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Variation in gas release profiles in vitro as influenced by volatile fatty acid composition and rate of addition to two standard incubation media

Published online by Cambridge University Press:  20 November 2017

E. Krystallidou
Affiliation:
Department of Agriculture, The University of Reading, Earley Gate, PO Box 237, Reading, RG6 6AR, U.K.
F.L. Mould
Affiliation:
Department of Agriculture, The University of Reading, Earley Gate, PO Box 237, Reading, RG6 6AR, U.K.
E. Owen
Affiliation:
Department of Agriculture, The University of Reading, Earley Gate, PO Box 237, Reading, RG6 6AR, U.K.
E.A. Butler
Affiliation:
Department of Agriculture, The University of Reading, Earley Gate, PO Box 237, Reading, RG6 6AR, U.K.
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Extract

In vitro gas systems characterise substrate degradation by estimating fermentation gas release over time. However, as this offers little information regarding feedstuff utilisation, the extent of organic matter degradation (OMD) must be measured to provide an estimate of the metabolizable end-products (VFA and microbial protein) produced. Systems where capacity is limited use either an incubation end-point derived partitioning factor (PF) to estimate degradation from gas or attempt to model OMD stoichiometrically from VFA analyses or assumed gas / VFA relationships. These estimates contain numerous errors. For instance the PF is not constant and the stoichiometric calculations used assume that all OM degraded is carbohydrate composed of hexose sugars. A further potential error is the estimate of the proportion of released gas that originates from VFA neutralisation, as this varies with buffer composition and both proportion and rate (i.e. concentration) of VFA production.

Type
Poster Presentations
Copyright
Copyright © The British Society of Animal Science 2002

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References

Mauricio, R.M., Mould, F.L., Dhanoa, M.S., Owen, E., Channa, K.S. and Theodorou, M.K. 1999. A semi-automated in vitro gas production technique for ruminant feedstuff evaluation. Animal Feed Science and Technology 79: 312330.Google Scholar
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