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Glucose and lactate catabolism by bacteria of the pig large intestine and sheep rumen as assessed by 13 C nuclear magnetic resonance
Author(s) -
Stevani J.,
Grivet J.P.,
Hannequart G.,
Durand M.
Publication year - 1991
Publication title -
journal of applied bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 0021-8847
DOI - 10.1111/j.1365-2672.1991.tb03827.x
Subject(s) - rumen , propionate , hindgut , fermentation , biochemistry , bacteria , metabolism , catabolism , biology , clostridium , chemistry , botany , genetics , larva , midgut
J. STEVANI, J.P. GRIVET, G. HANNEQUART AND M. DURAND. 1991. The fermentation of [1‐ 13 C] glucose and [3‐ 13 C] lactate by bacteria isolated from sheep rumen and pig large intestine was compared by the nuclear magnetic resonance (NMR) technique. Washed cell suspensions were incubated directly in the NMR spectrometer and spectra were recorded every 10 min after injection of the labelled substrates. The results showed large differences in the fermentation patterns between rumen and hindgut bacteria. The latter pattern indicated a greater ability for formation and fermentation of lactate than that of the rumen. Moreover, with both substrates the amount of propionate formed via the acrylate pathway was always greater with hindgut than with rumen bacteria, 50% and 20% of the total, respectively. INTRODUCTION Dietary polysaccharides and oligosaccharides which are not digested by intestinal enzymes enter the large intestine (or hindgur) where they are fermented by the microflora. This anaerobic process is similar to that in the rumen (Miller & Wolin 1979; Bergman 1990) and leads to the formation of similar short chain fatty acids (SCFA) (one to seven carbon atoms). The microbial metabolism of the rumen ecosystem, which has been extensively studied is often taken as a model for hindgut bacterial metabolism. However, some discrepancies have been identified (Wolin & Miller 1983; Demeyer et al. 1989; Henderson & Demeyer 1989). They mainly concern interspecies transfer of hydrogen but also the biochemistry of propionate formation. As pointed out by Wolin & Miller (1983) the fermentative pathways of large intestinal microflora and especially the status of lactate as a possible fermentation intermediate are still uncertain. However, in humans it is considered that lactate may be an important intermediate of colonic bacteria particularly in the right colon in which fermentable carbohydrates are abundant or in in vitro cultures of starchy substances (G.T. Macfarlane, personal communication).