Taste- and flavor-guided behaviors following Roux-en-Y gastric bypass in rodent models

Roux-en-Y gastric bypass (RYGB) surgery is one of the most efficacious treatments for obesity, but the behavioral and physiological mechanisms through which it enacts its effects are not completely understood. The weight loss that follows RYGB surgery is due to some extent to decreased caloric intake. The perception of flavor and the sense of taste undoubtedly contribute to ingestion, and changes in taste sensation and flavor perception may, even in part, propel the altered feeding seen after RYGB surgery. Measuring observable behavior in non-human animal models of RYGB surgery is an objective way by which to evaluate underlying mechanism, including the influence of flavor and taste to intake changes after RYGB surgery, as well as the interaction of flavor and taste with post-oral consequences and learning phenomena. Collectively, the data in rodent models support the conclusion that neither palatability nor motivational potency are reduced following RYGB surgery. Indeed, rats still typically show preference for sweet and fatty solids and liquids, and positive flavor-guided hedonic responses for these substances remain stable in some tests. However, preference for these foods and fluids is reduced, and flavor-guided behaviors after long-term tests are reorganized. These patterns suggest that, while rats are still motivated to consume sweet and fatty consumables and find them palatable, they learn to limit their intake of them to avoid undesirable post-oral consequences. Examination of these interactions and elucidating their physiologic correlates may maximize the efficacy of RYGB surgery and/or promote the development of alternative or supplemental treatments.