CARBOHYDRATE, FAT, AND PROTEIN CONDITION SIMILAR FLAVOR PREFERENCES IN RATS USING AN ORAL-DELAY PROCEDURE

Flavor preferences conditioned by carbohydrate (Polycose), protein (ca sein hydrolysate), and fat (corn oil) were compared using an oral-dela y training method. In Experiment 1 separate groups of food deprived ra ts were trained to associate a CS+ flavor (e.g., grape-saccharin) with the delayed (10 min) presentation of isocaloric carbohydrate, protein , or fat sources. A CS- flavor (e.g., cherry-saccharin) was paired wit h the delayed presentation of an unflavored saccharin solution. In sub sequent two-bottle tests the carbohydrate, protein, and fat trained gr oups displayed significant preferences for the CS+ over the CS-. In Ex periment 2 each rat was trained to associate two new flavors with two of the three nutrients (e.g., orange with carbohydrate, and strawberry with protein). In subsequent two-bottle tests the rats equally prefer red the two nutrient-paired flavors. Experiment 3 compared the prefere nces for the new CS+ flavors vs. the original CS- flavor. The rats dis played similar preferences for carbohydrate-, protein- and fat-paired CS+ over the CS-. The similar preferences obtained with the three diff erent nutrients support the view that preference conditioning is media ted by the nutrients' caloric value. Other studies suggest, however, t hat nutrient specific signals are also involved in the conditioning pr ocess.