Trans-monounsaturated Fatty Acids Research Articles

Quality and sensory milk traits of goats grazing Caatinga or confined receiving either corn or spineless cactus-based diets in the Brazilian semiarid environment.

This study aimed to evaluate the yield, physical-chemical properties, fatty acid (FA) profile, and sensory traits of goat milk under different nutritional strategies in a Brazilian semiarid environment. Eighteen lactating crossbred dairy goats were distributed in a completely randomized design with three nutritional strategies: Caatinga strategy (1.5% of body weight with a concentrate supplementation), Corn-based confined strategy, and Spineless Cactus confined strategy. Daily milk yield was recorded, and milk samples were collected from all animals. Goats fed the spineless cactus-based diet presented a higher milk yield than goats feed the other strategies. Moreover, milk from goats fed with a spineless Cactus confined strategy presented higher saturated FA (SFA), and a lower proportion of cis- monounsaturated FA, trans-monounsaturated FA, and c9,t11-18:2 than milk from goats feed the other strategies. Milk from goats in the pasture system presented the highest proportions of 18:2n-6, 18:3n-3, and thus of polyunsaturated FA, when compared with milk from confined goats. We assume that milk from goats grazing in Caatinga pastures presents more benefits to human health due to the positive effects of this diet on the milk's fat content and FA profile, and this feeding strategy also results in a better sensory evaluation that may increase the acceptability of goat milk by consumers. All nutritional strategies evaluated herein and adopted in the semiarid region of Brazil are recommended for maintaining the yield, physical-chemical properties, and acceptability of milk goats.

Differential Effects of Ruminant and Industrial 18-Carbon trans-Monounsaturated Fatty Acids (trans Vaccenic and Elaidic) on the Inflammatory Responses of an Endothelial Cell Line.

Endothelial dysfunction and inflammation are recognised factors in the development of atherosclerosis. Evidence suggests that intake of industrial trans fatty acids (TFAs) promotes endothelial dysfunction, while ruminant TFAs may have the opposite effect. The aim of this study was to compare the effects of elaidic acid (EA (18:1n-9t); an industrially produced TFA) and trans vaccenic acid (TVA (18:1n-7t); a natural TFA found in ruminant milk and meat) on inflammatory responses of endothelial cells (ECs). ECs (EA.hy926 cells) were cultured under standard conditions and exposed to TFAs (1 to 50 μM) for 48 h. Then, the cells were cultured for a further 6 or 24 h with tumour necrosis factor alpha (TNF-α, 1 ng/mL) as an inflammatory stimulant. ECs remained viable after treatments. TFAs were incorporated into ECs in a dose-dependent manner. Preincubation with EA (50 µM) increased production of MCP-1, RANTES, and IL-8 in response to TNF-α, while preincubation with TVA (1 µM) decreased production of ICAM-1 and RANTES in response to TNF-α. Preincubation with EA (50 µM) upregulated toll-like receptor 4 and cyclooxygenase 2 gene expression in response to TNF-α. In contrast, preincubation with TVA (1 µM) downregulated TNF-α induced nuclear factor kappa B subunit 1 gene expression. Preincubation of ECs with EA (50 µM) increased THP-1 monocyte adhesion. In contrast, preincubation of ECs with TVA (1 µM) reduced THP-1 monocyte adhesion, while preincubation of ECs with TVA (50 µM) decreased the level of surface expression of ICAM-1 seen following TNF-α stimulation. The results suggest that TVA has some anti-inflammatory properties, while EA enhances the response to an inflammatory stimulus. These findings suggest differential effects induced by the TFAs tested, fitting with the idea that industrial TFAs and ruminant TFAs can have different and perhaps opposing biological actions in an inflammatory context.

Cyclopropane Fatty Acids as Quality Biomarkers of Cheeses from Ewes Fed Hay- and Silage-Based Diets.

This study aimed to investigate cyclopropane fatty acids (CPFAs) as quality biomarkers of forage feedings in cheese fat obtained from ewe's milk, based on two different dietary treatments (hay and silage). The gas chromatography-mass spectrometry (GC-MS) analysis detected CPFAs in most cheese samples, both from hay and silage-based diets. CPFA levels in cheese fat from hay feeding were positively correlated to the total trans-monounsaturated fatty acids (MUFAs) and n-6 polyunsaturated fatty acids (PUFAs), whereas they were negatively correlated to cis-MUFAs, odd- and branched-chain fatty acids (i.e., C13:0 anteiso, C16:0 iso, and C17:1), and C22:5n-3, which are mainly associated with a low starch intake and grass pasture. Overall, the presence of CPFAs in ovine cheese fat suggests the use of silage, but it can also be an indicator of poor-quality hay forages. This approach confirmed the reliability of CPFAs as biomarkers of forage quality, especially in relation to the use of conserved forages and good livestock practices.

Combined effects of 3-nitrooxypropanol and canola oil supplementation on methane emissions, rumen fermentation and biohydrogenation, and total tract digestibility in beef cattle.

The individual and combined effects of 3-nitrooxypropanol (3-NOP) and canola oil (OIL) supplementation on enteric methane (CH4) and hydrogen (H2) emissions, rumen fermentation and biohydrogenation, and total tract nutrient digestibility were investigated in beef cattle. Eight beef heifers (mean body weight ± SD, 732 ± 43 kg) with ruminal fistulas were used in a replicated 4 × 4 Latin square with a 2 (with and without 3-NOP) × 2 (with and without OIL) arrangement of treatments and 28-d periods (13 d adaption and 15 d measurements). The four treatments were: control (no 3-NOP, no OIL), 3-NOP (200 mg/kg dry matter [DM]), OIL (50 g/kg DM), and 3-NOP (200 mg/kg DM) plus OIL (50 g/kg DM). Animals were fed restrictively (7.6 kg DM/d) a basal diet of 900 g/kg DM barley silage and 100 g/kg DM supplement. 3-NOP and OIL decreased (P < 0.01) CH4 yield (g/kg DM intake) by 31.6% and 27.4%, respectively, with no 3-NOP × OIL interaction (P = 0.85). Feeding 3-NOP plus OIL decreased CH4 yield by 51% compared with control. There was a 3-NOP × OIL interaction (P = 0.02) for H2 yield (g/kg DM intake); the increase in H2 yield (P < 0.01) due to 3-NOP was less when it was combined with OIL. There were 3-NOP × OIL interactions for molar percentages of acetate and propionate (P < 0.01); individually, 3-NOP and OIL decreased acetate and increased propionate percentages with no further effect when supplemented together. 3-NOP slightly increased crude protein (P = 0.02) and starch (P = 0.01) digestibilities, while OIL decreased the digestibilities of DM (P < 0.01) and neutral detergent fiber (P < 0.01) with no interactions (P = 0.15 and 0.10, respectively). 3-NOP and OIL increased (P = 0.04 and P < 0.01, respectively) saturated fatty acid concentration in rumen fluid, with no interaction effect. Interactions for ruminal trans-monounsaturated fatty acids (t-MUFA) concentration and percentage were observed (P = 0.02 and P < 0.01); 3-NOP had no effect on t-MUFA concentration and percentage, while OIL increased the concentration (P < 0.01) and percentage (P < 0.01) of t-MUFA but to a lesser extent when combined with 3-NOP. In conclusion, the CH4-mitigating effects of 3-NOP and OIL were independent and incremental. Supplementing ruminant diets with a combination of 3-NOP and OIL may help mitigate CH4 emissions, but the decrease in total tract digestibility due to OIL may decrease animal performance and needs further investigation.

Feeding unsaleable carrots to lambs increased performance and carcass characteristics while maintaining meat quality

This study investigated the effect of feeding unsaleable carrots to lambs within a total-mixed ration (TMR) on performance, carcass characteristics, meat quality and sensory parameters. Thirty-six Australian Merino wether lambs were fed a control (barley-based) or carrot-based TMR for 11-weeks. Carrot-fed lambs had 2.7% higher cold dressing percentage (P = 0.03) while consuming less than control lambs. Subcutaneous fat of carrot-fed lambs contained less branch-chained, and more cis- and trans-monounsaturated fatty acids (FA; P ≤ 0.01) compared to control-fed lambs, which tended (P = 0.08) to have higher concentrations of polyunsaturated FA, despite the Longissimus lumborum (LL) muscle being unchanged by diet. Under retail display conditions, L* and hue values were lower (P ≤ 0.04) for 5 d aged LL samples from carrot-fed lambs. No differences were observed in other meat quality and sensory parameters between diets. Therefore, feeding unsaleable carrots at 45% DM in a TMR can improve lamb performance and carcass characteristics, while maintaining meat quality and FA composition.

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.

Effect of cis- and trans-Monounsaturated Fatty Acids on Palmitate Toxicity and on Palmitate-induced Accumulation of Ceramides and Diglycerides.

Dietary trans fatty acids (TFAs) have been implicated in serious health risks, yet little is known about their cellular effects and metabolism. We aim to undertake an in vitro comparison of two representative TFAs (elaidate and vaccenate) to the best-characterized endogenous cis-unsaturated FA (oleate). The present study addresses the possible protective action of TFAs on palmitate-treated RINm5F insulinoma cells with special regards to apoptosis, endoplasmic reticulum stress and the underlying ceramide and diglyceride (DG) accumulation. Both TFAs significantly improved cell viability and reduced apoptosis in palmitate-treated cells. They mildly attenuated palmitate-induced XBP-1 mRNA cleavage and phosphorylation of eukaryotic initiation factor 2α (eIF2α) and stress-activated protein kinase (SAPK)/c-Jun N-terminal kinase (JNK), but they were markedly less potent than oleate. Accordingly, all the three unsaturated FAs markedly reduced cellular palmitate incorporation and prevented harmful ceramide and DG accumulation. However, more elaidate or vaccenate than oleate was inserted into ceramides and DGs. Our results revealed a protective effect of TFAs in short-term palmitate toxicity, yet they also provide important in vitro evidence and even a potential mechanism for unfavorable long-term health effects of TFAs compared to oleate.

Effect of Rearing System on the Straight and Branched Fatty Acids of Goat Milk and Meat of Suckling Kids

Goat meat is considered healthy because it has fewer calories and fat than meat from other traditional meat species. It is also rich in branched chain fatty acids that have health advantages when consumed. We studied the effects of maternal milk and milk replacers fed to suckling kids of four breeds on the straight and branched fatty acid compositions of their muscle. In addition, the proximal and fatty acid compositions of colostrum and milk were studied. Goat colostrum had more protein and fat and less lactose than milk. Goat milk is an important source of healthy fatty acids such as C18:1 c9 and C18:2 n–6. Suckling kid meat was also an important source of C18:1c9. Dairy goat breeds had higher percentages of trans monounsaturated fatty acids (MUFAs) and most of the C18:1 isomers but lower amounts of total MUFAs than meat breeds. However, these dairy kids had meat with a lower percentage of conjugated linoleic acid (CLA) than meat kids. The meat of kids fed natural milk had higher amounts of CLA and branched chain fatty acids (BCFAs) and lower amounts of n–6 fatty acids than kids fed milk replacers. Both milk and meat are a source of linoleic, α-linolenic, docosahexaenoic, eicosapentaenoic and arachidonic fatty acids, which are essential fatty acids and healthy long-chain fatty acids.

Effects of the dietary inclusion of babassu oil or buriti oil on lamb performance, meat quality and fatty acid composition

The effects of adding babassu oil (BAO) or buriti oil (BUO) to lamb diets, on performance, carcass characteristics, meat quality and fatty acid (FA) composition were evaluated. Feeding BAO reduced (P = .02) dry matter intake, kidney fat and dressing percentage, but did not change energy intake and performance. Meat pH, color, protein content and sensorial evaluation were not affected by diet. However, BUO increased (P = .02) intramuscular and subcutaneous fat contents, but decreased shear force. BAO increased (P < .05) trans-monounsaturated FA, total biohydrogenation intermediates (BHI) and the t10:t11 ratio, in meat and subcutaneous fat, but decreased total FA and cis-monounsaturated FA, did not change SFA, and increased (P = .04) PUFA in meat. BUO supplementation promoted the highest (P < .05) SFA and total FA content in subcutaneous fat but did not change PUFA. BAO can be used as an alternative energy source for growing lambs, but does not improve the meat FA composition.

Using multivariate factor analysis to characterize the unbranched fatty acid profile in bovine rumen fluid

Background: Multivariate factor analysis (MFA) could be used for analyzing the complex pattern of correlations among fatty acids (FAs) in the rumen. Objective: To investigate the potential use of MFA to extract information on unbranched FAs metabolism in bovine rumen fluid. Methods: A dataset containing 107 individual records of 26 unbranched FAs from two in vitro ruminal incubation studies was constructed. The MFA was performed using the SPSS (Statistical Package for the Social Sciences) software. Results: The MFA extracted four latent factors, accounting for 86.7% of the total variance. The first factor was positively associated with short (6:0), medium (8:0, 10:0, 12:0, 14:0, and 16:0), and long (17:0, 20:0, and 23:0) saturated FAs (SFAs), as well as with cis and trans monounsaturated FAs (MUFAs) from 14 to 16 carbon atoms (14:1-t5, 14:1-c9, 15:1-t10, 16:1-c9, and 16:1-t9). The second factor was positively correlated with 18:0 and the majority of cis and trans MUFAs of 18 carbon atoms (18:1-t9, 18:1-t11, 18:1-c6, 18:1-c9, and 18:1-c11). The third factor was positively related to 18:3-c9,c12,c15 and 18:2-t11,c15, and negatively to 18:2-c9,t11. The fourth factor was positively correlated with 18:1-t6 and 19:0; however, 19:0 was also negatively associated with the second factor. The 18:2-c9,c12 was negatively correlated with the second and third factors. Conclusion: Multivariate factor analysis (MFA) allowed the reduction of a large number of fatty acids in bovine ruminal fluid to a few latent factors with biological meaning.

Caracterización comercial y nutricional de la grasa subcutánea de terneros y vacas de desvieje sacrificados en la Comunidad Autónoma del País Vasco

Este trabajo se ha llevado a cabo con el objetivo de comparar la calidad comercial de la canal y la composición de ácidos grasos de la grasa subcutánea de vacas de desvieje de raza Frisona de más de 30 meses de edad, y de terneros de 12 meses de edad de las razas Pirenaica y Salers sacrificados en un matadero comercial de la Comunidad Autónoma del País Vasco. Las vacas de raza Frisona presentaron canales de menor peso (p&lt;0,05), aunque similar al grupo de los terneros de raza Pirenaica y menor conformación (p&lt;0,001) y estado de engrasamiento (p&lt;0,01) en comparación con los grupos de terneros. La grasa subcutánea de las vacas de desvieje presentó un mayor contenido de ácidos grasos saturados (p&lt;0,001) y ramificados (p&lt;0,05), y un menor contenido de ácidos grasos monoinsaturados (p&lt;0,01) y poliinsaturados (p&lt;0,001) en comparación con la de los terneros de las razas Pirenaica y Salers. El porcentaje de ácidos grasos monoinsaturados de tipo trans fue significativamente superior en la grasa subcutánea de los terneros de raza Pirenaica (p&lt;0,001), mientras que el contenido de 10t-18:1 fue significativamente mayor en la grasa de terneros de raza Pirenaica, intermedio en la grasa de terneros de raza Salers, y menor en la grasa de las vacas de desvieje (p&lt;0,001). Esto dio lugar a una relación 10t/11t &lt;1 y un perfil isomérico relativo de trans-18:1 y ácidos linoleico conjugados más saludable en la grasa de las vacas de desvieje de raza Frisona en comparación con los grupos de terneros. Esta idea podría contribuir a la valorización de las canales procedentes de vacas de desvieje desde el punto de vista de su comercialización y de la rentabilidad de las explotaciones ganaderas de vacuno en la Comunidad Autónoma del País Vasco.

Nutritional enhancement of sheep meat fatty acid profile for human health and wellbeing

Dietary fatty acids (FA) consumed by sheep, like other ruminants, can undergo biohydrogenation resulting in high proportions of saturated FA (SFA) in meat. Biohydrogenation is typically less extensive in sheep than cattle, and consequently, sheep meat can contain higher proportions of omega (n)−3 polyunsaturated FA (PUFA), and PUFA biohydrogenation intermediates (PUFA-BHI) including conjugated linoleic acid (CLA) and trans-monounsaturated FAs (t-MUFA). Sheep meat is also noted for having characteristically higher contents of branched chain FA (BCFA). From a human health and wellness perspective, some SFA and trans-MUFA have been found to negatively affect blood lipid profiles, and are associated with increased risk of cardiovascular disease (CVD). On the other hand, n−3 PUFA, BCFA and some PUFA-BHI may have many potential beneficial effects on human health and wellbeing. In particular, vaccenic acid (VA), rumenic acid (RA) and BCFA may have potential for protecting against cancer and inflammatory disorders among other human health benefits. Several innovative strategies have been evaluated for their potential to enrich sheep meat with FA which may have human health benefits. To this end, dietary manipulation has been found to be the most effective strategy of improving the FA profile of sheep meat. However, there is a missing link between the FA profile of sheep meat, human consumption patterns of sheep FA and chronic diseases. The current review provides an overview of the nutritional strategies used to enhance the FA profile of sheep meat for human consumption.

Palatability of Beef from Cattle Fed Extruded Flaxseed before Hay or Mixed with Hay

This study was undertaken to evaluate the eating quality of longissimus thoracis steaks and hamburgers (80/20 gluteus medius to perirenal fat) with enhanced profiles of potentially healthy fatty acids. The profile of health favorable fatty acids (n-3, vaccenic and rumenic) was improved in beef by feeding co-extruded flaxseed (flaxseed, peas, and alfalfa) and alfalfa-grass hay as a total mixed ration (TMR), and further enhanced by feeding co-extruded flaxseed before alfalfa-grass hay (Non-TMR). Compared to TMR, feeding steers the Non-TMR resulted in tougher steaks (P &lt; 0.05) with lower beef flavor (P &lt; 0.01) and greater off-flavor (P &lt; 0.01) intensity to an extent that might be detectable by consumers. High levels of trans-monounsaturated fatty acids, mainly of vaccenic acid, were associated with a fishy off-flavor, although actual changes in flavor may relate to correlated combined effects of conjugated fatty acids, atypical dienoic acids and ɑ-linolenic acid. Diet had no significant effect on sensory attributes of hamburgers, but when panelists described off-flavors, they noted more ‘other’ off-flavors (P &lt; 0.05) with fishy and stale/cardboard notes being more prominant in Non-TMR hamburgers. Overall, beef samples with threshold levels of vaccenic acid over 6.12% of total fatty acids resulting from feeding flaxseed products, while of potentially greater health benefit, may pose challenges in terms of eating quality. Areas worthy of further investigation to ensure acceptable eating quality might be the influence of ageing on antioxidant capacity in beef with enhanced fatty acid profiles, and the potential use of protective packaging to limit deterioration.

Influence of Mg modifier on cis-trans selectivity in partial hydrogenation of biodiesel using different metal types

The catalytic performance of Pd, Pt, and Ni supported on SiO2 catalysts was investigated for partial hydrogenation of soybean methyl esters, in terms of FAME composition and biodiesel properties, especially oxidative stability and cold flow properties. The effect of Mg modifier over SiO2-supported catalysts on cis-trans selectivity of polyunsaturated FAMEs was also examined. The catalytic testing was performed under reaction conditions of 4bar hydrogen pressure and 80–120°C. Hydrogenation activity was presented by turnover frequency (TOF) of diunsaturated fatty acid (C18:2) within 4h of the reaction time. The highest TOF was obtained over Pd catalysts, while the lowest TOF was obtained from Ni catalysts. At high reaction temperature conditions showed a large amount of cis-monounsaturated fatty acid (cis-C18:1); however, it exhibited a large amount of trans-monounsaturated fatty acid (trans-C18:1) which has a negative impact on biodiesel properties. The XPS revealed that the introduction of Mg leads to a strong metal–support interaction caused by electron transfer from the support to the metal, which decreased trans-C18:1 formation and presented the higher oxidative stability than the catalysts without Mg modifier.

Limitation of using silver ion solid‐phase extraction for animal lipids with a low trans content

AbstractSilver ion solid‐phase extraction (Ag+‐SPE) was reported to provide effective separations compared to other Ag+ techniques but at a fraction of cost and time. Ag+‐SPE cartridges resolved fatty acid methyl esters (FAMEs) with different number and/or geometric configuration of double bonds. Here we attempted to determine the trans fatty acids (FA) contained in a low total trans FA sample, horse lipids; lamb was used as a control having a markedly higher total trans content. Gas chromatographic assessment of the fractions showed a good separation of the cis and trans monounsaturated FA (MUFA) fractions, but the relative high content of contaminants that coeluted with these FA impaired the identification of the latter in horse lipids. In lamb trans MUFA isomers could be identified since their abundance relative to impurities was greater. Several attempts were made to remove the contaminants from the SPE cartridges including an extensive prewash with acetone and hexane, a prewash with solvents that would elute the cis MUFA fraction, and a complete prewash of all solvents used in the fractionation, hexane, acetone, and acetonitrile. The prewash using all elution solvents removed most contaminants but subsequently impaired the separation of trans and cis MUFA fractions. The same samples were subjected to Ag+‐HPLC fractionation that showed no impurities demonstrating that they were derived from the Ag+‐SPE separation. The trans MUFA fraction collected from Ag+‐HPLC allowed for the identification of the trans 16:1 and 18:1 FA in horse lipids and is recommended for samples with low trans levels.Practical applications: The commercially available silver ion solid‐phase extraction (Ag+‐SPE) cartridges contain appreciable amounts of contaminants that can interfere with the subsequent GC‐FID elution of low levels of trans fatty acid methyl esters (FAMEs), especially when contaminants are leaked by the SPE tube in quantities comparable to the trans MUFA content. The contaminants could not be quantitatively removed by prewashing the cartridges with acetone and hexane. Acetonitrile removed most contaminants but altered the Ag+‐SPE tube ability to resolve the trans and cis MUFA fractions. Ag+‐HPLC fractionation is recommended for isolation of low levels of trans MUFA, since the washing and conditioning of the chromatographic column can be extended as needed.Ag+‐SPE cartridges are used to separate FAMEs based on number and geometric configuration of double bonds to aid in the identification of complex GC separations.

Silver ion solid‐phase extraction chromatography for the analysis of trans fatty acids

Summary This article describes the application of silver ion solid-phase extraction (Ag + -SPE) to the separation of the fatty acid methyl esters (FAMEs)prepared from a partially hydrogenated fish oil (PHFO) with a trans fatty acid (FA) content of 41%. The complex FAME mixture wasresolved into the following FAME fractions: saturated FA, trans-monounsaturated FA (trans-MUFA), cis-MUFA, and several polyunsatu-rated FA (PUFA) fractions with mixed geometric and positional isomers. Fractions were analyzed by gas chromatography (GC) using a 100 mcyanopropyl polysiloxane (CPS) coated capillary column. The GC analysis of the Ag + -SPE fractions allowed for the identification of the trans-andcis-MUFAandotherFAMEpreparedfromPHFO. Introduction As early as 1966 Morris [1] had concluded that argentation chroma-tography was third in importance to GC and thin-layer chromato-graphy (TLC) for the analysis of lipids. This optimistic predictionwas largely based on separations achieved by using Ag + -TLC toresolve FAMEs with different numbers and geometric configura-tions of double bonds. These results were essential to complementGC separations of FAMEs on packed columns that provided reso-lution determined by chain length and number of double bonds, butcould not resolve geometric isomers. One might have thought thatthe subsequent development of the very long, highly polar GC ca-pillary columns that now make it possible to resolve most geo-metric and positional isomers and PUFAs would have phased outthe need for silver ion (Ag

Effects of dehydrated lucerne and soya bean meal on milk production and composition, nutrient digestion, and methane and nitrogen losses in dairy cows receiving two different forages

Dehydrated lucerne is used as a protein source in dairy cow rations, but little is known about the effects of lucerne on greenhouse gas production by animals. Eight Holstein dairy cows (average weight: 582 kg) were used in a replicated 4×4 Latin square design. They received diets based on either maize silage (M) or grass silage (G) (45% of diet on dry matter (DM) basis), with either soya bean meal (15% of diet DM) completed with beet pulp (15% of diet DM) (SP) or dehydrated lucerne (L) (30% of diet DM) as protein sources; MSP, ML, GSP and GL diets were calculated to meet energy requirements for milk production by dairy cows and degradable protein for rumen microbes. Dry matter intake (DMI) did not differ among diets (18.0 kg/day DMI); milk production was higher with SP diets than with L diets (26.0 v. 24.1 kg/day), but milk production did not vary with forage type. Milk fatty-acid (FA) composition was modified by both forage and protein sources: L and G diets resulted in less saturated FA, less linoleic acid, more trans-monounsaturated FA, and more linolenic acid than SP and M diets, respectively. Enteric methane (CH4) production, measured by the SF6 tracer method, was higher for G diets than for M diets, but did not differ with protein source. The same effects were observed when CH4 was expressed per kg milk. Minor effects of diets on rumen fermentation pattern were observed. Manure CH4 emissions estimated from faecal organic matter were negatively related to diet digestibility and were thus higher for L than SP diets, and higher for M than G diets; the resulting difference in total CH4 production was small. Owing to diet formulation constraints, N intake was higher for SP than for L diets; interaction between forage type and protein source was significant for N intake. The same statistical effects were found for N in milk. Faecal and urinary N losses were determined from total faeces and urine collection. Faecal N output was lower for M than for G diets but did not differ between protein sources. Urinary N output did not differ between forage types, but was lower for cows fed L diets than for cows fed SP diets, potentially resulting in lower ammonia emissions with L diets. Replacing soya bean meal plus beet pulp with dehydrated lucerne did not change CH4 production, but resulted in more N in faeces and less N in urine.

At line prediction of PUFA and biohydrogenation intermediates in perirenal and subcutaneous fat from cattle fed sunflower or flaxseed by near infrared spectroscopy

NIRS potential to estimate the proportion of PUFA and their biohydrogenation products in adipose tissues from cattle fed sunflower or flaxseed was tested. Immediately after skinning, perirenal and subcutaneous fat samples from 63 steers were collected, scanned intact at 37°C and 33°C, respectively, over a NIR spectral range from 400 to 2498nm using benchtop equipment and then analyzed for fatty acid composition. NIRS calibrations in perirenal fat showed high predictability for total and major omega−6 and omega−3, conjugated linolenic acids, t,t-conjugated linoleic acids (CLA), non-CLA dienes and trans-monounsaturated fatty acids, with R2 (RMSECV, %) of 0.88–0.89 (0.16–0.20), 0.89–0.91 (0.07–0.08), 0.86–0.89 (0.01–0.09), 0.82 (0.07), 0.89 (0.46) and 0.86–0.88 (0.87–1.29), respectively. NIRS predictions in subcutaneous fat were less reliable, probably due to lower fatty acid variability. The results show NIRS to be a useful technique for the early, fast and relatively inexpensive estimation of proportions of fatty acids with potential human health effects in cattle perirenal fat.

Determining Milk Isolated and Conjugatedtrans-Unsaturated Fatty Acids Using Fourier Transform Raman Spectroscopy

The feasibility of Raman spectroscopy in combination with partial least-squares (PLS) regression for the determination of individual or grouped trans-monounsaturated fatty acids (trans-MUFA) and conjugated linoleic acids (CLA) in milk fat is demonstrated using spectra obtained at two temperature conditions: room temperature and after freezing at -80 °C. The PLS results displayed capability for direct semiroutine quantification of several individual CLA (cis-9,trans-11 and trans-10,cis-12 C18:2) and trans-MUFA (trans-4-15 C18:1) in minor concentrations (below 1.0 g/100 g of milk fat). Calibration models were based on reference data cross-correlation or determined by specific scattering signals in the Raman spectra. Distinct bands for trans-MUFA (1674 cm(-1)) and CLA (1653 cm(-1)) from the trans isolated and cis,trans conjugated C ═ C bonds were identified, as well as original evidence for the temperature effect (new bands, peak shifts, and higher intensities) on the Raman spectra of fatty acid methyl ester and triacylglyceride standards, are supplied.

Near infrared reflectance spectroscopy predicts the content of polyunsaturated fatty acids and biohydrogenation products in the subcutaneous fat of beef cows fed flaxseed

This study examined the ability of near infrared reflectance spectroscopy (NIRS) to estimate the concentration of polyunsaturated fatty acids and their biohydrogenation products in the subcutaneous fat of beef cows fed flaxseed. Subcutaneous fat samples at the 12th rib of 62 cows were stored at −80°C, thawed, scanned over a NIR spectral range from 400 to 2498nm at 31°C and 2°C, and subsequently analysed for fatty acid composition. Best NIRS calibrations were with samples at 31°C, showing high predictability for most of the n−3 (R2: 0.81–0.86; RMSECV: 0.11–1.56mgg−1 fat) and linolenic acid biohydrogenation products such as conjugated linolenic acids, conjugated linoleic acids (CLA), non-CLA dienes and trans-monounsaturated fatty acids with R2 (RMSECV, mgg−1 fat) of 0.85–0.85 (0.16–0.37), 0.84–0.90 (0.21–2.58), 0.90 (5.49) and 0.84–0.90 (4.24–8.83), respectively. NIRS could discriminate 100% of subcutaneous fat samples from beef cows fed diets with and without flaxseed.