Arabinoxylan fiber from a by-product of wheat flour processing behaves physiologically like a soluble, fermentable fiber in the large bowel of rats.
Arabinoxylan is a major dietary fiber component of many cereals. Its physiological effects in the colon are largely unknown. This study examined the effects of an arabinoxylan-rich fiber (AX) extracted from a by-product of wheat flour processing in the rat colon compared with well-characterized soluble/rapidly fermentable and insoluble/slowly fermentable fibers. Rats were fed diets containing no fiber (NF) or 100 g/kg of total dietary fiber from AX, guar gum (GG) or wheat bran (WB) for 4 wk. Cecal mass and short-chain fatty acid (SCFA) pool were significantly higher while pH was significantly lower in the fiber-supplemented groups, particularly in the AX and GG groups. The pattern of SCFA production in the cecum was altered; AX fiber was a good source for acetate while GG and WB favored propionate and butyrate production, respectively. Fecal output was 7-, 6- and 5-fold higher, respectively, in the AX, GG and WB than in the NF groups (P < 0.01). All epithelial proliferation indices (crypt column height, number of mitotic cells/crypt column and mitotic index) differed significantly across the groups in a descending order of AX > GG > WB > NF. Distal mucosal dipeptidyl peptidase IV activities, which indicate cell differentiation status, were significantly lower in fiber-supplemented groups than in the NF groups. Distal mucosal alkaline phosphatase activities, induced as a response to injury or stress, were significantly higher for the AX and GG groups than for the NF or WB groups (P < 0.001). These results indicate that AX fiber behaves like a rapidly fermentable, soluble fiber in the rat colon.
Center for Population Health and Nutrition, Monash University, Clayton, Victoria, Australia.
Z X
ZX
Lu
P R
PR
Gibson
J G
JG
Muir
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M
Fielding
K
K
O'Dea
D000818:Animals; D001835:Body Weight; D002455:Cell Division; D003106:Colon / Q000378:metabolism; D004043:Dietary Fiber / Q000378:metabolism*; D002149:Energy Intake; D005243:Feces; D005285:Fermentation; D005433:Flour; D005511:Food Handling; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism; D007420:Intestine, Large / Q000378:metabolism*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012995:Solubility; D014908:Triticum / Q000737:chemistry*; D014990:Xylans / Q000378:metabolism*
D004043:Dietary Fiber; D014990:Xylans; C085118:arabinoxylan