Influence of taste on dietary choice of rats fed amino acid imbalanced or deficient diets.

Diets with added quinine as the negative taste cue or saccharin as the positive taste cue were employed to determine the influence of taste on dietary choice of rats offered diets containing different proportions of amino acids (amino acid imbalance) and which differed in acceptability. The quinine was added to the protein-free or the corrected (corrected for amino acid imbalance) diet that animals normally preferred and the saccharine was added to the amino acid imbalanced or deficient diets that animals normally avoided. There appeared to be a balance in acceptance of a diet between the undesirability of the quinine and the degree of metabolic benefit from the diets with favorable metabolic or nutritional characteristics. Although the presence of higher levels of quinine could interfere with the normal dietary preference based on metabolic consequences, the animals invariably selected the metabolically favorable diet if they were forced to experience the metabolic characteristics of the diets by having to consume them exclusively. The presence of the taste cues appeared to enhance the acceptance or avoidance of diets in the choice regimens, possibly by aiding in their identification, especially to animals previously not exposed to the taste cues.