Retrieval of Pups by Female Rats Undernourished during the Pre- and Neonatal Period

Judith Felix,Carmen Torrero,Mirelta Regalado,Manuel Salas

doi:10.4236/jbbs.2014.47033

Abstract

Early mother-litter bonds alterations elicited by pre- and neonatal undernutrition are a source of long-lasting brain and functional disorders such as exploratory and emotional deficits and maternal unresponsiveness to the newborn. Here, we examined the prolonged effects of gestational and neonatal food restriction on the retrieval of pups and nest building activity by primiparous adult Wistar rats on postnatal days (PDs) 4, 8, and 12. In early undernourished dams, the latency to retrieve the first or the fifth pups in the litter was extended; and nest building activity was significantly reduced. Additionally, early underfed dams retrieved the pups in a rough manner, eliciting distress cries and grasping the pups by unusual body areas. The current findings suggest that pre- and neonatal food restriction may affect the anatomical and functional forebrain structures, modulating the cognitive and motor components underlying maternal responsiveness.

Highlights

In altricial species the maternal response is fundamental for newborn survival, interactions with the mother and environmental cues in the nest stimulate the normal brain developmental processes and promote subsequent brain plasticity changes that may have a variety of long-term anatomical and functional consequences
The ANOVA comparisons of the body weight scores between the Control Group (CG) and the Underfeed Group (UG) dams at gestational day 21 yielded a significant effect of diet, F(1, 22) = 33.72, p < 0.0001
After birth the UG dams weighed significantly less than CG mothers, F(1, 22) = 28.96, p < 0.00002, with a significant effect of age, F(3, 66) = 21.38, p < 0.00001, and without interaction between factors

Summary

Introduction

In altricial species the maternal response is fundamental for newborn survival, interactions with the mother and environmental cues in the nest stimulate the normal brain developmental processes and promote subsequent brain plasticity changes that may have a variety of long-term anatomical and functional consequences. Previous studies have shown that different paradigms of neonatal undernutrition or malnutrition in the rat produce severe alterations in the maternal response of adult lactating dams, including deficiencies in nest building, licking of pups, nursing time, and retrieval of the young [2]-[5]. Most of these long-term behavioral alterations result from an interference with programming of the hypothalamic-hypophysial axis that results in defects in activating hormonal targets [6]. These behavioral deficiencies of early underfed dams correlate well with their brain alterations in myelination, dendritic arbor growth, and the synaptic organization of the neuronal sensory systems, alterations that seriously interfere with the mother-litter interactions and cause functional deficiencies and brain disorders throughout the lifespan of the progeny [4] [7][13]

Methods

Results

Conclusion