Fiber type, meal frequency and colonic cytokinetics

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to digital@library.tamu.edu, referencing the URI of the item.Includes bibliographical references.The effects of dietary fiber type (cellulose, pectin or oat bran) and meal frequency (gorge or nibble) on colonic short chain fatty acids (SCFAs), in vivo colonic pH and epithelial cell proliferation were examined in male Sprague-Dawley rats. In vivo cell proliferation was measured by [3H]-thymidine incorporation into DNA. Luminal SCFAs were determined by gas chromatography. ber t e. The pectin and oat bran diets produced higher concentrations of all types of SCFAs and of total SCFA than did the cellulose diet at all sites. The higher the concentration of total SCFA in colonic contents, the lower the pH in cecum, proximal and distal colon (r=- O.92, -0.97, -0.88; p=0.01, 0.001, 0.02 respectively). Dry fecal weights were lowest with pectin supplementation and the highest with cellulose. The oat bran diet resulted in an intermediate fecal weight. There were significant negative correlations between pH and crypt height (HC) (r=-O.833, p=0.04); total cells per crypt (TC) (r=-O.817, p=0.05); labeling index (LI) (r=-O.926, p=0.008); and proliferation zone (PZ) (r=-O.981, p=0.0005) in the cecum. There were significant positive correlations between the concentration of total SCFA and HC, TC and PZ (r=0.961, 0.963, 0.845; p=0.01, 0.002, 0.03) in the cecum. No correlation was found between pH or SCFA and cell proliferation in the distal colon, although there were effects of fiber type on H(@, LI and PZ (p=0.03, 0.03, 0.07). The pectin diet produced a higher HC, TC, and PZ in the cecum and LI in the distal colon than did the cellulose diet (p < 0. 05). The oat bran diet resulted in higher HC, TC, LI and PZ than the cellulose diet in the cecum., but lower LI and PZ and higher HC than the pectin diet in the distal colon (p<0.05). Meal frequency. Effect of meal pattern was observed on HC and TC (p=0.0003, 0.0086) in the distal colon. HC and TC were larger in the gorging group than in the nibbling group (p < 0. 05). The results indicate that dietary fiber type affects the concentrations of SCFAS, pH, and cell proliferation throughout the large intestine; that effects of pH and concentrations of SCFAs on cell proliferation are found predominately in the cecum. Fecal bulking ability of the fibers may play a role in distal colonic cell proliferation. The data show that meal frequency affects cell proliferation in the distal colon only