Trends of serum phospholipid fatty acids over time in rural Uganda: evidence of nutritional transition?

Non-communicable diseases are projected to become the most common causes of death in Africa by 2030. The impact on health of epidemiological and nutritional transitions in sub-Saharan Africa remains unclear. To assess the trends of dietary fatty acids over time in Uganda, we examined fatty acids in serum collected from individuals in rural south-west Uganda, at three time points over two decades. Independent cross-sectional samples of 915 adults and children were selected from the general population cohort in 1990 (n 281), 2000 (n 283) and 2008 (n 351). Serum phospholipid fatty acids were measured by GC. Multivariate regression analyses were performed to compare the geometric means of fatty acids by time period. Serum fatty acid profiling showed high proportions of SFA, cis-MUFA and industrial trans-fatty acids (iTFA), likely to be biomarkers of high consumption of palm oil and hydrogenated fats. In contrast, proportions of n-6 and n-3 PUFA from vegetable oils and fish were low. From 1990 to 2008, serum phospholipids showed increases in absolute amounts of SFA (17·3 % increase in adults and 26·4 % in children), MUFA (16·7 % increase in adults and 16·8 % in children) and n-6:n-3 PUFA (40·1 % increase in adults and 39·8 % in children). The amount of elaidic acid, iTFA from hydrogenated fats, increased in children (60·1 % increase). In this rural Ugandan population, we show evidence of unfavourable trends over time of dietary fatty acids.

High Serum Phospholipid Dihomo-γ-Linoleic Acid Concentration and Low Δ5-Desaturase Activity Are Associated with Increased Risk of Type 2 Diabetes among Japanese Adults in the Hitachi Health Study.

Background: The association between the circulating fatty acid (FA) composition and type 2 diabetes (T2D) has been reported in Western populations, but evidence is scarce among Asian populations, including Japanese, who consume large amounts of fish.Objective: The objective of the present study was to prospectively examine the association between circulating concentrations of individual FAs and T2D incidence among Japanese adults.Methods: We conducted a nested case-control study in a cohort of 4754 employees, aged 34-69 y, who attended a comprehensive health checkup in 2008-2009 and donated blood samples for the Hitachi Health Study. During 5 y of follow-up, diabetes was identified on the basis of plasma glucose, glycated hemoglobin, and self-report. Two controls matched to each case by sex, age, and date of checkup were randomly chosen by using density sampling, resulting in 336 cases and 678 controls with FA measurements. GC was used to measure the FA composition in serum phospholipids. Cox proportional hazards regression was used to estimate the HRs and 95% CIs after adjusting for potential confounders. We examined the association of T2D risk with 25 different individual and combinations of FAs.Results: T2D risk was positively associated with serum dihomo-γ-linoleic acid concentration (highest compared with the lowest quartile-HR: 1.49; 95% CI: 1.04, 2.11; P-trend = 0.02) and inversely associated with Δ5-desaturase activity (highest compared with the lowest quartile-HR: 0.72; 95% CI: 0.52, 0.99; P-trend = 0.02), independent of body mass index (BMI). There were also inverse associations between T2D risk with serum total n-6 (ω-6) polyunsaturated fatty acids (PUFAs), linoleic acid, and cis-vaccenic acid, but these were attenuated and became nonsignificant after adjustment for BMI. Serum n-3 (ω-3) PUFAs and saturated fatty acids (SFAs) were not associated with T2D risk.Conclusions: T2D risk was associated with circulating concentrations of the n-6 PUFA dihomo-γ-linoleic acid and Δ5-desaturase activity but not with n-3 PUFA or SFA concentrations in Japanese adults.

The proportion of total C18:1 trans-fatty acids in red blood cell membranes relates to carotid plaque prevalence.

Consistent evidence supports the pro-atherogenic properties of dietary trans-fatty acids (TFAs). However, there are no clinical data on TFA intake and atheroma plaque. We cross sectionally investigated whether the proportion of total C18:1 TFA in red blood cells (RBCs), which mirrors dietary TFA intake, independently relates to carotid plaque prevalence in subjects with new-onset type 2 diabetes mellitus without prior cardiovascular disease (n=101, 56% men, mean age 61 years) and age- and sex-matched controls (n=96). RBC fatty acid composition was determined by gas chromatography. Plaque (defined as carotid intima-media thickness ≥1.5 mm) was sonographically assessed at three bilateral carotid segments. In multivariate models adjusting for group (diabetes or control) and classical cardiovascular risk factors, for each 0.1% increase in RBC total C18:1 TFA isomers, plaque prevalence increased by 53% (P=.002). In contrast, for each 0.1% increase in RBC alpha-linolenic acid, the vegetable omega-3 fatty acid, plaque prevalence decreased by 43% (P<.001). We conclude that the RBC membrane proportion of total C18:1 TFA, considered a proxy of intake, directly relates to the ultrasound feature that best predicts future cardiovascular events. Our findings support current recommendations to limit TFA intake for cardiovascular health promotion.

Trans-11 vaccenic acid improves insulin secretion in models of type 2 diabetes in vivo and in vitro.

SCOPE: Trans-11 vaccenic acid (VA) is a fatty acid produced by ruminants entering the human food supply through meat and dairy products, which appears not to have the health risks associated with industrially produced trans-fatty acids. In this study, we investigated the effect of VA on insulin secretion in vivo in rats and in vitro in human and rat islets after diabetogenic insult. METHODS AND RESULTS: Hyperglycemic clamp showed that VA dietary supplementation for 8 weeks significantly increased glucose turnover in rats with type 2 diabetes (T2D), accompanied by an elevated plasma C-peptide concentration, indicating improved insulin secretion. The ß-cell area and proliferation rate were higher in T2D+VA than T2D group. Isolated islets from T2D+VA rats had higher glucose-stimulated insulin secretion (GSIS) than T2D group. In vitro, VA treatment for 24 and 48 h significantly enhanced GSIS in rat and human islets after diabetogenic challenges. The mRNA expression of G-protein-coupled receptor 40 (GPR40) and regenerating islet-derived 1α (REG-1α) were consistently increased by VA in both rat and human islets. CONCLUSION: These results indicate that VA may improve insulin secretion and growth of islets in T2D, at least partly by altering GPR40 and REG-1α mRNA expression.

Oral Absorption and Disposition of alpha-Linolenic, Rumenic and Vaccenic Acids After Administration as a Naturally Enriched Goat Dairy Fat to Rats.

Although there is extensive information describing the positive biological effects of conjugated linoleic acid and its main isomer rumenic acid (RA; C18:2 cis 9, trans 11), and alpha-linolenic acid (ALA) and vaccenic acid (TVA), data about their bioavailability are not available. In this work, we investigated the oral absorption and disposition of these fatty acids in Wistar rats. A naturally enriched goat dairy fat (EDF) was obtained by supplementing ruminant diets with oils or oilseeds rich in polyunsaturated fatty acids (PUFA). The EDF was administered orally (single dose of 3000 mg EDF/kg body weight equivalent to 153 mg TVA/kg body weight, 46 mg RA/kg body weight and 31 mg ALA/kg body weight), and serial blood and liver samples were collected and TVA, RA and ALA concentrations determined by GC/MS. The fatty acids TVA, RA and ALA were rapidly absorbed (t1/2a, 0.36, 0.66 and 0.76 h, respectively, for plasma) and slowly eliminated (t1/2ß, 17.04, 18.40 and 16.52 h, respectively, for plasma). The maximum concentration (C max) was detected in liver > plasma > erythrocyte. Our study shows that when orally administered EDF, its components TVA, RA and ALA were rapidly absorbed and distributed throughout the body by the blood circulation to exert systemic effects.

Effect of High Fat Diets on Body Mass, Oleylethanolamide Plasma Levels and Oxytocin Expression in Growing Rats.

Obesity prevalence in developed countries has promoted the need to identify the mechanisms involved in control of feeding and energy balance. We have tested the hypothesis that different fats present in diet composition may contribute in body weight gain and body indexes by regulation of oxytocin gene (oxt) expression in hypothalamus and Oleylethanolamide (OEA) levels in plasma. Sprague-Dawley rats were fed two high fat diets, based on corn (HCO) and extra virgin olive oil (HOO) and results were compared to a low fat diet (LF). LC-MS/MS analysis showed an increasing trend of OEA plasma levels in HOO group, although no significant differences were found. However, body weight gain of LF and HOO were similar and significantly lower than HCO. HCO rats also had higher Lee index than HOO. Rats fed HOO diet showed higher levels of hypothalamic oxt mRNA expression, which could indicate that oxytocin may be modulated by dietary lipids.

Oleic acid content of a meal promotes oleoylethanolamide response and reduces subsequent energy intake in humans.

Animal data suggest that dietary fat composition may influence endocannabinoid (EC) response and dietary behavior. This study tested the hypothesis that fatty acid composition of a meal can influence the short-term response of ECs and subsequent energy intake in humans. Fifteen volunteers on three occasions were randomly offered a meal containing 30 g of bread and 30 mL of one of three selected oils: sunflower oil (SO), high oleic sunflower oil (HOSO) and virgin olive oil (VOO). Plasma EC concentrations and appetite ratings over 2 h and energy intake over 24 h following the experimental meal were measured. Results showed that after HOSO and VOO consumption the circulating oleoylethanolamide (OEA) was significantly higher than after SO consumption; a concomitantly significant reduction of energy intake was found. For the first time the oleic acid content of a meal was demonstrated to increase the post-prandial response of circulating OEA and to reduce energy intake at subsequent meals in humans.

Modulation of plasma N-acylethanolamine levels and physiological parameters by dietary fatty acid composition in humans.

N-Acylethanolamines (NAEs) are endogenous lipid-signaling molecules involved in satiety and energetics; however, how diet impacts circulating NAE concentrations and their downstream metabolic actions in humans remains unknown. Objectives were to examine effects of diets enriched with high-oleic canola oil (HOCO) or HOCO blended with flaxseed oil (FXCO), compared with a Western diet (WD), on plasma NAE levels and the association with energy expenditure and substrate oxidation. Using a randomized controlled crossover design, 36 hypercholesterolemic participants consumed three isoenergetic diets for 28 days, each containing 36% energy from fat, of which 70% was HOCO, FXCO, or WD. Ultra-performance liquid chromatography-MS/MS was used to measure plasma NAE levels and indirect calorimetry to assess energy expenditure and substrate oxidation. After 28 days, compared with WD, plasma oleoylethanolamide (OEA) and alpha-linolenoyl ethanolamide (ALEA) levels were significantly increased in response to HOCO and FXCO (P = 0.002, P < 0.001), respectively. Correlation analysis demonstrated an inverse association between plasma OEA levels and percent body fat (r = -0.21, P = 0.04), and a positive association was observed between the plasma arachidonoyl ethanolamide (AEA)/OEA ratio and android:gynoid fat (r = 0.23, P = 0.02), respectively. Results suggest that plasma NAE levels are upregulated via their dietary lipid substrates and may modulate regional and total fat mass through lipid-signaling mechanisms.

[Effects of teaseed oil on triglyceride and weight in hypertriglyceridemic subjects].

OBJECTIVE: To investigate the effects of teaseed oil on triglyceride and weight in hypertriglyceridemic subjects. METHODS: Twenty-five hypertriglyceridemic subjects were enrolled in the study. All subjects were required to ingest 25-30 g/d of the teaseed oil as cooking oil for 8 consecutive weeks. The height, body weight, BMI and the serum oleic acid (OA), total triglyceride (TG) , total cholesterol (TC) , blood glucose, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in hypertriglyceridemic subjects were measured. The daily total energy, macronutrients intake and activity level were recorded at the beginning and ending of the study. RESULTS: Twenty-one subjects completed the study. As compared to data at the beginning, the levels of OA in serum and dietary intakes of OA, monounsaturated fatty acids significantly increased. Polyunsaturated fatty acids intake and body weight, BMI decreased significantly. CONCLUSION: Teaseed oil could increase the serum levels of OA and reduce weight and BMI in the hypertriglyceridemic subjects with stable dietary intake and exercise.

Sheep cheese naturally enriched in α-linolenic, conjugated linoleic and vaccenic acids improves the lipid profile and reduces anandamide in the plasma of hypercholesterolaemic subjects.

Intake of dairy fat has long been considered as a risk factor for CVD. Pasture and dietary lipid supplementation have been reported to be reliable strategies in ruminant nutrition, in order to increase the content of α-linolenic acid (ALA), conjugated linoleic acid (CLA) and vaccenic acid (VA), and decrease SFA in milk fat. In the present study, we aimed at verifying whether consumption of a sheep cheese, naturally enriched in ALA, CLA and VA, would modify the plasma lipid and endocannabinoid profiles in mildly hypercholesterolaemic subjects. A total of forty-two adult volunteers (nineteen males and twenty-three females) with diagnosed mildly hypercholesterolaemia (total cholesterol 5·68-7·49 mmol/l) were randomly assigned to eat 90 g/d of a control or enriched cheese for 3 weeks, with a cross-over after 3 weeks of washout. Plasma lipids, endocannabinoids, adipokines and inflammatory markers were measured. The intake of enriched cheese significantly increased the plasma concentrations of CLA, VA, the n-3 fatty acids ALA and EPA, and more remarkably decreased that of the endocannabinoid anandamide. LDL-cholesterol decreased significantly (7%). No changes were detected in the levels of inflammatory markers; however, a significant correlation was found between the plasma levels of anandamide and leptin. The control cheese modified none of the parameters measured. The results obtained do not support the view that intake of dairy fat is detrimental to hypercholesterolaemic subjects. Indeed, they show that a naturally enriched cheese possesses beneficial properties, since it ameliorates the plasma lipid profile, and more remarkably reduces endocannabinoid biosynthesis.

Cannabidiol enhances anandamide signaling and alleviates psychotic symptoms of schizophrenia.

Cannabidiol is a component of marijuana that does not activate cannabinoid receptors, but moderately inhibits the degradation of the endocannabinoid anandamide. We previously reported that an elevation of anandamide levels in cerebrospinal fluid inversely correlated to psychotic symptoms. Furthermore, enhanced anandamide signaling let to a lower transition rate from initial prodromal states into frank psychosis as well as postponed transition. In our translational approach, we performed a double-blind, randomized clinical trial of cannabidiol vs amisulpride, a potent antipsychotic, in acute schizophrenia to evaluate the clinical relevance of our initial findings. Either treatment was safe and led to significant clinical improvement, but cannabidiol displayed a markedly superior side-effect profile. Moreover, cannabidiol treatment was accompanied by a significant increase in serum anandamide levels, which was significantly associated with clinical improvement. The results suggest that inhibition of anandamide deactivation may contribute to the antipsychotic effects of cannabidiol potentially representing a completely new mechanism in the treatment of schizophrenia.

Metabolomics reveals increased isoleukotoxin diol (12,13-DHOME) in human plasma after acute Intralipid infusion.

Intralipid is a fat emulsion that is regularly infused into humans and animals. Despite its routine use, Intralipid infusion can cause serious adverse reactions, including immunosuppression. Intralipid is a complex mix of proteins, lipids, and other small molecules, and the effect of its infusion on the human plasma metabolome is unknown. We hypothesized that untargeted metabolomics of human plasma after an Intralipid infusion would reveal novel insights into its effects. We infused Intralipid and saline into 10 healthy men in a double-blind, placebo-controlled experiment and used GC/MS, LC/MS, and NMR to profile the small-molecule composition of their plasma before and after infusion. Multivariate statistical analysis of the 40 resulting plasma samples revealed that after Intralipid infusion, a less-well-characterized pathway of linoleic acid metabolism had resulted in the appearance of (9Z)-12,13-dihydroxyoctadec-9-enoic acid (12,13-DHOME, P < 10(-3)), a leukotoxin that has powerful physiological effects and is known to inhibit the neutrophil respiratory burst. Intralipid infusion caused increased plasma 12,13-DHOME. Given that 12,13-DHOME is known to directly affect neutrophil function, we conclude that untargeted metabolomics may have revealed a hitherto-unknown mechanism of intralipid-induced immunosuppression.

Fatty acids in serum phospholipids and carotid intima-media thickness in Spanish subjects with primary dyslipidemia.

BACKGROUND: Low rates of incident ischemic heart disease (IHD) and cardiac death occur in Spain despite a high prevalence of cardiovascular risk factors. High consumption of unsaturated fatty acid-rich foods, such as olive oil, nuts, and seafood, might underlie this paradox. OBJECTIVE: We investigated whether serum phosphatidylcholine enrichment in oleic, linoleic, alpha-linolenic, and n-3 (omega-3) long-chain polyunsaturated fatty acids (as biomarkers of olive oil, seed oil, walnut, and fish intake, respectively) relate to carotid atherosclerosis in Spanish subjects at risk of IHD. DESIGN: In a cross-sectional study, we measured fatty acid concentrations in serum phosphatidylcholine and measured carotid intima-media thickness (IMT) by using ultrasound in 451 asymptomatic subjects (261 men, 190 women; mean age: 45 y) with primary dyslipidemia. Main and secondary outcomes were mean and maximum IMT in the common carotid artery (CCA) and other carotid segments, respectively. RESULTS: Phosphatidylcholine fatty acid composition was similar to that reported for other Spanish populations. Multiple regression analyses showed that proportions of oleic and docosahexaenoic acids were inversely related to mean CCA IMT (P < 0.02, all) after adjustment for several confounders. In similar models, alpha-linolenic acid related inversely to mean and maximum internal carotid artery IMT (P < 0.05 for all). Linoleic and eicosapentaenoic acids were unrelated to IMT. CONCLUSIONS: Higher phospholipid proportions of oleic, alpha-linolenic, and docosahexaenoic acids showed inverse associations with IMT at specific carotid segments in subjects with primary dyslipidemia. High intakes of healthy fats might explain, in part, the Spanish paradox of low IHD rates in the face of a high burden of cardiovascular risk factors.

Prominent role of liver in elevated plasma palmitoleate levels in response to rosiglitazone in mice fed high-fat diet.

UNLABELLED: In humans, antidiabetics thiazolidinediones (TZDs) upregulate stearoyl-CoA desaturase 1 (SCD1) gene in adipose tissue and increase plasma levels of SCD1 product palmitoleate, known to enhance muscle insulin sensitivity. Involvement of other tissues in the beneficial effects of TZDs on plasma lipid profile is unclear. In our previous study in mice, in which lipogenesis was suppressed by corn oil-based high-fat (cHF) diet, TZD rosiglitazone induced hepatic Scd1 expression, while liver triacylglycerol content increased, VLDL-triacylglycerol production decreased and plasma lipid profile and whole-body glycemic control improved. Aim of this study was to characterise contribution of liver to changes of plasma lipid profile in response to a 8-week-treatment by rosiglitazone in the cHF diet-fed mice. Rosiglitazone (10 mg/kg diet) upregulated expression of Scd1 in various tissues, with a stronger effect in liver as compared with adipose tissue or skeletal muscle. Rosiglitazone increased content of monounsaturated fatty acids in liver, adipose tissue and plasma, with palmitoleate being the most up-regulated fatty acid. In the liver, enhancement of SCD1 activity and specific enrichment of cholesteryl esters and phosphatidyl cholines with palmitoleate and vaccenate was found, while strong correlations between changes of various liver lipid fractions and total plasma lipids were observed (r=0.74-0.88). Insulin-stimulated glycogen synthesis was increased by rosiglitazone, with a stronger effect in muscle than in liver. CONCLUSIONS: changes in plasma lipid profile favouring monounsaturated fatty acids, mainly palmitoleate, due to the upregulation of Scd1 and enhancement of SCD1 activity in the liver, could be involved in the insulin-sensitizing effects of TZDs.

Trans-11-18 : 1 is effectively Delta9-desaturated compared with trans-12-18 : 1 in humans.

The aim of this human intervention study was to evaluate the Delta9-desaturation of trans-11-18 : 1 (trans-vaccenic acid; tVA) to cis-9,trans-11-18 : 2 (c9,t11 conjugated linoleic acid; CLA) and of trans-12-18 : 1 (t12) to cis-9,trans-12-18 : 2 after a short-term (7 d) and a long-term (42 d) supplementation period. The conversion rates of both trans-18 : 1 isomers were estimated by lipid analysis of serum and red blood cell membranes (RBCM). Subjects started with a 2-week adaptation period without supplements. During the 42 d intervention period, the diet of the test group was supplemented with 3 g/d of tVA and 3 g/d of t12. The diet of the control group was supplemented with a control oil. Serum tVA and t12 levels in the test group increased by fivefold and ninefold after 7 d, respectively, and by eight- and 12-fold after 42 d, respectively, when compared with the adaptation period (P< or =0.002). The serum c9,t11 CLA levels increased by 1.7- and 2.0-fold after 7 d and 42 d, respectively (P< or =0.001). After 42 d, the test group's RBCM c9,t11 CLA content was elevated by 20 % (P=0.021), whereas in the control group it was decreased by 50 % (P=0.002). The conversion rate of tVA was estimated at 24 % by serum and 19 % by RBCM. No increase in c9,t12-18 : 2 was observed in the serum and RBCM, and thus no conversion of t12 could be determined. In conclusion, the endogenous conversion of dietary tVA to c9,t11 CLA contributes approximately one quarter to the human CLA pool and should be considered when determining the CLA supply.

Cannabimimetic effects of osteopathic manipulative treatment.

Endogenous cannabinoids activate cannabinoid receptors in the brain and elicit mood-altering effects. Parallel effects (eg, anxiolysis, analgesia, sedation) may be elicited by osteopathic manipulative treatment (OMT), and previous research has shown that the endorphin system is not responsible for OMT's mood-altering effects. The authors investigate whether OMT generated cannabimimetic effects for 31 healthy subjects in a dual-blind, randomized controlled trial that measured changes in subjects' scores on the 67-item Drug Reaction Scale (DRS). Chemical ionization gas chromatography and mass spectrometry were also used to determine changes in serum levels of anandamide (AEA), 2-arachidonoylglycerol (2-AG), and oleylethanolamide (OEA). In subjects receiving OMT, posttreatment DRS scores increased significantly for the cannabimimetic descriptors good, high, hungry, light-headed, and stoned, with significant score decreases for the descriptors inhibited, sober, and uncomfortable. Mean posttreatment AEA levels (8.01 pmol/mL) increased 168% over pretreatment levels (2.99 pmol/mL), mean OEA levels decreased 27%, and no changes occurred in 2-AG levels in the group receiving OMT. Subjects in the sham manipulative treatment group recorded mixed DRS responses, with both increases and decreases in scores for cannabimimetic and noncannabimimetic descriptors and no changes in sera levels. When changes in serum AEA were correlated with changes in subjects' DRS scores, increased AEA correlated best with an increase for the descriptors cold and rational, and decreased sensations for the descriptors bad, paranoid, and warm. The authors propose that healing modalities popularly associated with changes in the endorphin system, such as OMT, may actually be mediated by the endocannabinoid system.

Incorporation of cis-9, trans-11 conjugated linoleic acid and vaccenic acid (trans-11 18 : 1) into plasma and leucocyte lipids in healthy men consuming dairy products naturally enriched in these fatty acids.

The present study investigated whether consuming dairy products naturally enriched in cis-9, trans-11 (c9,t11) conjugated linoleic acid (CLA) by modification of cattle feed increases the concentration of this isomer in plasma and cellular lipids in healthy men. The study had a double-blind cross-over design. Subjects aged 34-60 years consumed dairy products available from food retailers for 1 week and then either control (0.17 g c9,t11 CLA/d; 0.31 g trans-vaccenic acid (tVA)/d) or CLA-enriched (1.43 g c9,t11 CLA/d; 4.71 g tVA/d) dairy products for 6 weeks. After 7 weeks washout, this was repeated with the alternate products. c9,t11 CLA concentration in plasma lipids was lower after consuming the control products, which may reflect the two-fold greater c9,t11 CLA content of the commercial products. Consuming the CLA-enriched dairy products increased the c9,t11 CLA concentration in plasma phosphatidylcholine (PC) (38 %; P = 0.035), triacylglycerol (TAG) (22 %; P < 0.0001) and cholesteryl esters (205 %; P < 0.0001), and in peripheral blood mononuclear cells (PBMC) (238 %; P < 0.0001), while tVA concentration was greater in plasma PC (65 %; P = 0.035), TAG (98 %; P = 0.001) and PBMC (84 %; P = 0.004). Overall, the present study shows that consumption of naturally enriched dairy products in amounts similar to habitual intakes of these foods increased the c9,t11 CLA content of plasma and cellular lipids.

Conjugated linoleic acid and vaccenic acid in rumen, plasma, and milk of cows fed fish oil and fats differing in saturation of 18 carbon fatty acids.

The objective of this study was to examine the effect of feeding fish oil (FO) along with fat sources that varied in saturation of 18 carbon fatty acids (high stearic, high oleic, high linoleic, or high linolenic acids) on rumen, plasma, and milk fatty acid profiles. Four primiparous Holstein cows at 85 d in milk (+/- 40) were assigned to 4 x 4 Latin squares with 4-wk periods. Treatment diets were 1) 1% FO plus 2% commercial fat high in stearic acid (HS); 2) 1% FO plus 2% fat from high oleic acid sunflower seeds (HO); 3) 1% FO plus 2% fat from high linoleic acid sunflower seeds (HLO); and 4) 1% FO plus 2% fat from flax seeds (high linolenic; HLN). Diets were formulated to contain 18% crude protein and were composed of 50% (dry basis) concentrate mix, 25% corn silage, 12.5% alfalfa silage, and 12.5% alfalfa hay. Milk production, milk protein percentages and yields, and dry matter intake were similar across diets. Milk fat concentrations and yields were least for HO and HLO diets. The proportion of milk cis-9, trans-11 conjugated linoleic acid (CLA; 0.71, 0.99, 1.71, and 1.12 g/100 g fatty acids, respectively), and vaccenic acid (TVA; 1.85, 2.60, 4.14, and 2.16 g/100 g fatty acids, respectively) were greatest with the HLO diet. The proportions of ruminal cis-9, trans-11 CLA (0.09, 0.16, 0.18, and 0.16 g/100 g fatty acids, respectively) were similar for the HO, HLO, and HLN diets and all were higher than for the HS diet. The proportions of TVA (2.85, 4.36, 8.69, and 4.64 g/100 g fatty acids, respectively) increased with the HO, HLO, and HLN diets compared with the HS diets, and the increase was greatest with the HLO diet. The effects of fat supplements on ruminal TVA concentrations were also reflected in plasma triglycerides, (2.75, 4.64, 8.77, and 5.42 g/100 g fatty acids, respectively); however, there were no differences in the proportion of cis-9, trans-11 CLA (0.06, 0.07, 0.06, and 0.07 g/100 g fatty acids, respectively). This study further supports the significant role for mammary delta-9 desaturase in milk cis-9, trans-11 CLA production.

Fresh forage and solin supplementation on conjugated linoleic acid levels in plasma and milk.

Two experiments were run concurrently to determine the effect of fresh forage consumption on the production and proportions of plasma and milk fat vaccenic acid (VA), conjugated linoleic acid (CLA), and linolenic acid in diary cattle. In experiment 1, the cows consumed 50, 65, and 80% of their feed intake as pasture with the remainder of intake as a barley-based concentrate. The proportion of VA in milk fatty acids increased 12% when pasture intake increased from 50 to 65% of total dry matter intake and VA, CLA, and linolenic acid proportions increased 26, 18, and 27%, respectively, as pasture increased from 65 to 80% of dietary intake. In experiment 2, fresh forage was compared to conserved hay (cut from the same pasture the previous summer) to determine the effect on plasma and milk fat VA, CLA, and linolenic acid. Also, the effect of crushed solin seed (a flax cultivar that is high in linoleic acid) supplementation to the fresh forage diet was determined. Fresh forage compared to conserved hay in the diet, increased the proportion of CLA in the plasma very low density lipoproteins (VLDL) fraction by 71% but had no effect on linolenic acid. Supplementation of the fresh forage diet with a linoleic acid source increased VA and CLA in the plasma VLDL fraction 25 and 58% and slightly decreased the proportion of linolenic acid. Fresh forage, compared to conserved hay, increased milk fat VA and CLA proportions by 22 and 15%. Supplementing the fresh forage diet with linoleic acid from crushed solin seed further increased milk fat VA and CLA proportions 41 and 25%. Solin supplementation in a lactation diet is a superior method to increase CLA levels in milk fat than feeding fresh forage alone.

Elaidic and trans-vaccenic acids in plasma phospholipids as indicators of dietary intake of 18:1 trans-fatty acids.

Octadecenoic (18:1) trans-fatty acid fractions from margarine, butter and plasma phospholipids (PL) were isolated by silver ion TLC, and nine positional isomers (n-11-n-3) were identified by GC-MS based on their ozonolysis products. The GC analysis of the isolated fractions gave similar peak profiles and separated seven trans-isomers (n-11-n-6 and n-3). Without a preceding isolation step, the reproducibility of the GC method for plasma PL elaidic (18:1 n 9 trans) and trans-vaccenic acids (n-7) was 3.4 and 2.7% (R.S.D.), respectively. These trans-isomers were rapidly incorporated and cleared in plasma PL and they closely reflected both increased and decreased intake of 18:1 trans-fatty acids during moderate fat substitutions. Significant associations between high-density lipoprotein cholesterol (HDL-C) and PL elaidic and trans-vaccenic acids appeared in habitual margarine users only.