Developmental binge exposure to ethanol and artificial rearing do not affect the social transfer of diet preference

A previous study reported no effect of binge exposure to ethanol during the brain growth spurt on the social acquisition of enhanced diet preference in male rats. The objective of this study was to replicate this finding by using the artificial rearing technique and to investigate whether delay-dependent mnemonic deficits previously observed in the water maze would extend to social memory of diet preference. We also addressed whether this naturalistic behavior was dependent on the presentation of diet odor in the context of a rat-produced component in ethanol-exposed rats, as it is in normal controls.

Male rat pups were reared artificially from postnatal days 5 to 18, during which (postnatal days 6-9) they were fed either 6.5 g/kg/day of ethanol in a binge model or an isocaloric maltose-dextrin solution (gastrostomy controls). A third suckled control group was reared normally. These test rats were allowed to interact with conspecifics that had previously consumed a distinctive diet, X. Subsequently, the experimental rats were provided a choice between two novel diets, one of which was X, after delays of 0 hr (experiment 1), 24 hr, and 4 weeks (experiment 2). In experiment 3, the rats were again given the two-choice preference test, but after exposure to the diet odor alone.

All groups demonstrated a significant preference for the socially cued diet in experiments 1 and 2, and the strength of this inclination remained consistent across the 0-hr, 24-hr, and 4-week retention intervals. Moreover, all groups demonstrated sensitivity to the social context of this task, as shown by a lesser preference for the diet exposed alone in experiment 3.

Intact performance on the ethologically meaningful diet-preference test supports specificity in the cognitive/behavioral effects of developmental exposure to ethanol. Interestingly, early isolation, as experienced in the artificial-rearing procedure, also did not impair performance on this social task.