Short Term Dietary Fish Oil Supplementation Improves Motor Deficiencies Related to Reserpine-Induced Parkinsonism in Rats

Fish oil (FO) supplementation could cause an increase in the concentration of plasmatic free fatty acids and, consequently, could compete with pro-inflammatory arachidonic acid (ARA) derived from brain biomembranes metabolism in the cerebrospinal fluid. Essential fatty acids (EFA) (n-3) have been reported by their antioxidant and neuroprotective properties, and therefore the influence of the FO supplementation on the reserpine-induced motor disorders was studied. Wistar rats were orally treated with FO solution for 5 days, and co-treated with reserpine (R; 1 mg/kg/mL) or its vehicle for 3 days (every other day). Reserpine-induced orofacial dyskinesia and catalepsy (P < 0.05) were prevented by FO (P < 0.05). Biochemical evaluations showed that reserpine treatment increased the lipid peroxidation in the cortex and striatum (P < 0.05), while the FO supplementation prevented this oxidative effect in both brain regions (P < 0.05). Our results showed the protective role of FO in the brain lipid membranes, reinforcing the beneficial effect of n-3 fatty acids in the prevention of degenerative and motor disorders.     

Pea (<Emphasis Type="Italic">Pisum</Emphasis><Emphasis Type="Italic">sativum</Emphasis> L.) Seeds as an Alternative Dietary Protein Source for Broilers: Influence on Fatty Acid Composition,Lipid and Protein Oxidation of Dark and White Meats

An experiment was conducted to evaluate the production parameters, breast and leg muscle fatty acid composition and lipid and protein oxidative stability of broilers fed peas (Pisum sativum L.). The trial involved 120 birds (Hubbard strain) allotted to two groups: group I—control group, fed a basal diet containing soybean meal (195 g kg⁻¹) as the main protein source; whereas group II—experimental group fed diet containing peas (400 g kg⁻¹) as a substitute for conventional soybean. No significant differences were observed for body weight, feed intake or feed conversion ratio (P > 0.05). The total lipids were lower (P < 0.05) in the breast and leg muscles of broilers fed peas. The content of total n-3 polyunsaturated fatty acids were higher (P < 0.05) in the white and dark meat of birds fed the pea diet compared with soybean control diet. After 7 days of refrigerated storage, the levels of thiobarbituric acid-reactive substances, lipid hydroperoxides and carbonyl proteins expressed as dinitrophenylhydrazine were similar (P > 0.05) in white and dark meat of chicks fed either diet. The data indicates that dietary pea inclusion does not cause detrimental changes in lipid and protein oxidation of poultry dark and white meats, suggesting the possibility of replacing soybean meal with peas.     

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.     

Influence of triacylglycerol structure and fatty acid profile of dietary fats on milk triacylglycerols in the rat. A two-generation study

We investigated the influence of dietary fatty acid profile and triacylglycerol structure on the fatty acid profile and triacylglycerol structure of milk lipids in two generations of rats. Three groups of rats received diets containing 20% fat of which approximately 20% was n-3 fatty acids located in different positions of the triacylglycerol: a fish oil-based diet [docosahexaenoic acid (22:6n-3) predominantly in thesn-2 position], a seal oil-based diet (22:6n-3) predominantly in thesn-1/sn-3 position or a plant oil-based diet [α-linolenic acid (18:3n-3) distributed evenly between the three positions]. This design allowed us to investigate (i) the effect of the triacylglycerol structure of the dietary fat; (ii) the effect of receiving the n-3 fatty acids as long-chain derivatives or as the precursor, 18:3n-3; and (iii) the long-term effects over two generations. The fatty acid profiles of the milk lipids largely reflected the diets, but in the second generation, the level of medium-chain fatty acids was higher (P<0.05) in the milk from rats fed the fish oil diet (24%) compared with the other dietary groups (15 and 18%). This suggests an increased endogenous synthesis of fatty acids in the mammary glands of the fish oil-fed rats. The levels of long-chain n-3 fatty acids in milk were higher (P<0.05) in rats fed maire n-3 fatty acids in milk were higher (P<0.05) in rats fed marie oils (8–12%) compared with rats fed vegetable oil (1%) in both generations. The level of long-chain n-3 fatty acids was significantly higher in the milk from the fish oil-fed rats (12.3%) compared to the seal-oil fed rats (8.0%) in the first generation, but not in the second generation (8.9 vs. 9.1%). The general structure of milk triacylglycerols was maintained in the three experimental groups with 16:0 acylated in thesn-2 position and 18:1 in thesn-1/sn-3 positions. The triacylglycerol structure of mammalian milk appears to be conserved even during extreme dietary manipulation over two generations and an extensive enrichment with long-chain n-3 polyunsaturated fatty acids requires their presence in the diet.     

Maintenance of Arachidonic Acid and Evidence of Δ5 Desaturation in Cats Fed γ-Linolenic and Linoleic Acid Enriched Diets

Cats have limited Δ6 desaturase activity. However, γ-linolenate (GLA) feeding may by-pass the Δ6 desaturase step allowing arachidonate (ARA) accumulation via Δ5-desaturation. Alternatively, high dietary linoleate (LNA) may induce limited Δ6 desaturase also resulting in ARA accumulation. Fatty acid profiles were determined after feeding high LNA, high GLA, or adequate LNA diets. Adult female cats (n = 29) were assigned to one of three groups and fed for 8 weeks. Plasma samples were collected at weeks 0, 2, 4 and 8 for plasma triacylglycerol (TAG), total cholesterol (TC), lipoprotein (LP), and plasma and red blood cell membrane phospholipid fatty acid determinations. Time, but no diet, effects were observed for TAG, TC, and LP fractions at weeks 2 and 4 with significant increases likely due to increased dietary fat. However, all values were within feline normal limits. The GLA diet resulted in increased dihomo-γ-linolenic acid (DGLA) and ARA as early as week 2, supporting a ∆5 desaturase. Further evidence of Δ5 desaturase was found at high dietary LNA with the appearance of a novel fatty acid, 20:3 ∆7, 11, 14, apparently formed via ∆5 desaturation and chain elongation of LNA. However, Δ6 desaturase induction at high dietary LNA concentration was not observed. Cats are able to maintain plasma and red blood cell ARA when fed a practical diet containing GLA using what appears to be an active Δ5 desaturase enzyme.     

Identification and Ruminal Outflow of Long-Chain Fatty Acid Biohydrogenation Intermediates in Cows Fed Diets Containing Fish Oil

The abundance of 20- to 24-carbon fatty acids in omasal digesta of cows fed grass silage-based diets supplemented with 0 (Control) and 250 g/day of fish oil (FO) was examined to investigate the fate of long-chain unsaturated fatty acids in the rumen. Complimentary argentation thin-layer chromatography and gas-chromatography mass-spectrometry analysis of fatty acid methyl esters and corresponding 4,4-dimethyloxazoline derivatives prepared from fish oil and omasal digesta enabled the structure of novel 20- to 22-carbon fatty acids to be elucidated. Compared with the Control, the FO treatment resulted in the formation and accumulation of 27 novel 20- and 22-carbon biohydrogenation intermediates containing at least one trans double bond and the appearance of cis-14 20:1, 20:2n-3, 21:4n-3 and 22:3n-6 not contained in fish oil. No conjugated ≥20-carbon fatty acids were detected in Control or FO digesta. In conclusion, fish oil in the diet results in the formation of numerous long-chain biohydrogenation intermediates in the rumen of lactating cows. Comparison of the intake and flow of 20-, 21- and 22-carbon fatty acids at the omasum in cows fed the Control and FO treatments suggests that the first committed steps of 20:5n-3, 21:5n-3 and 22:6n-3 hydrogenation in the rumen involve the reduction and/or isomerisation of double bonds closest to the carboxyl group.     

Early and Sustained Enrichment of Serum n-3 Long Chain Polyunsaturated Fatty Acids in Dogs Fed a Flaxseed Supplemented Diet

A study was conducted in dogs to assess n-3 long chain polyunsaturated fatty acid incorporation after feeding an α-linolenic (ALA)-rich flaxseed supplemented diet (FLX) for 84 days. Serum total phospholipids (PL), triacylglycerol (TG), and cholesteryl esters (CE) were isolated at selected times and fatty acid methyl esters were analyzed. Increased LA was seen in the FLX-PL fraction after 28 days and an expected decrease in PL–AA. Enrichment of ALA, eicosapentaenoic acid (EPA) and docosapentaenoic acid n-3 (DPAn-3) in the FLX-group occurred early on (day 4) in both PL and TG fractions but no docosahexaenoic acid (DHA) was found, consistent with data from other species including humans. In contrast, no accumulation of DPAn-3 was seen in serum-CE, suggesting that this fatty acid does not participate in reverse-cholesterol transport. The accumulation of DPAn-3 in fasting PL and TG fractions is likely due to post-absorptive secretion after tissue synthesis. Because conversion of DPAn-3 to DHA occurs in canine neurologic tissues, this DPAn-3 may provide a circulating reservoir for DHA synthesis in such tissues. The absence of DPAn-3 in serum-CE suggests that such transport may be unidirectional. Although conversion of DPAn-3 to DHA is slow in most species, one-way transport of DPAn-3 in the circulation may help conserve this fatty acid as a substrate for DHA synthesis in brain and retinal tissues especially when dietary intakes of DHA are low.     

Fish Oil and Olive Oil Supplementation in Late Pregnancy and Lactation Differentially Affect Oxidative Stress and Inflammation in Sows and Piglets

This study was conducted to compare the effects of fish oil and olive oil supplementation in late pregnancy and during lactation on oxidative stress and inflammation in sows and their piglets. A total of 24 sows were fed a basal diet supplemented with additional corn starch (CON), fish oil (FO) or olive oil (OO). Sows fed an OO diet during late gestation had a higher piglet birth weight compared with CON‐fed and FO‐fed sows (P < 0.05). Furthermore, sows from the OO group had a higher milk fat content than sows from CON and FO groups, and a lower pre‐weaning mortality of piglets was observed in the OO group (P < 0.05). Maternal FO supplementation resulted in increased malondialdehyde concentration in sow plasma, colostrum, milk and piglet plasma than in CON and OO groups (P < 0.05). However, an increased total antioxidant capacity (T‐ACC) and activities of glutathione peroxidase (GSH‐Px) and total superoxide dismutase (T‐SOD) were also observed in the FO group (P < 0.05). Sows fed an OO diet had significantly decreased interleukin‐1β (IL‐1β), interleukin‐6 (IL‐6) and tumor necrosis factor‐α (TNF‐α) concentrations in milk compared with CON and FO fed sows (P < 0.05). Moreover, lower plasma IL‐1β and TNF‐α levels were observed in piglets from the OO group compared with the CON group (P < 0.05). Collectively, these results suggest that an OO diet is most beneficial in late gestation and during lactation in sows. However, FO increases the susceptibility to oxidative stress in sows and piglets.     

Dietary long-chain polyunsaturated fatty acids modify heart,kidney, and lung fatty acid composition in weanling rats

The fatty acid composition of heart, kidney, and lung was studied in weanling rats fed three diets differing in their polyunsaturated fatty acid content for 0, 2, and 4 wk. The first group had a 10% w/w fat semipurified diet which consisted of a mixture of olive oil (62.5%), soybean oil (11.1%), and refined coconut oil (26.4%) and provided 18:1n-9, 18:2n-6, and 18:3n-3 in similar amounts to a maternal human milk (diet HO). The second group received 7% of HO fat and 3% fish oil (0.4% 20:4n-6 and 5% 22:6n-3 of total fatty acids) (diet FO), and the third group was fed 7% HO fat, 1.5% of the same fish oil, and 1.5% of a purified pig brain phospholipid concentrate (0.6% 20:4n-6 and 3.5% 22:6n-3 of total fatty acids) (diet FO+BPL). The experimental diets increased tissue monounsaturated fatty acids in comparison with rats at weaning. Tissue lipid content of 20:4n-6 was increased and 22:6n-3 decreased in Group HO compared with weanling rats, whereas opposite changes were observed in Group FO. Feeding diet FO+BPL increased 22:6n:3 in tissue lipids compared with diet HO, and increased 20:4n-6 content in relation to diet FO. Our results indicate that rat heart, kidney, and lung are highly responsive to dietary n-3 and n-6 long-chain polyunsaturated fatty acids during postnatal life.     

Dietary fish oil inhibits human breast carcinoma growth: A function of increased lipid peroxidation

Female athymic nude mice were implanted subcutaneously with human breast carcinoma MDA-MB231. Seven to ten days later, the mice were divided into groups and fed a purified diet containing the following types of fat (% of diet):(i) 20% corn oil (CO); (ii) 15% CO:5% fish (menhaden) oil (FO); (iii) 10% CO:10% FO; (iv) 5% CO:15% FO; (v) 1% CO:19% FO; and (vi) 1% CO:19% FO plus antioxidants (α-tocopherol acetate, 2000 IU/kg diet and tertiary butyl-hydroquinone, 2% of the total fat). The linoleic acid levels (% of diet) of the groups were 12.0, 9.1, 6.2, 3.3, 0.9 and 0.9%, respectively. After 6–8 wk, the carcinomas were assessed for tumor volume (cm³) and assayed for thiobarbituric acid reactive substances (TBARS). Human breast carcinoma growth was suppressed in mice consuming FO diets without antioxidants as compared to mice fed CO; the greater the amount of dietary FO fed, the greater the carcinoma growth suppression (P<0.05). The addition of antioxidants to the FO diet significantly (P<0.05) reversed the FO-induced carcinoma growth suppression. Concentrations of TBARS in the human breast carcinomas were increased in all the FO (without antioxidants) fed mice, compared to mice fed CO; the level of increase in TBARS was directly related to the increase in the level of FO fed (P<0.05). The addition of antioxidants to the FO diet significantly (P<0.05) reduced the concentration of TBARS in the breast carcinomas. Thus, these results provide evidence that dietary FO can significantly suppress growth of human breast carcinoma MDA-MB231, even in the presence of substantial amounts of linoleic acid (3.3–9.1%). The inhibitory effect of FO on growth of these carcinomas was associated with an increased concentration of TBARS in the tumor tissue. In conclusion, dietary FO induced suppression of human breast carcinoma growth is a function, at least in part, of an accumulation of lipid peroxidation products in the tumor tissues.     

Dietary lipid modification of myocardial eicosanoids following ischemia and reperfusion in the rat

Several different edible oils were compared for their ability to modify eicosanoid biosynthesis following experimentally-induced myocardial ischemia and reperfusion in the rat. Two types of palm oil [neutralized, bleached, and deodorized (NBDPO) and refined, bleached, and deodorized (RBDPO)] and partially hydrogenated soybean oil (SBO) were tested against a diet supplemented with sunflower seed oil (SSO) rich in n−6 polyunsaturated fatty acids (PUFA). Fish oil (FO) rich in n−3 PUFA, with its known cardioprotective actions, served as an internal reference point for the study. Test oils were fed as a 12% (w/w) supplement for nine months before the induction of myocardial ischemia and reperfusion. Palm oil diets exerted effects indistinguishable from the SBO group against cardiac arrhythmia, which occurred following alterations to coronary blood flow. Arrhythmic potentials, as expressed by a hierarchical scale (0–9) of arrhythmia score, were: SSO, 1.5±0.5; FO, 0.9±0.4; SBO; 3.1±0.5^*; NBDPO, 3.2±0.5^*; RBDPO, 3.3±0.6^*,^* P<0.05 vs. SSO. Following ischemia and reperfusion, both SSO and RBDPO groups tended to show an increase in myocardial prostacyclin, with the effect being more prominent in the RBDPO group (SSO, 10%; RBDPO, 25%). Thromboxane production was reduced in the FO group. Interestingly, cardiac muscle from both FO and palm oil groups displayed a reduced capacity to produce 12-hydroxyeicosatetraenoic acid SSO, 591.9±95.8; SBO, 375.5±48.9; NBDPO, 287.2±64.7^*; RBDPO, 230.9±80.2^**; FO, 203.7±81.4^** (ng/g dry wt,^* P<0.05,^** P<0.01). No clear relationship was seen between the availability of 20∶4n−6 in myocardial phospholipids and eicosanoid profile. Data suggests that fatty acid composition of edible oils is not the only determinant of arrhythmic vulnerability and eicosanoid production. Based on a paper presented at the PORIM International Palm Oil Congress, Kuala Lumpur, Malaysia, September 1993.     

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.     

Forms of n‐3 (ALA,C18:3n‐3 or DHA,C22:6n‐3) Fatty Acids Affect Carcass Yield,Blood Lipids,Muscle n‐3 Fatty Acids and Liver Gene Expression in Lambs

The effects of supplementing diets with n‐3 alpha‐linolenic acid (ALA) and docosahexaenoic acid (DHA) on plasma metabolites, carcass yield, muscle n‐3 fatty acids and liver messenger RNA (mRNA) in lambs were investigated. Lambs (n = 120) were stratified to 12 groups based on body weight (35 ± 3.1 kg), and within groups randomly allocated to four dietary treatments: basal diet (BAS), BAS with 10.7 % flaxseed supplement (Flax), BAS with 1.8 % algae supplement (DHA), BAS with Flax and DHA (FlaxDHA). Lambs were fed for 56 days. Blood samples were collected on day 0 and day 56, and plasma analysed for insulin and lipids. Lambs were slaughtered, and carcass traits measured. At 30 min and 24 h, liver and muscle samples, respectively, were collected for determination of mRNA (FADS1, FADS2, CPT1A, ACOX1) and fatty acid composition. Lambs fed Flax had higher plasma triacylglycerol, body weight, body fat and carcass yield compared with the BAS group (P < 0.001). DHA supplementation increased carcass yield and muscle DHA while lowering plasma insulin compared with the BAS diet (P < 0.01). Flax treatment increased (P < 0.001) muscle ALA concentration, while DHA treatment increased (P < 0.001) muscle DHA concentration. Liver mRNA FADS2 was higher and CPT1A lower in the DHA group (P < 0.05). The FlaxDHA diet had additive effects, including higher FADS1 and ACOX1 mRNA than for the Flax or DHA diet. In summary, supplementation with ALA or DHA modulated plasma metabolites, muscle DHA, body fat and liver gene expression differently.     

Decreasing the Linoleic Acid to α-Linolenic Acid Diet Ratio Increases Eicosapentaenoic Acid in Erythrocytes in Adults

The n-6/n-3 fatty acid (FA) ratio has increased in the Western-style diet to ~10–15:1 during the last century, which may have contributed to the rise in cardiovascular disease (CVD). Prior studies have evaluated the effects on CVD risk factors of manipulating the levels of n-6 and n-3 FA using food and supplements or investigated the metabolic fate of linoleic acid (LNA) and α-linolenic acid (ALA) by varying the n-6/n-3 ratios. However, no previous studies have investigated the potential interaction between diet ratios and supplementation with eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3). We used a factorial design approach with adults (n = 24) in a controlled feeding trial to compare the accretion of EPA and DHA into red blood cell membranes (RBC) by adding a direct source (algal oil supplement) of EPA and DHA in a diet with a 10:1 versus 2:1 ratio of n-6/n-3 FA. Subjects were randomized into 8-week crossover diet sequences and each subject consumed three of four diets [10:1, 10:1 plus supplement (10:1 + S), 2:1 and 2:1 + S]. LNA and ALA intakes were 9.4 and 7.7%, and 1.0 and 3.0% during the low and high ALA diets, respectively. Compared to the Western-style 10:1 diet, the 2:1 diet increased EPA by 60% (P < 0.0001) in RBC membranes without the direct EPA source and a 34% increase (P = 0.027) was observed with the 10:1 + S diet; however, DHA levels increased in both diet ratios only with a direct DHA source. Shifting towards a 2:1 diet is a valid alternative to taking EPA-containing supplements.     

Dietary fatty acid profile affects endurance in rats

Typically, athletes are advised to increase their consumption of carbohydrates for energy and, along with the general population, to reduce consumption of saturated fats. It is now recognized that fats are not identical in their influence on metabolism, and we argue that the composition of the polyunsaturated fat component should not be ignored. The aim of this study was to manipulate the dietary fatty acid profile in a high-carbohydrate diet in order to investigate the effect of dietary polyunsaturates on submaximal endurance performance in rats. Rats were fed one of three isoenergetic diets containing 22 energy percentage (E%) fat for 9 wk. The diets comprised an essential fatty acid-deficient diet (containing mainly saturated fatty acids); a diet high in n-6 fatty acids, High n-6; and a diet enriched with n-3 fatty acids, High n-3. Submaximal endurance in rats fed the High n-3 diet was 44% less than in rats fed the High n-6 diet (P<0.02). All rats were then fed a standard commercial laboratory diet for a 6-wk recovery period, and their performances were reevaluated. Although endurance in all groups was lower than at 9 wk, it was again significantly 50% lower in the High n-3 group than the High n-6 group (P<0.005). Although n-3 fats are considered beneficial for cardiovascular health, they appear to reduce endurance times, and their side effects need to be further investigated.     

Inclusion of Flaxseed in Hay- and Barley Silage Diets Increases Alpha-Linolenic Acid in Cow Plasma Independent of Forage Type

Feeding flaxseed to cattle may be a means of increasing omega-3 fatty acid levels in ruminant products, but possible interactions with conserved forages have not been investigated. Twelve Holstein cows were used in a replicated 4 × 4 Latin Square experiment. Cows were fed one of four 50:50 forage:concentrate diets (DM basis): hay (hay control, HC), hay plus 15% ground flaxseed (hay-flaxseed, HF), barley silage (silage control, SC), and barley silage plus 15% ground flaxseed (silage-flaxseed, SF). Plasma concentrations of alpha-linolenic acid (ALA) did not differ between SC and HC diets. Flaxseed increased ALA (P < 0.05), but levels were not influenced by forage type. Flaxseed slightly increased 18:2n-6 (P < 0.05) and some n-6 and n-3 elongation and desaturation products, particularly arachidonic acid (ARA) and eicosapentaenoic acid (EPA). Flaxseed also increased C18:0 (P < 0.05) with this increase being greater (P < 0.01) for cows fed SF than HF. Feeding flaxseed also increased plasma C18:1-trans isomers (P < 0.01), predominantly vaccenic acid (VAA, 18:1-t11), with this increase being greater (P < 0.05) in cows fed HF than SF. Although conjugated linoleic acid (CLA) was increased (P < 0.001) with flaxseed it was not influenced by forage type (P = 0.06). Overall, feeding flaxseed increased plasma ALA, EPA, ARA and CLA independently of forage type. Feeding flaxseed with silage, however, resulted in more 18:0, while feeding flaxseed with hay resulted in greater accumulations of plasma 18:1-trans isomers mainly in the form of VAA.     

Dietary CLA Combined with Palm Oil or Ovine Fat Differentially Influences Fatty Acid Deposition in Tissues of Obese Zucker Rats

The effect of dietary conjugated linoleic acid (CLA) supplementation in combination with fat from vegetable versus animal origin on the fatty acid deposition, including that of individual 18:1 and 18:2 (conjugated and non-conjugated) isomers, in the liver and muscle of obese rats was investigated. For this purpose, 32 male Zucker rats were randomly assigned to one of four diets containing palm oil or ovine fat, supplemented or not with 1% of 1:1 cis(c)9,trans(t)11 and t10,c12 CLA isomers mixture. Total fatty acid content decreased in the liver and muscle of CLA-fed rats. In the liver, CLA increased saturated fatty acids (SFA) in 11.9% and decreased monounsaturated fatty acids (MUFA) in 6.5%. n-3 Polyunsaturated fatty acids (PUFA) relative proportions were increased in 30.6% by CLA when supplemented to the ovine fat diet. In the muscle, CLA did not affect SFA but decreased MUFA and PUFA percentages. The estimation of Δ9-indices 16 and 18 suggested that CLA inhibited the stearoyl-CoA desaturase activity in the liver (a decrease of 13–38%), in particular when supplemented to the ovine fat diet. Concerning CLA supplementation, the t10,c12 isomer percentage was 60–80% higher in the muscle than in the liver. It is of relevance that rats fed ovine fat, containing bio-formed CLA, had more c9,t11 CLA isomer deposited in both tissues than rats fed palm oil plus synthetic CLA. These results highlight the importance to further clarify the biological effects of consuming foods naturally enriched in CLA, alternatively to CLA dietary supplementation.     

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.     

Dietary fats and energy levels differently affect tissue lipogenic enzyme activity in finishing pigs

The aim of the present study was to determine the relationship between high and low digestible energy levels (9.5 vs. 15.4 MJ ME/kg) and either tallow or soy oil supplementation (5%rpar; on lipogenic activities and fatty acid profile of the backfat tissue outer layer and liver tissue in finishing pigs. Twenty Large White pigs averaging 30 (initial) to 106 kg (final) live weight were allocated into four dietary groups and fed the diets ad libitum. The lipid content and fatty acid composition of the tissues were determined and glucose-6-phosphate dehydrogenase (G6PDH), malic enzyme (ME), and fatty acid synthase (FAS) activity were measured. Growth performance and carcass measurements were affected by the dietary energy levels but not by the fat sources. Lipid deposition rate of animals fed the low energy diets was lowered regardless whether tallow or soy oil was supplemented. Unlike lipid deposition, fatty acid profile was influenced by both dietary factors. Pigs fed the low energy diet supplemented with soy oil exhibited the lowest level of saturated (P<0.001), monounsaturated (P<0.001), and the highest level of polyenic fatty acids in the backfat, the opposite was the case for the pigs fed the high energy diet supplemented with beef tallow. The fatty acid profile of the adipose tissue of animals fed the other two diets were intermediate, but clear distinction of the profile due to diets was visible. Independent of dietary treatments, lipogenic activities were up to 10 times higher in the backfat than in the liver. G6PDH activity was higher (P<0.05) due to high energy diet, whereas the activities of ME and FAS were not affected. Animals fed the high energy diet either supplemented with tallow or soy oil exhibited higher ME activity lpar;P<0.05) in the backfat, without any effects on G6PDH activity. In contrast, dietary fat sources affected the FAS activity, with lower activity lpar;P<0.05) exhibited in the backfat of animals fed the soy oil diets. The present results indicate that dietary manipulation, which change the flux through the pathway of lipogenesis and pentose-phosphate must affect differently the activities of the involved enzymes. The effect of the dietary energy level was stronger and overwhelmed the inducing effect of the PUFA on the activities of the collateral enzymes. In contrast the immediately involved lipogenic enzyme FAS responded more to dietary PUFA stimulation than to the energy supply.