caa a22 4500 388062428 CHVBK 20180307125124.0 cr unu---uuuuu 161130e199806 xx s 000 0 eng 10.1079/BJN19980090 doi S0007114598000919 pii (NATIONALLICENCE)cambridge-10.1079/BJN19980090 The use of cumulative gas and volatile fatty acid production to predict in vitro fermentation kinetics of Italian ryegrass leaf cell walls and contents at various time intervals [Elektronische Daten] Differences between the fermentation characteristics of cell contents (CC) and protease-treated cell walls (CW) of young leaves of Italian ryegrass (Lolium multiflorum Lam.) cultivar Multimo (tetraploid), were studied in vitro. Gas and volatile fatty acid (VFA) production rates were measured at regular intervals, as was the degradability of organic matter (OM) of CW. The measured VFA were used to predict the gas production and fermentable OM using stoichiometric calculations. For CW the volume and kinetics of measured gas production were the same as those predicted from the VFA formed. In contrast, the measured gas production for CC was consistently less than predicted, indicating that the stoichiometric equations were not valid for rapidly fermenting substrates. For both CC and CW, the relative rate of acetic acid production levelled off more slowly than for other VFA, resulting in an increasing gas yield (in ml/g fermentable OM) after 12 (CW)-24 (CC)h incubation. Consequently, the fermentation of OM was not linearly related to gas production kinetics. For CW, the kinetics of decline of degradable OM and fermentable OM were the same, after correction for a constant ‘lost fraction' of degradable OM of 205 g/kg OM. This work indicates the value of detailed studies of fermentation processes to evaluate herbage quality. In particular, the role of CC and the difference between degradation and fermentation require further attention. Copyright © The Nutrition Society 1998 Fermentation nationallicence Grass nationallicence Volatile fatty acids nationallicence Groot Jeroen C. J. C. T. de Wit Graduate School for Production Ecology, Department of Agronomy, Agricultural University, Haarweg 333, 6709 RZ Wageningen, The Netherlands Williams Barbara A. Wageningen Institute of Animal Science, Animal Nutrition Group, Agricultural University, Marijkeweg 40, 6709 PG Wageningen, The Netherlands Oostdam Arno J. Wageningen Institute of Animal Science, Animal Nutrition Group, Agricultural University, Marijkeweg 40, 6709 PG Wageningen, The Netherlands Boer Huug Wageningen Institute of Animal Science, Animal Nutrition Group, Agricultural University, Marijkeweg 40, 6709 PG Wageningen, The Netherlands Tamminga Seerp Wageningen Institute of Animal Science, Animal Nutrition Group, Agricultural University, Marijkeweg 40, 6709 PG Wageningen, The Netherlands British Journal of Nutrition Cambridge University Press 79/6(1998-06), 519-525 0007-1145 79:6<519 1998 79 BJN https://doi.org/10.1079/BJN19980090 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1079/BJN19980090 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Groot Jeroen C. J. C. T. de Wit Graduate School for Production Ecology, Department of Agronomy, Agricultural University, Haarweg 333, 6709 RZ Wageningen, The Netherlands NATIONALLICENCE 700 1- Williams Barbara A. Wageningen Institute of Animal Science, Animal Nutrition Group, Agricultural University, Marijkeweg 40, 6709 PG Wageningen, The Netherlands NATIONALLICENCE 700 1- Oostdam Arno J. Wageningen Institute of Animal Science, Animal Nutrition Group, Agricultural University, Marijkeweg 40, 6709 PG Wageningen, The Netherlands NATIONALLICENCE 700 1- Boer Huug Wageningen Institute of Animal Science, Animal Nutrition Group, Agricultural University, Marijkeweg 40, 6709 PG Wageningen, The Netherlands NATIONALLICENCE 700 1- Tamminga Seerp Wageningen Institute of Animal Science, Animal Nutrition Group, Agricultural University, Marijkeweg 40, 6709 PG Wageningen, The Netherlands NATIONALLICENCE 773 0- British Journal of Nutrition Cambridge University Press 79/6(1998-06), 519-525 0007-1145 79:6<519 1998 79 BJN CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge