In vitro gas production profile and the formation of end products from non- washable, insoluble washable and soluble washable fractions in some concentrate ingredients

Authors

  • Arash Azarfar,

    Corresponding author
    1. Wageningen Institute of Animal Science, Animal Nutrition Group, Department of Animal Science, Wageningen University, Marijkeweg 40, P.O. Box 338, 6700 AH, Wageningen, The Netherlands
    2. University of Lorestan, P.O. Box 465, Khorramabad, Iran
    • Department of Animal science, Wageningen University, Marijkeweg 40, PO Box, 338, 6707 AH, Wageningen, The Netherlands
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  • Barbara A Williams,

    1. Wageningen Institute of Animal Science, Animal Nutrition Group, Department of Animal Science, Wageningen University, Marijkeweg 40, P.O. Box 338, 6700 AH, Wageningen, The Netherlands
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  • Huug Boer,

    1. Wageningen Institute of Animal Science, Animal Nutrition Group, Department of Animal Science, Wageningen University, Marijkeweg 40, P.O. Box 338, 6700 AH, Wageningen, The Netherlands
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  • Seerp Tamminga

    1. Wageningen Institute of Animal Science, Animal Nutrition Group, Department of Animal Science, Wageningen University, Marijkeweg 40, P.O. Box 338, 6700 AH, Wageningen, The Netherlands
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Abstract

A procedure that mimics washing in the in situ incubation technique, combined with an in vitro gas and volatile fatty acids (VFAs) production technique, was used to verify the assumption that rumen degradation behaviour of material washed out of nylon bags is instantaneous and complete. In a 6 × 4 factorial arrangement of treatments with three replicates, fractions of maize, barley, milo, yellow peas, lupins (a mixture of white and spotted lupins) and round-seeded brown faba beans were subjected to an in vitro incubation technique. Fractions were whole (WHO), non-washable (NWF), insoluble washable (ISWF) and soluble washable (SWF). In a manually operated in vitro fermentation system, another 24 samples of the same substrates were fermented for VFA and ammonia analysis. Except in lupins, ISWF in the concentrate ingredients was very rich in starch. SWF was relatively rich in ash, crude protein, soluble sugars, and a residual unknown fraction but contained only a negligible quantity of starch. Thus, the fermentation characteristics of ISWF were more like WHO and NWF than SWF. Total gas production of SWF was considerably lower than the other fractions. A very rapidly degradable fraction was seen in the first phase of degradation of SWF. The pattern of fermentation end-product formation for SWF differed from that of the other fractions. Copyright © 2007 Society of Chemical Industry

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