AVERSION-PREFERENCE PATTERNS IN AMINO ACID-DEFICIENT OR PROTEIN-DEFICIENT RATS - A COMPARISON WITH PREVIOUSLY REPORTED RESPONSES TO THIAMIN-DEFICIENT DIETS

The purpose of the present experiments was to extend previous data on the strategy used by adult rats to select feed appropriately when face d with diets devoid of protein or an essential amino acid (EAA), and t o compare this strategy with that used when facing vitamin (thiamin) d eficiency. Rats fed on either balanced or deficient (EAA or protein) d iets were offered a choice between a novel deficient and a familiar (d eficient or corrected) diet and their choice was monitored. It was sho wn that protein- and EAA-deficient rats acquired an aversion for their corresponding familiar devoid diet, which by itself promoted a neophi lia for the novel diet. This neophilia was not non-specific because pr otein-deficient rats facing a choice between a protein-devoid and an E AA-devoid diet did exhibit neophilia but only in the short term (less than 5 h), and then switched to a preference for the familiar protein- devoid diet. These results show that, in contrast to the case of vitam in deficiency, the protein- or EAA-devoid diet-induced neophilia can b e rapidly reversed if the novel feed happens to be more deleterious th an the familiar, inappropriate one. This behaviour suggests the existe nce of sensitive mechanisms able to reveal within a short time the EAA inadequacy of the ingested feed and to adapt the choice for the most appropriate feeds more promptly than in the face of thiamin deficiency . Thus it appears that balancing EAA is more urgent than balancing thi amin.