ENERGY-UTILIZATION OF DIETARY SORBOSE IN GROWING RATS

The energy value of L-sorbose in rats was estimated. Sorbose was shown to be stable under incubation with 0.05 M hydrochloric acid (pH about 1.3, 37-degrees-C, 120 min). The in vitro absorption rate of sorbose was lower than that of glucose. When C-14-labeled sorbose was injected intravenously (6.0 mg/100 g of body weight), about 50% was excreted in urine and about 30% was expired as CO2 in 24 h. C-14-Labeled sorbose or C-14-labeled glucose was orally administered (20 mg/100 g of body weight) to rats fed diets with or without antibiotics. The recovery of (CO2)-C-14 in glucose-administered rats was significantly higher than that of (CO2)-C-14 in sorbose-administered rats with or without antibiotics. The recovery of expired (CO2)-C-14 in rats without antibiotics was significantly higher than that of the corresponding antibiotics-treated group. Large amounts of sorbose were recovered in urine (16-19%) and feces (9-16%). The remainder which was not recovered in radioactivity after labeled sorbose doses would provide its full energy, so that available energy of sorbose for the rat could be calculated as about 1.3-2.2 kcal/g.