Effects of Maternal Stress Induced by Predator Odors during Gestation on Behavioral and Physiological Responses of Offspring in Brandt's vole (Lasiopodomys Brandi).

Maternal effects play a crucial role in regulating populations of small mammals and anti-predator behaviors of offspring. This study investigated the effects of maternal stress induced by exposure to predator odors during gestation on the behavioral and physiological responses of offspring in Brandt's vole (Lasiopodomys brandtii). Effects included changes in growth, behaviors, hormone levels in serum, and fosB/ΔfosB mRNA and FosB/ΔFosB protein expression in the hypothalamus. Our results showed that when pregnant voles were exposed to cat and rabbit urine odors for 18 days (1 h/day), the weight of the female offspring decreased; however, the thymus and ovary indices increased, compared with the control group. Male offspring of voles exposed to cat odor spent more time exploring and foraging, and showed a decrease in corticosterone (CORT), compared with those of voles in the control group. Both fosB/ΔfosB mRNA and FosB/ΔFosB protein expressions were down-regulated in the hypothalamus of male offspring in the cat odor-exposed group compared to that in offspring in the control group. However, the mRNA levels of fosB/ΔfosB in the hypothalamus of female offspring did not decrease in response to cat urine odor. Our findings suggested that maternal stress induced by predator odors during gestation restrained the growth of female offspring and increased the duration of exploring and foraging behaviors of male offspring by regulating the HPA axis, which in turn reduced the sensitivity of offspring to unfamiliar environments and increased their probability of becoming prey. This article is protected by copyright. All rights reserved.