Differences In Fatty Acid Profiles Research Articles

Abstract PO5-23-11: Elevated linoleic acid levels in red blood cells membrane predicts response to neoadjuvant chemotherapy in breast cancer patients

Abstract Introduction: Fatty acids (FA) consumed in the diet have been implicated in increasing the risk of breast cancer (BC). Humans have a wide variety of FAs, including saturated (SFA), monounsaturated (MUFA), and polyunsaturated (PUFA) FAs. PUFAs can be further classified into omega-3 (n-3) and omega-6 (n-6) PUFAs. While n-3 has been associated with reducing inflammation and promoting apoptosis in BC cells, n-6 has been linked to increased inflammation, oxidative stress, and the promotion of BC cell proliferation and treatment resistance. In healthy women, the n-3 content in mammary tissue correlates with n-3 content in red blood cells (RBCs). The FA profile of the RBC membrane provides an unbiased option to assess lipid intake and composition, reflecting long-term FA intake and providing an objective and sensitive measure of lipid intake and body fat deposits. Notably, BC patients have been found to display a high n-6:n-3 ratio in RBCs, which is associated with inflammatory and oxidative stress biomarkers. The neoadjuvant chemotherapy treatment (NACT) model presents a unique opportunity to study resistance mechanisms in non-metastatic BC patients. In this approach, the absence of tumor (pathologic complete response: pCR, or Residual Cancer Burden (RCB) = 0) after NACT indicates treatment sensitivity and better overall survival (OS). Objective: The objective of this study is to determine whether differences in FA profiles determined in the RBC membrane and plasma are associated with the response to NACT in non-metastatic BC patients. Methods: A prospective study was conducted, including non-metastatic BC patients scheduled to receive NACT. Blood samples were collected before the first cycle of NACT to measure plasma and RBC FA derivatives, SFAs, MUFAs, and PUFAs. The pathological complete response (pCR) and residual cancer burden (RCB) were assessed. Results: A total of twenty-eight BC patients were included in the study. When comparing pCR vs. no-pCR using total SFA, MUFA, and PUFA plasma samples, no significant differences were observed. However, in RBC, an increase in PUFA was associated with a higher rate of no-pCR (**p< 0.01). Furthermore, comparing omega-6 and omega-3 (both PUFA) levels, an increase in omega-6 was associated with no-pCR (**p< 0.01), while no significant differences were observed with omega-3. No differences were obtained in plasma samples for either omega-6 and omega-3. To determine which specific omega-6 PUFAs were responsible for the association with no-pCR, elevated levels of linoleic acid (LA) in RBC were found to be associated with no-pCR (**p< 0.01). Other omega-6 PUFAs, including gamma-linolenic acid (GLA), eicosadienoic acid (EDA), dihomo-gamma linolenic acid (DGLA), and arachidonic acid (ARA), showed no significant associations. Multivariate and regression analysis confirmed LA (C18:2 n-6, LA) as the most relevant FA when assessing RCB (0-1 vs. 2-3) in RBC membranes, but not in plasma. The receiver operating characteristic (ROC) curve analyzing LA levels in RBC showed an area under the curve (AUC) of 0.855 for RCB (sensitivity: 76.9%, specificity: 92.3%). Conclusions: To the best of our knowledge, this is the first study demonstrating a clear connection between RBC membrane FA composition, specifically LA concentration, and the pathological response in BC patients after NACT. The measurements taken in plasma did not show significant associations, suggesting that RBC membrane FA profile of could serve as a relevant prognostic biomarker for studying resistance mechanisms to NACT in early BC patients Table. Measured FAs in RBC membrane and plasma by pathologic complete response *Indicates p<0.05; abbreviations: pCR: pathological complete response; SD: standard deviation; yr: years; BMI: body mass index; HR: hormone receptor; HER2: human epidermal growth factor receptor type-2; NLR: neutrophil to lymphocyte ratio; HG: histological grade; RCB: residual cancer burden; NA: not applicable Citation Format: Benjamin Walbaum, César Sánchez, Francisco Acevedo. Elevated linoleic acid levels in red blood cells membrane predicts response to neoadjuvant chemotherapy in breast cancer patients [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-23-11.

Lipids and Fatty Acids in Some Mesopelagic Fish Species: General Characteristics and Peculiarities of Adaptive Response to Deep-Water Habitat

The lipid and fatty acid composition of muscles of mesopelagic fish species Lampanyctus macdonaldi, Bathylagus euryops, Serrivomer beanii, Scopelogadus beanii in the Irminger Sea at deep range were studied. The contents of the total lipids (TLs), total phospholipids (PLs), monoacylglycerols (MAGs), diacylglycerols (DAGs), triacylglycerols (TAGs), cholesterol (Chol), Chol esters, non-esterified fatty acids (NEFAs), and wax esters were determined by HPTLC; the PL classes were determined by HPLC; and fatty acids (FAs) were determined using GC. It was found significant differences in lipid profile of the studied fishes: Chol esters and waxes were dominant in L. macdonaldii and S. beanii, fish species with diel vertical migrations (DVM), while TAGs were prevalent in B. euryops and Sc. Beanii—non-migratory species. It was revealed the species-specific differences in FAs profiles of the studied fish. Along with this, it was detected the similarity of FAs in fish, which is associated with food sources. A comparative analysis of lipids and FAs among L. macdonaldi and S. beanii collected in the Irminger Sea and L. alatus and S. beanii collected in the Tropic Seamount revealed similar biochemical strategies for the accumulation of certain lipids characterized the mesopelagic inhabit despite latitude differences of the area of study.

Fatty acid profiles of selected traditional and new improved rice varieties of Sri Lanka

This study evaluated fatty acid profiles (FAPs) of fifteen pigmented and non-pigmented traditional and new improved rice varieties (RVs) of Sri Lanka. Fat was extracted from rice flour, derivatized to methyl esters and analyzed by gas chromatography (n = 3 each). Results showed significant (P < 0.05) differences in FAPs among the tested RVs. Total fatty acids, saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA) and total unsaturated fatty acids of selected RVs varied from 22.00–32.29, 4.85–7.36, 9.44–14.55, 6.87–10.31 and 16.96–24.87 mg/g of rice respectively. Further, PUFA/SFA ratios varied from 1.22 to 1.63. The major fatty acids palmitic, oleic and linoleic acids together contributed nearly 90–96 % of total fatty acids present in rice. Interestingly, differences among RVs in terms of FAPs were due to differences in individual fatty acids in RVs irrespective of traditional or new improved and red or white RVs. In conclusion, nutritionally sound healthy RVs can be selected by studying its total FAP. This is the 1st study to report total FAP of a large set of Sri Lankan rice varieties and report differences among FAP of traditional and new improved rice varieties world over.

Intra- and Inter-Specific Variation in Edible Jellyfish Biomarkers and Implications for Origin Traceability and Authentication

With the continuous development of jellyfish fisheries and food products around the world, an effective traceability system has become increasingly prominent. This study provides insight into the origin traceability and authentication of two commercially important jellyfish species, flame jellyfish Rhopilema esculentum and Nomura’s jellyfish Nemopilema nomurai, while investigating the intra- and inter-specific variation in fatty acid (FA) profiles and carbon and nitrogen stable isotope ratios (δ13C and δ15N). Results showed significant differences in FA profiles and isotopic values in fresh bell tissues between wild and farmed R. esculentum and among geographic origins, possibly due to different food sources, nutritional status, and energy costs that each group experiences at a given location. The linear discriminant analysis indicated that δ13C, δ15N, C16:0, C17:0, C18:0, C16:1n7, and C20:5n3 were suitable discriminatory variables with a high rate of correct classification for distinguishing origins of R. esculentum. In addition, inter-specific FA profiles/biomarkers, combined with isotopic values, suggests the variety of dietary sources and trophic positions of sympatric similar-sized R. esculentum and N. nomurai and the potential use of biomarkers, especially stable isotope analysis, for distinguishing sympatric jellyfish species. These results highlighted the complementarity of FA and stable isotope analyses and provide an alternative approach for improving the origin traceability and authenticity evaluation of untreated edible jellyfish. Furthermore, this study adds new information regarding the biochemical compositions of jellyfish species.

Biofortification of Hens Eggs with Polyunsaturated Fatty Acids by New Dietary Formulation: Supercritical Microalgal Extract.

Simple SummaryPolyunsaturated fatty acids (PUFAs) are essential components of the human diet. The consumption of PUFA can be increased by enriching animal products, such as eggs, with bioactive compounds. New dietary feed supplements were elaborated to increase the level of PUFAs in hens eggs. Nutritional and technological aspects related to the development of functional eggs were discussed. Experimental works dealing with feeding hens new supplements and an investigation of the bioavailability of PUFAs and their transfer to eggs content were undertaken. Analysis of the results obtained during tests showed that used additives may increase the content of such fatty acids (FAs) in eggs: docosapentaenoic acid (DPA, C22:5 n-3), eicosadienoic acid (C22:2 n-6), and the total omega-6 polyunsaturated fatty acids content (PUFA n-6). The investigated additives may also reduce the content of saturated fatty acids (SFA) such as pentadecanoic acid (C15:0).The aim of the study was to evaluate the effect of Spirulina platensis, formulation containing microalgal extract, post-extraction residue, and formulation without algal extract (containing only emulsifier) on the content of FAs in the eggs of laying hens. The experiment was conducted on 90 laying hens (ISA Brown) as a completely randomized design. Hens were assigned to five experimental groups (six replicates). The FAs content in eggs was determined after 30, 60, 90, and 120 days of the experiment. There were no statistically significant differences in FA profiles after 30 days of the experiment. It was shown that after 60, 90, and 120 days of the experiment, the investigated additives had a significant impact on the content of such acids as: dodecanoic acid (C12:0), C15:0, nonadecanoic acid (C19:0), myristoleic acid (C14:1 n-5), α-linolenic acid (ALA, C18:3 n-3), DPA, C20:2 n-6, and decosahexaenoic acid (DHA C22:6 n-6). There were also significant differences in total PUFA n-3, PUFA n-6, and n-6/n-3 ratio in eggs. The obtained results suggest that the use of algae extract and emulsifier in laying hens nutrition has the greatest impact on the FA profile in the eggs.

Conversion of rainforest to oil palm and rubber plantations alters energy channels in soil food webs.

In the last decades, lowland tropical rainforest has been converted in large into plantation systems. Despite the evident changes above ground, the effect of rainforest conversion on the channeling of energy in soil food webs was not studied. Here, we investigated community‐level neutral lipid fatty acid profiles in dominant soil fauna to track energy channels in rainforest, rubber, and oil palm plantations in Sumatra, Indonesia. Abundant macrofauna including Araneae, Chilopoda, and Diplopoda contained high amounts of plant and fungal biomarker fatty acids (FAs). Lumbricina had the lowest amount of plant, but the highest amount of animal‐synthesized C20 polyunsaturated FAs as compared to other soil taxa. Mesofauna detritivores (Collembola and Oribatida) contained high amounts of algal biomarker FAs. The differences in FA profiles between taxa were evident if data were analyzed across land‐use systems, suggesting that soil fauna of different size (macro‐ and mesofauna) are associated with different energy channels. Despite that, rainforest conversion changed the biomarker FA composition of soil fauna at the community level. Conversion of rainforest into oil palm plantations enhanced the plant energy channel in soil food webs and reduced the bacterial energy channel; conversion into rubber plantations reduced the AMF‐based energy channel. The changes in energy distribution within soil food webs may have significant implications for the functioning of tropical ecosystems and their response to environmental changes. At present, these responses are hard to predict considering the poor knowledge on structure and functioning of tropical soil food webs.

In vitro biohydrogenation of 13C-labeled α-linolenic acid in response to ruminal alterations associated with diet-induced milk fat depression in ewes

The basis for marine lipid-induced milk fat depression (MFD) has not been established yet, but recent reports suggest the putative contribution of shifts in the ruminal metabolism of α-linolenic acid (ALA). To test this hypothesis, an isotopic tracer approach was used in batch cultures of rumen microorganisms with inoculum collected from cannulated ewes fed either a total mixed ration without lipid supplementation (control inoculum) or the same diet supplemented with 2% of fish oil, which is known to cause MFD in lactating sheep (FO-MFD inoculum). The [1-13C]ALA was added at a dose of 1% of incubated dry matter and the proportions of 13C-labeled fatty acids (FA) were examined after 24 h of incubation, using complementary gas chromatography and gas chromatography-combustion isotope ratio mass spectrometry (GC-C-IRMS) analyses. Expected differences in FA profiles were confirmed between control and FO-MFD inocula (e.g., large decreases in 18:0 and increases in most 18:1 and 18:2 intermediates, particularly trans isomers, to fish oil supply). The biohydrogenation of 13ALA was extensive and yielded multiple metabolites, with a total of 48 chromatographic peaks showing 13C enrichment, regardless of the inoculum type. However, although ALA was biohydrogenated through common pathways under standard or MFD conditions, large changes in the accumulation of 13C-labeled FA suggest important differences in the relative contribution of each specific route. First, increased accumulation of trans-11-containing FA in FO-MFD incubations was accompanied by a general repression of the trans-13/14 pathway (supported by lower trans-13+14 18:1 or trans-11,trans-13 18:2 proportions), together with a lower production of cis FA (e.g., cis-9, -12, and -15 18:1 and some cis,cis 18:2). Results also downplayed the relevance of the trans-11 to trans-10 shift as an effective marker of diet-induced MFD in sheep, and challenged the involvement of some trans-10 intermediates (e.g., trans-10 18:1 and trans-10,cis-15 18:2) in the low-fat milk syndrome in this species. Conversely, increased abundance of most 18:3 intermediates (including some unidentified isomers) might be representative of ruminal alterations related to fish oil supplementation in ewes. Further research is necessary to examine the potential association between these findings and MFD in lactating animals.

Fatty Acid Profile and the sn-2 Position Distribution in Triacylglycerols of Breast Milk during Different Lactation Stages.

Fatty acid (FA) is the major energy resource in breast milk, which is important for infant development. FAs profiles with sn-2 positional preference were an important part of triacylglycerols due to their better availability. This profile is still not replicated in artificial formulas. This study quantified the FAs profile of total and sn-2 position in human breast milk samples from 103 healthy volunteers during colostrum, transitional, and mature stages. Multicomponent analysis showed significant differences in FAs profiles of different lactation periods, due to that with relative percentage less than 1%. Linoleic acid (LA), mostly located at the sn-1,3 positions of TAGs, was more common in the milk of Chinese women than in western women. The majority of the breast milk did not meet the standard for the ratio of LA/α-linolenic acid for infant formula. FAs related to brain development, mainly at sn-2 in TAGs, were enriched in colostrum. Capric and lauric acids were enriched in transitional and mature breast milk, and capric acid showed sn-1,3 selectivity in TAGs. This study will aid the development of infant formula containing TAGs more similar to human breast milk.

The inclusion of low quantities of lipids in the diet of ruminants fed low quality forages has little effect on rumen function

Biohydrogenation within rumen fluid (RF) proceeds to varying degrees depending on retention time (RT) and type of basal diet, especially the profile of fatty acid (FA) being hydrogenised. The objective of this study was to examine the FA profile and the RT of liquid in the rumen of steers fed a low crude protein (CP) tropical grass (Chloris gayana hay, 38g CP, 17g crude lipid and 752g neutral detergent fibre (aNDFom)/kg dry matter (DM)) supplemented with various lipids. Five rumen cannulated Bos indicus cross, five-year-old steers (799±15kg live weight (LW)) were allocated to a 5×5 Latin square design. The treatments were control, hay only, or the addition of 30g/kg hay DM of lipid sources: Coconut (high lauric acid), cottonseed and soybean (high linoleic acid) or fish oil (high long chain FA (LCFA)). Retention time decreased with addition of soybean oil (14h) but no differences between other treatments (mean 17h). Coconut oil increased lauric and myristic acids in RF. There were no changes in total saturated FA (TSFA) in RF, with exception of a lower concentration for fish oil treatment. Addition of fish oil also decreased the concentration in RF of stearic and linolenic acid, but no differences to coconut and cottonseed treatments for linolenic acid. Fish oil also resulted in higher LCFA, linoleic and total unsaturated FA (TUFA), but no differences to soybean oil for the latter two acids. The conjugated linoleic acid (CLA) was only different in RF between cottonseed and fish oil treatments. Differences in FA profile of oils were only partially translated into the FA profile in RF of steers fed a tropical hay, without great changes in the proportion of CLA isomers observed.

Spatio-temporal variability in the fatty acid profile of the adductor muscle of the common cockle Cerastoderma edule and its relevance for tracing geographic origin

The present study aimed to identify the potential existence of spatio-temporal variability in the fatty acid (FA) profile of the adductor muscle (AM) of a commercially important bivalve, the common cockle Cerastoderma edule, and determine if such variability can be used to trace their geographic origin post-harvesting. Common cockles were sampled in eight ecosystems along the coast of mainland Portugal, as well as in two different channels within one of those ecosystems over two consecutive years. Results showed significant differences in FA profiles among ecosystems, namely due to different levels of eicosapentaenoic acid (EPA; 20:5n-3), arachidonic acid (20:4n-6), ratio of polyunsaturated FA (PUFA) n-3/n-6, monounsaturated FA (MUFA; 18:1n-9 and 20:1n-9/11) and bacterial FA (15:0, 17:0 and 18:1n-7). FA profiles also displayed significant differences between two consecutive years in channels from the same ecosystem. Overall, while the FA profile displayed by the AM of C. edule can be successfully used to trace their geographic origin, the existence of temporal variability requires a periodical verification of FA signatures to identify potential shifts, namely when comparing specimens from the same ecosystem.

Resource partitioning between Pacific walruses and bearded seals in the Alaska Arctic and sub-Arctic.

Climate-mediated changes in the phenology of Arctic sea ice and primary production may alter benthic food webs that sustain populations of Pacific walruses (Odobenus rosmarus divergens) and bearded seals (Erignathus barbatus). Interspecific resource competition could place an additional strain on ice-associated marine mammals already facing loss of sea ice habitat. Using fatty acid (FA) profiles, FA trophic markers, and FA stable carbon isotope analyses, we found that walruses and bearded seals partitioned food resources in 2009-2011. Interspecific differences in FA profiles were largely driven by variation in non-methylene FAs, which are markers of benthic invertebrate prey taxa, indicating varying consumption of specific benthic prey. We used Bayesian multi-source FA stable isotope mixing models to estimate the proportional contributions of particulate organic matter (POM) from sympagic (ice algal), pelagic, and benthic sources to these apex predators. Proportional contributions of FAs to walruses and bearded seals from benthic POM sources were high [44 (17-67)% and 62 (38-83)%, respectively] relative to other sources of POM. Walruses also obtained considerable contributions of FAs from pelagic POM sources [51 (32-73)%]. Comparison of δ13C values of algal FAs from walruses and bearded seals to those from benthic prey from different feeding groups from the Chukchi and Bering seas revealed that different trophic pathways sustained walruses and bearded seals. Our findings suggest that (1) resource partitioning may mitigate interspecific competition, and (2) climate change impacts on Arctic food webs may elicit species-specific responses in these high trophic level consumers.

Fatty Acid Profiles Distinguish Channel Catfish from Three Reaches of the Lower Kaskaskia River and its Floodplain Lakes

AbstractDespite the increasing use of fatty acids (FAs) as biomarkers in aquatic food web analysis, little information is available regarding differences in FA profiles of fish among habitat types in river–floodplain ecosystems. The objectives of this study were to (i) test whether the FA profiles of channel catfish (Ictalurus punctatus) differed among three reaches of the lower Kaskaskia River and its floodplain lakes, and (ii) to compare FA profiles among muscle, liver, and adipose fin tissues collected from these fish. Profiles differed significantly among sites, especially between upper and lower river sites, and between river channel and oxbow lake sites, suggesting differences in FA availability for channel catfish occupying different habitats and river reaches in the Kaskaskia River system. Specifically, the essential FAs 18:2n‐6 and 18:3n‐3 increased in catfish tissues from upstream to downstream reaches, which could reflect increased floodplain connectivity and decreasing impoundment effects downstream. Ratios of n‐3 to n‐6 FAs were higher in fish from oxbow lakes, perhaps suggesting increased use of autochthonous production in the floodplain relative to the main river channel. Muscle and adipose fin FA profiles exhibited similar location‐related trends, whereas liver FA profiles were markedly different from the other tissue types. These results suggest that adipose fin tissue samples may be a viable, less‐invasive alternative to muscle tissue for analysis of FA profiles in channel catfish. Our study supports the use of tissue FA profiles in identifying habitat utilization by channel catfish, and perhaps habitat‐specific energy contributions to riverine consumers. Furthermore, our work highlights floodplain habitat as a potential source of essential n‐3 FA and the associated importance of maintaining river–floodplain connectivity to support aquatic food webs. Copyright © 2014 John Wiley &amp; Sons, Ltd.

Cultural transmission of tool use by Indo-Pacific bottlenose dolphins (Tursiops sp.) provides access to a novel foraging niche.

Culturally transmitted tool use has important ecological and evolutionary consequences and has been proposed as a significant driver of human evolution. Such evidence is still scarce in other animals. In cetaceans, tool use has been inferred using indirect evidence in one population of Indo-Pacific bottlenose dolphins (Tursiops sp.), where particular dolphins ('spongers') use marine sponges during foraging. To date, evidence of whether this foraging tactic actually provides access to novel food items is lacking. We used fatty acid (FA) signature analysis to identify dietary differences between spongers and non-spongers, analysing data from 11 spongers and 27 non-spongers from two different study sites. Both univariate and multivariate analyses revealed significant differences in FA profiles between spongers and non-spongers between and within study sites. Moreover, FA profiles differed significantly between spongers and non-spongers foraging within the same deep channel habitat, whereas the profiles of non-spongers from deep channel and shallow habitats at this site could not be distinguished. Our results indicate that sponge use by bottlenose dolphins is linked to significant differences in diet. It appears that cultural transmission of tool use in dolphins, as in humans, allows the exploitation of an otherwise unused niche.

Nutritional composition and fatty acids profile in cocoa beans and chocolates with different geographical origin and processing conditions

Nutritional composition and fatty acids (FA) profile were determined in cocoa and chocolates of different geographical origin and subject to different processing conditions. Cocoa butter was the major nutrient in cocoa beans and carbohydrates were the most important in chocolates. Cocoa composition and FA profile varied depending on geographical origin whilst in chocolates only carbohydrates and fat content varied significantly due to the effect of origin and no significant effect was observed for processing conditions. Both for cocoa and chocolates differences in FA profile were mainly explained as an effect of the geographical origin, and were not due to processing conditions in chocolate. For cocoa, differences in FA profile were found in C12:0, C14:0, C16:0, C16:1, C17:0, C17:1 and C18:0 whilst for chocolates only differences were found in C16:0, C18:0, C18:1 and C18:2. For all samples, C16:0, C18:0, C18:1 and C18:2 were quantitatively the most important FA. Ecuadorian chocolate showed a healthier FA profile having higher amounts of unsaturated FA and lower amounts of saturated FA than Ghanaian chocolate.

Fatty acid content and composition of sediments from Siberian eutrophic water bodies: Implications for biodiesel production

We studied lipids and fatty acids (FA) in bottom sediments from four Siberian water bodies, Bugach, Lesnoi and Krasnoyarsk freshwater reservoirs and brackish Shira lake, that differed in physico-chemical and biological conditions. We considered the potential of the bottom sediments as a feedstock for biodiesel production and estimated properties of the obtained biodiesel as a fuel on the basis of FA composition. Contents of lipids and FA in the sediments moderately varied and were generally close to the reported data from lacustrine and estuarine systems. We confirmed that long-term eutrophication of a water body resulted in the lipid-rich bottom sediments that make them a feedstock for biodiesel production. Each of the studied water bodies had specific FA composition of sediments likely due to different organic matter sources and transformation processes. Despite these differences in FA profiles, calculated key parameters (cetane number, iodine number and heat of combustion) of biodiesel produced from all the studied sediments met the limits established by current biodiesel standards. Thus, the variation in the sediment FA composition due to environmental characteristics of a water body likely has no principal significance for fuel properties of the obtained biodiesel.

Experimental Evaluation of Fatty Acid Profiles as a Technique to Determine Dietary Composition in Benthic Elasmobranchs

Fatty acid (FA) analysis is a tool for dietary investigation that complements traditional stomach content analyses. Controlled feeding experiments were used to determine the extent to which the FA composition of diet is reflected in the liver and muscle tissue of the Port Jackson shark Heterodontus portusjacksoni. Over 10 wk, two groups of sharks were fed prawns or squid, which have distinct FA profiles. The percentage of total FA was significantly different for shark liver and muscle tissue when comparing controls with prawn- and squid-fed sharks. Compared with experimentally fed sharks, control shark muscle and liver had higher levels of 18:1n-9 and 20:2n-9. When comparing prawn- and squid-fed sharks, only liver tissue showed a significant difference in FA profiles. The livers of prawn-fed sharks were comparatively higher in 18:1n-7, 22:5n-3, 20:0, and 18:1n-9, while the squid-fed sharks had higher levels of 16:0 and 22:6n-3. These FAs in shark liver tissue were all reflective of higher amounts in their respective dietary items, demonstrating the conservative transfer of FA from diet to liver tissue. This study shows that liver and muscle FA profiles can be used as indicators of dietary change through the comparison of controls and fed sharks. The timescale of this study may not have been sufficient for capturing the integration of FA into muscle tissue because only liver FA profiles were useful to distinguish between sharks fed different diets. These findings have important implications for sampling design where FA profiles are used to infer dietary preferences.

Similarity between predator and prey fatty acid profiles is tissue dependent in Greenland sharks (Somniosus microcephalus): Implications for diet reconstruction

Fatty acid (FA) analysis is increasingly being applied to study the feeding ecology of sharks. However, very little knowledge exists regarding how sharks alter dietary FAs prior to incorporation into their tissues, or which tissue provides the most accurate representation of diet. To provide insight into these questions, we compared FAs of muscle, liver and blood (plasma) of 18 individuals of a large elasmobranch, the Greenland shark Somniosus microcephalus (Bloch and Schneider, 1801), to FA profiles of several known prey. Greenland sharks fed predominantly on Greenland halibut (Reinhardtius hippoglossoides, Walbaum 1792) and ringed seal (Pusa hispida, Schreber, 1775) based on stomach contents. Shark muscle FA profiles were the most similar to prey FA profiles, both in relative proportions (e.g. muscle 18:1n−7=7.1±1.0%, ringed seal blubber=7.2±1.2%) and on a μgmg−1 basis (e.g. shark muscle 22:1n−11=47.9±12.0μgmg−1 dw, Greenland halibut muscle =59.9±18.5μgmg−1 dw), indicating direct incorporation of most FAs from the diet. Shark blood plasma FAs also corresponded to prey FAs, and were more similar to shark muscle than liver, which supports the suggestion that muscle FAs were of dietary origin. Shark liver had the most variable FA profiles among individuals and retained higher amounts of long-chain monounsaturated FAs (e.g. 20:1n−9) than were observed in prey. As a consequence, shark liver FAs differed the most from known prey like ringed seal. Our results indicate that the FA profiles of shark tissues will not always match those of dominant prey items, and highlight the use of non-lethal tissues, like muscle and plasma, for studying shark diet using FA analysis. Further work is required to unravel what mechanisms underlie the observed differences in FA profiles and shark–prey FA relationships among different shark species, but data presented here will aid future researchers in more accurately applying FAs to study the diet of large, mobile sharks.

Inter-individual and within-brood variability in the fatty acid profiles of Norway lobster, Nephrops norvegicus (L.) embryos

The present study investigated the existence of inter-individual and within-brood variability in the fatty acid (FA) profile of developing embryos of Nephrops norvegicus. In all surveyed females (n = 5), the quantitatively most important FAs were as follows: 22:6n-3 (20.8 ± 3.9% average of total FA ± standard error), 18:1n-9 (19.5 ± 2.0%), 16:0 (15.2 ± 3.4%), 20:5n-3 (10.2 ± 1.4%), 16:1n-7 (8.9 ± 1.6%), and 18:1n-7 (5.7 ± 1.3%). Differences in FA profiles of embryos in the same clutch were assessed using brooding chamber side (left and right) and pleopod (1st and 2nd, 3rd and 4th, and 5th) as predictive factors. There were no significant differences in the FA composition of embryos sampled from both sides of the brooding chamber in 4 of the 5 surveyed females. However, all females exhibited significant differences in the FA profiles of embryos sampled from different pleopods. Both saturated FA (SFA) and highly unsaturated FA (HUFA) present in developing embryos exhibited marked differences along the breeding chamber. Overall, FA reserves appeared to vary significantly within broods, which can ultimately be reflected on early larval survival. A potential cause for the within-brood variation recorded in the FA profile of developing embryos include (1) differential female investment during ovarian maturation, mainly due to variation in food quality/availability; (2) differential lipid catabolism during the incubation period of developing embryos, as a consequence of embryos position within the female’s brooding chamber; or (3) differential female investment during ovarian maturation amplified by differential lipid catabolism during the incubation period.

Effect of different grazing systems on upland pastures compared with hay diet on cheese sensory properties evaluated at different ripening times

Milk fatty acid (FA) profiles and sensory properties of Cantal cheese from three equivalent groups of 12 Montbéliarde cows kept indoors and fed hay and concentrates (I), grazing on upland pasture with a diversified flora under continuous mode (C), or grazing on upland re-naturalized temporary grassland under rotational mode (R) were compared. C milk was richer in total cis-C18:1 isomers, odd-and-branched-chain, mono-unsaturated, n-3 and n-6 FAs, while R milk was richer in total trans-C18:1 isomers, rumenic acid and poly-unsaturated FAs. Differences in FA profiles between R and C milks could be explained by differences in grass quality. Cheeses were made on three consecutive days. Panellists were unable to distinguish R and C cheeses at 12-week ripening; differences became perceptible after 24 weeks. The 24-week ripened C cheese gave more intense odour, more intense and persistent aroma, and sourer, more pungent and saltier taste than the corresponding R cheese.

Alterations in Circulating Fatty Acid Composition in Patients with Systemic Lupus Erythematosus

Circulating fatty acids (FAs) may play a role in the disease pathogenesis of patients with systemic lupus erythematosus (SLE). To compare red blood cell (RBC) and plasma FA composition: (1) between female SLE patients and age-matched healthy female (HF) controls and in SLE with history of cardiovascular disease (CVD) and those with no history (SLE+CVD vs SLE-CVD); and (2) between SLE patients who were or were not receiving prednisone treatment at the time of blood sampling. This cross-sectional study consisted of 33 female patients with SLE (11 SLE+CVD, 22 SLE-CVD) and 20 HF controls. Demographics, CVD risk, medication profile, blood biochemistry, and FA composition of RBC and plasma total lipids were determined. Waist circumference and body mass index were higher in SLE patients than in HF controls. These variables along with serum triglycerides, blood glucose, and systolic blood pressure were higher in SLE+CVD than SLE-CVD patients. RBC FA composition showed lower eicosapentaenoic acid (EPA, ω-3 active metabolite) and ω-3 index (EPA+ docosahexaenoic acid) in SLE patients compared with HF controls. The ratio of the RBC inflammatory metabolite, arachidonic acid, to the anti-inflammatory metabolite EPA was also significantly higher in SLE patients than in HF controls. No differences were seen in plasma FA between SLE and HF groups. However, SLE-CVD patients had a more favorable lipid profile than SLE+CVD patients. In SLE patients, the use of prednisone resulted in alteration of both RBC and plasma FA composition. SLE patients, regardless of their history of CVD, have altered plasma and RBC FA composition favoring inflammation. The use of prednisone was associated with differences in FA profile.