title: Increased luminal mucin does not disturb glucose or ovalbumin absorption in rats fed insoluble dietary fiber.
abstract: We tested whether increased mucin secretion due to ingestion of insoluble dietary fiber (IDF) affects small intestinal nutrient absorption in rats. Polystyrene foam (PSF) with a true expansion ratio of 54.9 was used as a model for IDF with high bulk-forming properties. In Expt. 1, rats were fed a control diet or diet containing 50 g PSF/kg for 1, 3, 5, or 7 d. Small intestinal mucin fractions were isolated, and O-linked oligosaccharide chains were measured. The luminal mucin content reached a maximum within 5 d after PSF ingestion. In Expt. 2, rats were fed a control diet or diet containing 50 g PSF/kg for 7 d, and then all rats were switched to the control diet for 1, 3, or 5 d. The increased capacity for luminal mucin secretion disappeared within 5 d after ceasing PSF ingestion. In Expt. 3, rats were fed a control diet or diet containing 70 g PSF/kg for 7 d. Glucose (1g/kg) was administered orally after 12 h of food deprivation. The blood glucose concentrations did not differ between the groups. In Expt. 4, rats were fed a control diet or diet containing 90 g PSF/kg for 14 d. At d 7, portal cannulae were installed. A mixed solution of glucose (1g/kg) and ovalbumin (OVA, 250 mg/kg) was orally administered after 12 h of food deprivation, and responses of portal glucose and OVA concentrations were monitored for 120 min. Although luminal mucin contents were almost doubled in the 9% PSF group compared with the control group, neither portal glucose nor OVA concentration differed at any time point. The results suggest that the short-term ingestion of IDF significantly increases the luminal mucin content, but that this does not disturb nutrient absorption.
authors.affiliation: Faculty of Nutritional Sciences, University of Shizuoka, Yada 52-1, Shizuoka 422-8526, Japan. actmori@agr.shizuoka.ac.jp
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Morita
authors.forename: Hiroki
authors.initials: H
authors.lastname: Tanabe
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ito
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Yuto
authors.forename: Takeshi
authors.initials: T
authors.lastname: Matsubara
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Matsuda
authors.forename: Kimio
authors.initials: K
authors.lastname: Sugiyama
authors.forename: Shuhachi
authors.initials: S
authors.lastname: Kiriyama
mesh_terms: D000818:Animals; D002236:Carbohydrate Conformation; D004043:Dietary Fiber / Q000008:administration & dosage*; D004591:Electrophoresis, Polyacrylamide Gel; D005508:Food Deprivation; D005947:Glucose / Q000008:administration & dosage / Q000493:pharmacokinetics*; D005951:Glucose Tolerance Test; D007408:Intestinal Absorption / Q000502:physiology*; D007421:Intestine, Small / Q000378:metabolism; D008297:Male; D009077:Mucins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D009844:Oligosaccharides / Q000032:analysis / Q000737:chemistry; D010047:Ovalbumin / Q000008:administration & dosage / Q000493:pharmacokinetics*; D011137:Polystyrenes; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D012995:Solubility
chemical_list: D004043:Dietary Fiber; D009077:Mucins; D009844:Oligosaccharides; D011137:Polystyrenes; D010047:Ovalbumin; D005947:Glucose