Study shows contradictions, mysteries in fetal nutrition research
According to the United Nations Food and Agriculture Organization, 925 million humans experienced undernutrition in 2010. The effects of undernutrition for pregnant women are especially dangerous, as studies have shown that their undernourished offspring are more likely to have lighter birth weight and learning disabilities.
To learn more about how prenatal undernutrition affects postnatal development, scientists from the French National Institute for Agricultural Research, AgroParisTech, and Alfort School of Veterinary Medicine restricted the feed of pregnant goats during the last third of pregnancy. Their paper, published July in the Journal of Animal Science, shows the results of maternal feed restriction on kids’ emotional and feeding behavior, growth and metabolism.
In an interview, study co-author Dr. Bérengère Laporte-Broux explained why she chose to compare goats and humans.
“As in humans, brain development in goats mainly occurs during gestation,” Laporte-Broux said. “The maturation of the main brain structure involved in feed-intake regulation, the hypothalamus, occurs in late pregnancy.”
As they expected, the feed-restricted kids had lighter birth weights. The smaller kids were also slower to process what fat reserves they had for energy. But, contrary to several previous studies in goats, the kids’ weight and fat reserves bounced back quickly once they received adequate nutrition.
“These differences between kids born to restricted goats and kids born to control goats disappeared rapidly after birth,” Laporte-Broux said.
She thinks perhaps his study had different results because feed restriction occurred late in pregnancy. A previous study on lambs restricted food until during the first thirty days of gestation, not the last third.
Because the brain develops dramatically late in pregnancy, the scientists also wanted to assess the kids’ emotional behavior. In one test, the kids were placed in unfamiliar pens, and stress was assessed by observing behaviors like jumping and bleating. To further test the kids’ reactions to novel, possibly stressful circumstances, they were also placed in a pen with a red traffic cone. The braver goats spent time approaching the cone and sniffing it and the stressed goats avoided the cone.
“Emotional behavior after maternal feed restriction has been studied very little in small ruminants,” Laporte-Broux said. “We hypothesized behavioral modifications (e.g. modifications of emotional reactivity) resulting from such brain modifications could be seen in the neonatal period.”
Interestingly, that hypothesis was not confirmed. The study showed no difference in emotional behavior between kids that experienced prenatal feed restriction and the control group kids.
Laporte-Broux said that while further studies are needed, it is possible to extend these findings to humans. Human babies are rarely threatened by traffic cones, but infants do experience stress. The ways infant brains develop can shape the ways they respond to new people, surroundings and even toys.
The paper is titled “Short-term effects of maternal feed restriction during pregnancy on goat kid morphology, metabolism, and behavior.” It can be read in full at http://journalofanimalscience.org/
ASAS Scientific Communications Associate