Early protein malnutrition in the rat: behavioral changes during rehabilitation.

Behavioral development was studied in 2 groups of rats during the postweaning period. Pups were selected from litters nursed by dams fed either a standard protein (25% casein by weight) or a low protein diet (12% casein) during lactation. Two pups from each litter were housed together and fed the control diet throughout rehabilitation. Behavioral observations were made by repeated time-lapse photography at 5-day intervals. Differences in home cage behavior were observed at the onset of rehabilitation in the postnatally malnourished rats. Increased feeding behavior was observed during the 1st week of rehabilitation. Locomotor behavior was depressed during the rehabilitation period in the experimental animals. Climbing activity, however, was significantly greater. Self-grooming activity was elevated throughout rehabilitation in post-natally malnourished animals. During the course of rehabilitation, the behavioral differences between the 2 groups gradually disappeared.