J. Anim Sci., doi: 10.2527/jas.2007-0588
©Copyright, 2007, The American Society of Animal Science
BOARD-INVITED REVIEW: Recent advances in biohydrogenation of unsaturated fatty acids within the rumen microbial ecosystem
T. C. Jenkins 1*,
R. J. Wallace 2,
P. J. Moate 3,
E. E. Mosley 4
1 Department of Animal and Veterinary Sciences, Clemson University, Clemson, SC 29634
2 Rowett Research Institute, Bucksburn, Aberdeen AB21 9SB, UK
3 University of Pennsylvania, Kennett Square, PA 19348
4 University of Idaho, Department of Animal and Veterinary Science, Moscow, ID 83844
* To whom correspondence should be addressed. E-mail: tjnkns{at}clemson.edu.
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Abstract |
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Recent chromatography advances in identification of CLA isomers combined with interest in their possible 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) promoting properties 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 oversimplied pathways over the decades. Recent work is now being directed at 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 about the role and contribution of specific microbial species in the process of biohydrogenation. With new insights on 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.
Key Words:
biohydrogenation, rumen, microorganisms, conjugated linoleic acid, modelling
