Hostname: page-component-78c5997874-m6dg7 Total loading time: 0 Render date: 2024-11-10T12:35:07.360Z Has data issue: false hasContentIssue false

The effect of lactulose, pectin, arabinogalactan and cellulose on the production of organic acids and metabolism of ammonia by intestinal bacteria in a faecal incubation system

Published online by Cambridge University Press:  09 March 2007

A. J. Vince
Affiliation:
Department of Medicine, The Rayne Institute, University College and Middlesex School of Medicine, University Street, London WCIE 6JJ
N. I. Mcneil
Affiliation:
Department of Medicine, The Rayne Institute, University College and Middlesex School of Medicine, University Street, London WCIE 6JJ
J. D. Wager
Affiliation:
Department of Medicine, The Rayne Institute, University College and Middlesex School of Medicine, University Street, London WCIE 6JJ
O. M. Wrong
Affiliation:
Department of Medicine, The Rayne Institute, University College and Middlesex School of Medicine, University Street, London WCIE 6JJ
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

An in vitro faecal incubation system was used to study the metabolism of complex carbohydrates by intestinal bacteria. Homogenates of human faeces were incubated anaerobically with added lactulose, pectin, the hemicellulose arabinogalactan, and cellulose, both before and after subjects had been pre-fed each carbohydrate. Fermentation of added substrate was assessed by the production of short-chain fatty acids (SCFA) and suppression of net ammonia generation over 48 h of incubation. Control faecal homogenates to which carbohydrate was not added yielded an average increment of SCFA of 43 mmol/l, equivalent to 172 mmol/kg in the original stool. The addition of lactulose, pectin and arabinogalactan each increased the yield of SCFA by a similar amount, averaging 6·5 mmol/g carbohydrate or 1·05 mol/mol hexose equivalent; organic acid yield was not increased by pre-feeding these substances for up to 2 weeks. Acetate was the major SCFA in all samples at all times and, after pre-feeding with extra carbohydrate, butyrate concentrations exceeded propionate in all samples. Faecal homogenates incubated with cellulose showed no greater SCFA production than controls over the first 48 h, but there was a slight increase when samples from two subjects pre-fed cellulose were incubated for 14 d. Net ammonia generation was markedly suppressed by addition of lactulose to faecal incubates with an initial period of net bacterial uptake of ammonia. Pectin and arabinogalactan also decreased ammonia generation, but the reductions were not significant unless subjects were pre-fed these materials; cellulose had no effect on ammonia generation.

Type
Carbohydrate Digestion by Colonic Microflora
Copyright
Copyright © The Nutrition Society 1990

References

REFERENCES

Alexander, F. (1952). Some functions of the large intestine of the horse. Quarterly Journal of Experimental Physiology 37, 205214.CrossRefGoogle ScholarPubMed
Bernhart, F.W., Gagliardi, E.D., Tomarelli, R.M. & Stribley, R.C. (1965). Lactulose in modified milk products for infant nutrition. Journal of Dairy Science 48, 399400.Google Scholar
Bingham, S., Cummings, J.H. & McNeil, N.I. (1979). Intake and sources of dietary fibre in the British population. American Journal of Clinical Nutrition 32, 13131319.CrossRefGoogle ScholarPubMed
Bowie, W.C. (1962). In vitro studies of rumen microorganisms, using a continuous-flow system. American Journal of Veterinary Research 23, 858867.Google Scholar
Bugaut, M. (1987). Occurrence, absorption and metabolism of short chain fatty acids in the digestive tract of mammals. Comparative Biochemistry and Physiology 86B, 439472.Google Scholar
Chadwick, V.S., Vince, A., Killingley, M. & Wrong, O.M. (1978). The metabolism of tartrate in man and the rat. Clinical Science and Molecular Medicine 54, 273281.Google Scholar
Cochrane, G.C. (1975). A review of the analysis of free fatty acids. Journal of Chromatographic Science 13, 440447.CrossRefGoogle Scholar
Collin, D.P. & McCormick, P.G. (1974). Determination of short-chain fatty acids in stool ultrafiltrate and urine. Clinical Chemistry 20, 11731180.Google Scholar
Conway, E.J. & Byrne, A. (1936). An absorption apparatus for the micro-determination of certain volatile substances. 1. The micro-determination of ammonia. Biochemical Journal 27, 419429.Google Scholar
Crossley, I.R. & Williams, R. (1984). Progress in the treatment of chronic portasystemic encephalopathy. Gut 25, 8598.Google Scholar
Cummings, J.H. (1981 a). Dietary fibre. British Medical Bulletin 37, 6570.CrossRefGoogle ScholarPubMed
Cummings, J.H. (1981 b). Short chain fatty acids in the human colon. Gut 25, 763779.CrossRefGoogle Scholar
Cummings, J.H., Pomare, E.W., Branch, W.J., Naylor, C.P.E. & MacFarlane, G.T. (1987). Short chain fatty acids in large intestine, portal, hepatic and venous blood. Gut 28, 12211227.CrossRefGoogle ScholarPubMed
Cummings, J.H., Southgate, D.A.T., Branch, W.J., Wiggins, G.S., Houston, H., Jenkins, D.J.A., Jivraj, T. & Hill, M.J. (1979). The digestion of pectin in the human gut and its effect on calcium absorption and large bowel function. British Journal of Nutrition 71, 477485.CrossRefGoogle Scholar
Elsden, S.R., Hitchcock, M.W.S., Marshall, R.A. & Phillipson, A.T. (1946). Volatile acid in the digesta of ruminants and other animals. Journal of Experimental Biology 22, 191202.CrossRefGoogle ScholarPubMed
Englyst, H.N., Hay, S. & MacFarlane, G.T. (1987). Polysaccharide breakdown by mixed populations of human faecal bacteria. FEMS Microbiology Ecology 45, 163171.CrossRefGoogle Scholar
Halliwell, G. & Bryant, M.P. (1963). The cellulolytic activity of pure strains of bacteria from the rumen of cattle. Journal of General Microbiology 32, 441448.CrossRefGoogle ScholarPubMed
Hentges, D.J. (1970). Enteric pathogen-normal flora interactions. American Journal of Clinical Nutrition 23, 14511456.Google Scholar
Hungate, R.E. (1966). The Rumen and its Microbes. New York: Academic Press.Google Scholar
Kelleher, J., Walters, M.P., Srinivasan, T.R., Hart, G., Findlay, J.M. & Losowsky, M.S. (1984). Degradation of cellulose within the gastrointestinal tract in man. Gut 25, 811815.CrossRefGoogle ScholarPubMed
McNeil, N.I. (1988). Nutritional implications of human and mammalian large intestinal function. In World Review of Nutrition and Dietetics, vol. 56, pp. 142 [Bourne, G.H., editor]. Basel: Karger.Google Scholar
McNeil, N.I., Cummings, J.H. & James, W.P.T. (1978). Short chain fatty acid absorption by the human large intestine. Gut 19, 819822.CrossRefGoogle ScholarPubMed
Miller, T.L. & Wolin, M.J. (1979). Fermentations by saccharolytic intestinal bacteria. American Journal of Clinical Nutrition 32, 164172.Google Scholar
Prynne, C.J. & Southgate, D.A.T. (1979). The effects of a supplement of dietary fibre on faecal excretion by human subjects. British Journal of Nutrition 41, 495503.CrossRefGoogle ScholarPubMed
Roediger, W.E.W. (1980). The colonic epithelium in ulcerative colitis: an energy-deficiency disease? Lancet ii, 712715.CrossRefGoogle ScholarPubMed
Roediger, W.E.W. (1982). Utilization of nutrients by isolated epithelial cells of the rat colon. Gastroenterology 83, 424429.Google Scholar
Rolfe, R.D. (1984). Interactions among microorganisms of the indigenous intestinal flora and their influence on the host. Reviews of Infectious Disease 6, 573579.CrossRefGoogle ScholarPubMed
Rubinstein, R., Howard, A.V. & Wrong, O.M. (1969). In-vivo dialysis of faeces as a method of stool analysis. IV. The organic anion component. Clinical Science 37, 549564.Google Scholar
Salyers, A.A. (1979). Energy sources of major intestinal fermentative anaerobes. American Journal of Clinical Nutrition 32, 158163.CrossRefGoogle ScholarPubMed
Sandberg, A.S., Ahderinne, R., Andersson, H., Hallgren, B. & Hulten, L. (1983). The effect of citrus pectin on the absorption of nutrients in the small intestine. Human Nutrition: Clinical Nutrition 37C, 171183.Google Scholar
Vince, A.J. (1986). Metabolism of ammonia, urea, and amino acids, and their significance in liver disease. In Microbial Metabolism in the Digestive Tract, pp. 83105, [Hill, M.J., editor]. Boca Raton, FL.: CRC Press.Google Scholar
Vince, A. & Burridge, S.M. (1980). Ammonia production by intestinal bacteria: the effects of lactose, lactulose and glucose. Journal of Medical Microbiology 13, 177191.Google Scholar
Vince, A., Dawson, A.M., Park, N. & O'Grady, F.W. (1973). Ammonia production by intestinal bacteria. Gut 14, 171177.Google Scholar
Vince, A., Down, P.J., Murison, J., Twigg, F.J. & Wrong, O.M. (1976). Generation of ammonia from non-urea sources in a faecal incubation system. Clinical Science and Molecular Medicine 51, 313322.Google Scholar
Vince, A., Killingley, M. & Wrong, O.M. (1978). Effect of lactulose on ammonia production in a fecal incubation system. Gastroenterology 74, 544549.CrossRefGoogle Scholar
Weber, F.L. (1981). The use of lactulose in the treatment of portal-systemic encephalopathy. In Nutritional Pharmacology pp. 217253 [Spiller, G.A., editor]. New York: Alan R. Liss.Google Scholar
Whitehead, J.S., Kim, J.S. & Prizont, R. (1976). A simple quantitative method to determine short chain fatty acid levels in biological fluids. Clinica Chimica Acta 72, 315318.Google Scholar
Wrong, O.M. (1988). Bacterial metabolism of protein and endogenous nitrogen compounds. In The Role of the Gut Flora in Toxicity and Cancer pp. 227262 [Rowland, I. R.editor] London: Academic Press.CrossRefGoogle Scholar
Wrong, O.M., Edmonds, C.J. & Chadwick, V.S. (1981). The Large Intestine: Its Role in Mammalian Nutrition and Homeostasis, p. 114. Lancaster: MTP Press Ltd.Google Scholar