Dietary Unsaturated Fatty Acids Research Articles

Effects of diets high in unsaturated Fatty acids on socially induced stress responses in Guinea pigs.

Unsaturated fatty acids (UFAs), such as omega-3 and omega-6 poly- and omega-9 monounsaturated fatty acids are important nutrients and major components of neuronal cell membranes. They play a major role in modulating brain functions and physiology and may therefore diminish behavioral and physiological stress reactions in corroboration with decreased cortisol concentrations. Functionally, cortisol itself can modulate several behaviors and also the fatty acid metabolism in the long term. But only little is known about the behavioral and physiological influences of dietary UFAs in a social group, where individuals are regularly exposed to stressful situations. Therefore, the aim of this study was to determine the effects of dietary UFAs on saliva cortisol concentrations and behavioral responses in socially confronted guinea pigs. Three groups of animals were additionally supplemented with 500 mg chia seeds (high in omega-3), walnuts (high in omega-6), or peanuts (high in omega-9) per kg bodyweight each day and compared to a control group. During social confrontation saliva cortisol concentrations significantly increased in all groups, which was accompanied by a loss in bodyweight. However, cortisol levels remained lower in the chia and walnut groups compared to controls. Additionally, the walnut group displayed significantly increased locomotion, while no differences between groups were detected in socio-positive, sexual, or aggressive behaviors. Total plasma omega-3, omega-6, and omega-9 fatty acids were significantly increased in the corresponding groups, due to the dietary supplementations. However, a significant decrease in plasma omega-3 and an increase in plasma n-6 fatty acids were detected in the chia group when comparing the measurements before and after social confrontation. We conclude that both omega-3 and omega-6 polyunsaturated fatty acids can diminish behavioral and physiological stress responses to the social environment, enabling individuals to cope with social stressors, but at the expense of plasma derived omega-3 fatty acids.

122 SEX-SPECIFIC EFFECTS OF PARENTAL DIET DURING PREGNANCY ON EMBRYO DEVELOPMENT IN THE LONG SNOUT SEAHORSE (HIPPOCAMPUS REIDI; GINSBURG, 1933)

As in mammals, seahorse embryos develop internally but, unlike in mammals, this process occurs within a paternal structure (the brood pouch). Functionally, the brood pouch supports developing embryos through placenta-like interactions, but as egg quality is determined by the female's diet, the seahorse system offers opportunities to study the effect of the male's diet on embryo development while varying the female's diet independently. In this study, we investigated the hypothesis that development of seahorse embryos is affected differentially by independent manipulation of the male and female parental diets. Adult males and females were fed separately with either wild-caught crustaceans (Male-W or Female-W, respectively) or commercial aquarium diet (Male-C or Female-C, respectively) for 1 month before conception and during the subsequent pregnancy (approximately 15 days). Dietary unsaturated fatty acid content (18:3n-3) and (20:4n-6) in the W diet was approximately double that in the C diet. In total, 5231 first-brood offspring were obtained from 4 treatment groups formed from (1) Male-W × Female-W; (2) Male-C × Female-W; (3) Male-W × Female-C; and (4) Male-C × Female-C. Each treatment was replicated with 4 couples. Newborns (10 from each brood) were weighed and dimensions measured. Fifteen-day postnatal survival rates were determined from 40 offspring/couple (N at Day 0 = 160/treatment) and fatty acid profiles were evaluated. Data were analysed by nested analyses of covariance (ANCOVA); replicates were nested within treatments and individual offspring measurements were nested within replicates (male and female parental sizes were used as covariates). Offspring produced by the Male-C × Female-W were ~10% taller (both as standard length and tail length; P < 0.05) than those produced by Male-W × Female-W couples but their 15-day survival was poorer (12.9% v. 39%; χ2 = 39.19, 1 DF; P < 0.001). Fifteen-day survival of the other groups was 0% in both cases. When both male and female parents were fed the commercial diet, their offspring were considerably smaller than those from all the other treatments (P < 0.05). The offspring produced by Male-W × Female-C couples showed distortion of the snout:head length ratio, a phenotypic feature that was highly consistent in the Male-W × Female-W treatment group. Fatty acid profiles of the offspring showed significant dependence on the preconception dietary treatment; 20:4n-6 and 22:6n-3 contents were significantly lower in Male-C × Female-C than in Male-W × Female-C (P < 0.01) offspring, showing that the male's pouch could compensate for the poorer quality of lipids derived directly from eggs. These results support the hypothesis that diet received during the preconception period and pregnancy by the males and females differentially affects embryonic growth and fatty acid content, and suggest that seahorses are a suitable model species for understanding the effects of parental diet on offspring health. Supported by the EU FP7/2007–2013 AquaExcel network (grant agreement No. 262336) and the COST Action (FA1201) (Epigenetics and Periconception Environment).

Short communication: Effects of molasses products on productivity and milk fatty acid profile of cows fed diets high in dried distillers grains with solubles

Previous research has shown that replacing up to 5% [of dietary dry matter (DM)] corn with cane molasses can partially alleviate milk fat depression when cows are fed high-concentrate, low-fiber rations containing dried distillers grains with solubles. The primary objective of this study was to determine whether dietary molasses alters milk fatty acid (FA) profile or improves solids-corrected milk yield in the context of a more typical lactation diet. A secondary objective was to assess production responses to increasing rumen-degradable protein supply when molasses was fed. Twelve primiparous and 28 multiparous Holstein cows (196±39 d in milk) were blocked by parity and assigned to 4 pens. Pens were randomly allocated to treatment sequence in a 4 × 4 Latin square design, balanced for carryover effects. Treatment periods were 21 d, with 17 d for diet adaptation and 4 d for sample and data collection. Treatments were a control diet, providing 20% dried distillers grains with solubles (DM basis), 35% neutral detergent fiber, 30% starch, and 5% ether extract; a diet with 4.4% cane molasses replacing a portion of the corn grain; a diet with 2.9% molasses supplement containing 32% crude protein on a DM basis; and a diet with 5.8% (DM basis) molasses supplement. Animal-level data were analyzed using mixed models, including the fixed effect of treatment and the random effects of period, pen, period × pen interaction, and cow within pen to recognize pen as the experimental unit. Diets did not alter DM intake, milk production, milk component concentration or yield, feed efficiency (DM intake/milk yield), body weight change, or milk somatic cell count. Milk stearic acid content was increased by the diet containing 5.8% molasses supplement compared with the control diet and the diet containing 2.9% molasses supplement, but the magnitude of the effect was small (12.27, 11.75, and 11.69±0.29 g/100g of FA). Production data revealed a dramatic effect of period on milk fat content and yield. Milk fat content decreased during the course of the experiment (least squares means = 3.16, 2.81, 2.93, and 2.64±0.09% for periods 1 to 4, respectively), as did milk fat yield (1.20, 1.03, 0.98, and 0.79±0.05 kg/d). Exchanging molasses-based products for corn at 2.9 to 5.8% of dietary DM did not influence productivity and had minute effects on milk FA profile. The limited responses in this study may have been influenced by dietary unsaturated FA content or the advancing stage of lactation of cows in the study.

Association of dietary fatty acids intake with pro-coagulation and inflammation in Saudi Adults.

The aim of the study was to understand whether dietary fatty acids such as saturated, polyunsaturated, and monounsaturated fatty acids act as inflammatory mediators or influence pro-coagulation in Saudi adults. The study sought to examine inflammatory factors such as C-reactive protein, tumor necrosis factor-alpha and activated plasminogen activator inhibitor 1. A total number of 232 consenting Saudi adults, aged 18-60 years were randomly selected in this cross-sectional study. Independent Student t-test was done to compare means of normally distributed data. Spearman correlation between the variables was determined. The values of different fatty acids and adipokines were transformed logarithmically/square root to normalize data before correlations were determined and statistical analyses performed. Statistical significance was set at p<0.05. The results show a significant positive correlation of dietary intake of poly and monounsaturated fatty acids, but not saturated fatty acids, with activated plasminogen activator inhibitor 1 (r=0.31, p=0.02, r=0.32 p=0.04). On the other hand, dietary intake of saturated fatty acids showed a negative correlation with serum C-reactive protein levels (p=0.001) in males. Dietary unsaturated fatty acids is possibly associated with the production of a pro-coagulation factor without enhancing the secretion of pro-inflammatory molecules, while saturated fatty acids have no effect on activated plasminogen activator inhibitor 1, but their level is negatively associated with the inflammatory factor C-reactive protein. We conclude that dietary intake may exert a gender-specific effect in inflammatory processes among adults. Further studies are warranted to confirm present findings.

Effect of conjugated linoleic acid mixtures and different edible oils in body composition and lipid regulation in mice.

Evidences suggest that commercial and natural conjugated linoleic acids (CLA) differentially affect nutritional status and lipid metabolism. To investigate the differential effect of two types of CLA preparations supplemented to dietary fats containing different proportions of n-9, n-6 and n-3 fatty acids (FA) on body composition, triacylglycerol (TG) levels and lipid metabolism in mice. Growing mice were fed diets containing olive, maize and rapeseed oils supplemented with an equimolecular mixture of CLA (mix-CLA) or a rumenic acid (RA)-rich oil for 30 days. Body weight gain, carcass composition, tissue weights, plasma and tissue TG levels, and lipid regulation parameters were evaluated. Independently of the dietary fats, mix-CLA decreased body weight gain and fat depots related to lower energy efficiency, hepatomegaly, increase of serum TG and decrease of muscle TG. Rapeseed oil prevented the hepatic steatosis observed with mix-CLA supplementation to olive and maize oils by increasing TG secretion. RA-rich oil supplementation decreased fat depots without hepatomegaly, hepatic steatosis and hypertriglyceridemia. Olive oil, by an equilibrium between FA uptake/oxidation, prevented the increase of muscle TG induced by the RA-rich oil supplementation to maize and rapeseed oils. The proportions of dietary unsaturated FA modulated the different mix-CLA and RA-rich oil response to lipid metabolism in mice. Finally, rapeseed oil prevented the hepatic steatosis induced by mix-CLA, and the most beneficial effects of RA-rich oil were observed when supplemented to olive oil, due to the reduced lipid accretion without changes in TG levels.

A Review of the Metabolic Origins of Milk Fatty Acids

Milk fat and its fatty acid profile are important determinants of the technological, sensorial, and nutritional properties of milk and dairy products. The two major processes contributing to the presence of fatty acids in ruminant milk are the mammary lipogenesis and the lipid metabolism in the rumen. Among fatty acids, 4:0 to 12:0, almost all 14:0 and about a half of 16:0 in milk fat derive from de novo synthesis within the mammary gland. De novo synthesis utilizes as precursors acetate and butyrate produced through carbohydrates ruminal fermentation and involves acetyl-CoA carboxylase and fatty acid synthetase as key enzymes. The rest of 16:0 and all of the long-chain fatty acids derive from mammary uptake of circulating lipoproteins and nonesterified fatty acids that originate from digestive absorption of lipids and body fat mobilization. Further, long-chain fatty acids as well as medium-chain fatty acids entering the mammary gland can be desaturated via Δ-9 desaturase, an enzyme that acts by adding a cis-9-double bond on the fatty acid chain. Moreover, ruminal biohydrogenation of dietary unsaturated fatty acids results in the formation of numerous fatty acids available for incorporation into milk fat. Ruminal biohydrogenation is performed by rumen microbial population as a means of protection against the toxic effects of polyunsaturated fatty acids. Within the rumen microorganisms, bacteria are principally responsible for ruminal biohydrogenation when compared to protozoa and anaerobic fungi.

Wing (Ib) cells in frog taste discs detect dietary unsaturated fatty acids

The effects of unsaturated fatty acids on membrane properties were studied using conventional whole-cell patch-clamp recording of isolated wing (Ib) cells in bullfrog (Lithobates catesbeianus) taste discs. Applying arachidonic acid to the bath induced monophasic inward currents in 60% of wing cells and biphasic inward and outward currents in the other cells. The intracellular dialysis of arachidonic acid did not induce an inward current; however, it enhanced a slowly developing Ba2+-sensitive outward current. The effects of various unsaturated fatty acids were explored under the condition of Cs+ internal solution. Linoleic and α-linolenic acids induced large inward currents. Oleic, eicosapentaenoic and docosahexaenoic acids elicited the same inward currents as those of arachidonic acid. Wing cells, under the basal condition with Cs+ internal solution, displayed a small inward current of −1.1±0.1pA/pF at −50mV (n=40), in which the peak existed at a membrane potential of −49mV. Removing external Ca2+ further increased the inward current by −2.9±0.3pA/pF at −50mV (n=4) from the basal current and the peak was located at −55mV. External linoleic acid (50μM) also induced a similar inward current of −5.6±0.6pA/pF at −50mV (n=19) from the basal current and the peak was located at −61mV. External Ca2+-free saline and linoleic acid induced similar current/voltage (I/V) relationships elicited by a ramp voltage as well as voltage steps. Linoleic acid-induced currents were not influenced by replacing internal EGTA with BAPTA, whereas inward currents disappeared under the elimination of external Na+ and addition of flufenamic acid. These results suggest that dietary unsaturated fatty acids may depolarize wing (Ib) cells, which affects the excitability of these cells.

Seaweed extracts and unsaturated fatty acid constituents from the green alga Ulva lactuca as activators of the cytoprotective Nrf2–ARE pathway

Increased amounts of reactive oxygen species (ROS) have been implicated in many pathological conditions, including cancer. The major machinery that the cell employs to neutralize excess ROS is through the activation of the antioxidant-response element (ARE) that controls the activation of many phase II detoxification enzymes. The transcription factor that recognizes the ARE, Nrf2, can be activated by a variety of small molecules, most of which contain an α,β-unsaturated carbonyl system. In the pursuit of chemopreventive agents from marine organisms, we built, fractionated, and screened a library of 30 field-collected eukaryotic algae from Florida. An edible green alga, Ulva lactuca, yielded multiple active fractions by ARE–luciferase reporter assay. We isolated three monounsaturated fatty acid (MUFA) derivatives as active components, including a new keto-type C18 fatty acid (1), the corresponding shorter chain C16 acid (2), and an amide derivative (3) of the C18 acid. Their chemical structures were elucidated by NMR and mass spectrometry. All three contain the conjugated enone motif between C7 and C9, which is thought to be responsible for the ARE activity. Subsequent biological studies focused on 1, the most active and abundant ARE activator isolated. C18 acid 1 induced the expression of ARE-regulated cytoprotective genes, including NAD(P)H:quinone oxidoreductase 1, heme oxygenase 1, thioredoxin reductase 1, both subunits of the glutamate–cysteine ligase (catalytic subunit and modifier subunit), and the cystine/glutamate exchange transporter, in IMR-32 human neuroblastoma cells. Its cellular activity requires the presence of Nrf2 and PI3K function, based on RNA interference and pharmacological inhibitor studies, respectively. Treatment with 1 led only to Nrf2 activation, and not the increase in production of NRF2 mRNA. To test its ARE activity and cytoprotective potential in vivo, we treated mice with a single dose of a U. lactuca fraction that was enriched with 1, which showed ARE-activating effects similar to those observed in vitro. This could be owing to this fraction's ability to stabilize Nrf2 through inhibition of Keap1-mediated Nrf2 ubiquitination and the subsequent accumulation and nuclear translocation of Nrf2. The induction of many ARE-driven antioxidant genes in vivo and most prominently in the heart agreed with the commonly recognized cardioprotective properties of MUFAs. A significant increase in Nqo1 transcript levels was also found in other mouse tissues such as the brain, lung, and stomach. Collectively, this study provides new insight into why consumption of dietary seaweed may have health benefits, and the identified compounds add to the list of chemopreventive dietary unsaturated fatty acids.

Evaluating the In Vitro Metabolism of Docosahexaenoic Acid in Sheep Rumen Fluid

Rumen metabolism (e.g., biohydrogenation) of dietary unsaturated fatty acids (FA) is one of the main reasons why ruminant fats tend to be highly saturated and contain many isomerized FA intermediates. The process by which long-chain (20- to 24-carbon FA) polyunsaturated FA (LC-PUFA) are metabolized by rumen bacteria is not as well understood as that of linoleic or linolenic acids. In order to better understand the fate of LC-PUFA in the rumen several concentrations of docosahexaenoic acid (DHA) were evaluated in in vitro batch incubations ranging from 100 to 1,500μg per 6mL of incubation volume using rumen fluid from sheep and incubated for 0, 1, 2, 3, and 6h. From the results, it was shown that DHA was extensively metabolized at low (100 to 300μg/6mL incubation volume), but not at high level of inclusion (800μg). At 300μg of DHA most of the depleted DHA was recovered as LC-DHA metabolites within the first 6h of incubation, and at the lowest levels (100μg of incubation volume) further metabolism is apparent at 6h. Using SP-2560 GC columns several LC-DHA metabolites were shown to elute after 24:0 and just past DHA, a region generally free of interfering FA. The present in vitro study would appear to be a useful method to evaluate the production of DHA metabolites in combination with its depletion.

Isolation and identification of the NRO1 gene, which is responsible for recognition of fatty acid species in the yeast Saccharomyces cerevisiae

When dietary unsaturated fatty acids (UFAs) are present, Saccharomyces cerevisiae cells down‐regulate expression of the gene OLE1, which encodes the enzyme Δ9 desaturase, responsible for all endogenous production of UFAs. A screen was designed to isolate mutants defective in recognition of the presence of UFAs, and subsequent transcriptional regulation of the Δ9‐desaturase. Using a reporter gene construct controlled by the OLE1 promoter, several mutants were identified and one mutant, KH2, was chosen for additional characterization. The mutation that renders KH2 incapable of molecular response to UFAs is a recessive trait due to a single mutation, we call nro1 (no regulation of OLE1). KH2 does perform normal post‐transcriptional regulation of the desaturase, indicating its effect is limited to transcriptional regulation. In order to identify the gene responsible for this phenotype, a yeast genomic library was transformed into the nro1 mutant, and plasmids that returned the mutant to wild type phenotype were chosen for further evaluation. These plasmids may contain the gene NRO1, encoding the protein responsible for the sensing of exogenous UFAs. Supported by a Walker‐Barr Summer Research Scholar Award from Hope College Biology Department

The Role of Nro1p in Recognition and Signaling the Presence of Dietary Unsaturated Fatty Acids

The OLE1 gene in Saccharomyces cerevisiae encodes the sole fatty acyl desaturase in that species. OLE1 gene expression is controlled in part through transcriptional regulators Mga2p and Spt23p. These proteins reside in the ER, and when an insufficient supply of unsaturated fatty acids (UFAs) is detected, they are proteolytically cleaved and translocated into the nucleus, where they activate OLE1 expression. Recently our lab has isolated a mutant that is deficient in regulation of OLE1, called nro1 (no regulation of OLE1). The mechanism for the NRO1 protein's action is unknown. In this study, we report that growth tests using a reporter gene under control of the OLE1 promoter demonstrate that in wild type cells, normal regulation is observed with the UFAs 16:1Δ9 and 18:2Δ9, 12 but not with UFAs 18:1Δ9 or 17:1Δ9. Fatty acid profiles of nro1 mutant cells are similar to wildtype when cells are supplemented with the various UFAs, showing evidence of post‐transciptional regulation. Results examining the effect of nro1 on the proteolytic processing of Mga2p and Spt23p through western analysis are presented. Taken together, there is evidence that the NRO1 system helps to regulate OLE1 expression in response to fatty acids 16:1Δ9 and 18:2Δ9, 12, but not 18:1Δ9 or 17:1Δ9. Supported by a Summer Research Scholar Award from Hope College Biology Department

Characterization of the disappearance and formation of biohydrogenation intermediates during incubations of linoleic acid with rumen fluid in vitro1

Dietary unsaturated fatty acids are extensively hydrogenated in the rumen, resulting in the formation of numerous intermediates that may exert physiological effects and alter the fat composition of ruminant-derived foods. A batch culture method was used to characterize the hydrogenation of linoleic acid (LeA) by strained rumen fluid in vitro. Incubations (n=5) were performed in 100-mL flasks maintained at 39°C containing 400mg of grass hay, 50mL of buffered rumen fluid, and incremental amounts of LeA (0, 1.0, 2.5, 5.0, or 10.0mg) for 0, 1.5, 3.0, 4.5, 6.0, and 9.0h. The fatty acid composition of flask contents was determined using complimentary silver-ion thin-layer chromatography, gas chromatography mass-spectrometry, and silver-ion high-performance liquid chromatography. Linoleic acid was extensively (98.1, 97.6, 98.0, and 89.8% for additions of 1.0, 2.5, 5.0, and 10.0mg of LeA, respectively) hydrogenated over time. Complete reduction of LeA to 18:0 was inhibited in direct relation to the amount of added substrate, the extent of which was greatest for the highest amount of LeA addition. Recoveries of 1.0, 2.5, 5.0, and 10.0mg of added LeA as 18:0 averaged 73.6, 65.0, 57.3, and 10.7%, respectively. Incubation of incremental amounts of LeA resulted in a time-dependent accumulation of geometric isomers of 9,11 and 10,12 conjugated linoleic acid, several nonconjugated 18:2 isomers, and a wide range of cis 18:1 and trans 18:1 intermediates. Several unusual intermediates including cis-6,cis-12 18:2; cis-7,cis-12 18:2; and cis-8,cis-12 18:2, were found to accumulate in direct relation to the amount of added LeA, providing the first indications that hydrogenation of LeA by ruminal bacteria may also involve mechanisms other than hydrogen abstraction or isomerization of the cis-12 double bond. Fitting of single-pool, first-order kinetic models to experimental data indicated that the rate of LeA disappearance decreased with increases in substrate availability. Reduction of 18:1 and 18:2 intermediates occurred at much lower rates compared with conjugated linoleic acid and nonconjugated 18:2 isomer formation. In conclusion, the extent of LeA biohydrogenation in vitro was shown to be time- and dose-dependent with evidence that LeA is hydrogenated by ruminal bacteria via several distinct metabolic pathways. The accumulation of several unusual 18:2 isomers indicates that biohydrogenation of LeA also proceeds via mechanisms other than isomerization of the cis-12 double bond.

Fatty acid composition and bacterial community changes in the rumen fluid of lactating sheep fed sunflower oil plus incremental levels of marine algae

Supplementation of ruminant diets with plant oils and marine lipids is an effective strategy for lowering saturated fatty acid (FA) content and increasing the concentration of cis-9,trans-11 conjugated linoleic acid and long-chain n-3 FA in ruminant milk. However, changes in populations of ruminal microorganisms associated with altered biohydrogenation of dietary unsaturated FA are not well characterized. Twenty-five lactating Assaf ewes were allocated at random to 1 of 5 treatments composed of dehydrated alfalfa hay and concentrates containing no additional lipid (control), or supplemented with 25g of sunflower oil and 0 (SO), 8 (SOMA1), 16 (SOMA2), or 24 (SOMA3) g of marine algae/kg of diet dry matter. On d 28 on diet, samples of rumen fluid were collected for lipid analysis and microbial DNA extraction. Appearance and identification of biohydrogenation intermediates was determined based on complementary gas chromatography and Ag+-HPLC analysis of FA methyl esters. Total bacteria and the Butyrivibrio group were studied in microbial DNA by terminal RFLP analysis, and real-time PCR was used to quantify the known Butyrivibrio bacteria that produce trans-11 18:1 or 18:0. Dietary supplements of sunflower oil alone or in combination with marine algae altered the FA profile of rumen fluid, which was associated with changes in populations of specific bacteria. Inclusion of marine algae in diets containing sunflower oil resulted in the accumulation of trans 18:1 and 10-O-18:0 and a marked decrease in 18:0 concentrations in rumen fluid. At the highest levels of supplementation (SOMA2 and SOMA3), marine algae also promoted a shift in ruminal biohydrogenation pathways toward the formation of trans-10 18:1 at the expense of trans-11 18:1. Changes in the concentration of biohydrogenation intermediates were not accompanied by significant variations in the abundance of known cultivated ruminal bacteria capable of hydrogenating unsaturated FA. However, certain bacterial groups detected by terminal RFLP (such as potentially uncultured Lachnospiraceae strains or Quinella-related bacteria) exhibited variations in their relative frequency consistent with a potential role in one or more metabolic pathways of biohydrogenation in the rumen.

The Role of Rho/Rho-Kinase Pathway in the Expression of ICAM-1 by Linoleic Acid in Human Aortic Endothelial Cells

Linoleic acid (LA), a dietary unsaturated fatty acid, has been known to increase the expression of adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) through the activation of nuclear factor-kappa B. Rho/Rho-kinase (ROCK) pathway mediates various cellular functions related to cardiovascular disease and affects the expression of ICAM-1. However, the exact mechanism underlying this action has not been fully elucidated. In this study, we aimed to find out the role of Rho/ROCK pathway in LA-induced ICAM-1 expression in human aortic endothelial cells (HAECs). We found that LA increased ICAM-1 expression and phosphorylation of ROCK and MYPT-1, a distal signal of ROCK. Y-27632, a ROCK inhibitor, suppressed ICAM-1 expression and phosphorylation of MYPT-1 induced by LA. The effect of LA on the increased phosphorylation of MYPT1 and expression of ICAM-1 was abolished by knocking down RhoA and ROCK2 protein level expression using small interfering RNA. LA increased NF-κB DNA-binding activity, which was inhibited with pretreatment with Y-27632. This study suggests that Rho/ROCK pathway plays a role in LA-induced ICAM-1 expression, which is possibly mediated by NF-κB in HAECs.

Differential effects of saturated versus unsaturated dietary fatty acids on weight gain and myocellular lipid profiles in mice

Objective:In conditions of continuous high-fat (HF) intake, the degree of saturation of the fatty acids (FAs) in the diet might have a crucial role in the onset of obesity and its metabolic complications. In particular, the FA composition of the diet might influence the storage form of lipids inside skeletal muscle. The aim of the present study was to examine whether the FA composition of HF diets differentially affects weight gain and accumulation of myocellular triacylglycerol (TAG) and diacylglycerol (DAG). Furthermore, we examined whether the FA composition of the diet was reflected in the composition of the myocellular lipid intermediates.Design:C57Bl6 mice were fed HF diets (45% energy) mainly containing palm oil (PO), cocoa butter (CB), olive oil (OO) or safflower oil (SO; n=6 per group) for 8 weeks. A low-fat diet (10% energy, PO) was used as control. Body weight was monitored weekly. At the end of the dietary intervention, myocellular TAG and DAG content and profiles were measured.Results:We here show that HF_CB prevented weight gain after 8 weeks of HF feeding. Furthermore, the HF diet rich in SO prevented the accumulation of both myocellular TAG and DAG. Interestingly, the FA composition of DAG and TAG in skeletal muscle was a reflection of the dietary FA composition.Conclusion:Already after a relatively short period, the dietary FA intake relates to the FA composition of the lipid metabolites in the muscle. A diet rich in polyunsaturated FAs seems to prevent myocellular lipid accumulation.

Dietary unsaturated fatty acids affect the mammary gland integrity and health in lactating dairy cows

BackgroundInformation about the effects of unsaturated fatty acids (UFA) supplementation on the health and integrity of the mammary gland in lactating dairy cows is lacking. Therefore, the aim of this study was to determine the effects of unprotected dietary UFA on the global expression pattern of genes in the mammary gland tissue of grazing dairy cows, and to translate this information into relevant biological knowledge.MethodsTwenty-eight Holstein-Friesian dairy cows were randomly assigned to 4 different concentrated UFA-sources for 23 days after which all cows were switched to a non-UFA-supplemented concentrate for an additional 28 days. On the last day of both periods, mammary gland biopsies were taken to study genome-wide differences in gene expression on Bovine Genome Arrays.ResultsSupplementation with UFA reduced the concentration of short chain fatty acids (FA), C16 FA and saturated FA in the milk, whereas that of trans-FA increased. One major finding was that canonical pathways associated with remodelling and immune functions of the mammary gland were predominantly down-regulated during UFA supplementation and negatively correlated with the concentration of milk trans-FA.ConclusionsSupplementing grazing dairy cows with unprotected dietary UFA can affect the remodelling and immune functions of the mammary gland with potential consequences for its integrity and health, as well as milk quality.

Estradiol stimulation of prolactin secretion in horses: Interaction with type of secretagogue

s / Journal of Equine Veterinary Science 31 (2011) 230-356 308 [7] Bilby TR, Block J, do Amaral BC, Sa Filho O, Silvestre FT, Hansen PJ, Staples CR, Thatcher WW. Effects of dietary unsaturated fatty acids on oocyte quality and follicular development in lactating dairy cows in summer. J Dairy Sci 2006;89:3891-903. Estradiol stimulation of prolactin secretion in horses: Interaction with type of secretagogue D.L. Thompson, Jr., S.E. Clavier, P.B. Mitcham, and L.R. Earl LSU Agricultural Center, Louisiana Agricultural Experiment Station, Baton Rouge, LA, U.S.A Introduction: Combining estradiol pretreatment with administration of a dopamine antagonist, such as sulpiride or domperidone, greatly enhances prolactin secretion in horses relative to treatment with either estradiol or dopamine antagonist alone [1-3]. Kelley et al. [2] first used this combination to stimulate ovarian activity and ovulation in seasonally anovulatory mares. Given that both day-to-day secretion (blood levels) of prolactin are stimulated in the long-term (weeks), as well as the immediate release of hormone in response to a testing dose of sulpiride, it is concluded that production rates of prolactin in the pituitary gland must be greatly enhanced by the combined treatment. The current experiments were designed to determine whether secretagogues other than dopamine antagonists would interact with estradiol pretreatment in the same manner. Materials and Methods: Two experiments were conducted. The first (July, 2009) tested the effects of estradiol pretreatment in geldings on the prolactin responses to exercise, epinephrine injection, prostaglandin-F2 a (Lutalyse; animalhealth.pfizer. com) injection, and sulpiride injection. Six geldings were administered estradiol cypionate (ECP; betlabs.com) and six geldings were administered vegetable oil on day 0. All geldings were exercised (trotting for 5 min at hourly intervals for a total of 4 bouts) on day 5, were administered epinephrine at 5 mg/kg BW i.v. on day 7, were administered 10 mg Lutalyse i.v. on day 10, and were administered sulpiride (0.1 mg/kg BW i.v.) on day 12. Prolactin was measured in blood samples collected immediately before and at frequent intervals after each treatment. The second experiment (February, 2010) tested the effects of daily administration of thyrotropin releasing hormone (TRH) and(or) ECP on daily prolactin concentrations in a 2 x 2 factorial design with 4 geldings per subgroup. Half the geldings received 50 mg ECP i.m. on day 0 and the rest received vegetable oil. Starting on day 10, half of each of those groups received either daily TRH injections (1.5 mg i.m) or saline injections of similar volumes. The TRH-saline injections were repeated through day 30. Prolactin was measured in all samples with previously validated RIA [4]. Data in each experiment were analyzed via ANOVA in SAS in repeatedmeasures designs. Differences between groups within time periods were assessed by the LSD test. Results and Discussion: In the first experiment, ECP treatment increased (P 1⁄4 .07) plasma prolactin concentrations before the onset of exercise, and exercise stimulated (P < .001) plasma prolactin concentrations after each bout. There was no interaction with estradiol pretreatment. Epinephrine did not alter prolactin concentrations. Lutalyse administration stimulated (P < .001) prolactin concentrations, but there was no interaction with ECP pretreatment. Sulpiride administration stimulated (P < .001) prolactin concentrations, and there was a greater (P 1⁄4 .038) response in ECP-treated geldings relative to controls. In the second experiment, ECP administration did not affect prolactin concentrations. Injection of TRH stimulated prolactin concentrations on the first day of injection, but had no effect on prolactin concentrations otherwise. There was no interaction of ECP and TRH administration either on the prolactin response on the first day of TRH injection, or across the 20 days of treatment. Conclusion: Unlike the synergistic interaction of estradiol pretreatment and dopamine antagonist administration on prolactin secretion, there was no interaction of ECP and other types of prolactin secretagogues in the first experiment. Even though exercise and Lutalyse stimulated prolactin secretion, it was equally stimulated in ECP-treated and control geldings; subsequent administration of sulpiride revealed that the estradiol-dopamine antagonist interaction existed in the same geldings 2 days later. In some way, the mechanism of release of prolactin from estradiol-stimulated lactotropes differs for dopamine antagonists and other prolactin-releasing stimuli. This would indicate that the stimulus for prolactin secretion after exercise or Lutalyse is not a reduction in dopamine input to the pituitary gland. Unlike sulpiride or domperidone, daily TRH injection after ECP pretreatment did not stimulate long-term prolactin secretion. Thus, even though TRH is a secretagogue for prolactin, it is unable to enhance prolactin production in combination with estradiol stimulation. The practical impact of these data is that stimulation of prolactin concentrations after ECP treatment in winter, in an effort to stimulate ovarian activity in seasonally anovulatory mares, appears to be limited to dopamine antagonists.

Alteration of gene expression in mammary gland tissue of dairy cows in response to dietary unsaturated fatty acids

The aim of this study was to determine the effects of supplementing unprotected dietary unsaturated fatty acids (UFAs) from different plant oils on gene expression in the mammary gland of grazing dairy cows. A total of 28 Holstein–Friesian dairy cows in mid-lactation were blocked according to parity, days in milk, milk yield and fat percentage. The cows were then randomly assigned to four UFA sources based on rapeseed, soybean, linseed or a mixture of the three oils for 23 days, after which, all 28 cows were switched to a control diet for an additional 28 days. On the last day of both periods, mammary gland biopsies were taken to study genome-wide differences in gene expression on Affymetrix GeneChip® Bovine Genome Arrays (no. 900493) by ServiceXS (Leiden, The Netherlands). Supplementation with UFAs resulted in increased milk yield but decreased milk fat and protein percentages. Furthermore, the proportion of de novo fatty acids (FAs) in the milk was reduced, whereas that of long-chain FAs increased. Applying a statistical cut-off of false discovery rate of q-values <0.05 together with an absolute fold change of 1.3, a total of 972 genes were found to be significantly affected through UFA supplementation, indicating that large transcriptional adaptations occurred in the mammary gland when grazing dairy cows were supplemented with unprotected dietary UFA. Gene sets related to cell development and remodeling, apoptosis, nutrient metabolic process, as well as immune system response were predominantly downregulated during UFA supplementation. Such molecular knowledge on the physiology of the mammary gland might provide the basis for further functional research on dairy cows.

Dietary Unsaturated Fatty Acids and Risk of Mild Cognitive Impairment

An increasing body of epidemiological evidence suggested that elevated saturated fatty acids could have negative effects on age-related cognitive decline (ARCD) and mild cognitive impairment (MCI). Furthermore, a clear reduction of risk for cognitive decline has been found in population samples with elevated fish consumption, high intake of monounsaturated fatty acids, and polyunsaturated fatty acids (PUFA), particularly n-3 PUFA. In the present article, on the basis of increasing body of evidence from cross-sectional and longitudinal population-based studies, we discussed the issue of the possible impact of dietary PUFA (both n-6 and n-3) on ARCD, MCI, and Alzheimer's disease.

Changes in the rumen bacterial community in response to sunflower oil and fish oil supplements in the diet of dairy sheep

Rumen microbial biohydrogenation of dietary unsaturated fatty acids has a major effect on the process of developing healthier dairy products. This study aimed to investigate in vivo the effect of diet supplementation with sunflower (SO) and fish (FO) oils on the rumen bacterial community in dairy sheep. First, 32 lactating ewes, divided in 8 lots of 4 animals each (2 lots per treatment), were fed a high-concentrate total mixed ration supplemented with 0, 2% SO, 1% FO, or 2% SO plus 1% FO. After 21 d, rumen fluid samples were taken from each lot for DNA extraction and fluorescence in situ hybridization (FISH) analysis. In a second experiment, 5 cannulated ewes were first fed the same TMR, with the exception of a higher forage level, and then changed to the same diet supplemented with 2% SO plus 1% FO. After 0, 3, and 10 d, rumen content samples were taken for DNA extraction and FISH analysis (fluid). Total bacteria and the Butyrivibrio group were studied in microbial DNA by terminal RFLP analysis (T-RFLP), and real-time PCR was used to quantify Butyrivibrio bacteria that produce vaccenic acid or stearic acid. In rumen fluid samples, total bacteria and clostridial clusters IX and XIV were analyzed by FISH. Dietary supplementation with SO plus FO seemed to induce important changes in the total bacteria and Butyrivibrio populations, and a high interindividual variation was observed, and the speed of the effect of the lipid supplementation depended on the individual microbial composition. Analysis by T-RFLP and FISH showed increases in cluster IX bacteria with SO plus FO supplementation, presumably Quinella-like microorganisms. The abundances of vaccenic acid- and stearic acid-producing Butyrivibrio relative to total bacteria, estimated by real time PCR, were low (0.28 and 0.18%, respectively, in rumen fluid, and 0.86 and 0.81% in rumen contents) and only that of SA-producing bacteria seemed to be reduced by diets containing FO, although differences were only significant in lactating ewes. The T-RFLP analysis showed a variable effect of lipid supplementation on different bacteria of the family Lachnospiraceae, which includes the cultured bacteria known to be actively involved in rumen biohydrogenation. These results suggest that the latter bacteria do not play a dominant role in this process, and therefore other as-yet-uncultivated microorganisms might be more relevant.