Alternations in the maternal behavior of rats rearing malnourished offspring

Abstract

Investigations of maternal behavior of mothers fed a low-protein diet indicated deficits in retrieval and in the rate of nest-building. In addition, they indicated a concomitant increase in time spent with young when assessed during periods not associated with the retrieval/nest-building test session. The adrenalectomized mother, another case that produces growth-stunted progeny, was compared with both low-protein and control mothers for maternal behavior. Unlike the low-protein mother, the adrenalectomized mother did not exhibit retrieval or nest-building deficits; however, the adrenalectomized mother did display an increase in time spent with young. These data suggest that although deficits in retrieval and nest-building can be attributed to the nutritional condition of the mother, the stimulus characteristics of the malnourished pup are important in eliciting the increased time spent with the litter.

Effect of neonatal dexamethasone exposure on growth and neurological development in the adult rat

“…One possible explanation for the decreased somatic growth observed in the dexamethasone-treated pups is inadequate nutritional intake during the postnatal period due to inability to attach to the mother's nipples or poor suckling. Although we did not quantify these behaviors, it has been shown that the dam spends more time providing nutrition, stimulation, and warmth to a litter that is perceived to have poor health (15,65,91,101). On the other hand, dexamethasone prevents adequate growth, rapidly inducing protein catabolism beyond the capacity for an anabolic state, resulting in reduced growth and lean body mass (10,62,90,99).…”

Influence of the test situation on pup retrieval behavior of normal and undernourished lactating rats

“…In a more detailed second study, Wiener et al (12) reported that dams maintained on a low protein diet retrieved less than wellnourished dams after some retrieval tests, but during periods not associated with the tests, malnourished dams spent more time with their pups. Several other literature reports demonstrated that malnourished dams spend more time with litters when observations are made in the home cage with little disturbance of dam behavior (4,12,13,17,20).…”

“…The methods used to produce undernutrition in rats are accompanied by changes in mother-pup interaction (8)(9)(10)(11)(12) and it has been proposed that changes in maternal behavior tend to minimize the effects of undernutrition on offspring growth and development (13,14). Other studies have indicated that the changes in maternal behavior cause either beneficial effects (15) or no effect on the later behavior of offspring (16,17).…”

“…The maternal behavior of malnourished rats has been studied under disturbed condi-tions (11,12,18,19) as well as using a more natural approach by observing dam behavior in the home cage without disturbing the ongoing maternal behavior (4,11,12,17,20). Most of the studies which evaluate the pup retrieval behavior of undernourished dams (caused by food restriction or by feeding dams a low protein diet) showed a decrease in the efficiency of pup retrieval behavior as a function of days of testing (11,12,19,(21)(22)(23).…”

“…Most of the studies which evaluate the pup retrieval behavior of undernourished dams (caused by food restriction or by feeding dams a low protein diet) showed a decrease in the efficiency of pup retrieval behavior as a function of days of testing (11,12,19,(21)(22)(23). In a more detailed second study, Wiener et al (12) reported that dams maintained on a low protein diet retrieved less than wellnourished dams after some retrieval tests, but during periods not associated with the tests, malnourished dams spent more time with their pups. Several other literature reports demonstrated that malnourished dams spend more time with litters when observations are made in the home cage with little disturbance of dam behavior (4,12,13,17,20).…”