JDS
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J. Dairy Sci. 2007. 90:3874-3882. doi:10.3168/jds.2007-0191
© 2007 American Dairy Science Association ®
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Interpretive Summary
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Lee, M. R. F.
Right arrow Articles by Dewhurst, R. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Lee, M. R. F.
Right arrow Articles by Dewhurst, R. J.

Effects of Fatty Acid Oxidation Products (Green Odor) on Rumen Bacterial Populations and Lipid Metabolism In Vitro

M. R. F. Lee*,1, S. A. Huws*, N. D. Scollan* and R. J. Dewhurst{dagger}

* Institute of Grassland and Environmental Research, Plas Gogerddan, Aberystwyth, SY23 3EB, United Kingdom
{dagger} Agriculture and Life Sciences Division, Lincoln University, Canterbury, New Zealand

1 Corresponding author: michael.lee{at}bbsrc.ac.uk

This study investigated the effects of green odor fatty acid oxidation products (FAOP) from cut grass on lipid metabolism and microbial ecology using in vitro incubations of rumen microorganisms. These compounds have antimicrobial roles in plant defense, and we hypothesized that they may influence rumen lipid metabolism. Further, they may partially explain the higher levels of conjugated linoleic acid cis-9, trans-11 in milk from cows grazing pasture. The first of 2 batch culture experiments screened 6 FAOP (1 hydroperoxide, 3 aldehydes, 1 ketone, and 1 alcohol) for effects on lipid profile, and in particular C18 polyunsaturated fatty acid biohydrogenation. Experiment 2 used the most potent FAOP to determine effects of varying concentrations and identify relationships with effects on microbial ecology. Batch cultures contained anaerobic buffer, rumen liquor, and FAOP to a final concentration of 100 µM for experiment 1. Triplicates for each compound and controls (water addition) were incubated at 39°C for 6 h. The hydroperoxide (1,2-dimethylethyl hydroperoxide, 1,2-DMEH) and the long chain aldehyde (trans-2 decenal) had the largest effects on lipid metabolism with significant increases in C18:0 and C18:1 trans and reductions in C12:0, C14:0, C16:0, C18:1 cis, C18:2n-6, C18:3n-3, C20:0 and total branch and odd chain fatty acids compared with the control. This was associated with significantly higher biohydrogenation of C18 polyunsaturated fatty acid. In experiment 2, 1,2-DMEH was incubated at 50, 100, and 200 µM for 2, 6, and 24 h. Increasing 1,2-DMEH concentration resulted in a significant linear increase in C18:1 trans-10, trans-11, conjugated linoleic acid, and C18:0 and a linear decrease in C18:2n-6 and C18:3n-3, although the scale of this response declined with time. Microbial profiling techniques showed that 1,2-DMEH at concentrations of 100 and 200 µM changed the microbial community from as early as 2 h after addition, though microbial biomass remained similar. These preliminary studies have shown that FAOP can alter fatty acid biohydrogenation in the rumen. This change was associated with changes in the microbial population that were detected through DNA and branched- and odd-chain fatty acid profiling approaches.

Key Words: fatty acid oxidation product • conjugated linoleic acid • C18:1 trans-11 • rumen bacteria






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2007 by the American Dairy Science Association ®.