Changes in Tissue Lipid and Fatty Acid Composition of Farmed Rainbow Trout in Response to Dietary Camelina Oil as a Replacement of Fish Oil

Camelina oil (CO) replaced 50 and 100 % of fish oil (FO) in diets for farmed rainbow trout (initial weight 44 ± 3 g fish^?1). The oilseed is particularly unique due to its high lipid content (40 %) and high amount of 18:3n‐3 (α‐linolenic acid, ALA) (30 %). Replacing 100 % of fish oil with camelina oil did not negatively affect growth of rainbow trout after a 12‐week feeding trial (FO = 168 ± 32 g fish^?1; CO = 184 ± 35 g fish^?1). Lipid and fatty acid profiles of muscle, viscera and skin were significantly affected by the addition of CO after 12 weeks of feeding. However, final 22:6n‐3 [docosahexaenoic acid (DHA)] and 20:5n‐3 [eicosapentaenoic acid (EPA)] amounts (563 mg) in a 75 g fillet (1 serving) were enough to satisfy daily DHA and EPA requirements (250 mg) set by the World Health Organization. Other health benefits include lower SFA and higher MUFA in filets fed CO versus FO. Compound‐specific stable isotope analysis (CSIA) confirmed that the δ¹³C isotopic signature of DHA in CO fed trout shifted significantly compared to DHA in FO fed trout. The shift in DHA δ¹³C indicates mixing of a terrestrial isotopic signature compared to the isotopic signature of DHA in fish oil‐fed tissue. These results suggest that ~27 % of DHA was synthesized from the terrestrial and isotopically lighter ALA in the CO diet rather than incorporation of DHA from fish meal in the CO diet. This was the first study to use CSIA in a feeding experiment to demonstrate synthesis of DHA in fish.     

Flaxseed Oil or n-7 Fatty Acid-Enhanced Fish Oil Supplementation Alters Fatty Acid Composition,Plasma Insulin and Serum Ceramide Concentrations,and Gene Expression in Lambs

The objective of this study was to examine the effects of flaxseed (FLAX) oil or 16-carbon n-7 fatty acid -enhanced fish oil (Provinal; POA) supplementation on serum, liver and skeletal muscle fatty acid concentrations, serum ceramide and plasma insulin concentrations, and gene expression. Lambs [n = 18; 42 ± 5.6 kg body weight (BW); 7 months] were individually fed one of the three treatments: (1) control (CON), no oil supplement, (2) FLAX; at 0.1% of BW, or (3) POA at 0.1% of BW for 60 days. Daily feed intake and weight gain were decreased by 21% and 34%, respectively, for POA than FLAX. Liver and skeletal muscle concentrations of palmitoleic acid were greater by 396% and 87%, respectively, for POA than FLAX; whereas, liver and skeletal muscle α-linolenic acid concentrations were greater by 199% and 118%, respectively, for FLAX. Supplementation with POA also had greater serum and tissue concentrations of eicosapentaenoic and docosahexaenoic acids. Serum glucose and plasma insulin concentrations were elevated with FLAX supplementation at the end of the study. Supplementation with POA altered serum ceramide concentrations compared to CON or FLAX. Oil supplementation, both FLAX and POA, downregulated expression of unesterified fatty acid receptors (FFAR) 1 and FFAR4 in the liver; however, oil supplementation upregulated expression of FFAR1 in muscle. Interleukin-6 (IL6) and tumor necrosis factor-α (TNFA) expression were downregulated with oil supplementation in the liver; however, FLAX upregulated TNFA in muscle. These results show that oil supplementation can enhance uptake and deposition of unique fatty acids that alter ceramide concentrations and gene expression in tissues.     

n-3 Fatty Acid Distribution of Commercial Fish Species Components

For application of n-3 fatty acids, distribution of the fatty acid compositions of different parts of (head, tail, fins and skin = HTFS, liver, viscera and muscle tissue) five commercially important fish species from the Persian Gulf (Scomberomorus commersoni, Thunnus tonggol, Euthynnus affinis, Scomberomorus guttatus and Dussumieria acuta) as good sources of n-3 PUFA were studied. The richest source of n-3 were HTFS in S. guttatus and S. commersoni, liver in S. guttatus, total body of D. acuta, liver of E. affinis and T. tonggol, followed by viscera of E. affinis. The content of these fatty acids were the same in viscera of tonggol, liver of S. commersoni, and HTFS of E. affinis. Moreover, muscle of E. affinis and HTFS of T. tonggol and also muscle of S. guttatus and T. tonggol had the same n-3 contents as the viscera of S. commersoni. So, it was concluded that HTFS and viscera (which are discarded as residues) are as useful as muscle and liver and can be a source of economically available n-3 PUFA. Muscle had the lowest proportion of n-3 in E. affinis, T. tonggol, and S. guttatus in comparison with other organs of these fish species. The highest n-3:n-6 ratio was observed in D. acuta. Finally, the cluster analysis showed that with respect to n-3 and other PUFA contents, HTFS of S. commersoni and D. acuta with S. guttatus on the one hand, and HTFS of T. tonggol and E. affinis on the other hand were similar to each other. In addition, viscera of S. commersoni and S. guttatus were similar followed by T. tonggol and different from E. affinis and D. acuta. In the case of muscle, T. tonggol and S. guttatus had good similarity followed by E. affinis and had no significant similarity with S. commersoni and D. acuta. With regard to liver, the highest similarity was observed between T. tonggol and E. affinis followed by D. acuta and S. guttatus, while S. commersoni did not show similarity with the others.     

Genetic Background and Diet Impact Beef Fatty Acid Composition and Stearoyl-CoA Desaturase mRNA Expression

The intramuscular fat composition of ruminant meats influences the quality of the final product, which explains the increasing interest in assessing the fatty acid profile of meat from different production systems. In this study, it was hypothesized that there are breed- and diet-induced variations on lipid metabolism in the muscle, which may be, at least partially, modulated by the stearoyl-CoA desaturase (SCD) gene expression levels. Forty purebred young bulls from two phylogenetically distant autochthonous cattle breeds, Alentejana and Barrosã (n = 20 for each breed), were assigned to two different diets (low vs. high silage) and slaughtered at 18 months of age. Meat fatty acid composition, including the detailed conjugated linoleic acid (CLA) isomeric profile, was determined along with the SCD mRNA levels. Meat from Barrosã bulls fed the low silage diet was richer in monounsaturated fatty acids, CLA and trans fatty acids, when compared to that from Alentejana bulls. The meat content in polyunsaturated fatty acids was similar across experimental groups. Moderate positive correlations between the SCD mRNA levels and the products of this enzyme activity were found, although they were not reflected on the calculated desaturase indices. Overall, these findings highlight the importance of taking into account the genetic background while devising feeding strategies to manipulate beef fatty acid composition.     

Microwave-Assisted,Base-Catalyzed Synthesis of Fatty Acid Methyl Esters from Seeds and Fish Oil Supplements

Growing health awareness has resulted in the increased use of dietary supplements derived from plants and marine sources, leaving consumers unsure of their best options. There were three objectives of the present study. The first was to design and evaluate an efficient derivatization procedure. The second was to perform a comparative analysis of liquid oils and their corresponding capsules of hemp, chia, and flax seeds. The final objective was to determine the fatty acid (FA) composition of six fish oil products and compare it to the one provided on the label. For the FA profiling, we implemented two efficient, one-step, sustainable methods with high percentage recovery for the synthesis of FA methyl esters (FAME), which use base catalysis and microwave-assisted heating. Our results found no difference in nutritional value between liquid oils and capsules of the seed supplements, with flaxseed and chia offering a higher, beneficial n-3:n-6 ratio compared to hemp oil. Four of the fish oils analyzed contained significantly less eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) than their reported label, and the other two not only agreed with the manufacturers' declaration but were able to fulfill the daily adequate intake (AI) with fewer capsules.     

Bovine Brain Region‐Specific Stearoyl‐CoA Desaturase Expression and Fatty Acid Composition

In this study, we sought to determine the relationship between stearoyl‐CoA desaturase (SCD) gene isoform expression in the bovine brain and the accumulation of 18:1n‐9. Two SCD gene isoforms are found in cows—SCD1 and SCD5. Samples of six brain regions (cerebellum, frontal cortex, hippocampus, hypothalamus, midbrain, and pons) were collected from animals at four different ages (neonates, weanlings, yearlings, and adults) for mRNA isolation and fatty acid analysis. Expression of SCD1 and SCD5 mRNA was compared across age groups to determine its developmental regulation. Fatty acid composition and SCD isoform mRNA expression were compared to examine the correlation of SCD1 and SCD5 with 18:1n‐9 content in different brain regions. We found statistically significant correlations between SCD1 and SCD5 mRNA expression and the ratio of 18:1n‐9 to 18:0 across age groups, with stronger correlations observed for SCD5. Similarly, there was a significant correlation between the ratio of 18:1n‐9 to 18:0 and SCD5 mRNA expression across brain regions. SCD1 mRNA and the 18:1n‐9 to 18:0 ratio were negatively correlated in the hippocampus. There was no trend of increasing 18:1n‐9 content or SCD expression with age. Correlations indicated a stronger relationship between SCD5 mRNA expression and the 18:1n‐9 to 18:0 ratio, potentially indicating a strong contribution of the SCD5 isoform to brain 18:1n‐9 content. This is the first study examining a potential role for SCD5 in providing 18:1n‐9 for brain lipids.     

Cloning of Flax Oleic Fatty Acid Desaturase and Its Expression in Yeast

Fatty acid desaturases dehydrogenate acyl chains, which results in the formation of a double bond. Using PCR on flax genomic DNA, we cloned a putative Δ12 fatty acid desaturase (Fad2) gene encoding a 378 amino acid protein. Heterologous expression of this protein in yeast as an N-terminal fusion to GFP showed its localization within endoplasmic reticulum. Analysis of membrane lipids revealed the production of dienoic fatty acids, decreased levels of FAD2 substrates and an increased concentration of longer fatty acids. Higher peroxidation of lipids in FAD2-containing strains is not reflected by any visible phenotype in YPD medium. However, FAD2-containing strains with deleted superoxide dismutase genes exhibited significant growth reductions under oxidative stress.     

Application of Silver Ion High-Performance Liquid Chromatography for Quantitative Analysis of Selected n-3 and n-6 PUFA in Oil Supplements

The aim of this study was to develop a simple method for simultaneous determination of selected cis/cis PUFA–LNA (18:2), ALA (18:3), GLA (18:3), EPA (20:5), and DHA (22:6) by silver ion high‐performance liquid chromatography coupled to a diode array detector (Ag‐HPLC‐DAD). The separation was performed on three Luna SCX Silver Loaded columns connected in series maintained at 10 °C with isocratic elution by 1 % acetonitrile in n‐hexane. The applied chromatographic system allowed a baseline separation of standard mixture of n‐3 and n‐6 fatty acid methyl esters containing LNA, DHA, and EPA and partial separation of ALA and GLA positional isomers. The method was validated by means of linearity, precision, stability, and recovery. Limits of detection (LOD) for considered PUFA standard solutions ranged from 0.27 to 0.43 mg L^?1. The developed method was used to evaluate of n‐3 and n‐6 fatty acids contents in plant and fish softgel oil capsules, results were compared with reference GC‐FID based method.     

Dietary n-3 Fatty Acid Deficiency in Mice Enhances Anxiety Induced by Chronic Mild Stress

Docosahexaenoic acid (DHA), is the major polyunsaturated fatty acid in the brain and is important for both the structure and the function of the nervous system. Mice were fed either an n-3 fatty acid deficient (n-3 Def) or adequate (n-3 Adq) diet for two generations. The mice were housed under two conditions, as a group or in isolation and the major point of the study was to determine whether n-3 fatty acid deficiency would enhance isolation-induced anxiety. Isolation stress was assessed using the novelty suppressed feeding paradigm (NSF) after a 3-week period and the test lasted a maximal duration of 10 min. The number of successful mice consuming food pellets within 5 min in the n-3 Def diet group was low in both housing conditions (group housing, 33% and isolated, 30%), but was 92% in the group housed and 50% in the isolated group when fed the n-3 Adq diet. In the subsequent 5 min period, the isolated housing group consuming the n-3 Adq diet increased up to 79% and the group housed animals fed the n-3 Def diet increased to 67%. However, those that consumed the n-3 deficient diet combined with isolation stress exhibited no increase. These results suggested that the n-3 deficient mice had increased anxiety that was enhanced by the chronic mild stress of social isolation.     

Tissue Cultures of Rapeseed Glucosinolates and Fatty Acid Composition

Glucosinolates could not be detected as their aglycones in the lipid-free residues of tissue cultures of two varieties of rapeseed (Brassica napus). Erucic acid, a major fatty acid in the lipids from the seeds was found to be present in very small quantities.     

Supplementation of DHA-Rich Microalgal Oil or Fish Oil During the Suckling Period in Mildly n-3 Fatty Acid-Deficient Rat Pups

Long-chain polyunsaturated fatty acids (LC-PUFA), particularly arachidonic acid (ARA) and docosahexaenoic acid (DHA), are considered critical for the development of infants and are commonly supplemented in infant formulae. In this study, two common sources of n-3 LC-PUFA, fish oil (FO) and DHA-rich microalgal oil (DMO), were fed to rat pups of mildly n-3 PUFA-deficient dams to compare changes in LC-PUFA of tissue phospholipids. The milk from dams fed a n-3 PUFA-deficient diet contained less n-3 LC-PUFA than that of dams fed a control diet (AIN-93G). The pups' were given orally 1 mg/g weight of either FO or DMO for 17 days between the ages of 5 and 21 days, the pups were weaned, and sacrificed 1 week later for analysis of fatty acid compositions of brain, heart, kidney, spleen, and thymus phospholipids. Although both FO and DMO brought about a recovery in the tissue DHA levels compared to those of the control group (pups from AIN-93G-fed dams), DMO was more effective at restoring tissue LC-PUFA status because it was richer in DHA than FO. FO had a slightly lower PUFA level than that required to bring the LC-PUFA status completely to normal levels in this experiment, and EPA did not accumulate in tissues under the conditions tested here. These results demonstrate the effectiveness of ingesting either FO or DMO in the pre-weaning period for improving mild n-3 PUFA deficiency.     

Presence of Fatty‐Acid Ethyl Esters in Krill Oil Dietary Supplements

Krill oil dietary supplements are increasingly used for their high concentrations of phospholipids (PL), which offer reportedly greater bioavailability of n‐3 polyunsaturated fatty acids (PUFA) than those of triacylglycerols or fatty‐acid ethyl esters (FAEE) commonly found in fish oils and fish‐oil concentrates. This work evaluated the lipid composition of 22 commercial krill oil (CKO) supplements available in the US market, and found ten products (i.e. 45%) contained significant amounts of FAEE, varying from 41% to 75%, by weight. These concentrations of FAEE differed from the minor abundances of FAEE (<3%, by weight) found in manufacturer‐supplied krill oil. The potential clinical and regulatory implications for these findings warrant further investigation.     

Dietary n-3 Fatty Acids Significantly Suppress Lipogenesis in Bovine Muscle and Adipose Tissue: A Functional Genomics Approach

Changes in fatty acid composition of longissimus muscle and subcutaneous adipose tissue of German Holstein bulls induced by a grass-silage/n-3 fatty acid based intervention diet versus a maize-silage/n-6 fatty acid based control diet were analyzed and related to shifts in lipogenic gene expression, protein expression, and enzyme activity patterns. Significantly higher amounts of n-3 fatty acids and by mean factors of 2.2–2.5 decreased n-6/n-3 fatty acid ratios in both tissues were obtained upon n-3 fatty acid intervention. In longissimus muscle, these changes of fatty acid profiles were associated with reduced SREBP1c (p = 0.02), ACC (p = 0.00), FAS (p = 0.10) and SCD (p = 0.03) gene expression, Δ6D (p = 0.03) and SCD (p = 0.03) protein expression as well as SCD enzyme activity (p = 0.03). In subcutaneous adipose tissue, significantly reduced ACC (p = 0.00) and FAS (p = 0.01) gene expression, SCD protein expression (p = 0.02) and SCD enzyme activity (p = 0.03) were detected upon n-3 fatty acid intervention, although lower degrees of correlation between gene and corresponding gene products were obtained in relation to longissimus muscle. The study elucidates tissue-specific functional genomic responses to dietary fatty acid manipulation in regard to fatty acid profile tailoring of animal tissues.     

Contrasting Effects of n-3 and n-6 Fatty Acids on Cyclooxygenase-2 in Model Systems for Arthritis

Cyclooxygenase-2 (COX-2) is intimately involved in symptoms of arthritis while dietary n-3 polyunsaturated fatty acids (PUFA) are thought to be beneficial. In these experiments, using both bovine and human in vitro systems that mimic features of arthritis, we show that the n-3 PUFA eicosapentaenoic acid (EPA) is able to reduce mRNA and protein levels of COX-2. Activity, as assessed through prostaglandin E₂ formation, was also reduced in a dose-dependent manner. These effects of EPA contrasted noticeably with the n-6 PUFA, arachidonic acid. The data provide direct evidence for a molecular mechanism by which dietary n-3 PUFA, such as EPA, can reduce inflammation and, hence, associated symptoms in arthritis.     

Cyclopropenoid and Fatty Acid Composition of Kydia calycina Seed Oil

The seed oil of Kydia calycina is found to contain the following acids (Wt%): Lauric 3.7, myristic 6.0, palmitic 4.9, stearic 11.4, arachidic 2.8, behenic 2.5, oleic 60.6, linoleic 5.3, and cyclopropenoid fatty acid content 2.9.     

The Fatty Acid Composition of Human Follicular Fluid Is Altered by a 6-Week Dietary Intervention That Includes Marine Omega-3 Fatty Acids

The fatty acid composition of human follicular fluid is important for oocyte development and for pregnancy following in vitro fertilization (IVF). This study investigated whether a dietary intervention that included an increase in marine omega-3 fatty acids, olive oil and vitamin D alters the fatty acid composition of human follicular fluid. The association of lifestyle factors with follicular fluid fatty acid composition was also investigated. Fifty-five couples awaiting IVF were randomized to receive the 6-week treatment intervention of olive oil for cooking, an olive oil-based spread, and a daily supplement drink enriched with vitamin D and the marine omega-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) and 56 couples were randomized to receive placebo equivalents. Dietary questionnaires were completed, and samples of blood were taken before and after the intervention. Follicular fluid was collected at oocyte retrieval and the fatty acid profile assessed using gas chromatography. In the control group, individual fatty acids in red blood cells and follicular fluid were significantly correlated. Furthermore, a healthier diet was associated with a lower percentage of follicular fluid arachidonic acid. The follicular fluid of women in the treatment group contained significantly higher amounts of EPA and DHA compared to the control group, while the omega-6 fatty acids linoleic, γ-linolenic, dihomo-γ-linolenic, and arachidonic were lower. This is the first report of a dietary intervention altering the fatty acid composition of follicular fluid in humans. Further research is required to determine whether this intervention improves oocyte quality.     

灵芝孢子油脂肪酸组分分析

脂肪酸含量差异是目前油种真伪鉴别的主要方法,采用气相色谱(GC)法对灵芝孢子油脂肪酸组分进行了分析。结果显示:灵芝孢子油中检出15种脂肪酸,其中饱和脂肪酸占22.931%,主要为棕榈酸(15.729%)、硬脂酸(3.734%)和十七碳酸(1.402),不饱和脂肪酸占76.977%,主要为油酸(63.027%)和亚油酸(12.809%)。同时对市售5个不同品牌灵芝孢子油(100%)软胶囊中油的脂肪酸组分进行了分析,发现其脂肪酸组成及含量比较接近,棕榈酸、十七碳酸、硬脂酸、油酸和亚油酸含量占95%以上,其中棕榈酸平均含量为15.181%,十七碳酸平均含量为1.423%,硬脂酸平均含量为3.722%,油酸平均含量为63.444%,亚油酸含量为13.189%。     

Dietary ALA from Spinach Enhances Liver n-3 Fatty Acid Content to Greater Extent than Linseed Oil in Mice Fed Equivalent Amounts of ALA

Although several works have reported absorption rate differences of n‐3 polyunsaturated fatty acids (PUFA) bound to different lipid forms, such as ethyl ester, triacylglycerol (TAG), and phospholipids, no studies have investigated the effect of n‐3 PUFA from glycolipids (GL). The present study compared the fatty acid contents of tissue and serum lipids from normal C57BL/6J mice fed two types of α‐linolenic acid (ALA)‐rich lipids, spinach lipid (SPL), and linseed oil (LO). ALA was primarily present as the GL form in SPL, while it existed as TAG in LO. Supplementation of both lipids increased ALA and its n‐3 metabolites, eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid, and decreased n‐6 PUFA, linoleic acid and arachidonic acid, in the livers, small intestines, and sera of the treated mice compared with those of the control group. When the comparison between the SPL and LO diets containing the same amount of ALA was conducted, the EPA and DPA levels in the liver lipids from mice fed the SPL diet were significantly higher than those fed the LO diet. Additionally, the total contents of n‐3 PUFA of lipids from the livers, small intestines, and sera of the SPL group were higher than those of the LO group.     

The Brain Oxylipin Profile Is Resistant to Modulation by Dietary n-6 and n-3 Polyunsaturated Fatty Acids in Male and Female Rats

Oxylipins are bioactive lipids formed by the monooxygenation of polyunsaturated fatty acids (PUFA). Eicosanoids derived from arachidonic acid (ARA) are the most well-studied class of oxylipins that influence brain functions in normal health and in disease. However, comprehensive profiling of brain oxylipins from other PUFA with differing functions, and the examination of the effects of dietary PUFA and sex differences in oxylipins are warranted. Therefore, female and male Sprague–Dawley rats were provided standard rodent diets that provided additional levels of the individual n-3 PUFA α-linolenic acid (ALA), eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA), or the n-6 PUFA linoleic acid (LNA) alone or with ALA (LNA + ALA) compared to essential fatty acid-sufficient control diets. Oxylipins and PUFA were quantified in whole brains using HPLC-MS/MS and GC, respectively. Eighty-seven oxylipins were present at quantifiable levels: 51% and 17% of these were derived from ARA and DHA, respectively. At the mass level, ARA and DHA oxylipins comprised 81–90% and 6–12% of total oxylipins, while phospholipid ARA and DHA represented 25–35% and 49–62% of PUFA mass, respectively. Increasing dietary n-3 PUFA resulted in higher levels of oxylipins derived from their precursor PUFA; otherwise, the brain oxylipin profile was largely resistant to modulation by diet. Approximately 25% of oxylipins were higher in males, and this was largely unaffected by diet, further revealing a tight regulation of brain oxylipin levels. These fundamental data on brain oxylipin composition, diet effects, and sex differences will help guide future studies examining the functions of oxylipins in the brain.