Early undernourishment interferes with the maternal aggressive response triggered by an intruder entering the homing cage

Abstract

The maternal aggressive response (MAR) against intruders is temporarily expressed during lactation in association with the rearing and protection of offspring to promote their survival and growth in the nest. This normal component of maternal behaviour requires both the hormonal changes occurring at the end of pregnancy and the presence of pups for its establishment. Because early food restriction in the rat results in long-term maternal deficiencies, we analysed in Wistar rats the effects of perinatal undernutrition on the MAR to an intruder at days 1, 4, and 8 postpartum. The data showed that undernourished dams exhibited significant reductions of sniffing frequency on days 4 and 8 and significant increases of biting on day 4 and of lateral attacks on postpartum days 4 and 8. The finding of an altered MAR during the lactating period may be relevant for the survival and long-term behavioural development of the progeny.

Behaviour of postnatally growth-impaired mice during malnutrition and after partial weight recovery

“…13 A range of methods have been applied to induce the nutritional deficit: temporal maternal separation, manipulation of litter size, restriction of maternal protein-energy intake, or the surgical ligation of the dam's nipples to impair lactation. [14][15][16][17] Reported effects of postnatal protein malnutrition induced by these methods in rodent offspring include changes in social, aggressive, and maternal behaviour, 18,19 exploratory behaviour and anxiety, 20 altered learning and memory capacities, 21,22 differences in the behavioural response to the administration of drugs, 23,24 and the response threshold to aversive stimuli. 16 The extent and persistence of effects of a limited period of PEM on brain development, behaviour and cognition are not entirely explored; however, they seem to be partly reversible later in life.…”

Maternal Behavior Their Adjustments and Implicated Factors

“…Extreme forms of maternal deprivation have shown to have profoundly adverse effects on the development of maternal behavior. Early maternal stimulation in the nest also produces a decrease of the emotional reactivity of pups to novelty and stress when they become adults [87]. Reduction in stress reactivity are attributable in part to the increased density of hippocampal glucocorticoid receptors which normally mediate negative feedback effects of circulating adrenal glucocorticoids following hypothalamic-pituitary-adrenal (HPA) activation.…”