Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Record number 533848
Title Bigger is not always better: A study of the structure-activity relationship of oligomeric ellagitannins on ruminal fermentation in vitro
Author(s) Baert, Nicolas; Pellikaan, W.F.; Karonen, M.; Salminen, J.P.
Source Planta Medica 82 (2016)S 01. - ISSN 0032-0943
Event 9th Joint Meeting of AFERP, ASP, GA, JSP, PSE & SIF, Copenhagen, 2016-07-24/2016-07-27
Department(s) Animal Nutrition
Publication type Abstract in scientific journal or proceedings
Publication year 2016
Abstract The aim of this study was to investigate how the degree of oligomerization of ellagitannins (ET) influences their ability to alter ruminal fermentation. Dimeric to heptameric ET were isolated from rosebay willowherb (Epilobium angustifolium) flowers and purified. Ellagitannins were tested in vitro on a mixture of grass silage and buffered rumen fluid. Total gas production was measured in real time using an automated pressure evaluation system. Methane production was monitored at regular interval by gas chromatography for 72 h. The effect of ET was evaluated on 2 sources of rumen fluid using a randomized block design. Ammonia nitrogen, volatile fatty acid concentration, and pH were measured at the end of the experiment. Results show that oligomeric ET decreased gas production and total volatile fatty acid concentration proportionally to their degree of oligomerization. Methane production was also decreased by all the tested compounds and dimer was less effective than the larger ET, which showed similar levels of activity. Additionally, willowherb’s oligomeric ET decreased ammonia-nitrogen and branched-chain volatile fatty acid concentrations, thus indicating reduced protein degradation by ruminal bacteria. This effect showed a quadratic relationship with the degree of oligomerization and was maximal with the tetramer. In conclusion, this study shows that the degree of oligomerization of ET has more than a simple linear effect on fermentation parameters in vitro. Large oligomers, in fact, have more detrimental effects on volatile fatty acid and gas production than small ones, while being similarly effective at inhibiting methane production.
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