Desaturase Activity Indices Research Articles

Biofortified Wheat Increases Dietary Zinc Intake: A Randomised Controlled Efficacy Study of Zincol-2016 in Rural Pakistan.

A new variety of zinc biofortified wheat (Zincol-2016) was released in Pakistan in 2016. The primary aim of this study was to examine the effects of consuming Zincol-2016 wheat flour on biochemical and functional markers of zinc status in a population with widespread zinc deficiency. An individually-randomised, double-blind, placebo-controlled cross over design was used. Fifty households were recruited to participate in the study, with each household included at least one woman of reproductive age (16–49 years) who was neither pregnant nor breast feeding or currently taking nutritional supplements. All households were provided with control flour for an initial 2-week baseline period, followed by the intervention period where households were randomly allocated in a 1:1 ratio to receive biofortified flour (group A; n = 25) and control flour (group B; n = 25) for 8-weeks, then switched to the alternate flour for 8-weeks. The trial has been registered with the ISRCTN (https://www.isrctn.com), ID ISRCTN83678069. The primary outcome measure was plasma zinc concentration, and the secondary outcome measures were plasma selenium and copper concentrations, plasma copper:zinc ratio and fatty acid desaturase and elongase activity indices. Nutrient intake was assessed using 24-h dietary recall interviews. Mineral concentrations in plasma were measured using inductively coupled plasma mass spectrometry and free fatty acids and sphingolipids by mass spectrometry. Linear Mixed Model regression and General Linear Model with repeated measures were used to analyse the outcomes. Based on an average flour consumption of 224 g/day, Zincol-2016 flour provided an additional daily zinc intake of between 3.0 and 6.0 mg for white and whole grain flour, respectively. No serious adverse events were reported. This resulted in significant, increase in plasma zinc concentration after 4 weeks [mean difference 41.5 μg/L, 95% CI (6.9–76.1), p = 0.02]. This was not present after 8 weeks (p = 0.6). There were no consistent significant effects of the intervention on fatty acid desaturase and elongase activity indices. Regular consumption of Zincol-2016 flour increased the daily zinc intake of women of reproductive age by 30–60%, however this was not associated with a sustained improvement in indices of zinc status.

Short-Chain and Total Fatty Acid Profile of Faeces or Plasma as Predictors of Food-Responsive Enteropathy in Dogs: A Preliminary Study

Simple SummaryFood-responsive enteropathy is the most common diagnosis given for dogs with chronic enteropathy, and there are no tests that can replace treatment trials. Furthermore, there is a lack of information on the specific nutritional status of these patients regarding the lipid profile that could relate them to the state of health/disease. This study evaluated differences in short-chain fatty acids and the total fatty acid profile of faeces and plasma as possible indicators of food-responsive enteropathy (FRE), as well as its relationship with body condition and the chronic enteropathy activity index. Changes in the long-chain fatty acid of plasma, and short-chain, branched and odd-chain fatty acids of faeces were detected in sick dogs, and high correlations were observed between some of these compounds and the existing calculated indices.The aim of this study was to evaluate differences in short-chain fatty acids (SCFAs) and the total fatty acid profile of faeces or plasma as possible indicators of FRE in comparison with healthy dogs. FRE dogs had a lower concentration (p = 0.026) of plasma α-tocopherol as an indicator of the oxidative status of the animal, and lower C20:5n-3 (p = 0.033), C22:5n-3 (p = 0.005), polyunsaturated fatty acids (PUFA) (p = 0.021) and n-6 (p = 0.041) when compared with the control dogs; furthermore, sick dogs had higher proportions of plasma C20:3n-6 (p = 0.0056). The dogs with FRE showed a decrease in the production of faecal levels of SCFAs, mainly propionic acid (C3) (p = 0.0001) and isovaleric acid (iC5) (p = 0.014). FRE dogs also had a lower proportion of C15:0 (p = 0.0003), C16:1n-9 (p = 0.0095), C16:1n-7 (p = 0.0001), C20:5n-3 (p = 0.0034) and monounsaturated fatty acids (p = 0.0315), and tended to have lower n-3 (p = 0.058) and a reduced desaturase activity index in the stool when compared with the control group. However, the dogs with chronic enteropathy tended to have greater C20:4n-6 (p = 0.065) in their faeces as signs of damage at the intestinal level. The faecal parameters were better predictors than plasma. The highest correlations between faecal odd-chain, medium- or long-chain fatty acids and SCFAs were observed for C15:0 that correlated positively with faecal acetic acid (C2) (r = 0.72, p = 0.004), propionic acid (r = 0.95, p = 0.0001), isobutyric acid (iC4) (r = 0.59, p = 0.027) and isovaleric acid (r = 0.64, p = 0.0136), as well as with total SCFAs (r = 0.61, p = 0.02). Conversely, faecal C20:4n-6 showed a high inverse correlation (r = −0.83, p = 0.0002) with C2 and C3 (r = −0.59, p = 0.027). Canine inflammatory bowel disease (IBD) activity (CIBDAI) index correlated negatively mainly with faecal measurements, such as C3 (r = −0.869, p = 0.0005) and C15:0 (r = −0.825, p = 0.0018), followed by C16:1/C16:0 (r = −0.66, p= 0.0374) and iC5 (r = −0.648, p = 0.0310), which would indicate that these fatty acids could be good non-invasive indicators of the chronic inflammatory status, specifically FRE.

Serum Phospholipids Fatty Acids and Breast Cancer Risk by Pathological Subtype.

This study evaluates whether serum phospholipids fatty acids (PL-FAs) and markers of their endogenous metabolism are associated with breast cancer (BC) subtypes. EpiGEICAM is a Spanish multicenter matched case-control study. A lifestyle and food frequency questionnaire was completed by 1017 BC cases and healthy women pairs. Serum PL-FA percentages were measured by gas chromatography-mass spectrometry. Conditional and multinomial logistic regression models were used to quantify the association of PL-FA tertiles with BC risk, overall and by pathological subtype (luminal, HER2+ and triple negative). Stratified analyses by body mass index and menopausal status were also performed. Serum PL-FAs were measured in 795 (78%) pairs. Women with high serum levels of stearic acid (odds ratio (OR)T3vsT1 = 0.44; 95% confidence interval (CI) = 0.30–0.66), linoleic acid (ORT3vsT1 = 0.66; 95% CI = 0.49–0.90) and arachidonic to dihomo-γ-linolenic acid ratio (OR T3vsT1 = 0.64; 95% CI = 0.48–0.84) presented lower BC risk. Participants with high concentrations of palmitoleic acid (ORT3vsT1 = 1.65; 95% CI = 1.20–2.26), trans-ruminant palmitelaidic acid (ORT3vsT1 = 1.51; 95% CI = 1.12–2.02), trans-industrial elaidic acid (ORT3vsT1 = 1.52; 95% CI = 1.14–2.03), and high oleic to stearic acid ratio (ORT3vsT1 = 2.04; 95% CI = 1.45–2.87) showed higher risk. These associations were similar in all BC pathological subtypes. Our results emphasize the importance of analyzing fatty acids individually, as well as the desaturase activity indices.

Serum phospholipids fatty acids and breast cancer risk by pathological subtype: EpiGEICAM study.

e13604 Background: The role of fatty acids (FA) in breast cancer (BC) etiology is unclear. Most studies are based on self-reported dietary intake, without considering their internal transformation. This analysis tries to assess whether serum levels of 26 phospholipid FA (PL-FAs) and markers of their endogenous metabolism are associated with BC risk, both globally and by pathological BC subtype. Methods: EpiGEICAM-01 is a Spanish multicenter matched case-control study. BC cases and healthy women completed a lifestyle and a food frequency questionnaire, and serum samples were collected. Serum PL-FAs percentages were measured by gas chromatography-mass spectrometry (GC–MS). Conditional and multinomial logistic regression models were used to quantify the association of PL-FAs tertiles with BC risk, overall and by pathologic BC subtypes [luminal, HER2+ and triple negative]. Models were adjusted for age and region (multinomial models), education level, body mass index (BMI), menopausal status, age at menarche and at first birth, hormone replacement therapy, alcohol consumption, last year physical activity, history of benign breast disease, family history of BC and caloric intake, and were corrected for multiple testing. Stratified analyses by BMI and menopausal status were also performed. Results: Questionnaires and serum samples were collected from 795 case-control pairs. Women with high serum levels of stearic acid [odds ratio (OR)T3vsT1= 0.44; 95% confidence interval (CI) = 0.30-0.66], linoleic acid (ORT3vsT1= 0.66; 95% CI = 0.49-0.90) and arachidonic to dihomo-γ-linolenic acids ratio (OR T3vsT1= 0.64 95%; CI = 0.48-0.84; differences were remarkable in overweight/obese women) presented lower BC risk. Participants with high concentrations of palmitoleic acid (ORT3vsT1= 1.65; 95% CI = 1.20-2.26), trans-ruminant palmitelaidic acid (ORT3vsT1= 1.51; 95% CI = 1.12-2.02; differences observed were noticeable both in postmenopausal and in overweight/obese women), trans-industrial elaidic acid (ORT3vsT1= 1.52; 95% CI = 1.14-2.03; markedly both in premenopausal and in non-obese women), and high oleic to stearic acids ratio (ORT3vsT1= 2.04; 95% CI = 1.45-2.87) showed higher risk. These associations were similar in all BC pathological subtypes. Conclusions: Our results, which should be confirmed in future studies, emphasize the importance of analyzing fatty acids individually, as well as the desaturase activity indices. A decrease in the dietary intake of trans-monounsaturated fatty acids could be a good strategy for BC prevention.

Short communication: dietary vitamin A restriction may improve meat quality parameters in fat-tailed lambs

Thirty fat-tailed Mehraban ram lambs were randomly allotted into three vitamin A (VA) dietary treatment groups: either 100 (VA100), 50 (VA50), or 25% (VA25) of the recommended daily vitamin A requirements. Treatment had no effect on feed intake, daily live weight gain, cold carcass weight, and dressing percentage. In M. longissimus lumborum (LL) of VA100 lambs, malondialdehyde level was greater, but ether-extractable intramuscular fat concentration was lower. The proportion of C16:0 and C20:0 fatty acids in total fatty acids of LL was lower in VA100 lambs, compared to VA50 and VA25 lambs. Conversely, greater proportions of C17:0, C17:1, C18:1, and C18:2 fatty acids were recorded in VA100 lambs. Stearoyl-CoA desaturase activity index (the ratios of C16:0 to C16:1 and C18:0 to C18:1) was not influenced by dietary vitamin A level. Future research is needed to determine the optimum level of dietary vitamin A concentration for deposition of greater intramuscular fat in fat-tailed sheep.

Plasma stearoyl-CoA desaturase activity indices and bile acid concentrations after a low-fat meal: association with a genetic variant in the FTO gene.

PurposeDietary macronutrient composition, stearoyl-CoA desaturase (SCD) activity indices, and primary bile acid (BA) concentrations are among the factors that have been associated with lipid metabolism and contributed to obesity. We investigated the association between the polymorphic expression of the fat mass and obesity-associated (FTO) gene and its relationship with SCD activity indices and primary BA concentrations after a low-fat meal.Subjects and methodsBlood plasma samples were collected from 56 young (20–36 years) healthy subjects with different rs9939609 FTO genotypes. Fasting and post-meal (2 hours after a low-fat breakfast) blood samples were collected on the subsequent morning for the analysis of DNA methylation, SCD activity indices (product-to-precursor fatty acid ratios; 16:1n-7/16:0 and 18:1n-9/18:0), and chenodeoxycholic acid (CDCA) and cholic acid (CA) concentrations. Expression of lipogenic genes was investigated post-meal to assess the relationship between the CDCA and CA concentrations and mRNA levels of lipogenic genes.ResultsThe FTO AA (obesity risk) genotype group (n=18) had higher (P<0.05) post-meal SCD-16 activity index than the FTO TT (wild type) genotype group (n=26). In both the FTO TT (n=16) and AA (n=8) genotype groups, the post-meal concentrations of CDCA and CA were lower (P<0.05) compared with the fasted state. No difference in BA concentrations between the FTO TT and AA genotype groups in both meal states was observed. After adjusting for the body mass index, the highest 50% post-meal concentrations of CA were inversely (P=0.010) correlated with the level of mRNA SCD expression.ConclusionFTO AA carriers may be at a higher risk for obesity through higher SCD activity in a low-fat diet environment. This effect may be partly pronounced by very low CA concentrations.

Effects of dietary orange peel essential oil supplementation on milk yield and composition, and blood and milk antioxidant status of dairy ewes

Twenty eight lactating Chios ewes were used in an experiment to determine the effects of dietary orange peel essential oil (OEO) supplementation on milk yield, composition and fatty acid profile, as well as on antioxidant status in blood and milk. In the experiment, ewes after weaning, on day 43 postpartum, were allocated according to their milk yield and lactation number, into 4 treatment groups, being OEO0, OEO150, OEO300, and OEO450, of 7 ewes each and accommodated in individual pens. For a period of 60 days (i.e., days 43–102 postpartum), ewes were fed a concentrate (crude protein 175 g/kg, dry matter – DM basis; net energy for lactation 7.72 MJ/kg, DM basis) and alfalfa hay, with a concentrate-to-forage ratio of 57:43. The concentrate for treatment OEO0 (control) had no OEO, while that for treatments OEO150, OEO300 and OEO450 contained 150, 300 and 450 mg OEO/kg concentrate, respectively, after spraying OEO onto the concentrate of treatment OEO0. In the 60-day experimental period, DM intake quadraticaly (P < 0.05) increased, being higher in OEO150 and OEO300 treatments. Milk yield, as well as 6% fat corrected milk yield, and fat and ash yields, quadraticaly increased (P < 0.05), being higher in OEO150 and OEO300 treatments, whilst feed efficiency linearly increased (P < 0.05). Moreover, milk protein, lactose and ash content quadraticaly decreased (P < 0.05). Other yields of components, milk fat content, somatic cell counts and colony forming units were not affected (P > 0.05). Milk fat fatty acid (FA) analysis showed a quadratic increase (P < 0.05) in C4:0, C11:0, C14:0 and C16:0 concentrations, while a quadratic decrease (P < 0.05) was observed in C17:1, C18:0, cis-9 C18:1, trans-10 C18:1, C18:2n-6c, C18:3n-3 and C20:3n-3 concentrations, with increasing dietary OEO inclusion levels. Overall, monounsaturated FA (MUFA), polyunsaturated FA (PUFA) and unsaturated FA (UFA) quadraticaly decreased (P < 0.05), while saturated FA (SFA), the SFA/UFA ratio, the atherogenicity index (AI), as well as the Δ−9 desaturase activity index (C14:1/C14:0) quadraticaly increased (P < 0.05), as dietary OEO supplementation increased. Blood plasma glutathione peroxidase, glutathione reductase and superoxide dismutase, and milk lactoperoxidase activity, linearly increased (P < 0.05) when feeding ewes with different doses of OEO. Dietary OEO supplementation of lactating ewes, at levels up to 300 mg/kg concentrate, increased milk yield, fat yield and ash yield, but decreased milk UFA concentration and AI, whereas OEO supplementation at higher level (450 mg/kg concentrate), had no effect. Thus, OEO could be considered as a natural feed supplement in ewes’ diet and make it a suitable source of functional ingredient in animal nutrition to improve animals’ performance and health, as well as product quality and safety.

Does growth path influence beef lipid deposition and fatty acid composition?

Despite the recent advances in transcriptomics, gene expression studies addressing cattle´s skeletal muscle adaptations in response to compensatory growth are warranted, particularly regarding lipid metabolism due to its impact in meat sensory and nutritional traits. In the present study, in comparison to ad libitum feeding, a period of feed restriction was used in order to understand the changes in bull´s lipid metabolism and gene expression of the adipogenic and lipogenic pathways after re-alimentation. Thus, 40 young Alentejana bulls were either fed ad libitum (CG group) from 9 to 18 months of age or subjected to food restriction from 9 to 15 months of age, and fed ad libitum until 24 months of age (DG group). The intramuscular fat (IMF) and total fatty acids (FA) contents were similar between groups. The major FA (>2%) contents were similar (16:0, 16:1c9, 18:1c9 and 18:2n-6) between treatments with the exception of 18:0 content that was 15% lower in DG than in CG and 20:4n-6 that tended to be greater on DG bulls. Regarding minor FA (<2%), the DG group presented greater proportions (P<0.01) of 17:1c9, 18:1t9, 18:1t10 (, 18:1c11), 18:1c13, 18:3n-6, 22:0, 22:4n-6 and 22:6n-3 and lower (P<0.05) proportions of 20:0, 18:1t16+c14, and branched chain FA (iso-15:0, anteiso-15:0, iso-16:0 and anteiso-17:0) than the CG group. Delta-9 desaturase activity indices were consistently greater (P<0.05) in DG, when compared to the CG group. Regarding microarray analysis, differentially expressed genes between CG and DG bulls were grouped in 5 main biological functions: lipid and nucleic acid metabolisms, small molecule biochemistry, molecular transport and translational modification. Discontinuous growth down-regulated the expression of ACACB (FC (fold-change) = 1.32), FABP3 (FC = 1.45), HADHA (FC = 1.41) and SLC37A4 (FC = 1.40) genes, when compared to the CG system (FDR<0.05). In contrast, in the CG bulls, the expression of ELOVL5 (FC = 1.58) and FASN (FC = 1.71) was down-regulated when compared to DG bulls. These results were confirmed to be significant (P<0.05) in the case of ELOVL5, FASN and SLC37A4, and almost significant for FABP3 by qRT-PCR analysis. The SCD1 and SCD5 gene expressions were not found to be affected by growth path. These results contribute to the still scarce knowledge about the mechanisms involved in fatty acid metabolism during compensatory growth which have decisive role on meat quality produced in Mediterranean areas.

Risk of secondary lymphedema in breast cancer survivors is related to serum phospholipid fatty acid desaturation.

Secondary lymphedema is a common irreversible side effect of breast cancer surgery. We investigated if risk of secondary lymphedema in breast cancer survivors was related to changes in serum phospholipid fatty acid composition. Study subjects were voluntarily recruited into the following three groups: breast cancer survivors who had sentinel lymph node biopsy without lymphedema (SLNB), those who had auxillary lymph node dissection without lymphedema (ALND), and those who had ALND with lymphedema (ALND + LE). Body mass index (BMI), serum lipid profiles, bioimpedance data with single-frequency bioimpedance analysis (SFBIA), and serum phospholipid compositions were analyzed and compared among the groups. BMI, serum total cholesterol (total-C), and low-density lipoprotein cholesterol (LDL-C) and SFBIA ratios increased only in the ALND + LE. High polyunsaturated fatty acids (PUFAs) and high C20:4 to C18:2 n-6 PUFAs (arachidonic acid [AA]/linoleic acid [LA]) was detected in the ALND and ALND + LE groups compared to SLNB. The ALND + LE group showed increased activity indices for delta 6 desaturase (D6D) and D5D and increased ratio of AA to eicosapentaenoic acid (AA/EPA) compared to the ALND and SLNB groups. Correlation and regression analysis indicated that D6D, D5D, and AA/EPA were associated with SFBIA ratios. We demonstrated that breast cancer survivors with lymphedema had elevated total PUFAs, fatty acid desaturase activity indices, and AA/EPA in serum phospholipids. Our findings suggested that desaturation extent of fatty acid composition might be related to the risk of secondary lymphedema in breast cancer survivors.

Longitudinal circulating concentrations of long-chain polyunsaturated fatty acids in the third trimester of pregnancy in gestational diabetes.

Gestational diabetes mellitus is a common complication of pregnancy. Long-chain polyunsaturated fatty acids (LCPUFA) are essential for fetal neurodevelopment. Docosahexaenoic acid (DHA) is the predominant n-3 LCPUFA in the brain and retina. Circulating absolute concentrations of total n-3 and n-6 LCPUFAs rise during normal pregnancy. It remains unclear whether gestational diabetes may affect the normal rise in circulating concentrations of LCPUFAs in the third trimester of pregnancy - a period of rapid fetal neurodevelopment. This study aimed to address this question. In a prospective singleton pregnancy cohort, fatty acids in fasting plasma total lipids were measured at 24-28 and 32-35 weeks of gestation in women with (n = 24) and without gestational diabetes mellitus (n = 116). Fatty acid desaturase activity indices were estimated by relevant product-to-precursor fatty acid ratios. Dietary nutrient intakes were estimated by a food frequency questionnaire. Plasma absolute concentrations of total n-6 LCPUFAs rose significantly between 24-28 and 32-35 weeks of gestation in women with or without gestational diabetes, whereas total n-3 LCPUFAs and DHA concentrations rose significantly only in women without gestational diabetes (all P < 0.01). Delta-5 desaturase indices (20:4n-6/20:3n-6) were similar, but delta-6 desaturase indices (18:3n-6/18:2n-6) were significantly lower in women with gestational diabetes at 32-35 weeks of gestation. Dietary intakes of all fatty acids were comparable. The normal rise in circulating absolute concentrations of DHA and total n-3 LCPUFAs in the third trimester of pregnancy may be compromised in gestational diabetes, probably due to impaired synthesis or mobilization rather than dietary intake difference.

The association of cardiovascular risk factors with saturated fatty acids and fatty acid desaturase indices in erythrocyte in middle-aged Korean adults.

BackgroundThe quality of dietary fats is associated with risk of cardiovascular diseases (CVD). We aimed to investigate the association between fatty acids in erythrocyte membrane phospholipids and CVD risk factors in middle-aged Korean adults.MethodsFifty-five middle-aged adults who underwent health examinations were included in this retrospective and cross-sectional study. Anthropometry, serum lipids, clinical parameters, and erythrocyte membrane phospholipid fatty acid data were obtained from a registry.ResultsThe proportion of C14:0 and C16:0 was greatly elevated in high quartile groups for triglyceride (TG) and systolic and diastolic blood pressure groups (SBP and DBP) (p = 0.042, p = 0.021, or p = 0.008 respectively) compared to low quartile groups. While C16:1n7 and/or C18:1n9 were positively associated with CVD risk factors, the delta 9 desaturase activity index (D9D) (C18:1n9/C18:0) was only significantly increased in high quartile groups for TG and blood pressures (p = 0.001, p = 0.002 or p = 0.003). Conversely, TG and blood pressures showed inverse relationships with C20:4n6 or D5D (C20:4n6/C20:3n6). C18:3n6 and/or D6D (C18:3n6/C18:2n6) were positively associated with insulin resistance and diabetic parameters. Particularly high D6D was detected in high quartile groups of FBS and insulin (p = 0.016 and p = 0.042). In linear regression analysis, D9D and/or C14:0 + C16:0 were significant contributors to serum TG and blood pressures. D6D was a contributing factor to FBS.ConclusionsThe indices of D9D and D6D from erythrocyte membrane phospholipids and the proportion of saturated fatty acids were increased as the cardiovascular risk factors, including serum TG, blood pressures, and FBS increased their levels (IRB number C2014199 (1396)).Electronic supplementary materialThe online version of this article (doi:10.1186/s12944-015-0135-x) contains supplementary material, which is available to authorized users.

Fucoxanthin Enhances Chain Elongation and Desaturation of Alpha-Linolenic Acid in HepG2 Cells.

Dietary fucoxanthin (FX), a carotenoid compound from brown algae, was found to increase docosahexaenoic acid (DHA, 22:6n-3) and arachidonic acid (ARA, 20:4n-6) in the liver of mice. DHA and ARA are known to be biosynthesized from the respective precursor α-linolenic acid (ALA, 18:3n-3) and linoleic acid (LNA, 18:2n-6), through desaturation and chain elongation. We examined the effect of FX on the fatty acid metabolism in HepG2 cells (Hepatocellular carcinoma, human). In the first experiment, cells were co-treated with ALA (100 μM) and FX (0-100 μM) or vehicle for 48 h. FX increased eicosapentaenoic acid (EPA, 20:5n-3), docosapentaenoic acid (DPA, 22:5n-3), DHA at concentrations of ≥ 50 μM. To clarify the change in the metabolism of polyunsaturated fatty acid (PUFA), in the second experiment, cells were co-treated with universally-[(13)C]-labeled (U-[(13)C]-) ALA (100 μM) and FX (100 μM) for 0.5, 3, 6, 24 and 48 h. [(13)C] labeled-EPA, DPA and DHA content in HepG2 cells were all increased by FX after 48 h treatment. Furthermore, estimated delta-5 desaturase (D5D) but not delta-6 desaturase (D6D) activity index was increased at 48 h. These results suggested that FX may enhance the conversion of ALA to longer chain n-3 PUFA through increasing D5D activity in the liver.

Atherogenicity index and health-related fatty acids in different stages of lactation from Friesian, Jersey and Friesian × Jersey cross cow milk under a pasture-based dairy system

The objective of the study was to investigate the effect of stage of lactation on the fatty acid profiles of milk from Friesian, Jersey and Friesian×Jersey cows. Linoleic acid in pastures was highest in the second phase which coincided with mid-lactation days (p<0.05). Highest milk moisture content and lowest fat free dry matter content was seen in early lactation (p<0.05). Higher fat content was observed in late lactation than early lactation. Highest butyric, caproic, linoleic, omega-6 and polyunsaturated fatty acids were observed for milk from Friesian cows. Highest conjugated fatty acids, α-linolenic acid, linoleic acid, saturated fatty acids, polyunsaturated fatty acids, omega-6, and omega-3 were observed in early lactation. Atherogenicity index and desaturase activity indices were highest in late lactation. In conclusion, stage of lactation and genotype affected milk health-related fatty acid profiles.

Indices of fatty acid desaturase activity in healthy human subjects: effects of different types of dietary fat

Δ9-Desaturase (stearoyl-CoA desaturase 1, SCD-1) regulates the desaturation of SFA, mainly stearic and palmitic, to MUFA. Δ6-Desaturase (D6D) and Δ5-desaturase (D5D) are involved in the metabolism of linoleic and α-linolenic acid to polyunsaturated metabolites. The objective of the present study was to study the effects of different types of dietary fat on indices of fatty acid desaturase (FADS) activity (evaluated as product:precursor ratios) in plasma and skeletal muscle in human subjects. A high SCD-1 index has been related to obesity and metabolic disorders, while the D5D index is associated with insulin sensitivity. Fatty acid composition of serum and skeletal muscle lipids was analysed by GLC during a randomised, controlled, 3-month dietary intervention in healthy subjects. A comparison of the effects of a diet containing butter fat (SFA, n 17) with a diet containing monounsaturated fat (MUFA, n 17), keeping all other dietary components constant, showed a reduced SCD-1 activity index by 20% on the MUFA diet compared with the SFA diet assessed in serum cholesteryl esters. The D6D and D5D indices remained unaffected. Supplementation with long-chain n-3 fatty acids reduced the SCD-1 index by a similar magnitude while the D6D index decreased and the D5D index increased. It is concluded that changes in the type of fat in the diet affect the indices of FADS activity in serum and skeletal muscle in human subjects. The desaturase activity indices estimated from the serum lipid ester composition are significantly related to corresponding indices studied in skeletal muscle phospholipids.

Total dietary fat and fatty acid content modifies plasma phospholipid fatty acids, desaturase activity indices, and urinary prostaglandin E in women

Compared with diets high in fat, low-fat diets are associated with reduced risk of cardiovascular disease. We hypothesized that a low-fat (LF) (20% fat) and an LF high-omega-3 (n-3) fatty acid diet (LFn3) (23% fat with 3% as α-linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid [DHA]) would enhance n-3 composition of plasma phospholipid fatty acid and reduce urinary prostaglandin E(2) (PGE(2)) relative to a high-fat diet (HF) (40% fat) and that these changes would be associated with alterations in δ5 desaturase (D5D) and δ6 desaturase (D6D) activity. Phospholipid fatty acids and urinary PGE(2) were measured, and D5D and D6D activity indices calculated in a crossover trial in 17 postmenopausal women fed each of 3 test diets (HF, LF, and LFn3) for 8-week feeding periods. Desaturase activity indices were calculated as D5D, 20:4n-6/20:3n-6, and D6D, 20:3n-6/18:2n-6. Plasma phospholipid fatty acid, α-linolenic acid, eicosapentaenoic acid, docosapentaenoic acid (DPA), DHA, and total n-3 fatty acids increased, whereas linoleic acid and arachidonic acid decreased with consumption of LFn3. The LF resulted in enhanced arachidonic acid and DHA. High fat reduced D6D, whereas both HF and LF increased D5D. Urinary PGE(2) was reduced in response to both the LF and LFn3 diets. Low-fat diets, with or without long-chain n-3 fatty acids, promote positive health effects due in part to favorable alteration of plasma phospholipid fatty acid profiles and modification in desaturase activity indices, suggesting that the type and amount of fat consumed are modifiable risk factors for the prevention of cardiovascular disease.

Omega-3 fatty acid deficiency increases stearoyl-CoA desaturase expression and activity indices in rat liver: Positive association with non-fasting plasma triglyceride levels

Although omega-3 ( n−3) fatty acids negatively regulate triglyceride biosynthesis, the mechanisms mediating this effect are poorly understood, and emerging evidence suggests that stearoyl-CoA desaturase (Scd1) is required for de novo triglyceride biosynthesis. To investigate this mechanism, we determined the effects of perinatal n−3 deficiency and postnatal repletion on rat liver Scd1 mRNA expression and activity indices (liver 16:1/16:0 and 18:1/18:0 ratios), and determined relationships with postprandial (non-fasting) plasma triglyceride levels. Rats were fed conventional diets with or without the n−3 fatty acid precursor α-linolenic acid (ALA, 18:3 n−3) during perinatal development (E0-P100), and a subset of rats fed the ALA− diet were switched to the ALA+ diet post-weaning (P21-P100, repletion). Compared with controls, rats fed the ALA− diet exhibited significantly lower liver long-chain n−3 fatty acid compositions and elevations in monounsaturated fatty acid composition, both of which were normalized in repleted rats. Liver Scd1 mRNA expression and activity indices (16:1/16:0 and 18:1/18:0 ratios) were significantly greater in n−3 deficient rats compared with controls and repleted rats. Among all rats, liver Scd1 mRNA expression was positively correlated with liver 18:1/18:0 and 16:1/16:0 ratios. Plasma triglyceride levels, but not glucose or insulin levels, were significantly greater in n−3 deficient rats compared with controls and repleted rats. Liver Scd1 mRNA expression and activity indices were positively correlated with plasma triglyceride levels. These preclinical findings demonstrate that n−3 fatty acid status is an important determinant of liver Scd1 mRNA expression and activity, and suggest that down-regulation of Scd1 is a mechanism by which n−3 fatty acids repress constitutive triglyceride biosynthesis.

The Heparan and Heparin Metabolism Pathway is Involved in Regulation of Fatty Acid Composition

Six genes involved in the heparan sulfate and heparin metabolism pathway, DSEL (dermatan sulfate epimerase-like), EXTL1 (exostoses (multiple)-like 1), HS6ST1 (heparan sulfate 6-O-sulfotransferase 1), HS6ST3 (heparan sulfate 6-O-sulfotransferase 3), NDST3 (N-deacetylase/N-sulfotransferase (heparan glucosaminyl) 3), and SULT1A1 (sulfotransferase family, cytosolic, 1A, phenol-preferring, member 1), were investigated for their associations with muscle lipid composition using cattle as a model organism. Nineteen single nucleotide polymorphisms (SNPs)/multiple nucleotide length polymorphisms (MNLPs) were identified in five of these six genes. Six of these mutations were then genotyped on 246 Wagyu x Limousin F(2) animals, which were measured for 5 carcass, 6 eating quality and 8 fatty acid composition traits. Association analysis revealed that DSEL, EXTL1 and HS6ST1 significantly affected two stearoyl-CoA desaturase activity indices, the amount of conjugated linoleic acid (CLA), and the relative amount of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) in skeletal muscle (P<0.05). In particular, HS6ST1 joined our previously reported SCD1 and UQCRC1 genes to form a three gene network for one of the stearoyl-CoA desaturase activity indices. These results provide evidence that genes involved in heparan sulfate and heparin metabolism are also involved in regulation of lipid metabolism in bovine muscle. Whether the SNPs affected heparan sulfate proteoglycan structure is unknown and warrants further investigation.

The fatty acid composition of plasma cholesteryl esters and estimated desaturase activities in patients with nonalcoholic fatty liver disease and the effect of long-term ezetimibe therapy on these levels

The aim of this study was to investigate the relationship between fatty acid composition of plasma cholesteryl esters (CEs) and estimated desaturase activity and the development and progression of nonalcoholic fatty liver disease (NAFLD). The study also assessed the effect of ezetimibe on CE levels. Plasma CEs fatty acid composition was analyzed in 3 groups: patients with a NAFLD activity score (NAS) ≤ 4 (n=31) or NAS ≥ 5 (n=32) and normal controls (n=25). The estimated desaturase activities were calculated using ratios of 16:1n-7/16:0 (D9-16D), 18:1n-9/18:0 (D9-18D), 18:3n-6/18:2n-6 (D6D) and 20:4n-6/20:3n-6 (D5D). Compared with controls, the levels of palmitate, palmitoleate, γ-linoleate, D9-16D and D6D were significantly increased, whereas levels of linoleate and D5D were significantly decreased. Patients with NAS ≥ 5 had significantly higher palmitate levels than patients with NAS ≤ 4. The levels of these fatty acids, especially palmitate and palmitoleate, correlated with NAFLD-related lipid, metabolic, and inflammatory parameters. Long-term therapy with ezetimibe caused significant improvements in the levels of these fatty acids, estimated desaturase activity index and NAFLD-related parameters. Our results suggest that fatty acids and desaturase activity associate with the development and progression of NAFLD, and that ezetimibe may be a novel treatment for this disorder.

Effect of vitamin A restriction on carcass characteristics and immune status of beef steers

Sixty-eight Angus-based steers (224 +/- 7.6 kg of BW) were used to evaluate the effects of a prolonged dietary vitamin A restriction on marbling and immunocompetency. Steers were allotted randomly to 1 of 2 treatments: LOW (no supplemental vitamin A) and HIGH (diet supplemented with 2,200 IU of vitamin A/kg of DM). Diets contained 60% high-moisture corn, 20% roasted soybeans, 10% corn silage, and 10% of a protein supplement. Steers were penned and fed individually. For the first 141 d, steers were program-fed to achieve a gain of 1.1 kg/d. The last 75 d of the experiment, steers were offered feed for ad libitum intake. At slaughter, serum and liver samples were taken to determine their retinol content. To evaluate immunocompetency, 10 steers per treatment were selected randomly on d 141 and received an ovalbumen vaccine, and 21 d later, the steers were revaccinated. On d 182, blood samples were taken from the vaccinated steers to determine serum antibody titers by ELISA. Steers were slaughtered after 216 d on feed. Carcass characteristics were determined, and LM samples were taken for composition analysis. Subcutaneous fat samples were taken for fatty acid composition analysis. Performance (ADG, DMI, and G:F) was not affected by vitamin A restriction (all P > 0.10). Hot carcass weight, 12th-rib fat, and yield grade did not differ between LOW and HIGH steers (all P > 0.10). Marbling score (LOW = 574 vs. HIGH = 568, P = 0.79) and i.m. fat (LOW = 5.0 vs. HIGH = 4.7% ether-extractable fat, P = 0.57) were not increased by vitamin A restriction. Serum (LOW = 18.7 vs. HIGH = 35.7 mug/dL, P < 0.01) and liver (LOW = 6.3 vs. HIGH = 38.1 mug/g, P < 0.01) retinol levels were lower in LOW steers compared with HIGH steers at slaughter. Response to ovalbumin vaccination was not affected by vitamin A restriction (LOW = 13.1 vs. HIGH = 12.8 log(2) titers, P = 0.60). Slight changes in the fatty acid profile of s.c. fat of the steers were detected. A greater proportion of MUFA (LOW = 41.7 vs. HIGH = 39.9%, P = 0.03) and fewer SFA (LOW = 47.1 vs. 48.7, P = 0.03) were observed in vitamin A-restricted steers. This suggests that vitamin A restriction may affect the activity of desaturase enzyme (desaturase activity index, LOW = 46.9 vs. HIGH = 44.9, P = 0.01). Feeding a low vitamin A diet for 216 d to Angus-based steers did not affect performance, marbling score, or animal health and immunocompetency. Slight changes in the fatty acid profile of s.c. fat were observed, suggesting that vitamin A restriction may have affected desaturase enzyme activity.

The interaction between breed and diet on CLA and fatty acids content of milk fat of four sheep breeds kept indoors or at grass

An experiment was conducted with the objective to study the interaction between breed and diet on conjugated linoleic acid (CLA) and fatty acids profile (FA) content of milk fat of four pure of dairy sheep breeds (Awassi, Lacaune, Friesland and Chios). All sheep used in this study were kept in one flock under the same management. During the winter months (from October to March) all sheep were kept indoors and fed with alfalfa hay and concentrates without any grazing and from April onwards were grazing native pastures without any supplementary feed. A total of 160 individual milk samples were taken from the four breeds at two sampling times: in January ( n = 80) and in May ( n = 80), when the ewes were in average, on 62 and 185 days in milk. These milk samples were analyzed for FA profile. The results of this experiment showed that the sheep breed had no effect on milk FA profile or on atherogenicity index (AI). The only significant effect was on Δ −9 desaturase activity index expressed as C 18:1/ C 18:0. On the contrary, the diet affected significantly the FA profile of all ewes milk fat, with pasture to cause lower proportions of saturated and higher proportions of unsaturated FA, compared with those of sheep kept and fed indoors. The interaction between breed and diet was significant for the FA C 10:0, C 14:0, C 15:0, C 16:0, C 17:1, C 18:1, C 18:2n6c, C 18:2n6t, C 18:3n6 and CLA and for FA groups SCFA, MCFA, LCFA and MUFA. The S/U FA ratio and the Δ −9 desaturase indexes ( C 14:1/ C 14:0 and C 18:1/ C 18:0) were also affected by the breed × diet interaction. In conclusion, pasture feeding when compared with supplementary diet, induce large variation in the milk FA profile. In addition pasture increases FA in milk fat which has potential interest for human health. Breed has small effect on milk FA profile, but it can be ignored as it is shown from the interaction breed × diet.