Repeated Cat Odor Exposure Affects Maternal Behavior And Offspring's Behavior And Physiology Of Brandt's Voles In Lactation Period

Predation risk is conducive to promoting the co-evolution of predators and prey.At the same time,prey will affect offspring through maternal effect.This experiment was to investigate the effect of the mother exposing the predator odor on maternal behavior and its offspring behavior and physiology by using the Brandt's voles as experimental objects,the distilled water as a control group,rabbit odor as a negative control and cat odor as a positive control under laboratory condition,and discuss the maternal effect of the Brandt's voles exposing the predator odor in lactation period.The following results were obtained:1) Under acute cat odor exposure,female in group exposed to cat odor had a lower percentage of reintroduced pups than that in control group and rabbit odor group.Compared with the control group,the nesting behavior,licking behavior,and prone behavior of the female in cat group and in rabbit group were reduced significantly.Compared with the female in the rabbit group,the females in the cat group spent less time on prone and licking behaviors and spent more time on non-social behaviors.This shows that acute cat odor exposure was more destructive to maternal behavior in lactating Brandt's voles.Under repeated cat odor exposure,the percentage of reintroduced pups in the cat group decreased significantly,and this effect was slowly eliminated with time.2) Cat and rabbit odor exposing to lactating female voles did not affect the weight gain of its young voles before weaning,and did not affect the survival rate of the young vole and the immune and reproductive organs of adult offspring.3) Cat odor exposing to lactating female voles increased the total distance of adolescent offspring,reduced the duration of immobility,the rearing behavior of female offspring and declined the rearing behavior of male offspring,had no effect on the anxiety-like behavior of the offspring4) Observing the behavioral response to male offspring of Brandt's voles when they mothers were exposed to different odors during lactation period,it was found that the duration of grooming behavior and head out behavior of the male offspring in the cat group and in the rabbit group were significantly lower than those in the distilled water control group when exposed to cat odor,the duration of immobility behavior in the rabbit group was significantly lower than that in the cat and control groups,the frequency of head out behavior in the rabbit odor group was significantly lower than that in the control group,and the vigilant rearing behavior of the offspring in the cat group was significantly lower than that in the rabbit and control groups when male offspring exposed to rabbit odor.5) Observing the behavioral response to male offspring of Brandt's voles when they mothers were exposed to different odors during lactation period,it was found that,the frequency of head out behavior of the female offspring in the cat group was significantly higher than that of the distilled water group,the duration and frequency of immobility behavior in the cat group were significantly lower than those in the rabbit and distilled water groups when exposed to cat odor and other behaviors of the offspring in the rabbit group were significantly lower than those of the cat and rabbit groups when exposed to rabbit odor.6) When its mother Brandt's vole exposing to different odors,ATCH and CORT concentrations in the plasma of adult male offspring were not significantly different,and ATCH concentrations in the plasma of adult female offspring in the cat group were significantly lower than that in the control group,the CORT concentration was significantly lower that in the rabbit and control groups;the IgG levels in the spleens of adult male offspring in the cat group were significantly lower than those in the rabbit and control groups,IgM levels in the spleens of adult female offspring in the cat group were significantly higher than those in the rabbit group,and IgG levels were significantly lower than those in the control group;there was no difference in the expression of CRH protein in the adult male hypothalamus,the expression of CRH protein in the hypothalamus of the adult female offspring in the cat group was significantly higher than that in the rabbit and control groups.The above results showed that the cat odor exposure of lactating vole could decrease the maternal behavior and restored to original level along with the time,and this increased the exploring behavior,autonomous behavior,anti-predatory behavior and the immune level of male and female offspring in unfamiliar environments.This indicated that the stress of mother Brandt's vole exposing predator's odor had regeneration effect and the immune response partly was its machnism.