A Practical Guide to the Isolation, Analysis and Identification of Conjugated Linoleic Acid

Christie, William W.; Dobson, Gary; Adlof, R. O.

doi:10.1007/s11745-007-3107-8

Cited by 128 publications

(129 citation statements)

References 37 publications

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“…The different positional and geometric isomers of CLA are similar chemically and typically difficult to separate from each other (Christie et al, 2001). They are also subject to racemization under relatively mild conditions (Christie et al, 2001).…”

Section: Discussionmentioning

confidence: 99%

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Metabolism of conjugated linoleic acids and 18 : 1 fatty acids by ruminal bacteria: products and mechanisms

2010

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Cultures of ruminal bacteria known to metabolize unsaturated fatty acids were grown in medium containing 50 mg ml "1 of geometric and positional isomers of conjugated linoleic acid (CLA) or 18 : 1 fatty acids and 37.4 % deuterium oxide to investigate the mechanisms responsible for fatty acid metabolism. Butyrivibrio fibrisolvens JW11 converted cis-9,trans-11-18 : 2 and trans-9,trans-11-18 : 2 to trans-11-18 : 1 as the main product, labelled at C-9, and metabolized trans-10,cis-12-18 : 2 to trans-10-18 : 1, labelled at C-13, and smaller amounts of trans-12-18 : 1 and cis-12-18 : 1. Butyrivibrio proteoclasticus P-18 did not grow in the presence of cis-9,trans-11-18 : 2 or trans-10,cis-12-18 : 2, but grew in medium containing trans-9,trans-11-18 : 2, forming 18 : 0. Propionibacterium acnes, a ruminal species that isomerizes linoleic acid to trans-10,cis-12-18 : 2, did not metabolize CLA isomers further. B. fibrisolvens metabolized small amounts of trans-10-18 : 1, trans-11-18 : 1 and cis-9-18 : 1, but the products formed were not detected. B. proteoclasticus, on the other hand, carried out substantial conversion of 18 : 1 substrates to 18 : 0. P. acnes hydrated cis-9-18 : 1 and trans-11-18 : 1 to 10-OH-18 : 0, which was further oxidized to yield 10-O-18 : 0. The deuterium enrichment in the intermediates formed during incubations with 9,11 geometric isomers of CLA was about half that of the products from trans-10,cis-12 CLA and 18 : 1 isomers, suggesting that the reduction of 9,11 geometric isomers CLA by ruminal bacteria occurs via different mechanisms compared with the metabolism of other unsaturated fatty acids.

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Section: Discussionmentioning

confidence: 99%

“…They are also subject to racemization under relatively mild conditions (Christie et al, 2001). Thus, although impurities were present in the substrates used here, it would in practice be difficult to improve upon their quality.…”

Section: Discussionmentioning

confidence: 99%

Metabolism of conjugated linoleic acids and 18 : 1 fatty acids by ruminal bacteria: products and mechanisms

2010

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“…Fatty acid composition and cholesterol concentration of adipose membranes After membrane vesicle lyophilisation (at 2608C and 2.0 hPa), fatty acids were converted to methyl esters (FAME) (Raes et al, 2001;Christie et al, 2007). The resulting FAME were then analysed by gas chromatography, using a capillary column (30 m 3 0.25 mm i.d., Omegawax 250; 0.25 mm film thickness; Supelco, Bellefont, CA, USA), equipped with a flame-ionization detector.…”

Section: Methodsmentioning

confidence: 99%

Differential mesenteric fat deposition in bovines fed on silage or concentrate is independent of glycerol membrane permeability

Martins

Lopes²,

Costa³

et al. 2011

Animal

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In the meat industry, the manipulation of fat deposition in cattle is of pivotal importance to improve production efficiency, carcass composition and ultimately meat quality. There is an increasing interest in the identification of key factors and molecular mechanisms responsible for the development of specific fat depots. This study aimed at elucidating the influence of breed and diet on adipose tissue membrane permeability and fluidity and their interplay on fat deposition in bovines. Two Portuguese autochthonous breeds, Alentejana and Barrosã , recognized as late-and early-maturing breeds, respectively, were chosen to examine the effects of breed and diet on fat deposition and on adipose membrane composition and permeability. Twenty-four male bovines from these breeds were fed on silage-based or concentrate-based diets for 11 months. Animals were slaughtered to determine their live slaughter and hot carcass weights, as well as weights of subcutaneous and visceral adipose depots. Mesenteric fat depots were excised and used to isolate adipocyte membrane vesicles where cholesterol content, fatty acid profile as well as permeability and fluidity were determined. Total accumulation of neither subcutaneous nor visceral fat was influenced by breed. In contrast, mesenteric and omental fat depots weights were higher in concentrate-fed bulls relative to silage-fed animals. Membrane fluidity and permeability to water and glycerol in mesenteric adipose tissue were found to be independent of breed and diet. Moreover, the deposition of cholesterol and unsaturated fatty acids, which may influence membrane properties, were unchanged among experimental groups. Adipose membrane lipids from the mesenteric fat depot of ruminants were rich in saturated fatty acids, and unaffected by polyunsaturated fatty acids dietary levels. Our results provide evidence against the involvement of cellular membrane permeability to glycerol on fat accumulation in mesenteric fat tissue of concentrate-fed bovines, which is consistent with the unchanged membrane lipid profile found among experimental groups.

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“…17 Based on the same, or close, procedure, a commercial ChromSpher Lipids TM (CSL) column by Varian-Chrompack International (Middelburg, Netherlands) appeared later and is presently dominating in Ag-HPLC. Because of unclear and not openly commented limitations in mobile-phase compositions for use with CSL columns, efficient resolution of complex FA, like conjugated linoleic acids (CLA), 18 and TAG mixtures, like TAG containing CLA 19 or positionally isomeric TAG, 20 was achieved by connecting of two to six CSL columns in series.…”

Section: ·3 High-performance Liquid Chromatography 2·3·1 Columnsmentioning

confidence: 99%

Advances in Silver Ion Chromatography for the Analysis of Fatty Acids and Triacylglycerols—2001 to 2011

Momchilova

Nikolova‐Damyanova

2012

ANAL. SCI.

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A Practical Guide to the Isolation, Analysis and Identification of Conjugated Linoleic Acid

Cited by 128 publications

References 37 publications

Metabolism of conjugated linoleic acids and 18 : 1 fatty acids by ruminal bacteria: products and mechanisms

Metabolism of conjugated linoleic acids and 18 : 1 fatty acids by ruminal bacteria: products and mechanisms

Differential mesenteric fat deposition in bovines fed on silage or concentrate is independent of glycerol membrane permeability

Advances in Silver Ion Chromatography for the Analysis of Fatty Acids and Triacylglycerols—2001 to 2011

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