Effect and mechanism of father’s companionship on defensive attack behavior of adult male offspring mice

Sociocultural changes in recent decades have promoted fathers' involvement in childcare, which is crucial for the brain and behavioral plasticity of offspring. The study elucidates the effect and mechanism of father's companionship on defensive attack behavior of adult male offspring mice. The study comprises a father companionship group, where offspring cohabited with sire and dam until weaning, and a control group, where offspring cohabited solely with the dam until weaning. The study shows that father's companionship increases defensive attack behavior of adult offspring. Additionally, the metabolite L-aspartic acid is upregulated in the father's companionship group compared to the control group in male offspring, and intracerebroventricular micro-injection of L-aspartic acid confirms its impact on defensive attack behavior. C-Fos immunohistochemistry reveals that c-Fos expression in lateral periaqueductal gray (LPAG) is activated. Subsequently, micro-injection of L-aspartic acid into LPAG increases defensive attack behavior. Additionally, 16S rRNA sequencing reveals a higher abundance of Bilophila and a lower abundance of Bifidobacterium in the father companionship group, which correlates with L-aspartic acid levels, suggesting a gut-brain axis mechanism for the effect of father companionship on defensive attack behavior.