The bioconversion of dietary α-linolenic acid to eicosapentaenoic acid in Bombyx mori.

n-3 Long-chain polyunsaturated fatty acids (n-3 LC-PUFAs), including eicosapentaenoic acid (EPA), are essential multifunctional nutrients in animals. Microorganisms such as microalgae are known to be n-3 LC-PUFA producers in aquatic environments. Various aquatic invertebrates, including Harpacticoida copepods, and a few terrestrial invertebrates, such as the nematode Caenorhabditis elegans, possess n-3 LC-PUFA biosynthetic enzymes. However, the capacity for n-3 LC-PUFA biosynthesis and the underlying molecular mechanisms in terrestrial insects are largely unclear. In this study, we investigated the fatty acid biosynthetic pathway in the silkworm Bombyx mori and found that EPA was present in silkworms throughout their development. Stable isotope tracing revealed that dietary α-linolenic acid (ALA) was metabolized to EPA in silkworm larvae. These results indicated that silkworms synthesize EPA from ALA. Given that EPA is enriched in the central nervous system, we propose that EPA confers optimal neuronal functions, similar to docosahexaenoic acid, in the mammalian nervous system.

Fish oil replacement with different vegetable oils in Onychostoma macrolepis: Effects on fatty acid metabolism based on whole-body fatty acid balance method and genes expression.

To evaluate the fatty acid (FA) metabolism status and possibility as a DHA source of farmed Onychostoma macrolepis, a total of 168 fish (2.03 ± 0.23 g) were fed four diets supplemented with fish oil (FO), linseed oil (LO), soybean oil (SO), and a mixture of LO and SO oil (MO), respectively, for 70 days. Body FA compositions were modified reflecting dietary FAs. Comparing liver and intestine fatty acids with fish fed four diets, the content of ARA in fish fed SO was significantly higher than others (P < 0.05), but showed no difference in muscle. The tissue FA profile showed that the FO-fed group successfully deposited DHA, while the LO-fed group converted ALA to DHA effectively, as well as the liver and intestine EPA was notably highest in the FO group, whereas no difference between the FO and LO group in the muscle. The FA results showed that the DHA contents in the muscle of Onychostoma macrolepis are at a medium-high level compared with several other fish species with the highest aquaculture yield. Correspondingly, in the fish fed diet with LO, SO, and MO, the genes of most FA biosynthesis, transportation, and transcriptional regulation factors were increased in the liver and muscle, but no significant difference was observed in the gene expression of Elovl4b, FATP1, and FABP10 in the muscle. In addition, the enzyme activity involved in PUFA metabolism was higher in fish fed vegetable oil-based diets, corroborating the results of the gene expression. Increased in vivo elongase and desaturase (Δ5, Δ6, and Δ9) activities were recorded in fish fed fish oil-devoid diets, which resulted in the appearance of products associated with elongase and desaturase activities in fish. Besides, as the specific n-3 PUFA synthesis substrate, the dietary supplementation of ALA not only retains most of the nutrition value but also ensures the muscular texture, such as fiber diameter and density. It is concluded that farmed O. macrolepis owns strong n-3 LC-PUFA biosynthetic capacity and high DHA contents so it can be a good DHA source for the population.

Docosahexaenoic Acid Supplementation in Lactating Women Increases Breast Milk and Erythrocyte Membrane Docosahexaenoic Acid Concentrations and Alters Infant n-6:n-3 Fatty Acid Ratio.

Background: Low concentrations of docosahexaenoic acid (DHA) or high n-6 (ω-6):n-3 ratio in pregnant women is associated with poor fetal growth velocity and suboptimal neurodevelopment. However, there is a lack of data on levels of important n-6 and n-3 fatty acids (FAs) at different time points during pregnancy and lactation from India. Data on how much DHA is transferred during actual supplementation are also scarce. Objectives: We report the concentrations of n-6 and n-3 FAs in maternal and infant blood and in breast milk following maternal supplementation with DHA or placebo. Methods: A total of 957 pregnant women (≤20 wk) from Belagavi, Karnataka, were randomly assigned to receive either 400 mg/d of algal DHA or placebo through 6 mo postpartum. Blood samples were collected from the mother at recruitment/baseline, delivery, and 6 mo postpartum and from the infant at birth (cord) and 12 mo (venous). Breast milk samples were collected from a subsample at delivery, 1 mo and 6 mo postpartum. The FA profile was analyzed using gas chromatography. Results: The concentration of DHA appeared to be higher in erythrocyte and breast milk samples of the DHA-supplemented group at all subsequent time points. The n-6:n-3 ratio was lower among women in the DHA group at delivery [DHA: 4.08 (1.79); placebo: 5.84 (3.57); P < 0.001] and at 6 mo postpartum [DHA: 5.34 (2.64); placebo: 7.69 (2.9); P < 0.001]. Infants of DHA-supplemented mothers also had a lower n-6:n-3 ratio at delivery and 12 mo. The n-6:n-3 ratio of breast milk increased from delivery through 1 to 6 mo but remained lower in the DHA-supplemented group than in the placebo. Conclusions: Maternal DHA supplementation with 400 mg/d from early pregnancy through 6 mo postpartum significantly increased circulating DHA in breast milk and infant erythrocyte, whereas decreased erythrocyte and breast milk n-6:n-3 ratio. However, maternal supplementation did not get the ratio to the recommended levels.

Influence of Dietary n-3 Long Chain Polyunsaturated Fatty Acid Intake on Oxylipins in Erythrocytes of Women with Rheumatoid Arthritis.

Oxylipins derived from n-3 fatty acids are suggested as the link between these fatty acids and reduced inflammation. The aim of the present study was to explore the effect of a randomized controlled cross-over intervention on oxylipin patterns in erythrocytes. Twenty-three women with rheumatoid arthritis completed 2 × 11-weeks exchanging one cooked meal per day, 5 days a week, for a meal including 75 g blue mussels (source for n-3 fatty acids) or 75 g meat. Erythrocyte oxylipins were quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The results were analyzed with multivariate data analysis. Orthogonal projections to latent structures (OPLS) with effect projections and with discriminant analysis were performed to compare the two diets' effects on oxylipins. Wilcoxon signed rank test was used to test pre and post values for each dietary period as well as post blue-mussel vs. post meat. The blue-mussel diet led to significant changes in a few oxylipins from the precursor fatty acids arachidonic acid and dihomo-É£-linolenic acid. Despite significant changes in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and free EPA in erythrocytes in the mussel group, no concurrent changes in their oxylipins were seen. Further research is needed to study the link between n-3 fatty-acid intake, blood oxylipins, and inflammation.

The Potential of the Marine Microalga Diacronema lutheri in the Prevention of Obesity and Metabolic Syndrome in High-Fat-Fed Wistar Rats.

Long-chain polyunsaturated fatty acids n-3 series (n-3 LC-PUFAs), especially eicosapentaenoic and docosahexaenoic acids, are known to exert preventive effects on obesity and metabolic syndrome. Mainly consumed in the form of fish oil, LC-PUFAs n-3 are also found in significant quantities in other sources such as certain microalgae. The aim of this study was to evaluate the effects of Diacronema lutheri (Dia), a microalga rich in n-3 LC-PUFAs, on metabolic disorders associated with obesity. Three groups of male Wistar rats (n = 6 per group) were submitted for eight weeks to a standard diet or high-fat and high-fructose diet (HF), supplemented or not with 12% of Dia (HF-Dia). Compared to HF rats, HF-Dia rats showed a 41% decrease in plasma triacylglycerol (TAG) and an increase in plasma cholesterol (+35%) as well as in high-density lipoprotein cholesterol (+51%) without change to low-density lipoprotein cholesterol levels. Although fasting glycemia did not change, glucose and insulin tolerance tests highlighted an improvement in glucose and insulin homeostasis. Dia supplementation restored body weight and fat mass, and decreased levels of liver TAG (-75%) and cholesterol (-84%). In HF-Dia rats, leptin was decreased (-30%) below the control level corresponding to a reduction of 68% compared to HF rats. Similarly, the anti-inflammatory cytokines interleukin-4 (IL-4) and IL-10 were restored up to control levels, corresponding to a 74% and 58% increase in HF rats, respectively. In contrast, the level of IL-6 remained similar in the HF and HF-Dia groups and about twice that of the control. In conclusion, these results indicated that the D. lutheri microalga may be beneficial for the prevention of weight gain and improvement in lipid and glucose homeostasis.

The Potential of Phaeodactylum as a Natural Source of Antioxidants for Fish Oil Stabilization.

Worldwide, fish oil is an important and rich source of the health-beneficial omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA). It is, however, troubled by its high susceptibility towards lipid oxidation. This can be prevented by the addition of (preferably natural) antioxidants. The current research investigates the potential of Phaeodactylum carotenoids in this regard. The oxidative stability of fish oil and fish oil with Phaeodactylum addition is evaluated by analyzing both primary (PV) and secondary (volatiles) oxidation products in an accelerated storage experiment (37 °C). A first experimental set-up shows that the addition of 2.5% (w/w) Phaeodactylum biomass is not capable of inhibiting oxidation. Although carotenoids from the Phaeodactylum biomass are measured in the fish oil phase, their presence does not suffice. In a second, more elucidating experimental set-up, fish oil is mixed in different proportions with a Phaeodactylum total lipid extract, and oxidative stability is again evaluated. It was shown that the amount of carotenoids relative to the n-3 LC-PUFA content determined oxidative stability. Systems with a fucoxanthin/n-3 LC-PUFA ratio ≥ 0.101 shows extreme oxidative stability, while systems with a fucoxanthin/n-3 LC-PUFA ratio ≤ 0.0078 are extremely oxidatively unstable. This explains why the Phaeodactylum biomass addition did not induce oxidative stability.

Photo-Oxidative Stability of Aqueous Model Systems Enriched with Omega-3 Long-Chain Polyunsaturated Fatty Acid-Rich Microalgae as Compared to Autoxidative Stability.

Several species of microalgae are promising as an alternative source of omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA). Photoautotrophic species show the greatest potential, since incorporating them into food products leads to oxidatively stable products; however, the presence of photosensitizers could reduce the shelf-life due to the appearance of photo-oxidation on exposure to light. This study investigated the oxidative impact of illumination for aqueous model suspensions enriched with Phaeodactylum (phototrophic microalgae─containing potential photosensitizers) and Schizochytrium (heterotrophic microalgae─lacking photosensitizers) during storage for 28 days at 37 °C. Primary (peroxide value) and secondary (volatiles with gas chromatography (GC)-mass spectrometry) oxidation products, n-3 LC-PUFA content (GC), and pigments (high-pressure liquid chromatography) were assessed. The results showed that photo-oxidation did not cause oxidative instability for Phaeodactylum samples compared with strong autoxidation in Schizochytrium samples. For the Phaeodactylum-enriched suspensions, only minimal photo-oxidation could be detected and the n-3 LC-PUFA content remained stable throughout storage regardless of illumination.

Climate change and n-3 LC-PUFA availability.

Omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) are essential fatty acids for the growth, development and survival of virtually all organisms. There is increasing evidence that anthropogenic climate change has a direct and indirect impact on the availability of natural n-3 LC-PUFA. However, this information is fragmented and not well organized. Therefore, this article reviewed published data from laboratory experiments, field experiments and model simulations to reveal the impact of climate change on the global supply of natural n-3 LC-PUFA and how this will limit the availability of n-3 LC-PUFA in the future food web. In general, climate change can significantly reduce the availability of natural n-3 LC-PUFA in grazing food webs in the following ways: 1) decrease the total biomass of phytoplankton and shift the plankton community structure to a smaller size, which also reduce the biomass of animals in higher trophics; 2) reduce the n-3 LC-PUFA content and/or quality (n-3: n-6 ratio) of all marine organisms; 3) reduce the transfer efficiency of n-3 LC-PUFA in grazing food web. In addition, as an anthropogenic climate adaptation measure, this review also proposed some alternative sources of n-3 LC-PUFA and determined the direction of future research. The information in this article is very useful for providing a critical analysis of the impact of climate change on the supply of natural n-3 LC-PUFA. Such information will aid to establish climate adaptation or management measures, and determine the direction of future research.

Tilapia can be a Beneficial n-3 LC-PUFA Source due to Its High Biosynthetic Capacity in the Liver and Intestine.

To assess whether farmed tilapia can be a beneficial n-3 long-chain polyunsaturated fatty acid (LC-PUFA) source for human health, four diets with linoleic acid (LA) to α-linolenic acid (ALA) ratios at 9, 6, 3, and 1 were prepared to feed juveniles for 10 weeks, and the LC-PUFA biosynthetic characteristics in the liver, intestine, and brain and the muscular quality were analyzed. It was shown that the n-3 LC-PUFA levels of the intestine and liver increased in a parallel pattern with the dietary ALA levels. Correspondingly, in the fish fed diet with high ALA levels, the mRNA levels of genes related to LC-PUFA biosynthesis including fads2, elovl5, and pparα in the intestine and elovl5 in the liver were increased, and the muscular n-3 LC-PUFA levels and textures were improved. The results demonstrated that tilapia intestine and liver possess high n-3 LC-PUFA biosynthetic capacity, which suggests that farmed tilapia can be a beneficial n-3 LC-PUFA source.

Diet Prevents Social Stress-Induced Maladaptive Neurobehavioural and Gut Microbiota Changes in a Histamine-Dependent Manner.

Exposure to repeated social stress may cause maladaptive emotional reactions that can be reduced by healthy nutritional supplementation. Histaminergic neurotransmission has a central role in orchestrating specific behavioural responses depending on the homeostatic state of a subject, but it remains to be established if it participates in the protective effects against the insults of chronic stress afforded by a healthy diet. By using C57BL/6J male mice that do not synthesize histamine (Hdc-/-) and their wild type (Hdc+/+) congeners we evaluated if the histaminergic system participates in the protective action of a diet enriched with polyunsaturated fatty acids and vitamin A on the deleterious effect of chronic stress. Behavioural tests across domains relevant to cognition and anxiety were performed. Hippocampal synaptic plasticity, cytokine expression, hippocampal fatty acids, oxylipins and microbiota composition were also assessed. Chronic stress induced social avoidance, poor recognition memory, affected hippocampal long-term potentiation, changed the microbiota profile, brain cytokines, fatty acid and oxylipins composition of both Hdc-/- and Hdc+/+ mice. Dietary enrichment counteracted stress-induced deficits only in Hdc+/+ mice as histamine deficiency prevented almost all the diet-related beneficial effects. Interpretation: Our results reveal a previously unexplored and novel role for brain histamine as a mediator of many favorable effects of the enriched diet. These data present long-reaching perspectives in the field of nutritional neuropsychopharmacology.

Lipid nutritional quality of marine and freshwater bivalves and their aquaculture potential.

Omega-3 Long-chain polyunsaturated fatty acids (n-3 LC-PUFA) are beneficial to human health. Since the industrial revolution, with the tremendous increase of human population, the supply of natural n-3 LC-PUFA is far lower than the nutritional need of n-3 LC-PUFA. Therefore, a new alternative source of natural n-3 LC-PUFA is urgently needed to reduce the supply and demand gap of n-3 LC-PUFA. Mollusks, mainly bivalves, are rich in n-3 LC-PUFA, but the information of bivalves' lipid profile is not well organized. Therefore, this study aims to analyze the published fatty acid profiles of bivalves and reveal the potential of bivalve aquaculture in meeting the nutritional needs of human for n-3 LC-PUFA. There are growing evidence show that the nutritional quality of bivalve lipid is not only species-specific, but also geographical specific. To date, bivalve aquaculture has not been evenly practiced across the globe. It can be seen that aquaculture is predominant in Asia, especially China. Unlike fish aquaculture, bivalve aquaculture does not rely on fishmeal and fish oil inputs, so it has better room for expansion. In order to unleash the full potential of bivalve aquaculture, there are some challenges need to be addressed, including recurrent mass mortalities of farmed bivalves, food safety and food security issues. The information of this article is very useful to provide an overview of lipid nutritional quality of bivalves, and reveal the potential of bivalve aquaculture in meeting the growing demand of human for n-3 LC-PUFA.

Next Generation Sequencing of Single Nucleotide Polymorphic DNA-Markers in Selecting for Intramuscular Fat, Fat Melting Point, Omega-3 Long-Chain Polyunsaturated Fatty Acids and Meat Eating Quality in Tattykeel Australian White MARGRA Lamb.

Meat quality data can only be obtained after slaughter when selection decisions about the live animal are already too late. Carcass estimated breeding values present major precision problems due to low accuracy, and by the time an informed decision on the genetic merit for meat quality is made, the animal is already dead. We report for the first time, a targeted next-generation sequencing (NGS) of single nucleotide polymorphisms (SNP) of lipid metabolism genes in Tattykeel Australian White (TAW) sheep of the MARGRA lamb brand, utilizing an innovative and minimally invasive muscle biopsy sampling technique for directly quantifying the genetic worth of live lambs for health-beneficial omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA), intramuscular fat (IMF), and fat melting point (FMP). NGS of stearoyl-CoA desaturase (SCD), fatty acid binding protein-4 (FABP4), and fatty acid synthase (FASN) genes identified functional SNP with unique DNA marker signatures for TAW genetics. The SCD g.23881050T>C locus was significantly associated with IMF, C22:6n-3, and C22:5n-3; FASN g.12323864A>G locus with FMP, C18:3n-3, C18:1n-9, C18:0, C16:0, MUFA, and FABP4 g.62829478A>T locus with IMF. These add new knowledge, precision, and reliability in directly making early and informed decisions on live sheep selection and breeding for health-beneficial n-3 LC-PUFA, FMP, IMF and superior meat-eating quality at the farmgate level. The findings provide evidence that significant associations exist between SNP of lipid metabolism genes and n-3 LC-PUFA, IMF, and FMP, thus underpinning potential marker-assisted selection for meat-eating quality traits in TAW lambs.

Seawater Culture Increases Omega-3 Long-Chain Polyunsaturated Fatty Acids (N-3 LC-PUFA) Levels in Japanese Sea Bass (Lateolabrax japonicus), Probably by Upregulating Elovl5.

The fatty acid compositions of the fish muscle and liver are substantially affected by rearing environment. However, the mechanisms underlying this effect have not been thoroughly described. In this study, we investigated the effects of different culture patterns, i.e., marine cage culture and freshwater pond culture, on long-chain polyunsaturated fatty acids (LC-PUFA) biosynthesis in an aquaculturally important fish, the Japanese sea bass (Lateolabrax japonicus). Fish were obtained from two commercial farms in the Guangdong province, one of which raises Japanese sea bass in freshwater, while the other cultures sea bass in marine cages. Fish were fed the same commercial diet. We found that omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) levels in the livers and muscles of the marine cage cultured fish were significantly higher than those in the livers and muscles of the freshwater pond cultured fish. Quantitative real-time PCRs indicated that fatty acid desaturase 2 (FADS2) transcript abundance was significantly lower in the livers of the marine cage reared fish as compared to the freshwater pond reared fish, but that fatty acid elongase 5 (Elovl5) transcript abundance was significantly higher. Consistent with this, two of the 28 CpG loci in the FADS2 promoter region were heavily methylated in the marine cage cultured fish, but were only slightly methylated in freshwater pond cultured fish (n = 5 per group). Although the Elovl5 promoter was less methylated in the marine cage reared fish as compared to the freshwater pond reared fish, this difference was not significant. Thus, our results might indicate that Elovl5, not FADS2, plays an important role in the enhancing LC-PUFA synthesis in marine cage cultures.

Effect of Carotenoids from Phaeodactylum tricornutum on Palmitate-Treated HepG2 Cells.

Non-alcoholic fatty liver disease represents the most common liver disease and is characterized by an excess of lipid accumulation in hepatocytes, mainly stored as triglycerides. Phaeodactylum tricornutum is a marine microalga, which is rich in bioactive molecules known to be hepatoprotective, such as n-3 long-chain polyunsaturated fatty acids and fucoxanthin. The aim of this study was to investigate the effects of a carotenoid extract from P. tricornutum in a cellular model of non-alcoholic fatty liver disease induced by palmitate treatment. The combined effects of carotenoids and lipids, especially n-3 long-chain polyunsaturated fatty acids, were also investigated by using a total lipophilic extract. HepG2 cells were exposed for 24 h to 250 µM palmitate with or without the addition of carotenoid extract (6 µg/mL) or total lipophilic extract (100 µg/mL). The addition of carotenoid extract or total lipophilic extract prevented the accumulation of triglycerides, total cholesterol and cholesterol esters. The carotenoid extract and total lipophilic extract also decreased the mRNA expression levels of genes involved in lipogenesis (ACACA, FASN, SCD and DGAT1) and cholesterol esterification (ACAT1/SOAT1). In addition, the total lipophilic extract also downregulated the LXR/NR1H3 and SREBF1 genes, which are involved in lipogenesis regulation. By contrast, the carotenoid extract increased the mRNA level of CPT1A, a ß-oxidation related gene, and reduced the lipid droplet accumulation. In conclusion, this study highlights the preventive effects against non-alcoholic fatty liver disease of the two microalga extracts.

Fish oil supplementation in cancer patients. Capsules or nutritional drink supplements? A controlled study of compliance.

BACKGROUND & AIMS: Fish-oil, rich in Omega-3 long chain polyunsaturated fatty acids (n-3 LC PUFAs), may in high doses inhibit the development or progression of cancer cachexia. However, poor compliance to oral nutritional supplements is a well-known problem. We aimed to investigate acceptability and compliance to a nutritional drink with fish-oil compared to an equivalent dose of fish-oil administered as capsules in patients receiving chemotherapy for GI tract cancers. Moreover, we aimed to investigate, if there was a difference between a nutritional drink or capsules with respect to nutritional status and side effects. Finally, we aimed to examine, if n-3 LC PUFAs affect leukocyte and platelet counts, and markers of dose-limiting toxicities of chemotherapy. METHODS: We consecutively included 41 patients with advanced cancer in the controlled study. Patients were allocated (not randomized) to ingest either 10 capsules/day for four weeks or 400 mL/day of a nutritional drink with same dose of n-3 LC PUFA dose. Compliance was assessed by daily self-registration and n-3 LC PUFAs in whole blood. Side effects were assessed by 10 cm visual analog scales. RESULTS: Compliance and daily consumption of n-3 LC PUFAs were 96.4% (94.1-99.3) and 4.8 (4.7-4.9) g/day in the capsule group and 80.8 (55.4-93.6) % and 4.0 (2.8-4.7) g/day in the group, respectively (p ≤ 0.02). We found no differences between the groups with respect to changes in whole blood n-3 LC PUFAs, weight, nutritional status, acceptability or side effects. However, in the capsule group the whole blood n-3 LC PUFAs correlated negatively with the increase in nausea (rs = -0.39, p = 0.05), but not in the nutritional drink group. Nausea, reduced appetite and loose stools were of greatest importance for the deviations from recommended doses. The number of capsules had a negative impact on acceptability and compliance, whereas this was mainly related to taste and texture in the nutritional drink group. No changes in median thrombocyte or leukocyte blood counts were observed. CONCLUSIONS: Fish oil in capsules appeared to result in better compliance compared to a nutritional drink with an equivalent dose of n-3 LC PUFAs. However, capsules and the drink did not differ with respect to the effect on nutritional status or side effects. TRIAL REGISTRATION CLINICALTRIALS. GOV IDENTIFIER: NCT03751384.

Influence of blue mussel (Mytilus edulis) intake on fatty acid composition in erythrocytes and plasma phospholipids and serum metabolites in women with rheumatoid arthritis.

Intake of blue mussels decreased disease activity in women with rheumatoid arthritis (RA) in the randomized cross-over MIRA (Mussels, inflammation and RA) trial. This study investigates potential causes of the decreased disease activity by analysing fatty acid composition in erythrocytes and plasma phospholipids and serum metabolites in samples from the participants of the MIRA trial. Twenty-three women completed the randomized 2 × 11-week cross-over dietary intervention, exchanging one cooked meal per day, 5 days a week, with a meal including 75 g blue mussels or 75 g meat. Fatty acid composition in erythrocytes and plasma and 1H Nuclear Magnetic Resonance (1H NMR) metabolomics data were analysed with multivariate data analysis. Orthogonal Projections to Latent Structures with Discriminant Analysis (OPLS-DA) and OPLS with effect projections (OPLS-EP) were performed to compare the two diets. The fatty acid profile in erythrocytes was different after intake of blue mussels compared to the control diet, and all samples were correctly classified to either the blue mussel diet or control diet. Changes following blue mussel intake included significant increases in omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) at the group level but not for all individuals. The fatty acid profile in plasma phospholipids and 1H NMR serum metabolites did not differ significantly between the diets. To conclude, modelling fatty acids in erythrocytes may be a better biomarker for seafood intake than only EPA and DHA content. The change in fatty acid pattern in erythrocytes could be related to reduction in disease activity, although it cannot be excluded that other factors than omega-3 fatty acids potentiate the effect.

Preventive Effects of the Marine Microalga Phaeodactylum tricornutum, Used as a Food Supplement, on Risk Factors Associated with Metabolic Syndrome in Wistar Rats.

Long-chain polyunsaturated fatty acids, n-3 series (n-3 LC-PUFA), are known for their preventive effects against cardiovascular disease. In an unfavourable economic and environmental context of fish oil production, marine microalgae could be an alternative source of n-3 LC-PUFA and are of interest for human nutrition. The aim of this study was to evaluate the effects of P. tricornutum, a microalga rich in eicosapentaenoic acid and used as a food supplement, on the metabolic disorders associated with metabolic syndrome and obesity development. Three male Wistar rat groups (n = 6) were submitted for eight weeks to a standard diet or high-fat diet (HF) with 10% fructose in drinking water, supplemented or not with 12% of P. tricornutum (HF-Phaeo). Supplementation led to n-3 LC-PUFA enrichment of lipids in the liver, plasma and erythrocytes. Plasma transaminases showed no difference between the HF and HF-Phaeo groups. Body weight, fat mass, inflammatory markers and insulinemia decreased in HF-Phaeo rats versus the HF group. Plasma total cholesterol, triacylglycerols and leptine diminished in HF-Phaeo rats, while HDL-cholesterol increased. In conclusion, this study highlights the beneficial effects of P. tricornutum in reducing the metabolic disorders associated with metabolic syndrome.

Enhancing Omega-3 Long-Chain Polyunsaturated Fatty Acid Content of Dairy-Derived Foods for Human Consumption.

Omega-3 polyunsaturated fatty acids (n-3 PUFA) are termed essential fatty acids because they cannot be synthesized de novo by humans due to the lack of delta-12 and delta-15 desaturase enzymes and must therefore be acquired from the diet. n-3 PUFA include α-linolenic acid (ALA, 18:3n-3), eicosapentaenoic (EPA, 20:5n-3), docosahexaenoic (DHA, 22:6n-3), and the less recognized docosapentaenoic acid (DPA, 22:5n-3). The three long-chain (≥C20) n-3 PUFA (n-3 LC-PUFA), EPA, DHA, and DPA play an important role in human health by reducing the risk of chronic diseases. Up to the present time, seafood, and in particular, fish oil-derived products, have been the richest sources of n-3 LC-PUFA. The human diet generally contains insufficient amounts of these essential FA due largely to the low consumption of seafood. This issue provides opportunities to enrich the content of n-3 PUFA in other common food groups. Milk and milk products have traditionally been a major component of human diets, but are also among some of the poorest sources of n-3 PUFA. Consideration of the high consumption of milk and its processed products worldwide and the human health benefits has led to a large number of studies targeting the enhancement of n-3 PUFA content in dairy products. The main objective of this review was to evaluate the major strategies that have been employed to enhance n-3 PUFA content in dairy products and to unravel potential knowledge gaps for further research on this topic. Nutritional manipulation to date has been the main approach for altering milk fatty acids (FA) in ruminants. However, the main challenge is ruminal biohydrogenation in which dietary PUFA are hydrogenated into monounsaturated FA and/or ultimately, saturated FA, due to rumen microbial activities. The inclusion of oil seed and vegetable oil in dairy animal diets significantly elevates ALA content, while the addition of rumen-protected marine-derived supplements is the most effective way to increase the concentration of EPA, DHA, and DPA in dairy products. In our view, the mechanisms of n-3 LC-PUFA biosynthesis pathway from ALA and the biohydrogenation of individual n-3 LC-PUFA in ruminants need to be better elucidated. Identified knowledge gaps regarding the activities of candidate genes regulating the concentrations of n-3 PUFA and the responses of ruminants to specific lipid supplementation regimes are also critical to a greater understanding of nutrition-genetics interactions driving lipid metabolism.

Endogenous biosynthesis of n-3 long-chain PUFA in Atlantic salmon.

A more efficient utilisation of marine-derived sources of dietary n-3 long-chain PUFA (n-3 LC PUFA) in cultured Atlantic salmon (Salmo salar L.) could be achieved by nutritional strategies that maximise endogenous n-3 LC PUFA synthesis. The objective of the present study was to quantify the extent of n-3 LC PUFA biosynthesis and the resultant effect on fillet nutritional quality in large fish. Four diets were manufactured, providing altered levels of dietary n-3 substrate, namely, 18 : 3n-3, and end products, namely, 20 : 5n-3 and 22 : 6n-3. After 283 d of feeding, fish grew in excess of 3000 g and no differences in growth performance or biometrical parameters were recorded. An analysis of fatty acid composition and in vivo metabolism revealed that endogenous production of n-3 LC PUFA in fish fed a diet containing no added fish oil resulted in fillet levels of n-3 LC PUFA comparable with fish fed a diet with added fish oil. However, this result was not consistent among all treatments. Another major finding of this study was the presence of abundant dietary n-3 substrate, with the addition of dietary n-3 end product (i.e. fish oil) served to increase final fillet levels of n-3 LC PUFA. Specifically, preferential ß-oxidation of dietary C18 n-3 PUFA resulted in conservation of n-3 LC PUFA from catabolism. Ultimately, this study highlights the potential for endogenous synthesis of n-3 LC PUFA to, partially, support a substantial reduction in the amount of dietary fish oil in diets for Atlantic salmon reared in seawater.

Enhanced Omega-3 Polyunsaturated Fatty Acid Contents in Muscle and Edible Organs of Australian Prime Lambs Grazing Lucerne and Cocksfoot Pastures.

The enhancement of health-beneficial omega-3 long⁻chain (≥C20) polyunsaturated fatty acid (n-3 LC-PUFA) contents in the muscle, liver, heart, and kidney of Australian prime lambs through pasture grazing and supplementation with oil infused pellets was investigated. Forty-eight first-cross prime lambs were randomly assigned into a split-plot design with pasture type as the main plot effect and pellet supplementation as a sub-plot effect in a feeding trial that lasted for nine weeks. The n-3 LC-PUFA content in Longissimus dorsi muscle of all lambs was well above the 30 mg threshold for "omega-3 source" nutrition claim under the Australian Food Standards and Guidelines. Pasture type impacted the fatty acid contents in muscle, heart, and kidney of prime lambs. Lambs grazing cocksfoot grass only had high 18:3n-3 (ALA) and n-3 LC-PUFA contents (67.1 mg/100 g and 55.2 mg/100 g, respectively) in the Longissimus dorsi muscle, which was not significantly different (p > 0.8990) from the contents of lambs grazing only lucerne. Supplementation of pellets with or without oil infusion to grazing lambs generally decreased the ALA and n-3 LC-PUFA contents and increased the n-6/n-3 ratio in the Longissimus dorsi muscle. The fatty acid content in the internal organs of grazing lambs was also affected by pellet supplementation. The liver and kidney of grazing lambs were both "good sources" (60 mg/100 g) of omega-3. The cocksfoot grass showed considerable potential for producing healthy, premium quality meat with high contents of n-3 and n-3 LC-PUFA, which may consequently enhance the omega-3 intake of Australian lamb consumers.