The role of taste in dietary self-selection in rats.

Conducted 3 experiments with 78 male albino Harlan and Sprague-Dawley rats in which Ss were subjected to 2 degrees of gustatory deafferentation—either the chorda tympani was sectioned alone or in combination with the glossopharyngeal nerve and the pharyngeal branch of the vagus. Ss were then presented with 2 diets, only 1 of which contained protein. Findings reveal that, after surgery, deficits were observed in body weight, food and water intake, and diet selection that were proportional to the extent of deafferentation. Approximately 76% of the Ss increased protein and decreased carbohydrate intake, but all Ss continued to select a nutritionally balanced diet (Exp I). When subjected to a nutritional challenge of intragastric protein or carbohydrate supplementation, the Ss compensated for calories and nutrients by selectively adjusting oral intake (Exp II). In saccharin preference tests, the preference as well as the total consumption of the test solutions was reduced (Exp III). Results support the hypothesis that dietary selection pattern of an animal not only reflects intrinsic factors (metabolic/physiological state) but also extrinsic factors such as the pallatability and accessibility of the diet. Findings are contrasted to the effects of oral somatosensory deafferentation and are interpreted as a change in preference within the limits of metabolic requirements. The different roles/mechanisms of the 2 sensory systems in regard to dietary self-selection are discussed. (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)