Effect of feeding amaranth (food red no. 2) on the jejunal sucrase and digestion-absorption capacity of the jejunum in rats.

To clarify the effect of feeding 5% amaranth (Food Red No. 2, Am) alone or with 5% dietary fiber on jejunal mucosal integrity, change in jejunal sucrase activity before and after the feeding was compared between rats fed and fasted previously. Digestion-absorption capacity of the jejunum was also examined by perfusing 15 mmol/liter sucrose and 30 mmol/liter glycylglycine through the anesthetized rat jejunum after 14 days of feeding Am. Gobo dietary fiber (GDF) was prepared from the roots of edible burdock (Arctium lappa L.). At the end of 3 days' fasting, rats had 20% less body weight, 30% less mucosal protein and 50% less jejunal sucrase activity per unit length than those before fasting. Although rats fed Am showed severe diarrhea and growth retardation as observed in previous reports, initial sucrase level was not changed by feeding Am for 3 days even in the fasted rats. When sucrase activity on day 3 after feeding was compared among inter-groups, however, rats fed Am showed sucrase activity lower than that of rats fed either the basal diet or the basal diet containing Am plus GDF only when they had been fasted previously. After 14 days of feeding, rats fed Am after 3 days' fasting regained sucrase activity up to that of rats fed the basal diet despite the remarkable growth retardation. Jejunal perfusion in situ showed that digestion-absorption capacity for sucrose and glycylglycine in rats fed 5% Am for 14 days was also the same as that in rats fed the basal diet. These results suggest that feeding Am can reduce neither jejunal sucrase nor digestion-absorption capacity of epithelial cells of the jejunum, but retards the regain of the lowered sucrase level at earlier stage of feeding when rats have been fasted before the feeding, and that concurrent feeding of GDF promotes catch-up of the sucrase level lowered by the fasting.