Effects of dietary amino acid pattern on food preference behavior of rats.

Abstract

Rats offered a diet in which there is an imbalance of amino acids together with a protein-free diet eat very little of the imbalanced diet; however, when rats that were selecting the protein-free diet were fed a single meal (1-3 gm.) of a diet in which the imbalance was corrected, their preference was reversed, but only temporarily. As the sensory properties of the imbalanced and corrected diets are very similar, this suggests that (a) the rat associates a beneficial effect with ingestion of the corrected diet; (b) it does not immediately thereafter recognize the imbalanced diet as a novel diet; (c) subsequently, ingestion of the imbalanced diet is associated with an undesirable effect and aversion to the imbalanced diet again develops.

Disruption of appetite but not hunger or satiety following small lesions in the amygdala of rats.

“…Essential amino acids, those which the body cannot synthesize, need to be consumed in a particular dietary balance peculiar to each species. When a rat is confronted with a diet that is imbalanced in one essential amino acid relative to the others, it will (a) refuse to consume a substantial portion of the diet, eating only enough calories for body maintenance or (b) show preference for a protein-free diet over the imbalanced diet when given a choice (Harper et al, 1970;Zahler & Harper, 1972). This behavior has been likened to conditioned taste aversion (Zahler & Harper, 1972).…”

Neurochemistry of appetite mechanisms

“…Leung, Rogers & Harper (1968), Booth 8z Simson (1971) and Zahler & Harper (1972) have shown that, in at least some instances, the rats acquire a dislike for whatever distinctive sensory characteristics the deficient diet possesses. Some effect of absorbing the deficient amino acid mixture conditions an aversion to the correlated food cues.…”