Tissue Fatty Acid Research Articles

Lipid Storage, Lipolysis, and Lipotoxicity in Obesity.

The ratio of free fatty acid (FFA) turnover decreases significantly with the expansion of white adipose tissue. Adipose tissue and dietary saturated fatty acid levels significantly correlate with an increase in fat cell size and number. The G0/G1 switch gene 2 increases lipid content in adipocytes and promotes adipocyte hypertrophy through the restriction of triglyceride (triacylglycerol: TAG) turnover. Hypoxia in obese adipose tissue due to hypertrophic adipocytes results in excess deposition of extracellular matrix (ECM) components. Cluster of differentiation (CD) 44, as the main receptor of the extracellular matrix component regulates cell-cell and cell-matrix interactions including diet-induced insulin resistance. Excess TAGs, sterols, and sterol esters are surrounded by the phospholipid monolayer surface and form lipid droplets (LDs). Once LDs are formed, they grow up because of the excessive amount of intracellular FFA stored and reach a final size. The ratio of FFA turnover/lipolysis decreases significantly with increases in the degree of obesity. Dysfunctional adipose tissue is unable to expand further to store excess dietary lipids, increased fluxes of plasma FFAs lead to ectopic fatty acid deposition and lipotoxicity. Reduced neo-adipogenesis and dysfunctional lipid-overloaded adipocytes are hallmarks of hypertrophic obesity linked to insulin resistance. Obesity-associated adipocyte death exhibits feature of necrosis-like programmed cell death. Adipocyte death is a prerequisite for the transition from hypertrophic to hyperplastic obesity. Increased adipocyte number in obesity has life-long effects on white adipose tissue mass. The positive correlation between the adipose tissue volume and magnetic resonance imaging proton density fat fraction estimation is used for characterization of the obesity phenotype, as well as the risk stratification and selection of appropriate treatment strategies. In obese patients with type 2 diabetes, visceral adipocytes exposed to chronic/intermittent hyperglycemia develop a new microRNAs' (miRNAs') expression pattern. Visceral preadipocytes memorize the effect of hyperglycemia via changes in miRNAs' expression profile and contribute to the progression of diabetic phenotype. Nonsteroidal anti-inflammatory drugs, metformin, and statins can be beneficial in treating the local or systemic consequences of white adipose tissue inflammation. Rapamycin inhibits leptin-induced LD formation. Collectively, in this chapter, the concept of adipose tissue remodeling in response to adipocyte death or adipogenesis, and the complexity of LD interactions with the other cellular organelles are reviewed. Furthermore, clinical perspective of fat cell turnover in obesity is also debated.

Dietary fatty acids and flight-training influence the expression of the eicosanoid hormone prostacyclin in songbirds

Diet shifts can alter tissue fatty acid composition in birds, which is subsequently related to metabolic patterns. Eicosanoids, short-lived fatty acid-derived hormones, have been proposed to mediate these relationships but neither baseline concentrations nor the responses to diet and exercise have been measured in songbirds. We quantified a stable derivative of the vasodilatory eicosanoid prostacyclin in the plasma of male European Starlings (Sturnus vulgaris, N = 25) fed semisynthetic diets with either high (PUFA) or low (MUFA) amounts of n6 fatty acid precursors to prostacyclin. Plasma samples were taken from each bird before, immediately after, and two days following a 15-day flight-training regimen that a subset of birds (N = 17) underwent. We found elevated prostacyclin levels in flight-trained birds fed the PUFA diet compared to those fed the MUFA diet and a positive relationship between prostacyclin and body condition, indexed by fat score. Prostacyclin concentrations also significantly decreased at the final time point. These results are consistent with the proposed influences of precursor availability (i.e., dietary fatty acids) and regulatory feedback associated with exercise (i.e., fuel supply and inflammation), and suggest that prostacyclin may be an important mediator of dietary influence on songbird physiology.

Effects of Aurantiochytrium acetophilum as a source of docosahexaenoic acid for juvenile Atlantic salmon (Salmo salar) on growth, nutrient apparent digestibility, tissue fatty acid composition and expression of lipid metabolism-related genes

Thraustochytrids are a group of unicellular marine protists that are noted for their ability to produce high amounts of lipids, especially docosahexaenoic acid (DHA), making them a valuable source for replacing fish oil in aquafeeds. Varying levels of Aurantiochrytrium acetophilum meal (TM) were evaluated as replacement of fish oil in extruded diets for juvenile Atlantic salmon on growth, nutrient apparent digestibility, fatty acid composition in muscle and liver and expression of genes associated with lipid metabolism. Four experimental diets were tested: a control diet without the inclusion of A. acetophilum meal and three experimental diets derived from the control diet, in which fish oil was progressively replaced by the addition of A. acetophilum meal at 2.5% (TM 2.5), 6.5% (TM 6.5) and 12% (TM 12) respectively. After 12 weeks of feeding, the growth, feed conversion, condition factor and survival of the fish were not affected by the inclusion of A. acetophilum in the diet. However, the 12% inclusion significantly decreased the viscerosomatic index of the fish and the digestibility of protein, lipids, ash and energy compared to the other experimental diets. The lipid content and fatty acid profile of the liver and muscle were significantly affected by diet composition. In both tissues, fish fed the TM 12 diet retained the highest levels of DHA. However, it was also observed that EPA concentrations lessened with increasing dietary content of A. acetophilum meal. Finally, the decrease in the expression of Δ5fad in the fish fed with the TM 6.5 and TM 12 diets showed that fish do not require a higher expression of this desaturase for DHA production, due to the high content of this fatty acid in A. acetophilum meal.

Growth, reproduction, fatty acid profiles and offspring performance of broodstock yellow catfish Pelteobagrus fulvidraco fed diets with different lipid levels

Parental nutrition plays important roles in reproductive performance and offspring health of broodstock yellow catfish. However, there is a lack of relevant knowledge concerning the broodstocks of many fish species. This study investigated the influence of dietary lipid levels on growth, spawning performance, tissue fatty acid profiles, sex hormone secretion, and offspring health status of yellow catfish (Pelteobagrus fulvidraco). Five experimental diets were designed containing a 7:3 ratio of fish oil and corn oil blends with graded lipid levels (6.3%, 8.2%, 10.8%, 12.2%, and 14.4% by dry weight) and were fed to female broodstock yellow catfish for 8 weeks. The results showed that weight gain, egg diameter, fertilization ratio, and hatching ratio increased initially and then decreased with increasing dietary lipid levels, reaching optimal peaks in the L10.8 group. Broodstock fed a diet with 10.8% lipid obtained the highest 17-β estradiol concentration. The deposition of highly unsaturated fatty acids in tissues increased initially and then decreased with the increase in dietary lipids, reaching a peak in the 10.8% group. Plasma superoxide dismutase activity and total glutathione content were lowest in fish fed a diet with a 6.3% lipid level, while the contents of malondialdehyde and cortisol in larvae 3 days post-hatching showed an opposite trend, indicating that a low-fat diet reduced the antioxidant capacity of broodstock and induced a stress response that had negative effects on offspring health. Broodstock fed a diet with an appropriate lipid level could increase the expression of antioxidant enzymes by activating the nrf2 signaling pathway. Based on the regression of dietary lipid level and weight gain, reproductive performance, and egg quality of fish, the optimal dietary lipid level was 10.1–11.7% for broodstock yellow catfish.

Supplementing graded levels of Fish oil in the feeds of Labeo rohita fingerlings: Effects on tissue n-3 LC-PUFA deposition, Δ6 fad gene expression, blood metabolites and fish performance

A 60-day feeding trial was conducted to study the effects of levels of fish oil (FO), 0 (FO-0), 30 (FO-30), 60(FO-60), 90 (FO-90),120 (FO-120) and 150 (FO-150) g kg−1 feed on growth, nutrient utilisation, whole-body chemical composition, tissue fatty acids profile, blood metabolites and Δ6 fad gene expression in Labeo rohita fingerlings. Two hundred and seventy fingerlings of average body weight 13.03 ± 0.03 g were randomly stocked in 18 500 L concrete tanks, each with 15 fingerlings. Triplicate tanks, all fitted with flow-through water systems, were allocated under each dietary treatment. The fish were hand-fed twice daily till satiation. The feed intake decreased with increasing dietary FO levels. The body weight gain, specific growth rate (SGR) and protein efficiency ratio (PER) increased significantly with increasing dietary FO supplementation level of 60 g kg−1 feed. Above this level, the values plateaued. The feed conversion ratio (FCR) showed the reverse trend of growth. The fish fed with FO-120 had the highest whole-body lipid deposition. Increasing dietary FO levels up to 90 g kg−1 feed enhanced muscle n-3 LC-PUFA content significantly (P < 0.05), and further increasing the FO level did not further influence the fatty acid. Supplementation of FO in the feeds significantly (P < 0.05) suppressed the Δ6 fad gene expression in muscle, liver, and intestine tissues. In muscle and liver tissues, the suppression of the Δ6 fad gene expression was the highest when the dietary FO level was above 90 g FO kg−1 feed, whereas in the intestine tissue above 60 g FO kg−1. Increasing dietary FO levels increased serum cholesterol and high-density lipoprotein (HDL) contents and decreased low-density lipoprotein (LDL) and very low-density lipoprotein (VLDL) concentrations. The second-order polynomial regression graphs suggest a 104 g lipid kg−1 feed is optimum for the best growth and nutrient utilisation, whereas 113 g FO kg−1 feed is required to maximise n-3 LC-PUFA deposition in the muscle of L. rohita fingerlings.

Effects of dietary arachidonic acid on growth, gonadal development, and tissue fatty acid composition in the hermaphroditic swamp eel (Monopterus albus)

10-week dietary arachidonic acid (ARA) feeding trials were conducted in 14-month-old swamp eel (Monopterus albus) to evaluate the effects on growth performance, gonadal development, tissue fatty acid profile, and gene expression related to lipid metabolism. The results showed that swamp eels fed diets supplemented with 1.4% or 2.8% ARA had a significantly higher weight gain rate (WGR) and specific growth rate (SGR) than those fed the control diet. Dietary supplementation with ARA improved oocyte development and maturation. Higher gonadosomatic index (GSI) was detected in 1.4% and 2.8% ARA groups. ARA supplementation delayed sexual reversal in females. The ARA content in the muscle, liver and gonads increased with increasing dietary ARA concentration; however, ARA supplementation significantly reduced the transcriptional expression of lipid metabolism-related genes in the gonads, such as fad2, pla2g4a, and elovl5. Serum alanine aminotransferase (ALT) levels in the ARA 1.4% group were significantly lower than those in the control and ARA 2.8% groups. Total cholesterol (T-CHO) and triglyceride (TG) levels were significantly lower in the 1.4% and 2.8% ARA groups than in the control group. Catalase (CAT) and high-density lipoprotein cholesterol (HDL-C) increased with dietary ARA concentrations. This study found that dietary ARA is important for improving growth, Ovarian development, and antioxidant capacity in swamp eels.

Selenium-dependent glutathione peroxidase 1 regulates transcription of elongase 3 in murine tissues

We have previously shown dysregulated lipid metabolism in tissues of glutathione peroxidase 1 (GPX1) overexpressing (OE) or deficient (KO) mice. This study explored underlying mechanisms of GPX1 in regulating tissue fatty acid (FA) biosynthesis. GPX1 OE, KO, and wild-type (WT) mice (n = 5, male, 3–6 months old) were fed a Se-adequate diet (0.3 mg/kg) and assayed for liver and adipose tissue FA profiles and mRNA levels of key enzymes of FA biosynthesis and redox-responsive transcriptional factors (TFs). These three genotypes of mice (n = 5) were injected intraperitoneally with diquat, ebselen, and N-acetylcysteine (NAC) at 10, 50, and 50 mg/kg of body weight, respectively, and killed at 0 and 12 h after the injections to detect mRNA levels of FA elongases and desaturases and the TFs in the liver and adipose tissue. A luciferase reporter assay with targeted deletions of mouse Elovl3 promoter was performed to determine transcriptional regulations of the gene by GPX1 mimic ebselen in HEK293T cells. Compared with WT, GPX1 OE and KO mice had 9–42% lower (p < 0.05) and 36–161% higher (p < 0.05) concentrations of C20:0, C22:0, and C24:0 in these two tissues, respectively, along with reciprocal increases and decreases (p < 0.05) of Elovl3 transcripts. Ebselen and NAC decreased (p < 0.05), whereas diquat decreased (p < 0.05), Elovl3 transcripts in the two tissues. Overexpression and knockout of GPX1 decreased (p < 0.05) and increased (p < 0.05) ELOVL3 levels in the two tissues, respectively. Three TFs (GABP, SP1, and DBP) were identified to bind the Elovl3 promoter (−1164/+33 base pairs). Deletion of DBP (−98/−86 base pairs) binding domain in the promoter attenuated (13%, p < 0.05) inhibition of ebselen on Elovl3 promoter activation. In summary, GPX1 overexpression down-regulated very long-chain FA biosynthesis via transcriptional inhibition of the Elovl3 promoter activation.

Postnatal growth restriction impairs rat lung structure and function.

The negative impact of nutritional deficits in the development of bronchopulmonary dysplasia is well recognized, yet mechanisms by which nutrition alters lung outcomes and nutritional strategies that optimize development and protect the lung remain elusive. Here, we use a rat model to assess the isolated effects of postnatal nutrition on lung structural development without concomitant lung injury. We hypothesize that postnatal growth restriction (PGR) impairs lung structure and function, critical mediators of lung development, and fatty acid profiles at postnatal day 21 in the rat. Rat pups were cross-fostered at birth to rat dams with litter sizes of 8 (control) or 16 (PGR). Lung structure and function, as well as serum and lung tissue fatty acids, and lung molecular mediators of development, were measured. Male and female PGR rat pups had thicker airspace walls, decreased lung compliance, and increased tissue damping. Male rats also had increased lung elastance, increased lung elastin protein abundance, and lysol oxidase expression, and increased elastic fiber deposition. Female rat lungs had increased conducting airway resistance and reduced levels of docosahexaenoic acid in lung tissue. We conclude that PGR impairs lung structure and function in both male and female rats, with sex-divergent changes in lung molecular mediators of development.

In parenteral nutrition-fed piglets, fatty acids vary by lipid emulsion and tissue sampled.

Children with intestinal failure without liver disease may be given soy-based lipid emulsion (SLE) or mixed lipid emulsion (MLE; containing soy, medium-chain triglyceride, olive, and/or fish oils). Both differ in essential fatty acid content: MLE has added arachidonic acid (AA) and docosahexaenoic acid (DHA). The aim of this study, in neonatal piglets, was to compare serum and tissue fatty acid composition when the emulsions were given at unrestricted doses. We compared SLE (n = 15) and MLE (n = 15) at doses of 10-15 g/kg/day in parenteral nutrition (PN). On day 14 we collected serum and tissues. Using gas-liquid chromatography, percentage fatty acids were measured in serum, brain, and liver phospholipid. Comparisons were made to reference values from litter-matched controls (n = 8). Comparing median values, linoleic acid (LA) was lower for MLE vs SLE in serum (-27%), liver (-45%), and brain (-33%) (P < 0.001). AA was lower for MLE in serum (-25%), liver (-40%), and brain (-10%). DHA was higher for MLE in serum (+50%), liver (+200%), and brain (+10%). AA levels were lower for MLE vs control piglets in serum (-81%), liver (-63%), and brain (-9%). DHA levels were higher in serum (+41%), liver (+38%), and brain (+19%). This study in piglets has shown that, at unrestricted doses, MLE treatment is associated with low serum and tissue AA compared with SLE and healthy litter-matched controls. Although not yet proven, low tissue AA levels may have functional consequences, and these data support current practice avoiding MLE dose restriction.

Effect of a pescetarian and vegan diet on fatty acid composition in blood and spermatozoa in young healthy men

IntroductionThere is a growing interest in vegetarian and vegan diets, but both can potentially affect tissue fatty acids (FA) composition. We aimed to evaluate the effect of vegetarian diets on plasma, erythrocytes, and sperm n-3 polyunsaturated fatty acids (n-3 PUFA) status in healthy young men. MethodsFour groups were studied: i) men consuming a regular omnivore diet (OMV-1, n = 35); ii) men consuming an omnivore diet but excluding fish and seafood (OMV-2, n = 34); iii) men consuming a pescetarian diet (including dairy, eggs, fish, and seafood) (PESC, n = 36); and iv) men following a strict vegan diet (VEG, n = 35). Participants in each group should follow their diet for at least the previous 12 months. Diet evaluation used a structured validated food frequency questionnaire. FA composition was measured in plasma, erythrocyte phospho-lipids, and spermatozoa by gas-liquid chromatography, expressed as a mole percentage of the total FA content. ResultsMain findings showed higher alpha-linolenic fatty acid (ALA) and total n-3 PUFA dietary intake in the VEG group. In plasma, arachidonic and eicosapentaenoic acids were higher in OMV and PESC groups, whereas docosahexaenoic acid (DHA) level was lower in VEG. Higher ALA, but reduced DHA and total n-3 PUFA levels were found in erythrocytes and spermatozoa in the VEG group. ConclusionHigher dietary ALA intake was found in pescetarians and vegan men. However, the higher ALA intake was not reflected in higher DHA content in the evaluated tissues. PUFA assessment, with particular emphasis in DHA, are necessary to improve PUFA status in vegan men.

Adipose tissue fatty acids as biomarkers for metabolic dysfunction in obese females: Implication of menopause and ageing

Fatty acids (FA) are biomarkers of metabolic dysfunction. Adipose tissue is the largest reservoir of FA and acts differently in obese individuals. Menopause by itself significantly alters metabolism, lipid metabolism dysregulation, and adipose tissue distribution. How adipose tissue FA alters an obese individual's metabolism depending on a female's menopausal status is yet poorly understood.Hence, the subcutaneous (scAT) and visceral adipose tissue (vAT) FA profile for 173 obese premenopausal and postmenopausal women was measured and associated with biochemical parameters. scAT and vAT FA profiles were distinct by themselves and in menopause. In total 816 associations were found with biochemical parameters, where only 58 were independent of the menopausal status.The associations found to emphasize the importance of assessing the adipose tissue FA profile and how their behavior changes with menopause. The FA are crucial in metabolic processes and can be helpful biomarkers in the prevention/treatment and follow-up of female obesity.

Nutritional effect of substituting microalgal concentrates with microencapsulated diets in Mytilus galloprovincialis spat

The expansion of mussel aquaculture is limited by the availability of spat and production on land is dependent on costly cultures of microalgae as feed. Substitution of algae with microencapsulated feeds can reduce feed contaminations, ease the storage and extend the shelf life, ensuring stable production of consistent quality at sustainable costs. This study investigated the effects of the substitution of commercial preserved microalgal concentrates (A) with different inclusion levels of Schizochytrium-microencapsulated feed (BioBullets, B) for Mytilus galloprovincialis spat: no substitution, A (100%A; 0%B); low substitution, ABL (40%A; 60%B); medium substitution, ABM (20%A; 80%B); complete substitution, B (0%A; 100 %B). For 8 weeks, spat of <1 cm were cultured under dietary treatments and survival, growth, condition index, digestive gland atrophy and adipogranular cell index were compared, using spat unsupplemented with any feeds as negative control (NC). Diet had a significant effect on spat growth and tissue biochemical and fatty acid composition, demonstrating the assimilation of microencapsulated diets. Spat growth was positively correlated with dietary and spat tissue protein, monounsaturated fatty acids and eicosapentaenoic acid content and was highest in spat fed A and ABL. <10% dietary proteins equally sustained M. galloprovincialis spat growth through dietary replacement with higher proportions of lipids (x3) and carbohydrates (x2). With manufacturing improvements, 60% substitution of preserved microalgal concentrates by microencapsulated Schizochytrium can be considered in attempting to enhance economic feasibility in spat production.

Antioxidant Enzyme System Modulation by Dietary Palm Oils, Palm Kernel Oil and Soybean Oil in Laying Hens.

Palm-based oils (palm oil and kernel oil) and soybean oil have unique fatty acid and antioxidant profiles based on the compounds present in them. Hence, this study elucidated the antioxidant properties of crude palm oil (CPO), red palm oil (RPO), refined palm oil (RBD), palm kernel oil (PKO) and soybean oil (SBO) and the influence of dietary oils on blood lipid profiles, tissue fatty acid deposition and the expression of hepatic lipid and lipoprotein metabolism genes in laying hens. The oils were analyzed for color, beta-carotene, free fatty acid and acid value, phenolic content and lipid peroxidation. In an in vivo trial, 150 laying hens were allotted into five groups and supplemented with either CPO, RPO, RBD, PKO or SBO for 16 weeks. High antioxidant compounds present in palm oils help reduce the oxidation of oils. Dietary supplementation with palm oils, particularly CPO and RPO, contributed to the lower liver, serum and jejunal mucosal antioxidant enzyme activities. The antioxidant enzyme genes in the jejunal mucosa were downregulated in palm oils and PKO, but there was no difference between oils in antioxidant enzyme genes in the liver. In conclusion, dietary supplementation with oils with high antioxidant content contributed to protection against oxidation and was associated with a lower requirement for producing antioxidant enzymes.

Endothelial cell CD36 regulates membrane ceramide formation, exosome fatty acid transfer and circulating fatty acid levels

Endothelial cell (EC) CD36 controls tissue fatty acid (FA) uptake. Here we examine how ECs transfer FAs. FA interaction with apical membrane CD36 induces Src phosphorylation of caveolin-1 tyrosine-14 (Cav-1Y14) and ceramide generation in caveolae. Ensuing fission of caveolae yields vesicles containing FAs, CD36 and ceramide that are secreted basolaterally as small (80–100 nm) exosome-like extracellular vesicles (sEVs). We visualize in transwells EC transfer of FAs in sEVs to underlying myotubes. In mice with EC-expression of the exosome marker emeraldGFP-CD63, muscle fibers accumulate circulating FAs in emGFP-labeled puncta. The FA-sEV pathway is mapped through its suppression by CD36 depletion, blocking actin-remodeling, Src inhibition, Cav-1Y14 mutation, and neutral sphingomyelinase 2 inhibition. Suppression of sEV formation in mice reduces muscle FA uptake, raises circulating FAs, which remain in blood vessels, and lowers glucose, mimicking prominent Cd36−/− mice phenotypes. The findings show that FA uptake influences membrane ceramide, endocytosis, and EC communication with parenchymal cells.

Inhibition of ghrelin activity by the receptor antagonist [D-Lys3]-GHRP-6 enhances hepatic fatty acid oxidation and gluconeogenesis in a growing pig model

Despite its central role in regulating energy intake and metabolism, ghrelin is little understood when it comes to its effects on hepatic lipid and glucose metabolism. Growing pigs were intravenously injected with ghrelin receptor antagonist [D-Lys3]-GHRP-6 (DLys; 6 mg/kg body weight) for seven days to determine whether ghrelin plays a role in glucose and lipid metabolism. DLys treatment significantly reduced body weight gain and adipose histopathology found that DLys treatment dramatically reduced adipocyte size. DLys treatment significantly increased serum NEFA and insulin levels, hepatic glucose level and HOMA-IR, and significantly decreased serum TBA level of growing pigs after fasting. Moreover, DLys treatment changed the dynamics of serum metabolic parameters, including glucose, NEFA, TBA, insulin, GH, leptin, and cortisol. Liver transcriptome showed that DLys treatment affected the metabolism-related pathways. Compared with the control group, adipose tissue lipolysis (the adipose triglyceride lipase level was significantly increased), hepatic gluconeogenesis (the G6PC protein level was significantly increased) and fatty acid oxidation (the CPT1A protein level was significantly increased) were promoted in the DLys group. DLys treatment expanded degrees of oxidative phosphorylation in the liver, coming about in a higher NAD+ /NADH proportion and enactment of the SIRT1 signaling pathway. Additionally, the liver protein levels of the DLys group were significantly higher than those of the control group for GHSR, PPAR alpha, and PGC-1. To summarize, inhibition of ghrelin activity can significantly affect metabolism and alter energy levels by enhancing fat mobilization, hepatic fatty acid oxidation and gluconeogenesis without affecting fatty acid uptake and synthesis in the liver.

Oxidized fish oil in the diet negatively affect rearing performance, health, and tissue fatty acid composition of juvenile spotted rose snapper Lutjanus guttatus (Steindachner, 1869)

Oxidized fish oil in the diet negatively affect rearing performance, health, and tissue fatty acid composition of juvenile spotted rose snapper Lutjanus guttatus (Steindachner, 1869)

Investigation of the functions of n-3 very-long-chain PUFAs in skin using in vivo Atlantic salmon and in vitro human and fish skin models.

The purpose of this study was to investigate the effect of dietary n-3 very-long-chain PUFA (n-3 VLC-PUFA) on the maturation and development of skin tissue in juvenile Atlantic salmon (Salmo salar) in vivo, as well as their effects on skin keratocyte and human skin fibroblast cell migration in vitro. Atlantic salmon were fed different dietary levels of n-3 VLC-PUFA from an initial weight of 6 g to a final weight of 11 g. Changes in skin morphology were analysed at two time points during the experiment, and the effects on skin tissue fatty acid composition were determined. Additionally, in vitro experiments using human dermal fibroblasts and primary Atlantic salmon keratocytes were conducted to investigate the effect of VLC-PUFA on the migration capacity of the cells. The results demonstrated that increased dietary levels of n-3 VLC-PUFA led to an increased epidermis thickness and more rapid scale maturation in Atlantic salmon skin in vivo, leading to a more mature skin morphology, and possibly more robust skin, at an earlier life stage. Additionally, human skin fibroblasts and salmon skin keratocytes supplemented with n-3 VLC-PUFA in vitro showed more rapid migration, indicating potentially beneficial effects of VLC-PUFA in wound healing. In conclusion, VLC-PUFA may have beneficial effects on skin tissue development, function and integrity.

A simple and cost‐effective direct transmethylation procedure for plant lipid analysis

AbstractMeasuring acyl lipid content and fatty acid composition is important in plant lipid research, and direct transmethylation followed by analysis with gas chromatography‐flame ionization detection has been broadly used in various studies. However, many existing protocols are time‐consuming and labor‐intensive, and the long reaction time under high temperature may artificially change fatty acid compositions of the samples. In this study, we optimized the direct transmethylation method for seed and leaf samples with a wide range of seed and tissue sizes, oil contents, and fatty acid profiles, which can be completed in 2 h. We also demonstrated that commercial disposable pipet tips, as well as polypropylene tubes under certain conditions, could be reliably used to replace glass tubes, Pasteur pipettes, and rubber bulbs to improve efficiency. Taken together, this optimized and generalized method could be used as a reliable and less time‐ and labor‐intensive approach to analyze acyl lipid content and fatty acid profile of plant samples.

53 Hemp seed oil as a novel fatty acid supplement for horses

Polyunsaturated fatty acids (PUFA) play a role in regulating the body's response to inflammation. Most grains fed to horses are high in linoleic acid (LA), a pro-inflammatory n6 PUFA, compared with α-linolenic acid (ALA), an anti-inflammatory n3 PUFA. Recent interest in hemp (Cannabis sativa) seed oil (HSO) as a PUFA source has arisen due to its unique fatty acid (FA) profile, which includes γ-linolenic acid (GLA), an n6 PUFA with anti-inflammatory properties. Dietary GLA is rapidly converted to dihomo-γ-linolenic acid (DGLA), a precursor to anti-inflammatory eicosanoids. Manipulating dietary FA may lead to alterations in tissue FA profiles in the horse which could promote a reduced inflammatory response. Thus, our objective was to determine if oral supplementation of HSO for 28 d would cause detectable changes in FA composition in synovial fluid (SF) and skeletal muscle (MUS). Six Thoroughbred geldings (11 ± 3.2 yrs, 568 ± 26 kg BW) were used in a crossover experiment with 2 consecutive 63d periods. Horses were offered a control (CON) basal diet of hay and concentrate or the basal diet with the addition of 166 mL HSO delivering 5g GLA. Diets were designed to be isocaloric. Over 7d, HSO was introduced gradually, maintained for another 28d, and then removed and horses resumed basal diets for an additional 28d. Horses were weighed, and body condition score (BCS) assessed weekly. MUS and SF samples werecollected on d0, d35, and d63 of each period. MUS biopsies were taken from the middle gluteus muscle at a depth of 8cm. SF was collected from the left carpus joint. FA were extracted from MUS and SF and analyzed by GC. Individual FA are represented as g of FA per 100g of total fatty acids. Data were analyzed using Proc MIXED in SAS (v.15.1 SAS Institute Inc., Cary, NC). No changes in BW or BCS were observed throughout the study. In SF, GLA was detected after 28d of HSO supplementation (0.32 ± 0.06g/100g) but not at any other time point. On d 28, horses supplemented with HSO also had greater SF DGLA (0.31 ± 0.04g/100g) than CON (0.19 ± 0.04g/100g; P = 0.04). MUS ALA tended (P = 0.07) to be greater in horses fed CON compared with HSO. No other differences were observed for FA in MUS or SF. These results indicate that 28d of HSO supplementation can modify FA profiles in equine skeletal muscle and synovial fluid. This could potentially influence inflammation signaling molecules and subsequently the inflammatory response, however, longer studies with more horses are needed to determine peak incorporation and the effects of varying quantities of HSO in the diet.

Gastrointestinal permeability and inflammatory status of preweaning dairy calves in response to decreasing the ratio of n-6 to n-3 fatty acid in milk replacer

The ratio of n-6 to n-3 fatty acid (FA) is between 2 and 10 times higher in milk replacer (MR) than in whole milk, which may promote inflammation and compromise the integrity of the intestinal epithelium. To evaluate how decreasing the n-6:n-3 FA ratio of MR affects gastrointestinal (GIT) permeability and inflammatory status, 30 dairy calves (2.8 ± 1.06 d of age; mean ± standard deviation) were randomly assigned to be fed an MR with an n-6:n-3 FA ratio of 40:1 (CON; 29.3% crude fat of DM; n = 15) or 6.5:1 (n-3; 29.1% crude fat of DM; n = 15). Calves were fed 7.0 L/d in 2 meals. Calves were weighed and fecal consistency was analyzed weekly. On d 22, calves were administered Cr-EDTA, lactulose, and d-mannitol to assess GIT permeability. Blood and total urine were sequentially collected for 6 and 24 h, respectively, and analyzed for marker content. Whole blood collected 4 h after the meal was subjected to an ex vivo lipopolysaccharide (LPS) challenge to evaluate cytokine secretion from blood cells. Calves were euthanized on d 25 for collection of intestinal tissue samples. Tissue samples were processed to assess FA composition by gas chromatography, histomorphology by bright-field microscopy, and gene expression of tight junction proteins, lipid metabolism enzymes, and immune molecules by real-time quantitative PCR. Data were analyzed using PROC GLIMMIX in SAS (version 9.4, SAS Institute Inc.). Growth performance and fecal consistency were unaffected. Calves fed MR with a lower ratio of n-6 to n-3 FA had 2-fold higher n-3 FA contents and 2-fold lower ratios of n-6 to n-3 FA in proximal jejunum and ileum tissues. Total urinary recovery (0-24 h relative to marker administration) and plasma concentrations of the markers were unaffected. Expression of TJP1 tended to be higher in proximal jejunum tissue and lower in ileum tissue of n-3 calves. The expression of TLR4 and TNFA tended to be higher and CD14 was higher in ileum tissue of n-3 calves. Plasma concentrations of interleukin-4 were decreased in response to the ex vivo LPS challenge in n-3 calves. Histomorphology and GIT permeability were largely unaffected by treatment. Furthermore, the inclusion of linseed and algae oil may promote inflammation, as suggested by greater concentrations of the acute-phase proteins haptoglobin and serum amyloid A postprandially, demonstrating that fat sources should be evaluated for their suitability for MR formulations. Understanding how MR composition affects dairy calf health may improve nutritional strategies on farm.