Dietary Fat in Relation to Erythrocyte Fatty Acid Composition in Men

Erythrocyte membrane fatty acid (EMFA) composition is used in the validation of food frequency questionnaires (FFQ) and the evaluation of dietary fat quality. In this cross-sectional study we aimed to investigate associations of diet with EMFA. Altogether, 1,033 randomly selected Finnish men, aged from 47 to 75 years filled in a FFQ and their EMFA composition was analyzed. Marine polyunsaturated fatty acid (PUFA) intake correlated positively with erythrocyte eicosapentaenoic and docosahexaenoic acids (r _s = 0.415 and r _s = 0.340, respectively, P < 0.001) and inversely with all n-6 PUFA analyzed (P < 0.001). PUFA intake from spreads and cooking fats correlated positively with alpha-linolenic (ALA), linoleic (LNA) and nervonic acids (r _s = 0.229, r _s = 0.160 and r _s = 0.143, respectively, P < 0.001). Milk fat intake was associated with myristic and behenic acids (r _s = 0.186 and r _s = 0.132, respectively P < 0.001). Butter users had lower ALA and LNA proportions (mol%) than non-users (0.16 ± 0.04 vs. 0.19 ± 0.05, P < 0.001 and 7.77 ± 1.02 vs. 8.12 ± 1.11, P = 0.001). Higher PUFA intake from meat was related to decreased long-chain n-3 (P < 0.001) and increased n-6 PUFA (P < 0.001) proportions. In conclusion, EMFA composition reflects particularly well the intakes of n-3 PUFA, whereas other associations remained lower. Yet, all main sources of dietary fat were related with EMFA. The dietary effect on the nervonic acid proportion was confirmed.     

Role of Flaxseed Meal Feeding for Different Durations in the Lipid Deposition and Meat Quality in Broiler Chickens

This study investigated the role of flaxseed meal (FSM), a rich terrestrial source of ω-3 fatty acids, in the alteration of the fatty acid profile and metabolism, health indices, physicochemical properties, and sensory quality of broiler chicken meat. The broiler chickens were fed 100 g FSM kg⁻¹ diet for different time periods (1, 2, 3, 4, and 5 weeks). The results revealed that 100 g FSM feeding in broiler chickens for at least 3 weeks increased (P < 0.01) the EPA, DHA, MUFA, PUFA, ω-3 PUFA, and ω-6 PUFA of broiler chicken meat with the corresponding decrease in palmitic acid, stearic acid, and SFA content. 100 g FSM feeding up to 3 weeks has increased the Δ⁹-desaturases (P < 0.05), thioesterase index (P < 0.01), and Δ⁵-desaturase + Δ⁶-desaturase activity (P < 0.01) along with an improvement in health indices (P < 0.01) of chicken meat. Similarly, a reduction in meat cholesterol and fat content of thigh meat (P < 0.01) was observed by feeding 100 g FSM for at least 3 weeks with no effect on the pH, color scores, and sensory evaluation of broiler chicken meat. The water-holding capacity (WHC) and extract release volume (ERV) decreased, whereas, drip loss of meat increased (P < 0.01) due to the feeding of 100 g FSM beyond 3 weeks. Thus, this study concluded that 100 g FSM feeding for 3 weeks in broiler chickens significantly improves the fatty acid profile, lipid metabolism, and health indices of meat, without compromising the physicochemical properties of broiler chicken meat.     

Sequential Feeding of Lipid Supplement Enriches Beef Adipose Tissues with 18:3n-3 Biohydrogenation Intermediates

The present study was designed to determine if feeding steers extruded flaxseed and hay (25 and 75%; DM basis) together as a total mixed ration (TMR), or sequentially (non-TMR) would result in different enrichments of polyunsaturated fatty acids (PUFA) and their biohydrogenation intermediates (BHI) in beef adipose tissues [subcutaneous (SC) vs perirenal (PR) fat]. Forty-eight Angus cross steers (325 ± 16 kg) were stratified by weight to six pens, and pens were randomized to either TMR or non-TMR and fed ad libitum for an average of 242 days. The concentrations of α-linolenic acid increased by 18 mol% in both SC and PR in non-TMR steers compared to TMR steers (P < 0.01). trans 18:1 isomers were more concentrated in PR than SC (14.4 vs 9.5 mol%; P < 0.01) and increased by 10 mol% in both fat depots for non-TMR (P < 0.01). Other BHI including non-methylene-interrupted 18:2 (atypical dienes), conjugated linoleic acids and conjugated linolenic acids (CLnA) were affected by diet × tissue interactions (P < 0.01). The CLnA and CLA contents were higher in both fat depots when feeding the non-TMR, but the effect of diet was more pronounced in PR than in SC (P < 0.01). Atypical dienes were highest in PR from non-TMR and lowest in TMR fed steers (4.3 and 3.6 mol%) with SC contents being intermediate. The sequential feeding of lipid supplement can thus profoundly affect the enrichment of PUFA and their BHI in beef fat and their differentially enrichment is also fat depot dependant.     

The Consumption of Food Products from Linseed-Fed Animals Maintains Erythrocyte Omega-3 Fatty Acids in Obese Humans

Based on mechanistic and epidemiological data, we raise the question of the relationship between qualitative dietary polyunsaturated fatty acids (PUFA) changes and increase in obesity. In this double-blind trial, we studied the effects on 160 overweight volunteers (body mass index, BMI >30) of a 90 days experimental diet rich principally in animal fat with a low PUFA/saturated fatty acid (SFA) ratio but a low n-6/n-3 ratio, using animal products obtained from linseed-fed animals. The control diet provided less animal fat, a higher PUFA/SFA ratio and a higher n-6/n-3 ratio. Both diets excluded seafood. In the experimental group, we observed a significant increase in red blood cell (RBC) α-linolenic acid content and a slight increase in EPA and DHA derivatives, while in the control group we observed a significant reduction in EPA and DHA content. Between groups now, the difference in the three n-3 fatty acids changes in RBC was significant. This demonstrates that plasma EPA and DHA levels can be maintained without fish if products from linseed-fed animals are used. During the diets, we noted a significant reduction in weight, BMI and hip circumference within both groups of volunteers. However, no significant difference was observed between the control group and the experimental group. Interestingly, 150 days after the end of the trial (i.e., day 240), we noted a significant weight gain in the control group, whereas no significant weight gain was observed in the experimental group. This was also observed for the BMI and hip circumference. Moreover, significant differences in BMI (P < 0.05) and weight (P = 0.05) appeared between the two groups, showing in both cases a smaller increase in the experimental group. During the 90 days trial, we did not observe any differences between groups in terms of total cholesterol, HDL cholesterol, LDL cholesterol or triglycerides, suggesting that the saturate content and the P/S ratio are not as important as the n-6 and n-3 fatty acid composition.     

Comparative Effects of Sandalwood Seed Oil on Fatty Acid Profiles and Inflammatory Factors in Rats

The aim of the present study was to investigate the effect of sandalwood seed oil on fatty acid (FA) profiles and inflammatory factors in rats. Fifty male Sprague–Dawley rats were randomly divided into five different dietary groups: 10 % soybean oil (SO), 10 % olive oil (OO), 10 % safflower oil (SFO), 10 % linseed oil (LSO) and 8 % sandalwood seed oil blended with 2 % SO (SWSO) for 8 weeks. The SWSO group had a higher total n-3 polyunsaturated fatty acids (PUFA) levels but lower n-6:n-3 PUFA ratios in both adipose tissue and liver than those in the SO, OO and SFO groups (p < 0.05). Although the SWSO group had a much lower 18:3n-3 level (4.51 %) in their dietary lipids than the LSO group (58.88 %), the levels of docosahexaenoic acid (DHA: 22:6n-3) in liver lipids and phospholipids of the SWSO group (7.52 and 11.77 %) were comparable to those of the LSO group (7.07 and 13.16 %). Ximenynic acid, a predominant acetylenic FA in sandalwood seed oil, was found to be highly incorporated into adipose tissue (13.73 %), but relatively lower in liver (0.51 %) in the SWSO group. The levels of prostaglandin F_2α, prostaglandin E₂, thromboxane B₂, leukotriene B₄, tumor necrosis factor-α and interleukin-1β in both liver and plasma were positively correlated with the n-6:n-3 ratios, suggesting that increased n-6 PUFA appear to increase the formation of pro-inflammatory cytokines, whereas n-3 PUFA exhibit anti-inflammatory activity. The present results suggest that sandalwood seed oil could increase tissue levels of n-3 PUFA, DHA and reduce the n-6:n-3 ratio, and may increase the anti-inflammatory activity in rats.     

n-3 Polyunsaturated Fatty Acids and Atopy in Korean Preschoolers

Atopy is a growing problem for Korean children. Since eicosapentaenoic acid is a precursor of less active inflammatory eicosanoids, n-3 polyunsaturated fatty acids (PUFA) may have a protective effect on atopy. This study was undertaken to determine whether n-3 PUFA in red blood cells (RBC) is lower in atopic than in non-atopic preschoolers. Three hundred and eight Korean children aged 4–6 years were enrolled. Total RBC fatty acid composition was measured by gas chromatography. The prevalence of atopic dermatitis, allergic rhinitis, or asthma was 29%. Total RBC n-3 PUFA were lower in preschoolers with atopy than controls (9.8 ± 1.2 vs. 11.4 ± 1.6%; P < 0.05), while n-6 PUFA (33.0 ± 1.4 vs. 32.2 ± 1.0%; P < 0.05) and n-6/n-3 PUFA ratio (3.4 ± 0.6 vs. 2.8 ± 0.5; P < 0.05) were greater. The following factors were also associated with an increase in atopy: higher saturated fatty acids (39.6 ± 1.4 vs. 40.6 ± 1.9; P < 0.05) and arachidonic acid (15.3 ± 1.6 vs. 16.0 ± 2.9; P < 0.05), and lower total PUFA (43.8 ± 0.7 vs. 42.8 ± 1.4; P < 0.05) and omega-3 index (EPA + DHA; 9.1 ± 0.8 vs. 7.8 ± 0.5; P < 0.05) in RBC. Maternal history of atopy was a significant (P < 0.05) risk factor, while lactation was not. The results suggest that a reduced content of n-3 PUFA in the RBC membrane could play a role in early children atopy.     

Dietary Oil Type and Late Feed Restriction Elicit Synergistic Effects on Growth,Caeca Bacteria,Carcass, Fat Accretion,and Muscle Lipids in Female Broilers

The influence of dietary oil type (OT) and late feed restriction (FR) on growth, caeca bacteria count, carcass, separable fat depots, serum and muscle lipids, and meat quality in broilers is examined. In total, 224, 21-day-old female Arbor acres broilers are randomly allotted to either PN, Unrestricted+50 g kg⁻¹ palm oil (PO); PR, 25%-FR+PO; SN, Unrestricted+50 g kg⁻¹ soybean oil (SO); or SR, 25%-FR+SO for 21 d. The SN and PR birds have the heaviest and lightest body weight gain (BWG), respectively. Feed conversion ratio (FCR) is poorer in the PN birds. Feed-restricted birds have more caeca Lactobacillus and lower Salmonella, serum cholesterol, and triglycerides. Carcass yield is higher in SR birds and lower in PN birds. The FR-OT interaction is significant for muscle lipids and weight of fat depots. The PN birds deposit more abdominal, intramuscular, sartorial, mesentery and neck fats, muscle saturated fatty acids, and C18:1n-9 and lower C18:3n-3 and C20:5n-3 than other birds. Neither OT nor FR affects the pH, color, water holding capacity, and oxidative stability of breast meat. The changes elicited by 25%-FR on BWG, FCR, carcass yield, depot fats, and muscle lipids in female broilers are dependent on dietary OT. Practical Application: Fast growth rate and unrestricted access to feed can predispose broiler chickens to excessive fat accretion, which is counterproductive. Producing high-quality carcasses that meet consumers’ expectation is crucial for sustainable and efficient broiler production. The possible interaction between dietary OT and late quantitative FR in mitigating excessive fat accretion and altering production indices in female broilers is explored. Late quantitative FR reduces BWG, FCR, serum lipids, caeca pH and Salmonella spp. and fat accretion in fat depots, and enhances carcass yield and caeca Lactobacillus spp. However, the impacts are more pronounced in the PO birds than the SO birds. Late FR improves the C18:3n-3 and C18:2n-6 contents in PO meat while reducing the C14:0 and C16:0 contents in SO meat. These findings explicate that dietary OT and late quantitative FR can be synergistically used to mitigate excessive fat accretion and alter growth, caeca microflora, and muscle lipids in broilers.     

Unusually High Levels of n-6 Polyunsaturated Fatty Acids in Whale Sharks and Reef Manta Rays

Fatty acid (FA) signature analysis has been increasingly used to assess dietary preferences and trophodynamics in marine animals. We investigated FA signatures of connective tissue of the whale shark Rhincodon typus and muscle tissue of the reef manta ray Manta alfredi. We found high levels of n-6 polyunsaturated fatty acids (PUFA), dominated by arachidonic acid (20:4n-6; 12–17 % of total FA), and comparatively lower levels of the essential n-3 PUFA—eicosapentaenoic acid (20:5n-3; ~1 %) and docosahexaenoic acid (22:6n-3; 3–10 %). Whale sharks and reef manta rays are regularly observed feeding on surface aggregations of coastal crustacean zooplankton during the day, which generally have FA profiles dominated by n-3 PUFA. The high levels of n-6 PUFA in both giant elasmobranchs raise new questions about the origin of their main food source.     

Dietary Supplementation of Tetracarpidium conophorum (African Walnut) Seed Enhances Muscle n‐3 Fatty Acids in Broiler Chickens

The influence of dietary Tetracarpidium conophorum (African Walnut) seed meal (TCSM) on fatty acids, productivity parameters, and physicochemical properties of breast and thigh muscles in broiler chickens are assessed. A total of 180, 28‐d‐old Arbor acre broiler chickens are randomly assigned to dietary treatments containing 0% (control), 2.5%, and 5% w/w TCSM, fed for 28 d, and euthanized. Dietary TCSM reduces (p < 0.05) feed intake, body weight gain (BWG), carcass weight, and abdominal fat. Diet does not affect feed efficiency and hematological parameters. The control birds have higher (p < 0.05) serum total cholesterol and triglycerides than do the supplemented birds. Diet has no effect on pH, water holding capacity, carbonyl and malondialdehyde contents, and organoleptic properties of breast and thigh muscles. The 5% TCSM has higher redness in breast muscle than do other treatments. Dietary TCSM improves (p < 0.05) the concentration of C18:3n‐3 (4.80–8.76% vs 1.56%), C20:5n‐3 (0.54–0.79% vs 0.39%), C22:5n‐3 (0.64–0.89% vs 0.18%), and C22:6n‐3 (0.75–0.97% vs 0.19%), and reduces (p <  0.05) the fat content (2.15–2.45% vs 3.15%) in breast and thigh muscles. Dietary TCSM enhances muscle n‐3 fatty acids without instigating oxidative deterioration, but reduces BWG in broiler chickens. Practical Application: Albeit that broiler meat is rich in polyunsaturated fatty acids (PUFA), its omega 6 (n‐6)/omega 3 (n‐3) is >4. Elevated n‐6/n‐3 could have adverse effect on human physiology thereby promoting the pathogenesis of certain diseases. This heightens the need to enhance the n‐3 PUFA content of broiler meat. Dietary TCSM induced up to a fourfold increase in n‐3 PUFA content of the breast and thigh muscles in broiler chickens. Moreover, dietary TCSM induced up to a tenfold decrease in the n‐6/n‐3 of the breast and thigh muscles in broiler chickens. This finding assumes great significance because the health concerns regarding dietary fat are the foremost factors responsible for the bad image suffered by meat. These results provide insights on the potential of TCSM to improve the nutritional quality without compromising the oxidative shelf life, organoleptic traits, and physicochemical properties of broiler meat.     

Dietary fatty acids influence the growth and fatty acid composition of the yellow mealworm <Emphasis Type="Italic">Tenebrio molitor</Emphasis> (Coleoptera: Tenebrionidae)

Fat is the second most abundant component of the nutrient composition of the mealworm Tenebrio molitor (Coleoptera: Tenebrionidae) that represents also an interesting source of PUFA, especially n-6 and n-3 fatty acids, involved in prevention of cardiovascular diseases. This study investigated the possibility of modifying the fat content and the FA composition of yellow mealworms through feeding and how this would be influenced by developmental stages, pupal sex, and generation with the future aim of applying this coleopteran as a diet supplement for human health. Growth rate and cumulative mortality percentage on the different feeding substrates were also evaluated to select the optimal conditions for a mass-raising of this insect species. Despite the different fat content in the six different breeding substrates used, T. molitor larvae and pupae contained a constant fat percentage (>34% in larvae and >30% in pupae). A similar total fat content was found comparing larvae and male and female pupae of the second generation to those of the first generation. On the contrary, FA composition differed both in larvae and pupae reared on the different feeding substrates. However, the exemplars reared on the diets based on 100% bread and 100% oat flour showed SFA, PUFA percentages, and an n-6/n-3 ratio more suitable for human consumption; the diet based on beer yeast, wheat flour, and oat flour resulted in a contemporary diet that most satisfied the balance between a fat composition of high quality and favorable growth conditions.     

Dietary Docosahexaenoic Acid and <Emphasis Type="Italic">trans</Emphasis>-10, <Emphasis Type="Italic">cis</Emphasis>-12-Conjugated Linoleic Acid Differentially Alter Oxylipin Profiles in Mouse Periuterine Adipose Tissue

Diets containing high n-3 polyunsaturated fatty acids (PUFA) decrease inflammation and the incidence of chronic diseases including cardiovascular disease and nonalcoholic fatty liver disease while trans-fatty acids (TFA) intake increases the incidence of these conditions. Some health benefits of n-3 PUFA are mediated through the impact of their oxygenated metabolites, i.e. oxylipins. The TFA, trans-10, cis-12-conjugated linoleic acid (CLA; 18:2n-6) is associated with adipose tissue (AT) inflammation, oxidative stress, and wasting. We examined the impact of a 4-week feeding of 0, 0.5, and 1.5% docosahexaenoic acid (DHA; 22:6n-3) in the presence and absence of 0.5% CLA on AT oxylipin profiles in female C57BL/6N mice. Esterified oxylipins in AT derived from linoleic acid (LNA), alpha-linolenic acid (ALA), arachidonic acid (ARA), eicosapentaenoic acid (EPA), DHA, and putative from CLA were quantified. CLA containing diets reduced AT mass by ~62%. Compared with the control diet, the DHA diet elevated concentrations of EPA-and DHA-derived alcohols and epoxides and LNA-derived alcohols, reduced ARA-derived alcohols, ketones, epoxides, and 6-keto-prostaglandin (PG) F_1α (P < 0.05), and had mixed effects on ALA-derived alcohols. Dietary CLA lowered EPA-, DHA-, and ALA-derived epoxides, ARA-derived ketones and epoxides, and ALA-derived alcohols. While dietary CLA induced variable effects in EPA-, DHA-, and LNA-derived alcohols and LNA-derived ketones, it elevated ARA-derived alcohols and PGF_1α, PGF_2α, and F2-isoprostanes. DHA counteracted CLA-induced effects in 67, 57, 43, and 29% of total DHA-, ARA-, EPA-, and ALA-derived oxylipins, respectively. Thus, CLA elevated proinflammatory oxylipins while DHA increased anti-inflammatory oxylipins and diminished concentration of CLA-induced pro-inflammatory oxylipins in AT.     

The Effect of Linseed on Intramuscular Fat Content and Adipogenesis Related Genes in Skeletal Muscle of Pigs

The aim of the study was to investigate the effect of n-3 PUFA enrichment in longissimus muscle on intramuscular fat (IMF) content and expression of related genes in growing-finishing barrows. Two isoenergetic, isonitrogenous and isolipidic diets were formulated: one was basal diet and the other contained 10% linseed. Twenty-four Landrace × NewDamLine barrows weighing 35 ± 3.7 kg were randomly assigned to four treatment groups with six pigs per group. During the whole experimental period of 90 days, all groups were first fed the basal diet and then the linseed diet for 0, 30, 60, and 90 days before slaughter, respectively. Meat quality, fatty acid composition, and expression of genes involved in adipogenesis in longissimus muscle were measured and analyzed. The IMF content increased linearly (P < 0.05) as the linseed diet feeding time prolonged. Meanwhile, n-3 PUFA content and expression of peroxisome proliferator-activated receptor δ (PPARδ), PPARγ, adipocyte fatty acid–binding protein (aP2) and lipoprotein lipase (LPL) increased linearly (P < 0.01) as well, while the expression of wingless related MMTV integration site 10b (Wnt10b) linearly decreased (P < 0.01). Furthermore, significant (P < 0.01) quadratic or linear relation was observed between n-3 PUFA enrichment and expression of these genes, while significant (P < 0.01) quadratic or linear relation was observed between the expression of PPARγ, aP2 or Wnt10b and IMF content. These data show that enhancing n-3 PUFA enrichment in muscle leads to significant increase in IMF content. A possible explanation is due to alterations in the expression of genes involved in adipogenesis, however this will need to be confirmed by protein and enzyme activity studies.     

Increased Prostaglandin Response to Oxytocin in Ewes Fed a Diet High in Omega-6 Polyunsaturated Fatty Acids

Diets high in omega-6 polyunsaturated fatty acids (n-6) are associated with increased prostaglandin F_2α (PGF_2α) synthesis in cattle, however, the specific effects on the potential prostaglandin response to an oxytocin challenge in sheep have not been reported. The aim of the current study was to determine whether oxytocin-stimulated PGF_2α was significantly increased when ewes were fed a diet high in n-6 compared with a control diet low in n-6. Merino x Border Leicester ewes (n = 30) received one of two dietary treatments, either high in n-6 (70 % oat grain) or low in n-6 (control diet, 100 % cereal/legume silage). Ewes consumed the diets for 44 days prior to two consecutive oxytocin challenges. Plasma n-6 and PGF_2α metabolite (PGFM) concentrations following oxytocin challenge were greater (P < 0.05) when ewes were fed a diet high in n-6 compared with the control diet. A higher availability of n-6 may have lead to an increased in vivo synthesis of PGF_2α, however, further research is required to determine the exact mechanisms involved.     

Effect of conjugated linoleic acid on body composition in mice

The effects of conjugated linoleic acid (CLA) on body composition were investigated. ICR mice were fed a control diet containing 5.5% corn oil or a CLA-supplemented diet (5.0% corn oil plus 0.5% CLA). Mice fed CLA-supplemented diet exhibited 57% and 60% lower body fat and 5% and 14% increased lean body mass relative to controls (P<0.05). Total carnitine palmitoyltransferase activity was increased by dietary CLA supplementation in both fat pad and skeletal muscle; the differences were significant for fat pad of fed mice and skeletal muscle of fasted mice. In cultured 3T3-L1 adipocytes CLA treatment (1×10⁻⁴ M) significantly reduced heparin-releasable lipoprotein lipase activity (−66%) and the intracellular concentrations of triacylglyceride (−8%) and glycerol (−15%), but significantly increased free glycerol in the culture medium (+22%) compared to control (P<0.05). The effects of CLA on body composition appear to be due in part to reduced fat deposition and increased lipolysis in adipocytes, possibly coupled with enhanced fatty acid oxidation in both muscle cells and adipocytes.     

Lipid Content and Fatty Acid Profile of Muscle,Brain and Eyes of Seven Freshwater Fish: a Comparative Study

The fatty acid and lipid content of the eyes, brain and muscle were determined for the following seven freshwater fish species in China: black carp, grass carp, silver carp, bighead carp, common carp, crucian carp, and Wuchang bream. Lipid contents of all seven freshwater fish were in the order of brain > eyes > muscle. Most of the freshwater fish demonstrated much lower n-3 PUFA than n-6 PUFA in all tissues with n-3/n-6 ratios varying between 0.07 and 0.40, while silver carp and bighead carp had much higher n-3 PUFA than n-6 PUFA. The percentage of PUFA in the muscle of all species are the highest compared to those of the eyes and brain, while no significant difference was observed in PUFA concentration between eyes and brain (p > 0.05). Multivariable analyses indicate that the fatty acid composition of the filter-feeder fish (silver carp and bighead carp) was distinct from the other four species.     

Regiospecificity profiles of storage and membrane lipids from the gill and muscle tissue of atlantic salmon (Salmo salar L.) grown at elevated temperature

Regiospecific and traditional analysis, of both storage and membrane lipids, was performed on gill, white muscle, and red muscle samples taken from Atlantic salmon (Salmo salar) to gauge the effect of elevated water temperature. The fish, fed a commercial diet, were held at an elevated water temperature of 19°C. Total n-3 PUFA, total PUFA, and n-3/n-6 and unsaturated/saturated fatty acid (UFA/SFA) ratios in the FA profile of the total lipid extract in the white muscle were fairly low compared with fish grown at 15°C. Adaptation of structural and storage lipids at elevated temperatures was shown by a significant (P<0.01) reduction in PUFA especially in the percentage of EPA (6–8%). Further adaptation was indicated by the percentages of SFA, which were significantly (P<0.05) higher in gill (56%) and white muscle (58%) polar lipid fractions and coincided with lower percentages of n-3, n-6, and total PUFA. The regiospecific profiles indicated a high affinity of DHA to the sn-2 position in both the TAG (61–68%) and polar lipid (35–60%) fractions. The combination of detailed regiospecific and lipid analyses demonstrated adaptation of cell membrane structure in Atlantic salmon grown at an elevated water temperature.     

Fatty Acid Contents in Fractions of Neutral Lipids and Phospholipids of Fillets of Tilapia Treated with Flaxseed Oil

The fatty acid composition in fractions of neutral lipids (NL) and phospholipids (PL) of the lipid content of muscle tissue of tilapia (Oreochromis niloticus) fed diets enriched with 7% of flaxseed oil was evaluated. Lipid profiles were evaluated every 15 days over 90 days. NL were predominant, with saturated and monounsaturated fatty acids being the major ones, and the PL fraction showed a great amount of polyunsaturated fatty acids (PUFA). The PUFA/SFA ratio values were lower in the NL fraction, ranging from 0.3 to 0.6, when compared to the PL fraction, which ranged from 1.0 to 1.1. The n-3 PUFA concentrations increased from the beginning of the treatment up to 90 days of treatment, while the n-6 PUFA concentrations decreased in the same period, thus improving the n-6/n-3 ratio of lipid content. The n-6/n-3 ratios in the NL class varied from 11.1 to 1.1 and in the PL class from 4.6 to 1.0, which contributed to an increase in the nutritional value of the fish meat. The PUFA/SFA ratio values increased during the treatment, whereas the n-6/n-3 ratios decreased. Thus, the addition of flaxseed oil to the tilapia diet led to an improvement in the quality of the fish meat in terms of physiological and nutritional properties.     

Comparison of Seal Oil to Tuna Oil on Plasma Lipid Levels and Blood Pressure in Hypertriglyceridaemic Subjects

As meat is a rich source of the omega-3 fatty acid docosapentaenoic acid (DPA) and Australians consume six times more meat than fish, investigation of the potential health benefit of DPA is warranted. The aims were to compare the effects of seal oil supplementation with fish oil, on measures of plasma lipids and blood pressure in hypertriglyceridaemic subjects. Forty-eight volunteers were recruited from the Wollongong community and were randomly allocated to one of three groups either receiving 1 g/day of long-chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA) using one of three oils: seal oil capsules (340 mg eicosapentaenoic acid (EPA), 230 mg DPA, 450 mg DHA), fish oil capsules (210 mg EPA, 30 mg DPA, 810 mg DHA) or placebo capsules (containing sunola oil) for 6 weeks. Plasma triglycerides remained unchanged in the placebo group, whilst reductions of 7 and 14% (P < 0.05) were seen in the fish oil and seal oil groups respectively. Systolic blood pressure improved by 8 and 5 mmHg with seal oil and fish oil respectively (P < 0.05). The mean arterial pressure was significantly lower after seal oil supplementation (P < 0.005) compared with the placebo group. These results indicate that seal oil is as effective as fish oil in lowering plasma triglycerides and blood pressure.     

Effect of ALA-Enriched Food Supply on Cardiovascular Risk Factors in Males

The outcome of a total dietary approach using a wide range of n-3 polyunsaturated fatty acids (PUFA) enriched food items on cardiovascular diseases called for further investigation. The study objective was to assess the effect of an ALA-enriched food supply on cardiovascular risk factors in healthy males. A dietary intervention (single-blind field trial with pre- and post-measurements) was performed with 59 healthy males in a Belgian prison. Over a period of 12 weeks they were supplied with an n-3 enriched diet (containing 6.5 g n-3 PUFA/day compared to 4 g n-3 PUFA/day in the standard diet) that was substituted for their regular diet, increasing mainly the α-linolenic acid intake (from 2.8 to around 5 g/day). The results indicated no impact on subjects waist circumference, weight and BMI or systolic blood pressure. In contrast, the diastolic blood pressure significantly decreased during the intervention period (from 74.6 ± 8.2 to 71.7 ± 10.1 mmHg; P < 0.02). Moreover, the HDL-cholesterol level increased in non-smoking participants (from 0.97 ± 0.25 to 1.06 ± 0.23 mmol/l; P < 0.03). In summary, the study demonstrated that enrichment of commonly eaten food items with n-3 fatty acids provides the opportunity to increase the n-3 fatty acid intake and to decrease the n-6/n-3 ratio which results in a decreasing diastolic blood pressure and an increase of HDL-cholesterol (in non-smokers). An erratum to this article can be found at     

Inhibition of Stearoyl-CoA Desaturase 1 Reduces Lipogenesis in Primary Bovine Adipocytes

The objectives were to determine the effect of stearoyl-CoA desaturase (SCD1) inhibition on adipocyte proliferation, differentiation and cellular lipid metabolism in bovine primary adipocytes. Inhibition of SCD1 activity by sterculic acid (SA) or conjugated linoleic acid, trans-10 cis-12 isomer, (t10, c12-CLA) did not alter adipocyte cellular proliferation, viability or differentiation. In 1,2-[¹³C]-acetate supplemented cells, the mass isotopomer distribution analysis showed that the fractional synthesis rate of [¹³C]-16:0 was reduced (P < 0.01) in SA and t10, c12-CLA treatments compared to control. Of the lipogenic genes, t10, c12-CLA treatment decreased (P < 0.05) the expression of SCD1, acetyl-CoA carboxylase (ACC), fatty acid synthase; whereas SA supplementation decreased (P < 0.05) the expression of ACC. Both SA and t10, c12-CLA increased (P < 0.05) the expression of hormone-sensitive lipase and carnitine palmitoyl transferase involved in lipolysis and oxidation. Inhibition of SCD1 in bovine adipocytes decreases de novo fatty acid synthesis by down-regulating genes involved in lipogenesis and up-regulating genes involved in lipolysis and oxidation.