Glucose and lactate catabolism by bacteria of the pig large intestine and sheep rumen as assessed by ¹³C nuclear magnetic resonance

Abstract

The fermentation of [1-13C] glucose and [3-13C]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.

Lactate is mainly fermented to butyrate by human intestinal microfloras but inter-individual variation is evident

“…Our finding that lactate is a precursor for butyrate synthesis is in marked contrast to the findings of those few studies available that are dedicated to lactate metabolism by the intestinal microflora of monogastrics. These have identified propionate and, to a lesser extent, acetate as the major end‐products of lactate metabolism (Stevani et al. 1991; Hove and Mortensen 1995; Ushida et al.…”

“…However, the present work differs fundamentally from these previous studies. First, the intestinal microfloras investigated by Stevani et al. (1991) and by Ushida et al.…”

“…A third probable cause of discrepancy is the pH value at which the incubations were performed. Working pH values were initially set at 6·5, 6·8 and 7·8 by Stevani et al. (1991), Ushida et al.…”

“…However, the present work differs fundamentally from these previous studies. First, the intestinal microfloras investigated by Stevani et al (1991) and by Ushida et al (2002) were isolated from pigs. Secondly, our study differed with respect to the composition of the incubation media.…”

Raw potato starch and short-chain fructo-oligosaccharides affect the composition and metabolic activity of rat intestinal microbiota differently depending on the caecocolonic segment involved

“…Bacteroides sp. ), is inducible by an excess of highly fermentable carbohydrates (Stevani et al 1991). Moreover, it sustains the idea that the role of LAPB in starch fermentation is limited to the initial stage of substrate depolymerization (Sharp and Macfarlane 2000).…”