Adding prebiotics to infant formula can help enhance memory and exploratory behaviour in babies, scientists have found.
New mothers are always encouraged to offer breast milk to newborns. Among other things, breast milk contains natural sources of prebiotics: small, indigestible fibre molecules that promote the growth of good bacteria in the baby's gut.
Yet for many families, breastfeeding is difficult or impossible.
"When we provide prebiotics in formula, our results confirm that we can not only benefit gut health, which is known, but we can also influence brain development," said Ryan Dilger, associate professor at University of Illinois in the US.
"We can actually change the way piglets learn and remember by influencing bacteria in the colon," said Dilger.
Piglets are widely considered a more informative model for human infants than mice and rats; their digestive systems, behavioural responses, and brain development are remarkably similar to human infants.
Therefore, researchers are increasingly turning to piglets to test hypotheses in pre-clinical trials related to human health, especially in the context of gut microbes and brain development.
"There hasn't been a lot of work looking at the gut-brain axis in humans, but a lot of rodent work is showing those connections," said Stephen Fleming, doctoral student at University of Illinois.
"This is taking it to an animal model that is a lot closer to human infants and asking if that connection still exists and if we can tease out possible mechanisms," said Fleming.
Researchers had earlier worked with piglets to show that a combination of innovative formula components, including prebiotics, may play a role in brain development and behaviour.
In the new study, the team concentrated solely on the effects of prebiotics.
Starting on the second day of life, piglets were given a cow's milk-based infant formula supplemented with polydextrose (PDX), a synthetic carbohydrate with prebiotic activity, and galactooligosaccharide (GOS), a naturally occurring prebiotic.
When the piglets were 25 days old, Fleming took them through several learning, memory, and stress tests. After 33 days, blood, brain, and intestinal tissues were collected for analysis.
The test for learning and memory gave piglets a chance to play with dog toys - one they had seen before and one brand- new toy.
If they spent more time with the new toy, that was an indication that the piglet recognised it as new and preferred it.
Pigs fed PDX and GOS spent more time playing with new objects than pigs who did not receive the prebiotic supplements.
The preference for novel objects, an indication of natural curiosity, is a sign of healthy brain development and points towards positive development of learning and memory.