[The effect of soy polysaccharide fiber on fecal weight and humidity in growing rats].

OBJECTIVE To compare the effect of soy polysaccharide on fecal weight and humidity in growing rats in relation to cellulose and a Soy formula without dietary fiber. METHODS Twelve, 21-day-old, Wistar male rats, were distributed into three groups and fed AIN-93G ration with varying amounts of dietary fiber: Polysaccharide Group, 5% fiber in the form of soy polysaccharide; Soy Formula Group, 5% soy formula without fiber; and Cellulose Group, 5% fiber in cellulose form. Feces were collected for three 72-hour periods beginning on days 7, 17 and 27. They were weighed while humid and then dried at 105 degrees C until a constant weight. The humidity was calculated using the formula [(humid fecal weight - dry fecal weight)/humid fecal weight] X 100. RESULTS The total humid fecal weight for Polysaccharide, Soy Formula and Cellulose groups was: 17.372-/+4.743 g; 6.045-/+0.619 g; and 16.012-/+2.600 g, (p = 0.001), respectively. There was no statistically significant difference between the Cellulose and Polysaccharide groups, but a statistically significant difference was observed between theses two groups and the soy formula group. Values for dry weight, in the same order, were: 6.463-/+1.177 g; 2.909-/+0.277 g; and 10.068-/+1.085 g, (p < 0.001), with a statistically significant difference between each of the groups. CONCLUSION Animals that received soy formula presented lower humid and dried fecal weight than the other two groups, while the soy polysaccharide caused higher fecal humidity than did cellulose, probably due to greater fermentation.