title: Effect of polydextrose on intestinal microbes and immune functions in pigs.
abstract: Dietary fibre has been proposed to decrease risk for colon cancer by altering the composition of intestinal microbes or their activity. In the present study, the changes in intestinal microbiota and its activity, and immunological characteristics, such as cyclo-oxygenase (COX)-2 gene expression in mucosa, in pigs fed with a high-energy-density diet, with and without supplementation of a soluble fibre (polydextrose; PDX) (30 g/d) were assessed in different intestinal compartments. PDX was gradually fermented throughout the intestine, and was still present in the distal colon. Irrespective of the diet throughout the intestine, of the four microbial groups determined by fluorescent in situ hybridisation, lactobacilli were found to be dominating, followed by clostridia and Bacteroides. Bifidobacteria represented a minority of the total intestinal microbiota. The numbers of bacteria increased approximately ten-fold from the distal small intestine to the distal colon. Concomitantly, also concentrations of SCFA and biogenic amines increased in the large intestine. In contrast, concentrations of luminal IgA decreased distally but the expression of mucosal COX-2 had a tendency to increase in the mucosa towards the distal colon. Addition of PDX to the diet significantly changed the fermentation endproducts, especially in the distal colon, whereas effects on bacterial composition were rather minor. There was a reduction in concentrations of SCFA and tryptamine, and an increase in concentrations of spermidine in the colon upon PDX supplementation. Furthermore, PDX tended to decrease the expression of mucosal COX-2, therefore possibly reducing the risk of developing colon cancer-promoting conditions in the distal intestine.
authors: Food Microbial Sciences Unit, School of Food Biosciences, University of Reading, Reading, UK.
authors: Francesca
authors: F
authors: Fava
authors: Harri
authors: H
authors: Mäkivuokko
authors: Hilkka
authors: H
authors: Siljander-Rasi
authors: Heli
authors: H
authors: Putaala
authors: Kirsti
authors: K
authors: Tiihonen
authors: Julian
authors: J
authors: Stowell
authors: Kieran
authors: K
authors: Tuohy
authors: Glenn
authors: G
authors: Gibson
authors: Nina
authors: N
authors: Rautonen
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000032:analysis; D002432:Cecum / Q000276:immunology / Q000382:microbiology; D003106:Colon / Q000276:immunology / Q000382:microbiology; D051545:Cyclooxygenase 1 / Q000235:genetics; D051546:Cyclooxygenase 2 / Q000235:genetics; D004043:Dietary Fiber / Q000008:administration & dosage* / Q000032:analysis; D019587:Dietary Supplements; D002149:Energy Intake / Q000276:immunology; D005232:Fatty Acids, Volatile / Q000032:analysis; D005260:Female; D005503:Food Additives / Q000008:administration & dosage* / Q000032:analysis; D015870:Gene Expression / Q000235:genetics; D005936:Glucans / Q000008:administration & dosage* / Q000032:analysis; D007070:Immunoglobulin A / Q000032:analysis; D007413:Intestinal Mucosa / Q000276:immunology; D007421:Intestine, Small / Q000276:immunology / Q000382:microbiology; D007422:Intestines / Q000276:immunology / Q000382:microbiology*; D008297:Male; D013552:Swine
chemical_list: D015415:Biomarkers; D004043:Dietary Fiber; D005232:Fatty Acids, Volatile; D005503:Food Additives; D005936:Glucans; D007070:Immunoglobulin A; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C033375:polydextrose