PRENATAL PROTEIN-MALNUTRITION AFFECTS THE SOCIAL INTERACTIONS OF JUVENILE RATS

The effects of prenatal protein malnutrition on juvenile social behavi or was investigated in male and female rats. Animals were provided wit h 25% (control) or 6% (low protein) casein diets before and during pre gnancy. After birth eight pups in each litter (six males and two femal es) were fostered to lactating control mothers. After weaning (21 days of age) all animals received a lab chow diet until behavioral testing began at 45 days of age. To assess social interaction, pairs of rats of the same gender, consisting of one malnourished and one control rat , were placed in a familiar rectangular arena on 3 consecutive days. P layful social behavior (pin), nonplayful social behaviors (anogenital sniff, walk-over, side-mount, and allogroom), and nonsocial behavior ( rear) were recorded in 10-min sessions. Prenatal malnutrition signific antly decreased both playful and nonplayful social behaviors, and incr eased nonsocial rearing. No significant gender differences were observ ed. The finding that early social behavior is altered by prenatal maln utrition opens the possibility that such changes may play an important role in determining some of the later behavioral differences describe d in the adult animal.