The methyl ester of an unsaturated fatty acid, methyllinoleate was reacted with oxygen in a pressurized system at a controlled temperature. A natural autoxidation of methyl linoleate was observed without the addition of an initiating reagent. This autoxidation process could be used to mimic the course of lipid peroxidation, which is the major cause ofradical damage to living cells. The technology of GC-MS was employed to monitor the autoxidation of methyllinoleate. Eight of the autoxidation products separated by GC column were identified by interpreting the corresponding EI ion mass spectra. The products from 9-alkoxy methyl linoleate radical were methyl octanate, 2,4-decadienal, nonanoic acid, 9-oxo-methyl ester, and its further oxidation product, nonanedioic acid, monomethyl ester. All of them formed through a pathway of beta-cleavage. The products from 13-alkoxy methyl linoleate radical were tridecanoic acid, 9, 11-diene-13-oxo-methyl ester, hex anal, and its further oxidation product, hexanoic acid. They were also formed through a mechanism of beta-cleavage. The fourth product from 13-alkoxy methyllinoleate radical was 13-keto-9, 11-octadecadienoic acid, methyl ester, which was obtained through a pathway of keto formation. Observation of their concentrations in the samples at different autoxidation periods revealed the time-course of formation of these products.

The potential for enhancing oleic acid (cis-18:1) and linoleic acid (18:2) content and lowering medium chain fatty acid (MCFA) content of bovine milk was investigated by abomasal infusion or dietary supplementation of oils. In experiment 1, olive oil, sesame oil, sunflower oil, or fish oil was abomasally infused (155 to 219 g/d) into Jersey cows during the last 6 d of each of four 14-d periods. In experiment 2, canola oil, olive oil, high-oleic sunflower oil, or distilled water (control) was abomasally infused (342 to 371 g/d) into three Holsteins and three Jerseys during the last 5 d of each of four 10-d periods. The intestinal digestibility and concentration of cis-18:1 and 18:2 in milk were proportional to flow of these fatty acids to the duodenum. Also, greater concentration of cis-18:1 in milk was associated with lowered yield of MCFA. During olive oil or sesame oil infusion in experiment 1, for each 100 g of cis-18:1 infused into the abomasum, milk cis-18:1 yield was increased by an average of 47 g, and MCFA yield was reduced by 42 g. The yield of 18:2 in milk was increased by approximately 46 g for each 100 g of infused 18:2 during olive oil or sesame oil infusion. Milk produced during sesame oil infusion, however, had an off-flavor when evaluated by a taste panel. In experiment 2, each 100 g of cis-18:1 infused daily increased milk cis-18:1 yield in Holsteins and Jerseys by 41 and 39 g/d, respectively, whereas recovery of infused 18:2 was 34 g/d for Jerseys and 42 g/d for Holsteins. In experiment 3, 22 Jersey cows were fed a basal diet, or the basal diet supplemented with 3.5% high-oleic canola oil, 3.5% soybean oil, or 1.75% high-oleic canola oil plus 1.75% soybean oil for 5 wk. Dietary canola oil supplementation increased conjugated linoleic acid (CLA) percentage in milk to a moderate level without raising trans-18:1 percentage, whereas feeding either supplement containing soybean oil raised both CLA and trans-18:1 percentages. Concentrations of trans-18:1 and CLA in milk apparently reflected the extent of unsaturated fatty acid biohydrogenation in the rumen. Dietary supplementation with canola oil increased yield of cis-18:1 in milk by 21 g for each 100 g of supplemental cis-18:1 intake. Yield of 18:2 in milk was raised by 3 g for each 100 g of supplemental 18:2 intake by cows fed soybean oil. Using abomasal infusion as an indicator of the maximum potential for apparent recovery of cis-18:1 in milk (39 to 49%), cis-18:1 recovery in response to supplemental cis-18:1 in the diet was approximately half of the potential response due to partial biohydrogenation in the rumen. The apparent recovery of dietary 18:2 in milk was reduced to only one-tenth of the potential yield (31 to 47%) indicated by abomasal infusion of seed oils. Results indicated that the fatty acid profile of bovine milk was altered in a manner that would be beneficial to human health when cows were fed supplemental oleic acid, but further research should focus on safe and economical methods to protect dietary unsaturated fatty acids from biohydrogenation. / Ph. D.

Akrylbaserat bencement är den gyllene standarden vid ryggförstärkningsförfaranden. Modifiering av akrylbencement med linolsyra har resulterat i attraktiva egenskaper vilka möjliggör lättare hantering för kirurger och minskar efterföljande komplikationer såsom närliggande ryggradsfrakturer. Även om de attraktiva egenskaperna hos linolsyramodifierat bencement är kända är ännu förståelsen för hur linolsyra påverkar egenskaperna outforskade. Som en komponent i bencement måste linolsyra steriliseras innan den används i bencement. Det finns emellertid oro för att autoklavsterilisering av linolsyra orsakar nedbrytning. Dessutom är det oklart vad som händer med linolsyra i härdat bencement över tid. I detta examensarbete utvärderades steriliserad och osteriliserad linolsyra. Linolsyra blandades med olika komponenter som finns i bencementet såsom aktivator, initiator, monomer och inhibitor, i närvaro och frånvaro av lösningsmedel. De efterföljande förändringarna studerades genom 1H NMR och UV-VIS. Resultaten visade att linolsyra bryts ned av sterilisering och oxidation. Oxidationen av linolsyra berodde på sterilisering, temperatur, lösningsmedel och mängden syrexponering. Det bekräftades genom 1H NMR och UV-VIS att linolsyra reagerade (steriliserad och osteriliserad) med aktivatorn, initiatorn och monomeren. Dessa reaktioner kan minska tillgängligheten av komponenterna för in situ-polymerisation av monomeren, och därmed förändra bencementens egenskaper, vilket i sin tur bidrar till lättare hantering under förstärkningsförfarandet och reducerar intilliggande ryggradsfrakturer efter operation. / Acrylic bone cement is the gold standard in vertebral augmentation procedures. Modification of acrylic bone cement using linoleic acid has resulted in attractive properties that enable convenient handling by surgeons and reduce follow-up complications such as adjacent vertebral fractures. Even though the attractive properties of linoleic acid-modified bone cement are acknowledged, the understanding of how it imparts those properties remain unexplored. As a component in bone cement, linoleic acid needs to be sterilized before its use in bone cement. However, there are apprehensions whether autoclave sterilization of linoleic acid causes degradation. In addition, it is unclear what happens with linoleic acid in hardened bone cement over time.  In this thesis, sterilized and unsterilized linoleic acid were evaluated alone and treated with different components of the bone cement such as activator, initiator, monomer, and inhibitor, in the presence and absence of solvent, and the ensuing changes were monitored through 1H NMR and UV-VIS. The results showed that linoleic acid degraded due to sterilization and oxidation. The oxidation of linoleic acid depended on sterilization, temperature, solvent, and the amount of oxygen exposure. As confirmed through 1H NMR and UV-VIS, linoleic acid (sterilized and unsterilized) reacted with the activator, initiator, and monomer. These reactions could reduce the availability of the components for the in-situ polymerization of the monomer, thus altering the properties of the bone cement including convenient handling during the operation and reduced adjacent vertebral fractures post the operation.

No description available.

No description available.

Studies were conducted to investigate: 1) desaturation of dietary trans-vaccenic acid (TVA, trans11-18:1) to the cis9,trans11-18:2 isomer of conjugated linoleic acid (9/11CLA), 2) effects of two conjugated linoleic acid isomers [9/11CLA or trans10,cis12-18:2 (10/12CLA)] and TVA on enzyme activities and mRNA abundance for lipogenic enzymes, and 3) regulation of stearoyl-CoA desaturase (SCD) gene transcription. In the first study, lactating mice were fed 3% linoleic acid (LA), or 2% LA plus 1% stearic acid (SA), 1% TVA, or 1% CLA mixture. Dietary TVA enriched the 9/11CLA content of carcass, liver, and mammary tissue of lactating mice. A similar enhancement of 9/11CLA also was observed in liver, but not carcass, of suckling pups nursing TVA-fed dams. The CLA mixture decreased mammary acetyl-CoA carboxylase (ACC) activity compared with other treatments. However, total fatty acid content of mammary tissue was reduced only when compared with TVA. In the second experiment, lactating mice were fed 3% canola oil (OA), or 2% OA plus 1% SA, 1% TVA, 1% 9/11CLA, or 1% 10/12CLA. Dietary TVA, 9/11CLA, and 10/12CLA decreased mRNA abundance for ACC and fatty acid synthase (FAS) in mammary tissue, suggesting each had the potential to reduce de novo fatty acid synthesis. However, only the CLA isomers decreased ACC activity in mammary tissue and concentration of medium-chain fatty acids (MCFA = 12:0+14:0+16:0) in milk fat. The 10/12CLA isomer caused greater reductions in MCFA and milk fat percentage than the 9/11CLA, indicating that 10/12CLA is the primary CLA isomer affecting lipid metabolism in the mammary gland. Dietary TVA, 9/11CLA, or 10/12CLA decreased SCD enzyme activity and mRNA abundance in mammary tissue. In study 3, mouse (COMMA-D/MME) and bovine (Mac-T) mammary epithelial cells were transfected with the putative promoter (600 bp) of SCD gene. The 9/11CLA reduced SCD gene transcription in mouse cells, but not bovine cells. Transcription, however, was reduced in both cell lines by 10/12CLA, linoleic acid, and linolenic acid. Thus, reduced SCD transcription in response to the CLA isomers in mouse mammary cells in vitro may provide an explanation for reduced SCD enzyme activity and mRNA abundance in mammary tissue when lactating mice were fed either of the CLA isomers. In contrast, stearic acid, oleic acid, and TVA did not affect SCD transcription. Although TVA did not reduce SCD transcription in mouse mammary cells in vitro, it did reduce SCD enzyme activity and mRNA abundance in mammary tissue when fed to lactating mice. The results suggested TVA may influence SCD mRNA processing or stability in the nucleus after transcription. Despite the reduction in SCD mRNA and enzyme activity, however, substantial quantities of TVA were desaturated to the 9/11CLA isomer when TVA was fed to lactating mice in the first two studies. Thus, dietary TVA provides an alternate supply of the anticarcinogenic 9/11CLA isomer in tissues. / Ph. D.

No / To analyze the fatty acid contents of Buddleja asiatica Lour, both the non-volatile oil and fat obtained from the n-hexane soluble sub-fraction were subjected to GC/MS using BSTFA (N,O-bis(trimethylsilyl) trifloroacetamide) derivatization. The oil showed the presence of six fatty acids including palmitic acid (46.75 %), linoleic acid (37.80 %), stearic acid (10.98 %), arachidic acid, margaric acid and lignoceric acid (< 3 %). Analysis of the fat revealed nine fatty acids including lignoceric acid (43.12 %), behenic acid (26.39 %), arachidic acid (9.29 %) and stearic acid (5.3 %). Cerotic acid, montanic acid, melissic acid and palmitic acid were found in low amounts (< 5 %) while trycosylic acid (4.83 %) was the only fatty acid with odd number of carbon atoms. The oil showed a low thermal stability. / Higher Education Commission Pakistan

Stearoyl-CoA desaturase1 (SCD1) catalyzes the synthesis of conjugated linoleic acid (CLA) and mono-unsaturated fatty acids (MUFA) in the mammary gland of ruminant animals. We hypothesized that single nucleotide polymorphisms (SNPs) in the coding region, 5' and 3' untranslted regions (UTRs) of the SCD1 gene would influence the activity of SCD1 enzyme and consequently account for some within-breed variations in milk CLA and MUFA. Sequence analysis of the coding region of the SCD1 gene of Jerseys and Holsteins revealed c.702A&rarr;G, c.762T&rarr;C and c.878C&rarr;T SNPs in exon 5 in both breeds and c.435G&rarr;A in exon 3 in Holsteins. The SNPs resulted in: A (G435A702T 762C878), A1 (A435A702T 762C878), B (G435G702C 762T878) and B1 (A435G702C 762T878) coding variants in Holsteins and only variants A and B in Jerseys. Only SNP 878C&rarr;T resulted in a non-synonymous codon change resulting in p.293Ala and p.293Val protein variants or alleles at the SCD1 locus. Subsequent association studies found significantly higher C10 index, C12 index and C14 index and consequently higher concentrations of C10:1 and C12:1 in p.293AA cows compared to the p.293VV cows in both breeds. The SCD1 genotype had no influence on concentrations of C141, C16:1, C18:1 and CLA in both breeds. / Sequence analysis of the 5' and 3' UTRs revealed no SNPs in the 5'UTR and a total of 14 SNPs in the 3'UTR of both breeds. The SNPs were in complete linkage disequilibrium resulting in 3 haplotypes or regulatory variants: H1 (G1571G1644C1763C2053A2584 A3007C3107G3208 T3290G 3497G3682A4399C4533G4881), H2 (G1571G1644A1763C2053A 2584G3007 C3107G3208T3290G3497G 3682A4399C4533G4881) and H3 (T 1571C1644A1763 T2053G2584G3007T 3107A3208C3290A3497A3682T 4399T4533A4881) in Holsteins and only H1 and H3 variants in Jerseys. A subsequent association study involving 862 Holstein cows, found the H1 regulatory variant to be associated with higher C10 and C12 desaturase indices and consequently with higher concentrations of C10:1 and C12:1 compared with the H3 variant. The effects of the H2 variant were intermediate to those of H1 and H3. 3'UTR genotype had no influence on the concentrations of C14:1, C16:1, C18:1 and CLA. The concentrations of C10:1 and C12:1 in milk fat could therefore be due to effects of SNPs in the open reading frame and the 3'UTR regions of the SCD1 gene. These results indicate that SNPs in the coding and 3'UTR regions of the SCD1 gene could be used as markers for genetic selection for increased C10:1 and C12:1 contents of milk.

No description available.

Consumer awareness of the link between dietary fats and health outcomes has led to increased demand for food products enriched with bioactive fatty acids (FA). Ruminant-derived fats, such as dairy fats, contribute significantly to the American diet and contain many unique beneficial FA, such as short- and medium-chain FA, n-3 FA, conjugated linoleic acids (CLA), vaccenic acid (VA), as well as odd-and branched-chain FA (OBCFA). Increasing these FA in dairy products by altering farm management practices, such as breed, lactation stage, and nutrition, may improve human health without a change to the diet. The overarching goal of this dissertation was to evaluate on-farm strategies to increase the content of bioactive FA in bovine milk. The first objective was to enrich milk fat with bioactive FA via supplementation with echium oil, a terrestrial oil rich in n-3 FA. Treatments were 1.5% and 3.0% dry matter as lipid encapsulated echium oil (EEO) which were compared to a control (no EEO). Milk fat contents of n-3 FA increased with EEO supplementation but the transfer of n-3 FA from EEO into milk fat was rather low (< 5%). In a subsequent trial, ruminal protection of EEO and post-ruminal release of EEO-derived FA was examined. EEO-derived FA were preferentially incorporated into plasma lipid fractions unavailable to the mammary gland. Moreover, fecal excretion of EEO-derived FA ranged from 7-14% of intake, and VA and CLA, the biohydrogenation and metabolism products of n-3 FA, increased in milk and feces with EEO supplementation. Therefore, lipid-encapsulation provided inadequate digestibility and low transfer efficiency of n-3 FA into milk. The second objective was to compare the bacterial community structure and unique bioactive FA in bacterial membranes and milk fat between Holstein (HO), Jersey (JE), and HO x JE crossbreeds (CB) across a lactation. Lactation stage had a prominent effect on rumen bacterial taxa, with Firmicutes being most abundant during early lactation. The FA composition of bacterial cells was affected by both lactation stage and genetics, and OBCFA in bacterial cells were positively correlated with several bacteria of the Firmicutes phylum. HO and CB exhibited greater contents of various bioactive FA in milk than JE. The highest content of all bioactive FA occurred at early lactation, while OBCFA were highest at late lactation. The third objective was to determine the effects of grazing a monoculture vs. a diverse pasture on rumen bacterial and protozoal taxa, their membrane FA composition, and milk FA. Microbial communities shifted in response to grazing regime accompanied with changes in their membrane FA profiles. Rumen microbiota from cows grazing a diverse pasture had higher contents of n-3 FA and VA, but lower contents of OBCFA. Microbial membrane FA correlated with microbial taxa, the contents of ALA and n-3 FA were positively correlated with the bacterial genus Butyrivibrio and the protozoal genus Eudioplodinium. Milk contents of CLA and n-3 FA increased when cows grazed a diverse pasture, while grazing a monoculture led to greater milk contents of OBCFA. In conclusion, grazing cows on a diverse pasture, when compared to genetic effects and lipid supplementation, was the most efficacious strategy to increase the content of bioactive FA in milk.