OBJECTIVE: The objective of the present work was to assess the nutritional impact of Saccharomyces cerevisiae cell wall fractions on some nutritional parameters in growing Wistar rats. METHODS: Yeast (Saccharomyces cerevisiae) biomass collected without undergoing thermolysis came from the mill São José, Zillo Lorenzetti (Macatuba, SP) in a suspension of approximately 20% p/v of cells. Fractionation of the cell wall material was done by differential extraction, centrifugation, and drying in "spray dryer". The importance of the yeast cell components as dietary fibers was assessed in recently weaned Wistar rats by measuring weight gain, diet consumption (28 days), diet efficiency ratio, apparent protein digestibility, total amount of feces and lipids and cholesterol excreted in feces. RESULTS: Rats which were submitted to diets containing glycan plus mannan gained less weight when compared with the other diets. The mannan-containing diet yielded the highest weight gain, followed by the standard AIN diet (S-AIN) and the insoluble glycan diet. Regarding diet efficiency ratio, the diet containing glycan plus mannan produced the lowest values throughout the 28 days. The highest apparent protein digestibility was obtained for the modified standard diet, for the standard AIN diet, as well as for the 10% mannan-containing diet (M). Total lipids and cholesterol excreted in the feces varied substantially among the diets. The diet containing 10% mannan was the one that promoted the greatest excretion of cholesterol. CONCLUSION: At the end of 28 days, the rats submitted to the glycan plus mannan-containing diets consumed less food and gained less body weight than those submitted to the other diets. Apparent digestibility of all diets was high, 98.6% on average. The amounts of total lipids and cholesterol excreted in the feces varied considerably; however, the mannan-containing diet promoted proportionally more cholesterol excretion than the other diets.
Mannans; Cell wall; Polysaccharides; Saccharomyces cerevisiae
