Effects of prenatal malnutrition on maternal behavior of the rat and behavioral development of the offspring

Crnic (1976) has pointed out that the behavioral results of miany studies involving early malnutrition have been confounded by disturbances in the maternal environment of the rat pup. Based on observations of maternal behavior reported by some investigators (Massaro et al., 1974; Seitz, 1954; Smart & Preece, 1973) it is clear that malnutrition during the lactation period results in observable changes in the maternal behavior of the rat. The major criticism of nutritional studies is that confounding variables which covary with the experimental variables are seldom controlled or even reported by the experimenter; this would include changes in (1) the amount of time the mother spends with the pups in the nest when litter size is increased (Grota & Ader, 1969) or food consumption by the mother is restricted (Simonson, Sherwin, Anilane, Yu, & Chow, 1969; Smart & Preece, 1973); (2) pup competition for milk when litter size is increased (Grota & Ader, 1979; Seitz, 1954), and (3) deficits in retrieval when the mother is restricted in the daily food consumption (Smart & Preece, 1973) or when protein content in the diet is restricted (Weiner, Fitzpatrick, Levin, Smotherman, & Levine, in press). At this point, it must be concluded that all methods for producing early malnutrition via the mother ultimately have an effect on the early maternal environment of the neonatal rat.