Abstract
The aim of the present study was to compare the effects of five different dietary monosaccharides on mineral and nitrogen utilization in female rats. The experimental diets contained 9.2% (w/w) of either glucose, xylose, arabinose, galacturonic acid or galactose. A restricted amount of feed was administered daily. After 21 days on the diets, urine and feces were collected separately and quantitatively for 7 days. Urine and feces were analysed for nitrogen, calcium, phosphorus and magnesium and the balances were calculated. Substantial fractions of the ingested xylose, arabinose and galactose groups were recovered in urine. There was no differential effect of the monosaccharides on body-weight gain and carcass composition. Apparent nitrogen absorption was reduced by the feeding of either xylose, arabinose or galacturonic acid when compared with glucose. Dietary galactose did not affect apparent nitrogen absorption. The lowering effect of xylose, arabinose and galacturonic acid may be explained by enhanced bacterial fermentation and increased fecal excretion of bacterial protein. The apparent absorption of magnesium was stimulated by the feeding of xylose, arabinose, galacturonic acid and galactose, when compared with glucose. Apparent calcium absorption was enhanced by xylose only and phosphorus absorption was raised by galacturonic acid only. The diet containing galacturonic acid produced a significant increase in kidney concentrations of calcium when compared with the glucose diet. This study shows that the feeding of xylose, arabinose, galacturonic acid or galactose did not influence body-weight gain and carcass composition, but there were different sugar type effects on apparent nitrogen absorption and mineral metabolism.