The in vitro rates of lipolysis and biohydrogenation in rumen contents

Hawke, J. C.; Silcock, W. Ross

doi:10.1016/0005-2760(70)90138-4

Cited by 54 publications

(17 citation statements)

References 18 publications

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“…Under this hypothesis, a slower release of FA from rolled seeds may lead to a more complete BH, whereas a more rapid release of FA may result in a higher bypass if the rates of isomerization and hydrogenation is lower than the rate of lipolysis. This latter hypothesis is consistent with in vitro and in vivo data [27,28]. Isomerization and hydrogenation rates may be lowered by the toxic effect of the free polyunsaturated FA released in the rumen.…”

Section: Duodenal Flow and Biohydrogenationsupporting

confidence: 89%

Effect of Linseed Fed as Rolled Seeds, Extruded Seeds or Oil on Fatty Acid Rumen Metabolism and Intestinal Digestibility in Cows

Doreau

Laverroux

Normand

et al. 2008

Lipids

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Linseed, a source of linolenic acid, is used in ruminant diets to increase polyunsaturated fatty acids (FA) in animal products. Seed processing is known to have an impact on FA rumen metabolism, but few data are available for linseed. We studied the effect of linseed lipid on ruminal metabolism and intestinal digestibility in cows. Three modes of linseed processing: rolled linseed (RL), extruded linseed (EL) and linseed oil plus linseed meal (LO), supplemented at 7.5% of DM intake, were compared to a control diet (C). Duodenal flows, intestinal digestibility and plasma composition were determined. The duodenal flow of linolenic acid was similar among diets. The sum of t10 and t11-18:1, which were coeluted, was increased with lipid-supplemented diets and represented more than 60% of trans 18:1 for EL and LO diets. The main 18:2 isomers were c9, c12 and t11, c15 among the non-conjugated isomers, and t11, t13 among CLA. Linseed supplementation increased the duodenal flow of unsaturated intermediates of biohydrogenation, and this effect was more pronounced for extruded seeds and oil than for rolled seeds. For most 18-carbon FA, intestinal digestibility was slightly higher for C and LO diets than for RL and EL. Plasma concentrations of non-conjugated 18:2 and linolenic acid were similar among the lipid-supplemented diets. Within diet, profiles of 18:1 isomers (except c9) remained very similar between duodenal and plasma FA.

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Section: Duodenal Flow and Biohydrogenationsupporting

confidence: 89%

Effect of Linseed Fed as Rolled Seeds, Extruded Seeds or Oil on Fatty Acid Rumen Metabolism and Intestinal Digestibility in Cows

Doreau

Laverroux

Normand

et al. 2008

Lipids

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“…Two factors affect this. The results of these experiments were similar to those done at about the same time, but with rather different aims, by Hawke and Silcock (1970), Viviani and Borgatti (1967) and Wilde and Dawson (1966), in which it was shown that, in the absence of food particles, biohydrogenation of linoleic or linolenic acids proceeded only as far as the trans-11 intermediate, if at all. Since the presence of a free carboxyl group is an absolute requirement for biohydrogenation, esters, salts or other modifications of the unsaturated fatty acid must be hydrolysed or ionized before hydrogenation can proceed.…”

Section: Factors Affecting Biohydrogenationsupporting

confidence: 84%

The Rumen Microbial Ecosystem

Hobson¹,

Stewart²

1997

347

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“…The requirement of a free carboxyl group for hydrogenation establishes that lipolysis must precede BH (Hawke and Silcock, 1970).…”

Section: Historical Perspective Of Bhmentioning

confidence: 99%

“…In many of the early in vivo and in vitro investigations of lipolysis and BH, and even in the majority of recent investigations, mathematical modeling has consisted of little more than a comparison of concentrations of various fatty acids at defined incubation times of a test feed in rumen fluid (Hawke and Silcock, 1970;Noble et al, 1974;Harfoot et al, 1975).…”

Section: Modeling Lipolysis and Bhmentioning

confidence: 99%

BOARD-INVITED REVIEW: Recent advances in biohydrogenation of unsaturated fatty acids within the rumen microbial ecosystem1

Jenkins

Wallace²,

Moate

et al. 2008

Journal of Animal Science

619

576

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Recent advances in chromatographic identification of CLA isomers, combined with interest in their possible properties in promoting human health (e.g., cancer prevention, decreased atherosclerosis, improved immune response) and animal performance (e.g., body composition, regulation of milk fat synthesis, milk production), has renewed interest in biohydrogenation and its regulation in the rumen. Conventional pathways of biohydrogenation traditionally ignored minor fatty acid intermediates, which led to the persistence of oversimplified pathways over the decades. Recent work is now being directed toward accounting for all possible trans-18:1 and CLA products formed, including the discovery of novel bioactive intermediates. Modern microbial genetics and molecular phylogenetic techniques for identifying and classifying microorganisms by their small-subunit rRNA gene sequences have advanced knowledge of the role and contribution of specific microbial species in the process of biohydrogenation. With new insights into the pathways of biohydrogenation now available, several attempts have been made at modeling the pathway to predict ruminal flows of unsaturated fatty acids and biohydrogenation intermediates across a range of ruminal conditions. After a brief historical account of major past accomplishments documenting biohydrogenation, this review summarizes recent advances in 4 major areas of biohydrogenation: the microorganisms involved, identification of intermediates, the biochemistry of key enzymes, and the development and testing of mathematical models to predict biohydrogenation outcomes.

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The in vitro rates of lipolysis and biohydrogenation in rumen contents

Cited by 54 publications

References 18 publications

Effect of Linseed Fed as Rolled Seeds, Extruded Seeds or Oil on Fatty Acid Rumen Metabolism and Intestinal Digestibility in Cows

Effect of Linseed Fed as Rolled Seeds, Extruded Seeds or Oil on Fatty Acid Rumen Metabolism and Intestinal Digestibility in Cows

The Rumen Microbial Ecosystem

BOARD-INVITED REVIEW: Recent advances in biohydrogenation of unsaturated fatty acids within the rumen microbial ecosystem1

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