[Gastric emptying of sugar solutions and cow's milk with and without carbohydrates in adult rats].

In this study, we determined the gastric retentions in rats of aqueous solutions or cow's milk containing different compositions of sugars. The following meals were tested: 1. aqueous solutions containing one sugar at 10% (lactose, sucrose or maltose), or 2. containing a combinations of two sugars (lactose + sucrose, lactose + maltose, sucrose + maltose), 3. cow's milk alone, or 4. containing one of the above sugar at 5%. Wistar male rats received a test meal (2 mL/100 g weight) with a marker: phenol red (6 mg/dL) in the sugars aqueous solutions ant polyethyleneglycol (PEG) 4000 (2 g/dL) in the cow's milk test meal. The gastric retention was measured by determining the amount of the marker remaining in the stomach by spectrophotometry. The results show larger gastric retention of maltose solutions, alone or in association with other sugar, than the lactose or sucrose ones. There was no difference between gastric retentions of cow's milk without sugar and those with addition of sucrose 5% or maltose 5%, 15 minutes after the administration of test meal. Nevertheless, 30 minutes later the administration, the gastric retention of whole cow's milk plus maltose 5% was larger than that of cow's milk without additional sugar. At the time of 45 minutes, the gastric retention of cow's milk plus sucrose 5% was larger than that of cow's milk without additional sugar. In conclusion the gastric emptying of maltose in aqueous or milk solution is smaller than those of lactose or sucrose in solutions at the same energetic density. Yet, this effect is seen even when the maltose is associated with one of the other two disaccharide in the same solution.