Behavioral specificity of effects of 2-mercaptoacetate on independent ingestion in developing rats

Blockade of fatty acid oxidation in rat pups using 2-Mercaptoacetate (MA) produces increases in independent ingestion by 12 days of age. In the present experiments, the behavioral specificity of the effects of MA on ingestion were examined. In the first experiment, administration of MA to pups aged 9 and 12 days of age failed to increase intake of an oral infusion of a milk diet. In the second experiment, administration of MA did enhance intake of a milk diet in a short-term test of consuming from the floor of a test container and the level of gastric fill appeared to determine intake during the test. Finally, administration of MA did not affect intake of water in 9- or 12-day-old pups. These results suggest that MA produces increases in intake through specific effects on selective ingestive responses and not through nonspecific behavioral arousal.