAs decreases lifespan and healthspan. Investigating this metabolic pathway may elucidate novel pharmacological drug targets and reveal affordable dietary supplements that could revolutionize chronic disease treatment and prevention.

Omega-3 on the fly: long-legged fly Machaerium maritimae as a potential source of eicosapentaenoic acid for aquafeeds

The need for more sustainable aquafeeds has prompted the exploration of insects as potential ingredients. However, commonly reared insects are not satisfactory regarding their fatty acid composition, lacking omega-3 long chain polyunsaturated fatty acids (n-3 LC PUFA), important nutrients for marine organisms. In this study, we present in detail the fatty acid profile of the long-legged fly Machaerium maritimae Haliday (Diptera: Dolichopodidae), an amphibiotic insect native to European coastal habitats. Specimens of this fly were collected in Ria de Aveiro coastal lagoon (Portugal) and the fatty acid profile was analysed through gas chromatography coupled with mass spectrometry. Results revealed a remarkably high level of n-3 LC PUFA, (11 μg/mg dry weight, 20% of the fatty acid profile) namely eicosapentaenoic acid, and a low level of saturated fatty acids. This value is higher than what is found in Hermetia illucens (black soldier fly), while comparable to other aquatic insects. We also report the presence of 50 distinct fatty acids, including multiple branched-chain and PUFA, and discuss potential implications of their presence on the ecology of this species. Variation in the fatty acid profile along the landscape is also presented. Our results indicate that M. maritimae can potentially be a high-quality lipid source for marine aquafeeds. Current legislation in Europe allowing the use of insects in aquaculture is restricted to a few selected species, often non-native, however, further research should consider native insects as potential alternatives to current ingredients in aquafeed.

Lipidomics and transcriptomics analyses of altered lipid species and pathways in oxaliplatin-treated colorectal cancer cells

Drug resistance and adverse reactions to oxaliplatin remain a considerable issue in clinical practice. Emerging evidence has suggested that alterations in the lipid metabolism during drug therapy affect cancer cells. To gain insight into the important process of lipid metabolism, we investigated the lipid and gene expression profile changes in HT29 cells treated with oxaliplatin. A total of 1403 lipid species from 16 lipid classes were identified by UHPLC-MS. Interestingly, phospholipids, including phosphatidylglycerol (PG), phosphatidic acid (PA), phosphatidylcholine (PC), and most of phosphatidylethanolamine (PE) with polyunsaturated fatty acid (PUFA) chains, were significantly higher due to oxaliplatin treatment, while triacylglycerols (TAGs) with a saturated fatty acid chain or monounsaturated fatty acid were significantly downregulated. Gene Set Enrichment Analysis (GSEA) based on RNA sequencing data suggested that neutral lipid metabolism was enriched in the control group, whereas the phospholipid metabolic process was enriched in the oxaliplatin-treated group. We observed that altered lipid metabolism enzyme genes were involved in the synthesis and lipolysis of TAGs and the Lands cycle pathway based on the network between the core lipid-related gene and lipid species, which was further verified by qRT-PCR. In summary, our findings revealed that oxaliplatin impressed a specific lipid profile signature and lipid transcriptional reprogramming in HT29 cells, which provides new insights into biomarker discovery and pathways for overcoming drug resistance and adverse reactions.

A Facile and Efficient Method for the Synthesis of Labeled and Unlabeled Very Long Chain Polyunsaturated Fatty Acids

AbstractSeveral methods are available for elongation of fatty acid acyl chains. The present paper describes adaptation to the fatty acid field of a previously published protocol for manganese‐based Wurtz type coupling of alkyl bromides. 22‐Bromo‐3(Z),6(Z),9(Z),12(Z),15(Z),18(Z)‐docosahexaene, easily prepared from 4(Z),7(Z),10(Z),13(Z),16(Z),19(Z)‐docosahexaenoic acid, was coupled to homologous ω‐bromoesters by stirring for 4 hours at 40°C in the presence of manganese powder, a nickel catalyst and terpyridine. This afforded in yields of 70–75% a series of ω3‐hexaenoates of chain lengths of 32–40 carbons. The corresponding fatty acids of &gt;98% purity were obtained following saponification and final purification. By using methyl [2,2,3,3,4,4‐2H6]10‐bromodecanoate as coupling partner it was possible to prepare a very long chain fatty acid in isotopically labeled form, i.e., [2,2,3,3,4,4‐2H6]14(Z),17(Z),20(Z),23(Z),26(Z),29(Z)‐dotriacontahexaenoic acid. Also prepared were the monounsaturated long chain fatty acids 15(Z)‐octadecenoic acid and 15(Z)‐tetracosenoic acid. Very long chain fatty acids have been isolated from retina and other tissues and are of biological relevance. The methodology described will assist in further analytical and biological studies in this field.

Co-expressing Eranthis hyemalis lysophosphatidic acid acyltransferase 2 and elongase improves two very long chain polyunsaturated fatty acid production in Brassica carinata

Docosadienoic acid (DDA, 22:2–13,16) and docosatrienoic acid (DTA, 22:3–13,16,19) are two very long chain polyunsaturated fatty acids (VLCPUFAs) that are recently shown to possess strong anti-inflammatory and antitumor properties. An ELO type elongase (EhELO1) from wild plant Eranthis hyemalis can synthesize the two fatty acids by sequential elongation of linoleic acid and alpha-linolenic acid, respectively. Seed-specific expression of this gene in oilseed crop Brassica carinata produced a considerable amount of DDA and DTA in transgenic seeds. However, these fatty acids were excluded from the sn-2 position of triacylglycerols (TAGs). To improve the production level and nutrition value of the VLCPUFAs in the transgenic oilseed crop, a cytoplasmic lysophosphatidic acid acyltransferase (EhLPAAT2) for the incorporation of the two fatty acids into the sn-2 position of triacylglycerols was identified from E. hyemalis. RT-PCR analysis showed that it was preferentially expressed in developing seeds where EhELO1 was exclusively expressed in E. hyemalis. Seed specific expression of EhLPAAT2 along with EhELO1 in B. carinata resulted in the effective incorporation of DDA and DTA at the sn-2 position of TAGs, thereby increasing the total amount of DDA and DTA in transgenic seeds. To our knowledge, this is the first plant LPAAT that can incorporate VLCPUFAs into TAGs. Improved production of DDA and DTA in the oilseed crop using EhLPAAT2 and EhELO1 provides a real commercial opportunity for high value agriculture products for nutraceutical uses.

N-3 LC-PUFA Enrichment Protocol for Red Earthworm, Eisenia fetida: A Cheap and Sustainable Method

This study assessed the potential of omega-3 long chain polyunsaturated fatty acids (n-3 LC-PUFA) enrichment in red earthworm (Eisenia fetida, REW), via the addition of fish oil (FO, anchovy oil) to the culture-compost. FO addition to compost was tested at graded inclusion doses (0, 2.5, 5 and 10 g/100 g compost) and for different timeperiods, up to 96h. Dose, time, as well as dose and time interactions of FO compost enrichment had significant effects on all fatty acids of earthworm bodies. The enrichment with 10 g FO/100 g compost sharply increased DHA levels of the worms (14.01 mol%) within just 24 h, compared to the control group (0.92 mol%). Similar increases (ranging between 10.99 and 15.55 mol%) occurred only after 48 and 96 h in lower FO enrichment levels (2.5 and 5.0 g/100 g compost, respectively). Therefore, it was concluded that, to obtain maximum n-3 LC-PUFA enrichment efficiency in REW, an enrichment period of 24 h is ideal and recommended for the 10 g FO/ 100 g compost, whereas longer enrichment periods (48-96 h) are more suitable for lower levels of FO inclusions (2.5 or 5 g/100 g compost).

Weaning strategies affect larval performance in yellowfin seabream (Acanthopagrus latus)

A 30-day study was carried out to determine the influence of different weaning strategies (WS) on growth and survival rates, stress resistance, digestive enzyme activities and whole body fatty acid profiles in yellowfin seabream (Acanthopagrus latus) larvae. Thus, eight WS were designed by combining live foods (LF) (rotifers and Artemia) and a microdiet (MD) (Gemma Micro™, Skretting). In the control group (100 LF), larvae were fed only LF (100%), including enriched rotifers (from 2 to 20 days post hatching, dph) and Artemia (nauplii + enriched metanauplii, from 18 to 30 dph). The other treatments were based on different proportions of LF with the MD: 75LF-25MD, 50LF-50MD, 25LF-75MD and 100 MD in which 25, 50, 75 and 100% of LF that applied in the control group were replaced with a fixed ration of MD, respectively. In addition, for determining the appropriate time of weaning, three WS were applied including: sudden weaning (SW): larvae were weaned on to MD with only rotifer from 2 to 5 days post hatch (dph); early weaning (EW): larvae were weaned on to MD with only rotifer from 2 to 14 dah and late weaning (LW): larvae were weaned on to MD with rotifer (from 2 to 14 dph) and Artemia nauplii (from 12 to 20 dph). Larvae were hand-fed with the MD hourly from 08:00 h to 18:00 h (11 times a day). Results showed that the lowest survival rates were found among larvae from 100MD (1.5%) and SW (1.9%) groups, whereas the highest survival rates were found in larvae from 100LF (31.0 ± 1.7%), 75LF-25MD (34.7 ± 4.5%) and 50LF-50MD (36.2 ± 4.0%). Larvae from the 50LF-50MD group showed the highest resistance against air exposure (70.0%) and osmotic stress (100.0%) challenges. At the end of the trial, larvae from 100LF, 75LF-25MD, 50LF-50MD and LW groups showed higher growth performance than the other groups. At 30 dph, larvae from the LW group had the highest level of alkaline phosphatase to leucine-alanine peptidase ratio, while those from the 100MD, SW and EW treatments showed the lowest ones. The fatty acid profile of larvae reflected that of the diet. In particular, larvae from 100MD and SW groups had generally lower levels of n-3 long chain polyunsaturated fatty acids compared to the other treatments. In conclusion, results of the present study indicated the time of weaning and proportion of LF and MD remarkably affect larvae performance in terms of growth, survival, digestive function and stress tolerance. In addition, the replacement of LF with MD up to 50% after mouth opening of larvae neither have detrimental effects on growth, survival and digestive enzymes activities, meanwhile enhanced stress resistance of A. latus larvae.

Functional Analysis of an Acyltransferase-Like Domain from Polyunsaturated Fatty Acid Synthase in Thraustochytrium.

Biosynthesis of very long chain polyunsaturated fatty acids (VLCPUFA) such as docosahexaenoic acid (DHA, 22:6-4,7,10,13,16,19) and docosapentaenoic acid (DPA, 22:5-4,7,10,13,16) in protist Thraustochytrium is catalyzed by a polyunsaturated fatty acids (PUFA) synthase comprising three large subunits, each with multiple catalytic domains. This study used complementation test, in vitro assays, and functional expression to characterize an acyltransferase (AT)-like domain in Subunit-B of a PUFA synthase from Thraustochytrium. Complementation test in Escherichia coli showed that the AT-like domain could not restore the growth phenotype of a temperature-sensitive mutant (∆fabDts) defective in malonyl-CoA:ACP transacylase activity. In vitro assays showed that the AT-like domain possessed thioesterase activity towards a few acyl-CoAs tested where docosahexaenoyl-CoA (DHA-CoA) was the preferred substrate. Expression of this domain in an E. coli mutant (∆fadD) defective in acyl-CoA synthetase activity resulted in the increased accumulation of free fatty acids. Site-directed mutagenesis showed that the substitution of two putative active site residues, serine at 96 (S96) and histidine at 220 (H220), in the AT-like domain significantly reduced its activity towards DHA-CoA and accumulation of free fatty acids in the ∆fadD mutant. These results indicate that the AT-like domain of the PUFA synthase does not function as a malonyl-CoA:ACP transacylase, rather it functions as a thioesterase. It might catalyze the last step of the VLCPUFA biosynthesis by releasing freshly synthesized VLCPUFAs attached to ACP domains of the PUFA synthase in Thraustochytrium.

Effect of salt stress on physiological parameters of microalgae Vischeria punctata strain IPPAS H-242, a superproducer of eicosapentaenoic acid

The strain IPPAS H-242 is an eustigmatophycean alga with good growth characteristics and high content of the long chain polyunsaturated eicosapentaenoic fatty acid (EPA) – a very-long-chain fatty acid with high nutraceutical value. In this study, based on 18S rRNA gene and ITS1–5.8S–ITS2 sequences the strain IPPAS H-242 was identified as an authentic strain of Vischeria punctata. The effect of salt stress (0.5 M NaCl) on growth, cell morphology, ultrastructure, and biochemical composition with the emphasis on the fatty acid (FA) profile was investigated in batch cultures. Under salt stress, biomass accumulation and cell division were severely inhibited; cells were bigger, with higher chloroplast volume and numerous mitochondria, they had more proteins (73 % from the initial concentration as compared to 23 % in control) and their lipids had higher EPA proportion (13.6 % of total FA as compared to 6.4 % of total FA in control). In salt-stressed cells, thylakoid organization and photosynthetic activity were impaired, and D1 protein content decreased to trace amounts. In spite of an increase in EPA proportion in total FA, salt stress causes a decrease in total EPA productivity (49 mg/L as compared to 130 mg/L in control).

Engineering a lipoxygenase from cyclocybe aegerita towards long chain polyunsaturated fatty acids

The basidiomycetous lipoxygenase Lox1 from Cyclocybe aegerita catalyzes the oxygenation of polyunsaturated fatty acids (PUFAs) with a high preference towards the C18-PUFA linoleic acid (C18:2 (ω-6)). In contrast, longer PUFAs, generally not present in the fungal cell such as eicosatrienoic acid (C20:3(ω-3)) and docosatrienoic acid (C22:3 (ω-3)), are converted with drastically lower activities. With site-directed mutagenesis, we were able to create two variants with enhanced activities towards longer chain PUFAs. The W330L variant showed a ~ 20 % increased specific activity towards C20:3(ω-3), while a ~ 2.5-fold increased activity against C22:3 (ω-3) was accomplished by the V581 variant.

Fish Hydrolysate Supplementation Containing n-3 Long Chain Polyunsaturated Fatty Acids and Peptides Prevents LPS-Induced Neuroinflammation.

Neuroinflammation constitutes a normal part of the brain immune response orchestrated by microglial cells. However, a sustained and uncontrolled production of proinflammatory factors together with microglial activation contribute to the onset of a chronic low-grade inflammation, leading to neuronal damage and cognitive as well as behavioral impairments. Hence, limiting brain inflammatory response and improving the resolution of inflammation could be particularly of interest to prevent these alterations. Dietary n-3 long chain polyunsaturated fatty acids (LC-PUFAs) and low molecular weight peptides are good candidates because of their immunomodulatory and proresolutive properties. These compounds are present in a fish hydrolysate derived from marine-derived byproducts. In this study, we compared the effect of an 18-day supplementation with this fish hydrolysate to a supplementation with docosahexaenoic acid (DHA) on lipopolysaccharide (LPS)-induced inflammation in mice. In response to peripherally injected LPS, the fish hydrolysate supplementation decreased the hippocampal mRNA expression of the proinflammatory cytokines IL-6 (p < 0.001), IL-1β (p = 0.0008) and TNF-α (p < 0.0001), whereas the DHA supplementation reduced only the expression of IL-6 (p = 0.004). This decline in proinflammatory cytokine expressions was associated with an increase in the protein expression of IκB (p = 0.014 and p = 0.0054 as compared to the DHA supplementation and control groups, respectively) and to a modulation of microglial activation markers in the hippocampus. The beneficial effects of the fish hydrolysate could be due in part to the switch of the hippocampal oxylipin profile towards a more anti-inflammatory profile as compared to the DHA supplementation. Thus, the valorization of fish byproducts seems very attractive to prevent and counteract neuroinflammation.

Rainbow Trout (Oncorhynchus mykiss) Skin as Potential n-3 Fatty Acid Source

The rise in the demand and the limited availability of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids claim to obtain these important long chain polyunsaturated fatty acids (LCPUFA) from novel sources. Skin of rainbow trout is a fish industry by-product but still contains valuable LCPUFA amounts with great potential applications in human nutrition and health. This study aimed to explore the nutritional composition of rainbow trout skin for its use as source of n-3 LCPUFA and its composition modification according to fish diet. Rainbow trout were fed three diets including increasing substitution levels of fishmeal with full-fat black soldier fly (Hermetia illucens) larvae meal (0%, 25%, 50% substitution levels) over 98 days. DHA was the major representative of the n-3 LCPUFA in the skin of all dietary groups, being the H25 group the richest in this fatty acid. The present study shows that the skin of rainbow trout can be a promising source of n-3 LCPUFA. Reusing the skin of farmed fish represents a possible way to decrease food industry by-products, to reduce n-3 LCPUFA shortfall and could lead to the development of functional foods and nutritional supplements including n-3 LCPUFA from fish skin.

Immunomodulating effects of 13- and 16-hydroxylated docosahexaenoyl ethanolamide in LPS stimulated RAW264.7 macrophages

Docosahexaenoyl ethanolamide (DHEA), the ethanolamine conjugate of the n-3 long chain polyunsaturated fatty acid docosahexaenoic acid, is endogenously present in the human circulation and in tissues. Its immunomodulating properties have been (partly) attributed to an interaction with the cyclooxygenase-2 (COX-2) enzyme. Recently, we discovered that COX-2 converts DHEA into two oxygenated metabolites, 13- and 16-hydroxylated-DHEA (13- and 16-HDHEA, respectively). It remained unclear whether these oxygenated metabolites also display immunomodulating properties like their parent DHEA. In the current study we investigated the immunomodulating properties of 13- and 16-HDHEA in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. The compounds reduced production of tumor necrosis factor alpha (TNFα), interleukin (IL)-1β and IL-1Ra, but did not affect nitric oxide (NO) and IL-6 release. Transcriptome analysis showed that the compounds inhibited the LPS-mediated induction of pro-inflammatory genes (InhbA, Ifit1) and suggested potential inhibition of regulators such as toll-like receptor 4 (TLR4), MyD88, and interferon regulatory factor 3 (IRF3), whereas anti-inflammatory genes (SerpinB2) and potential regulators IL-10, sirtuin 1 (Sirt-1), fluticasone propionate were induced. Additionally, transcriptome analysis of 13-HDHEA suggests a potential anti-angiogenic role. In contrast to the known oxylipin-lowering effects of DHEA, liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analyses revealed that 13- and 16-HDHEA did not affect oxylipin formation. Overall, the anti-inflammatory effects of 13-HDHEA and 16-HDHEA are less pronounced compared to their parent molecule DHEA. Therefore, we propose that COX-2 metabolism of DHEA acts as a regulatory mechanism to limit the anti-inflammatory properties of DHEA.

Plasmalogen-Based Liquid Crystalline Multiphase Structures Involving Docosapentaenoyl Derivatives Inspired by Biological Cubic Membranes.

Structural properties of plasmenyl-glycerophospholipids (plasmalogens) have been scarcely studied for plasmalogens with long polyunsaturated fatty acid (PUFA) chains, despite of their significance for the organization and functions of the cellular membranes. Elaboration of supramolecular assemblies involving PUFA-chain plasmalogens in nanostructured mixtures with lyotropic lipids may accelerate the development of nanomedicines for certain severe pathologies (e.g., peroxisomal disorders, cardiometabolic impairments, and neurodegenerative Alzheimer’s and Parkinson’s diseases). Here, we investigate the spontaneous self-assembly of bioinspired, custom-produced docosapentaenoyl (DPA) plasmenyl (ether) and ester phospholipids in aqueous environment (pH 7) by synchrotron small-angle X-ray scattering (SAXS) and cryogenic transmission electron microscopy (cryo-TEM). A coexistence of a liquid crystalline primitive cubic Im3m phase and an inverted hexagonal (HII) phase is observed for the DPA-ethanolamine plasmalogen (C16:1p-22:5n6 PE) derivative. A double-diamond cubic Pn3m phase is formed in mixed assemblies of the phosphoethanolamine plasmalogen (C16:1p-22:5n6 PE) and monoolein (MO), whereas a coexistence of cubic and lamellar liquid crystalline phases is established for the DPA-plasmenyl phosphocholine (C16:1p-22:5n6 PC)/MO mixture at ambient temperature. The DPA-diacyl phosphoinositol (22:5n6-22:5n6 PI) ester lipid displays a propensity for a lamellar phase formation. Double membrane vesicles and multilamellar onion topologies with inhomogeneous distribution of interfacial curvature are formed upon incorporation of the phosphoethanolamine plasmalogen (C16:1p-22:5n6 PE) into dioleoylphosphocholine (DOPC) bilayers. Nanoparticulate formulations of plasmalogen-loaded cubosomes, hexosomes, and various multiphase cubosome- and hexosome-derived architectures and mixed type nano-objects (e.g., oil droplet-embedding vesicles or core–shell particles with soft corona) are produced with PUFA-chain phospholipids and lipophilic antioxidant-containing membrane compositions that are characterized by synchrotron SAXS and cryo-TEM imaging. The obtained multiphase nanostructures reflect the changes in the membrane curvature induced by the inclusion of DPA-based PE and PC plasmalogens, as well as DPA-PI ester derivative, and open new opportunities for exploration of these bioinspired nanoassemblies.

Early performance, stress- and disease-sensitivity in rainbow trout fry (Oncorhynchus mykiss) after total dietary replacement of fish oil with rapeseed oil. Effects of EPA and DHA supplementation

Different vegetable oils have been investigated as potential substitutes of fish oil in aquaculture feed and several of them have proven to be successful in terms of fish growth rates, survival rates, biometric indices or feeding efficiency, even when used as the only oils in the feed. However, final fish product composition (fish whole body or fish fillet) usually reflects feed composition, and fish products from fish fed with only vegetable oils usually show a deficiency in long chain polyunsaturated fatty acids (PUFAs). The welfare and health consequences for the fish of these alterations of the fatty acid profile are not well known. In the current study, three experimental diets using supercritically defatted fish meal as well as rapeseed oil as a 100% replacement of fish oil, and differing in essential fatty acid (eicosapentaneoid acid - EPA, docosahexaenoic acid - DHA) supplementation, were tested in rainbow trout, Oncorhynchus mykiss. The growth performance, feed conversion ratio and digestive enzyme profiles were evaluated. Further, stress-and infection-challenge experiments were performed to assess the robustness of the fish against stress and disease. The trout fry fed the experimental diets showed a different fatty acid profile than fish fed a commercial diet, with lower EPA and DHA levels but higher linolenic acid (18:3n-3) and oleic acid (18:1n-9) levels. No significant effects were found in growth performance, feed conversion ratio or digestive enzymatic activity among diets. The fish stress responsiveness (brain and plasma stress marker response) to acute and repeated stressors was in general also similar irrespective of the diet. Infection trials, however, showed a differential ability of the fish to survive upon a controlled infection with the bacterium Flavobacterium psychrophilum. Fish fed with the experimental diets displayed higher mortalities than fish fed a commercial trout fry diet. The current results highlight the need of further research on nutritional requirements to optimize the disease resilience in farmed fish. These results also demonstrate that the adaptation of the fish to new formulated feed (in this case associated to plant oil ingredients) should not be assessed solely based on the growth performance of the fish. Other aquaculture relevant welfare indicators, as disease or stress resilience, should be part of a more complete assessment of feed adequacy for fish farming purposes.

Ewe's diet during gestation and lactation affects ready-to-eat meat from light lambs

Maternal grazing may benefit the fatty acid (FA) profile of lamb meat, although any improvement in terms of healthier polyunsaturated FAs (PUFA) may be impaired during subsequent culinary treatments. The objective was to assess the effects of a grass-based ewe diet on the FA profile of the ready-to-eat meat from grain-fed Segureña light lamb. The FA were determined in raw, grilled (G), Sous Vide (SV) cooked and cooked/hot-held (H) lamb leg patties resulting from two maternal rearing systems: grazing (Mediterranean trees, shrubs, herbs, stubble and fallow) or indoors (cereal grain and lucerne pellets). The grass-based ewe diet increased (P < 0.05) levels of n-3 PUFA and total linoleic conjugated acid (CLA), and decreased those of n-6 long chain PUFA and saturated FA (SFA) in the patties from all treatments. These changes in FA slightly increased (P < 0.05) the PUFA/SFA ratio and decreased (P < 0.05) the n-6/n-3 ratio in the raw (from 8.7 to 6.3), SV (from 8.8 to 6.2), G (from 9.0 to 6.3), SV + H (from 8.2 to 6.3) and G + H (from 9.3 to 6.4) patties, improving the atherogenic, thrombogenic and saturation indexes. The effects of the ewe's diet on lamb FA remained unaltered after successive culinary treatments, including aerobically mincing, cooking at an internal temperature of 72 °C and H at 65 °C for 4 h. Heating induced a partial degradation of meat PUFA but also favoured the loss of high saturated melted fat. Both facts balanced the PUFA/SFA ratio in cooked lamb despite the gradual formation of oxidised secondary lipids to the detriment of FA. Grilling or SV cooking did not affect the remaining levels of undegraded FA in the freshly cooked lamb, although SV improved the results obtained for the cooked/H lamb. Maternal diets based on grass result in a healthier ready-to-eat lamb.