Lipid Metabolism in the Rumen

Harfoot, C. G.

doi:10.1016/b978-0-08-023789-3.50006-4

Cited by 289 publications

(419 citation statements)

References 123 publications

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“…The electron impact mass spectra were recorded at 70 eV between 100 and 450 amu. The identified CLnA was 9,11,15 18:3, the most probable configuration being cis-9, trans-11, cis-15 18:3 (Harfoot and Hazlewood, 1988;Destaillats et al, 2005).…”

Section: Methodsmentioning

confidence: 94%

“…The same effect was observed for trans-11, cis-15 18:2 in milk fat, but not in plasma lipids where a high variability was noticed. Plasma and milk CLnA and trans-11, cis-15 18:2 originate from the ruminal BH of cis-9, cis-12, cis-15 18:3 (Harfoot and Hazlewood, 1988), so that increased values could be expected with linseed addition. Milk CLnA possibly could also originate from mammary D9-desaturation of trans-11, cis-15 18:2, but the ratio of CLnA to trans-11, cis-15 18:2 was higher in plasma lipids than in milk fat, which does not support this hypothesis.…”

Section: Conjugated Linoleic and Linolenic Acids In The Milk Of Cows mentioning

confidence: 99%

“…The main isomer of conjugated linoleic acid (CLA), cis-9, trans-11 18:2, is the first intermediate of cis-9, cis-12 18:2 BH, and has been shown to inhibit carcinogenesis (Parodi, 1999). In the rumen, CLA is reduced to trans-11 18:1, further hydrogenated to 18:0 (Harfoot and Hazlewood, 1988). The first step of cis-9, cis-12, cis-15 18:3 ruminal BH is an isomerisation of the cis-12 double bond to a trans-11 double bond, resulting in an isomer of conjugated linolenic acid (CLnA), cis-9, trans-11, cis-15 18:3 (Harfoot and Hazlewood, 1988); chemically prepared isomers of this natural CLnA exhibit stronger cytotoxic effects than CLA on human tumour cells (Igarashi and Miyazawa, 2000).…”

Section: Introductionmentioning

confidence: 99%

“…In the rumen, CLA is reduced to trans-11 18:1, further hydrogenated to 18:0 (Harfoot and Hazlewood, 1988). The first step of cis-9, cis-12, cis-15 18:3 ruminal BH is an isomerisation of the cis-12 double bond to a trans-11 double bond, resulting in an isomer of conjugated linolenic acid (CLnA), cis-9, trans-11, cis-15 18:3 (Harfoot and Hazlewood, 1988); chemically prepared isomers of this natural CLnA exhibit stronger cytotoxic effects than CLA on human tumour cells (Igarashi and Miyazawa, 2000). In the rumen, CLnA is reduced to trans-11, cis-15 18:2, which can be reduced to either trans-11 C18:1, cis-15 18:1 or trans-15 18:1; the latter two are not further hydrogenated in the rumen, but trans-11 18:1 can be reduced to 18:0 (Harfoot and Hazlewood, 1988).…”

Section: Introductionmentioning

confidence: 99%

“…The first step of cis-9, cis-12, cis-15 18:3 ruminal BH is an isomerisation of the cis-12 double bond to a trans-11 double bond, resulting in an isomer of conjugated linolenic acid (CLnA), cis-9, trans-11, cis-15 18:3 (Harfoot and Hazlewood, 1988); chemically prepared isomers of this natural CLnA exhibit stronger cytotoxic effects than CLA on human tumour cells (Igarashi and Miyazawa, 2000). In the rumen, CLnA is reduced to trans-11, cis-15 18:2, which can be reduced to either trans-11 C18:1, cis-15 18:1 or trans-15 18:1; the latter two are not further hydrogenated in the rumen, but trans-11 18:1 can be reduced to 18:0 (Harfoot and Hazlewood, 1988). Besides these well-known pathways, which mainly result in trans-11 isomers, rumen BH can result in many other cis or trans positional isomers of 18:2 or 18:1 FA, specially trans-13 and/or trans-14 isomers when linseed is added to the diet (Loor et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

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Conjugated linolenic acid (CLnA), conjugated linoleic acid (CLA) and other biohydrogenation intermediates in plasma and milk fat of cows fed raw or extruded linseed

Akraim

Nicot

Juanéda

et al. 2007

Animal

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Thirty lactating dairy cows were used in a 3 3 3 Latin-square design to investigate the effects of a raw or extruded blend of linseed and wheat bran (70:30) on plasma and milk fatty-acids (FA). Linseed diets, containing 16.6% linseed blend on a dry-matter basis, decreased milk yield and protein percentage. They decreased the proportions of FA with less than 18 carbons in plasma and milk and resulted in cis-9, cis-12, cis-15 18:3 proportions that were more than three and four times higher in plasma and milk, respectively, whereas cis-9, cis-12 18:2 proportions were decreased by 10-15%. The cis-9, trans-11, cis-15 18:3 isomer of conjugated linolenic acid was not detected in the milk of control cows, but was over 0.15% of total FA in the milk fat of linseed-supplemented cows. Similarly, linseed increased plasma and milk proportions of all biohydrogenation (BH) intermediates in plasma and milk, including the main isomer of conjugated linoleic acid cis-9, trans-11 18:2, except trans-4 18:1 and cis-11, trans-15 18:2 in plasma lipids. In milk fat, compared with raw linseed, extruded linseed further reduced 6:0-16:0 even-chain FA, did not significantly affect the proportions of 18:0, cis-9 18:1 and cis-9, cis-12 18:2, tended to increase cis-9, cis-12, cis-15 18:3, and resulted in an additional increase in the proportions of most BH intermediates. It was concluded that linseed addition can improve the proportion of conjugated linoleic and linolenic acids, and that extrusion further increases the proportions of intermediates of ruminal BH in milk fat.

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Section: Methodsmentioning

confidence: 94%

Section: Conjugated Linoleic and Linolenic Acids In The Milk Of Cows mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Conjugated linolenic acid (CLnA), conjugated linoleic acid (CLA) and other biohydrogenation intermediates in plasma and milk fat of cows fed raw or extruded linseed

Akraim

Nicot

Juanéda

et al. 2007

Animal

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Effect of lecithins partly replacing rumen-protected fat on fatty acid digestion and composition of cow milk

Wettstein

Scheeder

Sutter

et al. 2001

Eur. J. Lipid Sci. Technol.

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Effect of lecithins partly replacing rumenprotected fat on fatty acid digestion and composition of cow milkThe effects on fatty acid digestibility and milk fat composition of calcium soaps of palm oil fatty acids and of a 25% replacement of the Ca soaps by four different lecithins (raw, deoiled and deoiled/partially hydrolysed soy lecithin, raw canola lecithin) and soybean oil were investigated in six lactating cows each. The complete diets contained the lipid supplements at proportions of 30 g fatty acids/kg dry matter. Partial replacement of Ca soaps by soy or canola lecithins and soybean oil had small but significant effects on fatty acid digestion and utilisation, as well as the fatty acid profile in milk. Relative to Ca soaps alone, C16:0 digestibility was slightly higher with lecithins, and percentage of conjugated linoleic acid and trans C18:1 in milk fat increased while proportion of C16:0 decreased. Deoiling of lecithins slightly reduced the effects on C16:0 digestibility and excretion with milk. The influence of lecithin processing was higher than the differences between raw soy and raw canola lecithin. Nevertheless, most of the few effects observed may be related to the fatty acids supplied with the lecithins but, regarding C18:1 trans-11 and odd chain fatty acids, there is some evidence that lecithins impair rumen microbial activity less than soybean oil.

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Selective fermentation of carbohydrate and protein fractions of Scenedesmus, and biohydrogenation of its lipid fraction for enhanced recovery of saturated fatty acids

Lai

Parameswaran

et al. 2015

Biotech & Bioengineering

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Biofuels derived from microalgae have promise as carbon-neutral replacements for petroleum. However, difficulty extracting microalgae-derived lipids and the co-extraction of non-lipid components add major costs that detract from the benefits of microalgae-based biofuel. Selective fermentation could alleviate these problems by managing microbial degradation so that carbohydrates and proteins are hydrolyzed and fermented, but lipids remain intact. We evaluated selective fermentation of Scenedesmus biomass in batch experiments buffered at pH 5.5, 7, or 9. Carbohydrates were fermented up to 45% within the first 6 days, protein fermentation followed after about 20 days, and lipids (measured as fatty acid methyl esters, FAME) were conserved. Fermentation of the non-lipid components generated volatile fatty acids, with acetate, butyrate, and propionate being the dominant products. Selective fermentation of Scenedesmus biomass increased the amount of extractable FAME and the ratio of FAME to crude lipids. It also led to biohydrogenation of unsaturated FAME to more desirable saturated FAME (especially to C16:0 and C18:0), and the degree of saturation was inversely related to the accumulation of hydrogen gas after fermentation. Moreover, the microbial communities after selective fermentation were enriched in bacteria from families known to perform biohydrogenation, i.e., Porphyromonadaceae and Ruminococcaceae. Thus, this study provides proof-of-concept that selective fermentation can improve the quantity and quality of lipids that can be extracted from Scenedesmus.

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Lipid Metabolism in the Rumen

Cited by 289 publications

References 123 publications

Conjugated linolenic acid (CLnA), conjugated linoleic acid (CLA) and other biohydrogenation intermediates in plasma and milk fat of cows fed raw or extruded linseed

Conjugated linolenic acid (CLnA), conjugated linoleic acid (CLA) and other biohydrogenation intermediates in plasma and milk fat of cows fed raw or extruded linseed

Effect of lecithins partly replacing rumen-protected fat on fatty acid digestion and composition of cow milk

Selective fermentation of carbohydrate and protein fractions of Scenedesmus, and biohydrogenation of its lipid fraction for enhanced recovery of saturated fatty acids

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