Component and Content of Lipid Classes and Phospholipid Molecular Species of Eggs and Body of the Vietnamese Sea Urchin Tripneustes gratilla.

Sea urchins (Tripneustes gratilla) are among the most highly prized seafood products in Vietnam because of their nutritional value and medicinal properties. In this research, lipid classes and the phospholipid (PL) molecular species compositions from the body and eggs of T. gratilla collected in Hon Tam, Nha Trang, Khanh Hoa, Vietnam, were investigated. Hydrocarbon and wax (HW), triacylglycerol (TG), mono- and diacylglycerol (MDAG), free fatty acid (FFA), sterol (ST), polar lipid (PoL), and monoalkyl-diacylglycerol are the major lipid classes. In PL, five main glycerophospholipid classes have been identified, in which 137 PL molecular species were detected in the body and eggs of T. gratilla, including 20 inositol glycerophospholipids (PI), 11 serine glycerophospholipids (PS), 22 ethanolamine glycerophospholipids (PE), 11 phosphatidic acids (PA), and 73 choline glycerophospholipids (PC). PI 18:0/20:4, PS 20:1/20:1, PE 18:1e/20:4, PA 20:1/20:1, and PC 18:0e/20:4 are the most abundant species with the highest content values of 38.65-48.19%, 42.48-44.41%, 41.21-40.03%, 52.42-52.60%, and 7.77-7.18% in each class of the body-eggs, respectively. Interestingly, PL molecules predominant in the body sample were also found in the egg sample. The molecular species with the highest content account for more than 40% of the total species in each molecular class. However, in the PC class containing 73 molecular species, the highest content species amounted to only 7.77%. For both the body and egg TL samples of the sea urchin T. gratilla, a substantial portion of C20:4n polyunsaturated fatty acid was found in PI, PE, and PC, but C16, C18, C20, and C22 saturated fatty acids were reported at low levels. The most dominant polyunsaturated fatty acid in PI, PE, and PC was tetracosapolyenoic C20, while unsaturated fatty acid C20:1 was the most dominant in PS and PA. To our knowledge, this is the first time that the chemical properties of TL and phospholipid molecular species of the PoL of Vietnamese sea urchin (T. gratilla) have been studied.

The use of muscle lipids and fatty acids to assess shark diet and condition.

Following a lack of detected change in white shark Carcharodon carcharias L. 1758 diet and nutritional condition attributed to the interaction with the cage-diving industry, Lusseau and Derous (Tourism Management, 2019, 75, 547-549) cautioned the use of muscle lipids and fatty acids in this context, advocating for other biomarkers. This study provides additional evidence from peer-reviewed literature to contend the usefulness of elasmobranch muscle fatty acid profiles to detail diet and habitat use. It also presents findings from a controlled experiment on captive Port Jackson sharks Heterodontus portusjacksoni (Meyer 1793) whereby long-term (daily for 33 days) 3 min exhaustive chase exercise changed muscle lipid class profiles, supporting its use to infer nutritional condition after activities such as interactions with wildlife tourism operators. Conversely, the unaltered muscle fatty acid and lipid content suggests their use in trophic ecology is not confounded by activities such as interacting with tourism operators, remaining useful biomarkers to investigate diet and habitat use.

Phosphorus-Induced Lipid Class Alteration Revealed by Lipidomic and Transcriptomic Profiling in Oleaginous Microalga Nannochloropsis sp. PJ12.

Phytoplankton are primary producers in the marine ecosystem, where phosphorus is often a limiting factor of their growth. Hence, they have evolved strategies to recycle phosphorus by replacing membrane phospholipids with phosphorus-free lipids. However, mechanisms for replacement of lipid classes remain poorly understood. To improve our understanding, we performed the lipidomic and transcriptomic profiling analyses of an oleaginous marine microalga Nannochloropsis sp. PJ12 in response to phosphorus depletion (PD) and replenishing. In this study, by using (liquid chromatography couple with tandem mass spectrometry) LC-MS/MS-based lipidomic analysis, we show that membrane phospholipid levels are significantly reduced upon PD, while phosphorus-free betaine lipid levels are increased. However, levels of phosphorus-free photosynthetic galactolipid and sulfolipid are not increased upon PD, consistent with the reduced photosynthetic activity. RNA-seq-based transcriptomic analysis indicates that enzymes involved in phospholipid recycling and phosphorus-free lipid synthesis are upregulated, supporting the lipidomic analysis. Furthermore, enzymes involved in FASII (type II fatty acid synthesis) elongation cycle upon PD are transcriptionally downregulated. EPA (eicosapentaenoic acid) level decrease upon PD is revealed by both GC-MS (gas chromatography coupled with mass spectrometry) and LC-MS/MS-based lipidomic analyses. PD-induced alteration is reversed after phosphorus replenishing. Taken together, our results suggest that the alteration of lipid classes upon environmental change of phosphorus is a result of remodeling rather than de novo synthesis in Nannochloropsis sp. PJ12.

Glycerolipid Composition of the Red Macroalga Agarophyton Chilensis and Comparison to the Closely Related Agarophyton Vermiculophyllum Producing Different Types of Eicosanoids.

The red macroalga Agarophyton chilensis is a well-known producer of eicosanoids such as hydroxyeicosatetraenoic acids, but the alga produces almost no prostaglandins, unlike the closely related A. vermiculophyllum. This indicates that the related two algae would have different enzyme systems or substrate composition. To carry out more in-depth discussions on the metabolic pathway of eicosanoids between the two algae, we investigated the characteristics of glycerolipids, which are the substrates of eicosanoids production, of A. chilensis and compared them to the reported values of A. vermiculophyllum. In A. chilensis, monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG), sulfoquinovosyldiacylglycerol (SQDG), and phosphatidylcholine (PC) were the major lipid classes and accounted for 44.4% of the total lipid extract. The predominant fatty acids were arachidonic acid (20:4n-6), an eicosanoids precursor, and palmitic acid (16:0). The 20:4n-6 content was extremely high in MGDG and PC (>70%), and the 16:0 content was extremely high in DGDG and SQDG (>40%). A chiral-phase HPLC analysis showed that fatty acids were esterified at the sn-1 and sn-2 positions of those lipids. The glycerolipid molecular species were determined by reversed-phase HPLC⁻ESI⁻MS analysis. The main glycerolipid molecular species were 20:4n-6/20:4n-6 (sn-1/sn-2) for MGDG (63.8%) and PC (48.2%), 20:4n-6/16:0 for DGDG (71.1%) and SQDG (29.4%). These lipid characteristics of A. chilensis were almost the same as those of A. vermiculophyllum. Hence, the differences of the eicosanoids producing ability between the two algae would not be due to the difference of substrate composition but the difference of enzyme system.

Interspecific variability in phosphorus-induced lipid remodelling among marine eukaryotic phytoplankton.

The response of marine microalgal lipids to phosphorus is of central importance in phytoplankton ecology but remains poorly understood. We determined how taxonomically diverse microalgal species remodelled their lipid class profile in response to phosphorus availability and whether these changes coincided with those already known to occur in land plants and in the limited number of phytoplankton species for which data are available. The complete lipid class profile and specific lipid ratios influenced by phosphorus availability were quantified in two green microalgae and seven Chromalveolates exposed to phosphorus repletion, deprivation and replenishment. Lipid class cell quota changes in the two green microalgae resembled the currently described pattern of betaine lipids substituting for phospholipids under phosphorus depletion, whereas only two of the studied Chromalveolates showed this pattern. Sulpholipids counterbalanced phosphatidylglycerol only in Picochlorum atomus. In all other species, both lipids decreased simultaneously under phosphorus deprivation, although sulpholipids declined more slowly. Phosphorus deprivation always induced a decrease in digalactosyl-diacylglycerol. However, the ratio of digalactosyl-diacylglycerol to total phospholipids increased in eight species and remained unchanged in Isochrysis galbana. Marine phytoplankton seems to have evolved a diversified mechanism for remodelling its lipid class profile under the influence of phosphorus, with cryptophytes and particularly haptophytes exhibiting previously unobserved lipid responses to phosphorus.

Lipid Composition of Oil Extracted from Wasted Norway Lobster (Nephrops norvegicus) Heads and Comparison with Oil Extracted from Antarctic Krill (Euphasia superba).

In the UK, the Norway lobster (Nephrops norvegicus) supports its most important shellfish fishery. Nephrops are sold either whole, or as "tails-only" for the scampi trade. In the "tailing" process, the "head" (cephalothorax) is discarded as waste. A smaller crustacean species, the Antarctic krill Euphasia superba, represents an economically valuable industry, as its extractable oil is sold as a human dietary supplement. The aim of this study was to determine the amount and composition of the oil contained in discarded Nephrops heads and to compare its composition to the oil extracted from krill. Differences due to Geographical variation and seasonal patterns in the amount and composition of lipid were also noted. Results indicated that Nephrops head waste samples collected from more southern locations in Scotland (Clyde Sea area) contained higher levels of oil when compared to samples collected from northern locations in Iceland. Moreover, seasonal differences within the Clyde Sea area in Scotland were also observed, with oil extracted from Nephrops head waste peaking at around 11.5% during the summer months when larger and more mature females were caught by trawl. At this time of the year, the valuable fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) accounted for around 23% of the total fatty acid content in oil extracted from Nephrops head waste. A seasonal effect on EPA content was found, with higher levels obtained in the summer, while no trend was found in DHA percentages. Finally, oil from Nephrops head waste contained a higher proportion of EPA and DHA than krill oil but these fatty acids were more abundantly linked to the neutral lipids rather to than polar lipids. The characterization of lipid that could be extracted from Nephrops head waste should be seen as a first step for the commercial use of a valuable resource currently wasted. This approach is extremely relevant given the current limited supply of EPA and DHA and changes in the Common Fisheries Policy.

1H NMR-based lipidomics of rodent fur: species-specific lipid profiles and SCD1 inhibitor-related dermal toxicity.

A method is described that allows noninvasive identification and quantitative assessment of lipid classes present in sebaceous excretions in rodents. The method relies on direct high-field proton NMR analysis of common group lipid protons in deuterated organic solvent extracts of fur. Extracts from as little as 15 mg of fur from rat, mouse, and hamster provided acceptable results on a 600 MHz NMR equipped with a cryogenically cooled proton-observe probe. In rats, sex- and age-related differences in lipid composition are larger than differences in fur collected from various body regions within an individual and much larger than interanimal differences in age- and sex-matched specimens. The utility of this method to noninvasively monitor drug-induced sebaceous gland atrophy in rodents is demonstrated in rats dosed with a stearoyl-CoA desaturase 1 (SCD1) inhibitor. In this model, a 35% reduction in sebum lipids, extracted from fur, was observed. Finally, structural elucidation of cholesta-7,24-dien-3ß-ol ester as the most prominent, previously unidentified sebum sterol ester in male Syrian hamsters is described. The utility of this method for drug and cosmetic safety and efficacy assessment is discussed.

Effect of conventional and pressure frying on lipids and fatty acid composition of fried chicken and oil.

Lipid class and fatty acid profile of pressure fried (PF) and conventionally fried (CF) chicken and medium of frying were evaluated. Depending on the frying cycle, neutral lipid (NL) content of PF chicken varied from 75-86% as compared to that of CF (84-90%). Similarly, glycolipid (GL) content varied from 11-21% in PF and from 9-12% in case of CF. Phospholipid (PL) was the least among lipid classes in both the products. The fresh frying medium (oil before frying cycle started), NL, GL and PL were 89, 10 and 0.33%, respectively. After the frying cycles were over, NL content of oil used for CF decreased to 82% and GL content increased from 10 to 17%. There was no significant difference (p ≥ 0.05) between the contents of lipid classes of oil used for PF or CF. Fried chicken and frying medium had higher concentration of linoleic acid and oleic acid irrespective of the frying cycle or frying method. PF chicken had moisture content in the range of 56-58% and total fat was 14% whereas in case of CF chicken it ranged from 49-52% and 18% respectively. TBA and FFA values of CF chicken and oil on repeated frying were higher (p ≤ 0.05) than PF. In comparison to conventional frying, pressure frying resulted in relatively tender and juicier product presumably due to better retention of moisture (p ≤ 0.05) and low oil uptake.

Nutritional lipidomics for the characterization of lipids in food.

Lipids represent one out of three major macronutrient classes in the human diet. It is estimated to account for about 15-20% of the total dietary intake. Triacylglycerides comprise the majority of them, estimated 90-95%. Other lipid classes include free fatty acids, phospholipids, cholesterol, and plant sterols as minor components. Various methods are used for the characterization of nutritional lipids, however, lipidomics approaches become increasingly attractive for this purpose due to their wide coverage, comprehensiveness and holistic view on composition. In this chapter, analytical methodologies and workflows utilized for lipidomics profiling of food samples are outlined with focus on mass spectrometry-based assays. The chapter describes common lipid extraction protocols, the distinct instrumental mass-spectrometry based analytical platforms for data acquisition, chromatographic and ion-mobility spectrometry methods for lipid separation, briefly mentions alternative methods such as gas chromatography for fatty acid profiling and mass spectrometry imaging. Critical issues of important steps of lipidomics workflows such as structural annotation and identification, quantification and quality assurance are discussed as well. Applications reported over the period of the last 5years are summarized covering the discovery of new lipids in foodstuff, differential profiling approaches for comparing samples from different origin, species, varieties, cultivars and breeds, and for food processing quality control. Lipidomics as a powerful tool for personalized nutrition and nutritional intervention studies is briefly discussed as well. It is expected that this field is significantly growing in the near future and this chapter gives a short insight into the power of nutritional lipidomics approaches.

Growth, fatty acid profile in major lipid classes and lipid fluidity of Aurantiochytrium mangrovei SK-02 As a function of growth temperature.

Aurantiochytrium mangrovei Sk-02 was grown in a medium containing glucose (40 g/l), yeast extract (10 g/L) and sea salts (15 g/L) at temperatures ranging from 12 to 35°C. The fastest growth (µmax= 0.15 h(-1)) and highest fatty acid content of 415 mg/g-dry cell weight were found in the cells grown at 30°C. However, the cells grown at 12°C showed the highest percentage of polyunsaturated fatty acid (PUFA) (48.6% of total fatty acid). The percentage of docosahexaenoic acid (DHA) and pentadecanoic acid (C15:0) decreased with an increase in the growth temperature, whereas, palmitic acid (C16:0), stearic acid (C18:0) and DPA (C22:5n6) increased with an increase in the growth temperature. The composition of the major lipid class (%w/w) was slightly affected by the growth temperature. The fluidity of the organelle membrane or intracellular lipid (by DPH measurement) decreased with an increase in the growth temperatures, while the plasma membrane fluidity (by TMA-DPH measurement) could still maintain its fluidity in a wide range of temperatures (15 - 37°C). Furthermore, the distribution of DHA was found to be higher (36 - 54%) in phospholipid (PL) as compared to neutral lipid (NL) (20 - 41%).

Effects of free-fatty-acid content and saturation degree of the dietary oil sources on lipid-class content and fatty-acid digestibility along the gastrointestinal tract in broilers from 22 to 37 days of age.

The aim of the present study is to assess the effect of the free-fatty-acid (FFA) content and saturation degree of dietary fat (added at 6%) on the fatty-acid (FA) digestibility and lipid-class content along the gastrointestinal tract and excreta in broilers from 22 to 37 d of age. This is essential to determine the potential use of acid oils (refining by-products rich in FFA) in broiler diets as an alternative to crude oils. The study consisted of a 2 × 4 factorial arrangement, which included 2 fat sources (soybean oils - unsaturated, or palm oils - saturated) and 4 levels of FFA (5, 15, 35, and 50%). Samples of digestive content of the gizzard, duodenum, jejunum, ileum and of the excreta were obtained at 37 d of age. Irrespective of the dietary fat source, more than 80% of total FA (TFA) was absorbed in the jejunum. Broilers fed with unsaturated diets had a higher absorption efficiency of FA than did those fed with saturated diets. This conclusion is supported by the lower FFA content and the higher TFA and polyunsaturated FA (PUFA) digestibility coefficients in the ileum (P < 0.001) observed in the former group. The dietary FFA level did not affect the FA absorption process as much as the dietary fat source did. This was supported by the lack of statistical differences among the diets with a similar saturation degree but rather different levels of FFA, for TFA, saturated FA, and PUFA digestibility coefficients both in the jejunum and ileum. However, the interactions reported in the ileum for triacylglycerol and diacylglycerol contents (P < 0.001), as well as for monounsaturated FA digestibility coefficients (P < 0.05) show that the dietary FFA content affects the FA absorption process. The present results show that the inclusion of acid oils in grower-finisher broiler diets with FFA levels up to 35% does not have a negative impact on the FA absorption process.

Lipidomic analysis using hydrophilic interaction liquid chromatography microgradient fractionation of total lipid extracts.

Lipidomic samples are complex mixtures of structurally different species of a wide range of concentrations providing challenges in their characterization. In this work, we present a proof of concept for the application of a simple microgradient liquid chromatography device on the detailed analysis of lipid classes. Our lipidomic analysis is based on a lipid class microgradient fractionation of a total lipid extract using an in-house-prepared hydrophilic interaction liquid chromatography microcolumn followed by RP-LC/MS of the collected lipid class fractions. The final fractionation method uses a 40-mm-long microcolumn of 500 µm ID with silica stationary phase obtained from a commercially available chromatographic column and the microgradient of the mobile phase prepared in a microsyringe using methyl tert-butyl ether (MTBE) - methanol - water - ammonium acetate mixtures of various elution strengths. MTBE total lipid extract is directly separated by microgradient elution into lipid classes according to their polarity, which enables the collection of isolated fractions of most lipid classes. The method has been applied to the fractionation of porcine brain extract into nonpolar lipids, hexosylceramides, phosphoethanolamines, phosphocholines, sphingomyelins, and lysophosphocholines classes. Achieved repeatability, recovery, and advanced lipid coverage prove the applicability of the microgradient fractionation of total lipid extract for the comprehensive lipidomic analysis.

Application of Lipid Class Ratios for Sample Stability Monitoring-Evaluation of Murine Tissue Homogenates and SDS as a Stabilizer.

Lipids are a ubiquitous class of structurally complex molecules involved in various biological processes. In the fast-growing field of lipidomics, preanalytical issues are frequently neglected. Here, we investigated the stability of lipid profiles of murine liver, brain, lung, heart, and spleen homogenates by quantitative flow injection analysis using tandem mass spectrometry and high-resolution mass spectrometry. Storage of tissue homogenates at room temperature showed substantial alterations of the lipid profiles reflecting lipolytic action. Therefore, ratios of ceramide to sphingomyelin, lysophosphatidylethanolamine to phosphatidylethanolamine, lysophosphatidylcholine to phosphatidylcholine, and diglyceride to triglyceride were applied to monitor sample stability and the effect of sodium dodecyl sulfate (SDS) as a potential stabilizing agent. The addition of SDS led to a concentration-dependent stabilization of lipid profiles in liver, brain, and heart homogenates, while in lung and spleen homogenates, in particular, the lysophosphatidylethanolamine to phosphatidylethanolamine ratio increased upon addition of SDS. In conclusion, we demonstrated that lipid class ratios reflecting lipolytic activity could be applied to evaluate both the stability of samples and the influence of stabilizers.

Lipid classes and fatty acid profile of selected Indian fresh water fishes.

Lipid extracts from meat, head and viscera of Indian fresh water fishes, viz., catla, rohu, mrigal, common carp and tilapia were analyzed for lipid class distribution and fatty acid profile. The yield of meat ranged from 66.0-79.5% and total lipid content in meat was 0.8-3.8%. The total lipid content was higher (>4.0%) in head and viscera. Neutral lipids constituted 71.5-93.3% of the total lipid extract. Higher glycolipid content of 25.2% was observed in lipid extract from meat of common carp and higher phospholipid content (13.7%) was observed in lipid extract from meat of mrigal. Hydrocarbons, sterolesters and triacylglycerol were the major fractions of neutral lipids. Unsaturated fatty acids dominated in all the samples. Palmitic and oleic acids were the major fatty acids found in all the lipid extracts. Docosahexaenoic acid content was higher than 3% in lipid extract from meat of all the fishes. However, in most of the fishes, the content of eicosapentaenoic acid and docosahexaenoic acid were higher in visceral lipids.

Total Lipids Content, Lipid Class and Fatty Acid Composition of Ten Species of Microalgae.

Microalgae is a potential producer of functional lipids such as n-3 polyunsaturated fatty acids (PUFA) and fucoxanthin. In the present study, lipids from ten microalgae species were analyzed especially focusing on the fucoxanthin, lipid and fatty acid compositions. The study revealed a remarkable variation in total lipids content, fucoxanthin content, lipid class composition and n-3 PUFA content in individual species, although they belong to the same genus. Among microalgae examined, Pavlova lutheri contained the highest total lipids content (313.59 mg g-1 dry weight) and considerable amount of fucoxanthin (3.13 mg g-1 dry weight). It also had the highest level (28.01%) of total n-3 PUFA with high level of eicosapentaenoic acid (EPA) (17.76%) and docosahexaenoic acid (DHA) (7.61%). The highest fucoxanthin content (5.19 mg g-1 dry weight) was observed in Chaetoceros gracilis. C. gracilis also contained relatively high level of total lipids (228.87 mg g-1 dry weight) and 10.67% EPA. The results also demonstrated that Nannochloropsis oculata contained the greatest amount of EPA (26.21%), while Isochrysis galbana had the highest level of DHA (8.76%). And both microalgae contained 1.71 and 4.44 mg g-1 dry weight fucoxanthin, respectively. Microalgal lipids containing abundant fucoxanthin and n-3 PUFA such as EPA and DHA in the present study will be used as nutraceutical lipids with great commercial potential.

Characterization of glycerophospholipid molecular species in muscles from three species of cephalopods by direct infusion-tandem mass spectrometry.

More than 200 molecular species of glycerophospholipids (GP) including glycerophosphocholine (GPC), glycerophosphoethanolamine (GPE), glycerophosphoserine (GPS), lysoglycerophosphocholine (LGPC), lysoglycerophosphoethanolamine (LGPE) and lysoglycerophosphoserine (LGPS), as well as 18 kinds of sphingomyelin (SM) were characterized by using a direct infusion-tandem mass (MS/MS) spectrometry method for lipids from the muscles of cephalopods Sepiella maindroni, Octopus ocellatus and Loligo chinensis for the first time. The majority of the GP molecular species contained long-chain omega-3 polyunsaturated fatty acids (n-3 LC-PUFA), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Therefore, cephalopods can be a good possible source of dietary GP carrying n-3 LC-PUFA. The total lipids were composed of phospholipid (PL, 72.29-83.32 wt% of total lipids), cholesterol (12.70-23.60 wt% of total lipids), triacylglycerol (1.86-2.93 wt% of total lipids), diacylglycerol (0.15-1.09 wt% of total lipids), monoacylglycerol (0.06-0.18 wt% of total lipids) and free fatty acid (0.72-1.86 wt% of total lipids). For PL, phosphatidylcholine (44.47-62.30 mol%), phosphatidylethanolamine (22.57-39.08 mol%), phosphatidylserine (6.15-10.18 mol%), phosphatidylglycerol (0.68-3.11 mol%), phosphatidylinositol (2.41-7.15 mol%) and lysophosphatidylcholine (1.84-5.24 mol%) were detected. Furthermore, the total lipids from the muscles of cephalopods Sepiella maindroni, Octopus ocellatus and Loligo chinensis contained 41.80-50.02 mol% of saturated fatty acids, 11.53-21.54 mol% of monounsaturated fatty acids and 36.67-40.82 mol% of PUFA, whilst DHA (15.25-26.71 mol%) and EPA (6.29-16.57 mol%) were found to account for the majority of the PUFA. With these data presented, cephalopod muscle can be considered as a healthy food for humans.

Changes of Plasma Fatty Acids in Four Lipid Classes to Understand Energy Metabolism at Different Levels of Non-Esterified Fatty Acid (NEFA) in Dairy Cows.

The transition period is a central moment in dairy cows breeding because metabolic disorders may occur in relation to a dramatic increase in energy demand. This research aimed to identify new biomarkers for the diagnosis of hyperketonemia in bovine in early lactation phase with different value of plasmatic non-esterified fatty acid (NEFA). The profile of plasma fatty acids (FAs) divided into four lipid classes was evaluated using thin layer chromatography and gas chromatographic techniques (TLC-GC). A group of 60 multiparous Holstein-Friesian dairy cows were recruited in the present study. Blood samples were collected from the coccygeal vein and NEFA and the ß-hydroxybutyrate (BHB) were evaluated. All animals were divided in 2 groups based on NEFA, NEFA0 group had as mean value 0.24 ± 0.12 mEq/L and NEFA1 group had as mean value 0.87 ± 0.23 mEq/L. Plasma FA concentrations were analyzed separately in free fatty acids, cholesterol esters, phospholipids and triglycerides. Six FAs demonstrated a predictive value in the hyperketonemic dairy cows. In the free fatty acid class, the predictive FAs were C14:0 (AUC = 0.77), C18:1 ω 9 (AUC = 0.72), C18:1 ω 7 (AUC = 0.70) and C18:3 ω 3 (AUC = 0.68). In the phospholipids class the predictive parameters were C12:0 (AUC = 0.78) and C8:0 (AUC = 0.73). In cholesterol, esters and triglycerides lipidic classes no FA had a predictive function.

Liquid Chromatography-Mass Spectrometry (LC-MS)-Based Analysis for Lipophilic Compound Profiling in Plants.

Lipids are fascinating due to their chemical diversity, which is especially vast in the plant kingdom thanks to the high plasticity of the plant biosynthetic machinery. Lipidomic studies aim to simultaneously analyze a large number of lipid compounds of diverse classes in a given sample. The method presented here uses liquid chromatography-mass spectrometry (LC-MS)-based lipidomic profiling in a relatively fast, robust, and high-throughput manner for high-coverage quantification and annotation of lipophilic compounds. Protocols cover sample preparation, LC-MS-based measurement, and data extraction and annotation. An extensive lipid library for triacylglycerols, galactolipids, and phospholipids is provided. The extended profiling described here could be used in a range of applications and is suitable for integration with other omic datasets. © 2020 by John Wiley & Sons, Inc. Basic Protocol 1: Sample preparation and metabolite extraction Basic Protocol 2: Liquid chromatography-mass spectrometry (LC-MS) analysis Basic Protocol 3: Data extraction, annotation, and quantification.

Evaluation of the composition and oxidative status of omega-3 fatty acid supplements on the Finnish market using NMR and SPME-GC-MS in comparison with conventional methods.

Previous studies disagree on the oxidative status of omega-3 supplements. The great deviation raises concerns about quality and the methods used to monitor it. This study investigated 49 omega-3 products for their fatty acid content, lipid class and oxidative status using official methods, gas and liquid chromatography with mass spectrometry and nuclear magnetic resonance spectroscopy. With minor deviations, omega-3 fatty acid content and lipid class of all products were as declared. 24% of studied products exceeded thresholds set by The Global Organization for EPA and DHA Omega-3s for peroxide and/or p-anisidine value suggesting a compromised oxidative status. However, peroxide and/or p-anisidine value were only suitable for detection of lipid oxidation in 90% or 73%, respectively, of the products. Analysis of volatile oxidation compounds can be an alternative method for p-anisidine value. Nuclear magnetic resonance spectroscopy was shown to be a rapid method for determination of oil type and lipid class.

Effects of extraction method and storage of dry tissue on marine lipids and fatty acids.

Various protocols are currently used to study marine lipids, but there is a growing interest in working on dry samples that are easier to transport. However, reference protocols are still lacking for dry samples. In order to make recommendations on this use, lipid classes and fatty acids (FA) obtained from six analytical protocols using two different tissue states (dry vs wet) and three extraction methods (automat vs manual potter vs leaving the solvent to work on tissue) were compared. Three dry storage modes of tissue (freezer vs gas nitrogen vs dry room) during one and three months were also compared. These comparisons were made on seven marine species with different lipid profiles, including fishes, crustaceans and mollusks. Lipid classes and FA obtained from wet and dry tissues were similar, but they were affected by the extraction methods. Regardless of tissue state, "Leave to work" methods obtained the highest lipid quantities, followed by manual potter and automat methods (ca. 90% and 80% of "Leave to work" methods, respectively). Linear relationships allowed correction for lipid classes and FA concentrations obtained from different protocols. The repeatability of all protocols still needs to be improved, especially for fish species. Increasing the replicate number for each sample might be an indirect way to improve lipid quantification. Our results show that storing dry tissues in the freezer for more than one month was associated with a decrease in lipids, which is also observed for other storage methods. For qualitative studies of FA (expressed in %), a three-month storage of dry tissue in freezer did not affect the relative composition of species/tissues with a lipid content below 20% of dry weight.