16S rRNA gene (fecal bacteria of preterm pigs). gut metagenome

Background: Small enteral boluses with human milk may reduce the risk of feeding intolerance and necrotizing enterocolitis in preterm infants on parenteral nutrition (PN). We hypothesized that small enteral boluses with amniotic fluid, the natural enteral diet of the mammalian fetus, are well-tolerated in preterm neonates on PN and may improve gastrointestinal (GI) maturation. Material and Methods: Seventeen pigs were delivered by cesarean section at ~90% of gestation. Pigs were provided PN and fed boluses of amniotic fluid (AF; n = 13) or nothing orally (NPO; n = 14) for 5 d. Gastric emptying, intestinal permeability and hexose absorption, and gut peptide release were tested in vivo, while intestinal histology, brush-border enzymes, expression of inflammatory mediators, and the fecal microbiota were analyzed after euthanasia on d5. Results: Body weight gain was ~150% higher in AF than NPO pigs. Increased gastric residual volume and reduced meal-induced gut peptide release (GIP and GLP-2) indicated less rapid gastric emptying in AF pigs, while a reduced urinary lactulose/mannitol ratio indicated improved mucosal integrity in AF pigs. No effects were seen on GI weight, intestinal mucosal percentage or villous morphology, although AF increased crypt depth in the small intestine. Intestinal IL-1β levels and expression of IL1B and IL8 were increased in AF pigs, while the fecal microbiota remained unaffected by enteral amniotic fluid supplementation. Conclusions: Small enteral boluses of amniotic fluid were well tolerated in the first five days of life in preterm pigs on PN. Although enteral supplements with amniotic fluid before the transition to full enteral feeding may stimulate body growth in preterm infants on PN it may not improve GI maturation.