Comparison of the nutritional effects of fructo-oligosaccharides of different sugar chain length in rats

The influence of fructo-oligosaccharides of different sugar chain length on growth. nitrogen balance, and mineral balance was examined in rats fed diets containing either sucrose, l-kestose, nystose, or a mixture of these at 50 or 100 g/kg of diet. Rats were fed the experimental diets for six weeks, and nitrogen balance and mineral (Ca and Mg) balance were examined after the second and fourth week. Food intake and body weight gain did not differ significantly among the groups. Each fructo-oligosaccharide fed was found to increase Ca and Mg absorption dose-dependently during the first balance study period and the degrees of increase in Ca and Mg absorption were similar with each fructo-oligosaccharide fed regardless of the level present in the experimental diet. Also. each of the fructooligosaccharides was found to increase fecal excretion of nitrogen, but there was no clear dose-dependence and the extent of increase in fecal excretion of nitrogen was similar for each fructo-oligosaccharide fed. In conclusion, our findings demonstrate that ingestion of fructo-oligosaccharides leads to increases in Ca and Mg absorption and an increase in fecal excretion of nitrogen. however, differences in sugar chain length do not influence their nutritional effects considerably in rats. (C) 1998 Elsevier Science Inc.