Maternal Responsiveness of Neonatally Undernourished and Sensory Stimulated Rats: Rehabilitation of Maternal Behavior

Abstract

The interaction between neonatal food deprivation and early sensory stimulation on four maternal behavioral components of Wistar strain rats was investigated. Dams neonatally underfed by daily mother-litter separation (Experiment 1), showed significant reductions in nest-rating and nursing time as well as increased retrieving latencies and selfgrooming responses compared to controls. Mothers which were neonatally undernourished by the nipple-ligation of their mothers (Experiment 2), exhibited less alterations in nest ratings, nursing time and retrieving latencies with no significant differences in the frequency of self-grooming responses, in comparison to controls. Neonatal handling and the exposure to a sensory enriched environment in Experiment 1, ameliorated most of the alterations of neonatally underfed mothers. Moreover, in Experiment 2, the increase in the neonatal sensory stimulation only improves nest ratings performance without consistent effects upon other maternal behavioral responses. Data suggest that sensory stimulation at critical stages of brain ontogeny is able to compensate long-term maternal behavioral deficiencies associated to a severe neonatal undernutrition (Experiment 1), with variable effects following a mild food intake deprivation (Experiment 2).

Organization of olfactory glomeruli in neonatally undernourished rats

“…One possibility to explain the current results concerns the role of the OB olfactory input alterations associated with the underfeeding paradigm used here. In fact, it is known that this or similar food restriction procedures negatively influence the mother-litter bonds, thus affecting the cytoarchitectonic organization and functional OB maturation (Math and Davrainville 1980, Galler and Propert 1982, Salas et al 1984, Almli et al 1985, Regalado et al 1999, Torrero et al 2000. Thus, our experimental findings are supported by the abundant evidence of environmental influences on the morphology of the OB during development and even in adulthood (Meisami and Safari 1981, Brunjes and 1986, Panhuber and Laing 1987, Farbman 1990, Colín-Barenque et al 1999.…”

Effects of perinatal undernutrition on the development of neurons in the rat insular cortex

“…[1][2][3][4] Several studies indicate that early food restriction in the rat results in severe deficiencies in both the number and the dendritic arborization, with minor effects on the perikarya of neurons relaying ascending sensory information such as those in the rostral portion of the solitary tract, the external subnucleus of the parabrachial nucleus, and the central and medial amygdaloid complex. [5][6][7] Using various experimental models it has been demonstrated that perinatal undernutrition causes a gradual reduction in the protein and carbohydrate content of the milk secreted with smaller effects on lipids and growth factors, compared with that of the milk from control dams.…”

Perinatal undernourishment and handling: effects on olfactory discrimination in the newborn rat

“…The current findings agree with previous studies showing that perinatal undernourishment consistently interferes with the physical development of newborns and adults, and that food deprivation, which is usually associated with a deficiency of sensory stimulation, reduces body weight gain. [44][45][46]50 However, the significant increase in body weight at 7 and 12 days of age between CG and CHG rats indicates that early sensory stimulation here used was able to modify the body weight of subjects. Pups of all experimental groups received sensory stimulation during the mother-litter encounter in the living cage, 49 and it is known that this maternal stimulation has an ameliorating effect on adverse behavioral responses to stress in the offspring; however, its role in physical development and early olfactory discrimination is under investigation.…”

“…28,[36][37][38][39][40][41][42][43][44] In the rat, early handling has been used as a tool to attenuate morphological and behavioral damages associated with perinatal undernourishment and sensory deprivation. 41,45,46 The heart rate-orienting response to a new odor paradigm has been used to investigate the development of fine odor discrimination in infant rats. 8 Although odor discrimination performance is well documented in adult altricial rodents, little is known about its characteristics in pups undernourished during the preand neonatal periods of life, nor of the role of early handling on their ability to olfactory learning suggested by this paradigm.…”