Father's gut microbiome may affect infant health

Decreasing the diversity and abundance of gut microbes in male mice increases their offspring’s risk of low birth weight, stunted growth and premature death. This suggests that a father’s gut microbiome may impact infant health.

Plenty of research has established a link between microbes in mothers and infants, yet little is known about the impact of paternal gut health.

So Jamie Hackett at the European Molecular Biology Laboratory in Rome and his colleagues treated 28 male mice with antibiotics, which decreased the abundance of gut microbes in the animals by 10-fold and shifted their balance of microbial species.

The rodents – along with another 12 male mice that had stopped the antibiotic treatment two months earlier and 26 control mice not given antibiotics at all – then mated with females. Together the groups produced more than 400 offspring.

Pups from mice with impaired gut microbiomes had a variety of health issues not found in those whose fathers had not taken antibiotics or stopped the medication weeks before conception. They had significantly lower birth weights and were 2.5 times more likely to have severely stunted growth at 2 weeks old. Roughly 17 per cent of these pups died within three months, while only 5 per cent of those fathered by the control-group mice did.

How the gut microbiome exerts these effects is unclear. But further experiments did uncover some clues. For instance, mice treated with antibiotics had smaller testes and lower sperm counts than those that never took the medication. They also had different levels of certain hormones that influence reproductive health, such as leptin and testosterone, as well as differences in small molecules that regulate gene expression in sperm.

Mice impregnated by these animals also had changes to their placenta – namely, it couldn’t supply the fetus with enough nutrients.

“This paper represents a significant leap forward in our understanding of the intricate relationship between gut and reproductive health,” says Maria Gloria Dominguez-Bello at Rutgers University in New Jersey. It is the first time research has shown disruptions to the paternal gut microbiome may impact male reproductive health, sperm quality and infant health, she says.

It also indicates that paternal health may be important for pregnancy outcomes, since placental changes are related to pregnancy complications like preeclampsia in humans, says Hackett. But this is merely speculation, since research in mice does not necessarily apply to humans, he adds.