Insoluble dietary fiber of wheat bran increased viscosity of pig whole cecal contents in vitro

Viscosity of whole pig cecal contents with (2 g/200 mL) or without insoluble dietary fibers prepared from wheat bran of two particle sizes (WB fine 0.22 +/- 0.22 min(2), n= 1, 723; WB coarse 0.51 +/- 1.12 min(2), n=1,457, mean +/- SD) was measured using a rotary viscometer equipped with a vane spindle at the shear rates of 0.05, 0.16, 0.47, 0.78 and 1.56 (s(-1)) and at 0 and 2 h. Such measurements were repeated twice each for five different donor pig groups. We were able to measure the coefficient of viscosity of such samples over a wide range of shear rate. Coefficient of viscosity depended on shear rate. Addition of insoluble dietary fiber increased the coefficient of viscosity. Insoluble dietary fiber from WB coarse had a significantly stronger effect than that from WB fine. The above results demonstrated that insoluble dietary fibers of wheat bran increase the viscosity of gut contents, and thereby potentially retard digestion and absorption.