Gut microbes may enhance offspring survival in mice. Also of interest is that they may also influence sex ratios. In the Journal of Probiotics and Health, researchers pointed to the hormone oxytocin as the key mechanism in the effect.
Review: Oxytocin is produced in large quantities during birth. It also affects neuronal activity seen in mating. Deficiency in the hormone displays mice with reduced bonding behavior. There is also a role for oxytocin in autism and post-partum depression as well as anxiety and care by the mother.
The authors, most from Massachusetts Institute of Technology in Cambridge, Massachusetts report that:
- 1) Offspring survival depended on treatment with the
- probiotic Lactobacillus reuteri (LR)
- 2) Sex of mice depended on microbial
- exposures of their mother
- 3) Microbial effects depended on maternal oxytocin
- 4) Maternal microbial exposures regulated the effects of oxytocin.
To arrive at these conclusions the researchers used oxytocin-knockout mice and compared to matched controls.
What this means for humans remains to be seen. It’s fascinating nonetheless. And as we know, a Western diet changes gut microbiomes. But under more favorable conditions, probiotic bacteria could encourage female births.