Flavor preferences conditioned in C57BL/6 mice by intragastric carbohydrate self-infusion

This study determined the feasibility of conditioning flavor preferences in mice by self-administered intragastric (IG) nutrient infusions. Male C57BL/6J mice were surgically fitted with an IG catheter that was attached by a tether system to an infusion pump. The mice were given ad-libitum access to chow and a flavored solution 23 h/day. Drinking was monitored with a computerized lickometer system that controlled the infusion pumps. In Experiment 1, drinking one flavored solution (CS+, e.g., grape-saccharin) was paired with matched infusions of 8% maltodextrin, whereas drinking another solution (CS-, e.g., cherry-saccharin) was matched with water infusions across 6 one-bottle training days. During training, the mice drank more CS+ than CS-; this was due to an increase in bout size but not bout frequency. In subsequent two-bottle choice tests, the mice strongly preferred (91%) the CS+ to the CS-. Experiment 2 obtained a significant but less robust (71%) CS+ preference in mice trained with unsweetened CS solutions. These data indicate that mice, like rats, acquire an increased acceptance and preference for flavors paired with the postingestive actions of nutrients. Our understanding of flavor-nutrient learning can be advanced by studying this process in selected mouse strains and genetically modified animals. (C) 2003 Elsevier Inc. All rights reserved.