Non-digestible fibers increase the capacity to produce short-chain fatty acids in stool of very preterm infants.

Introduction: Preterm infants have delayed intestinal colonization, which could negatively impact maturation of the intestinal barrier and mucosal immunity. Supplementation of immune modulatory fibers to their diet might increase the production of beneficial short-chain-fatty acids profiles (SCFA) by intestinal microbes.Methods: in vitro fermentation using feces of preterm infants (GA<30 weeks) at 4 different time points (first stool, 40 ml/kg/day and 140 ml/kg/day enteral feeding, 4 weeks) with blank or fibers [short chain galacto-oligosaccharides/long chain fructo-oligosaccharides (scGOS/lcFOS) and corn arabinoxylon (CAX)]. Microbiota composition, characterized using RNA gene amplicon sequencing, and SCFA production were measured before and after fermentation.Results: Stool of 7 infants (gestational age 27.8±1.2 weeks, birthweight 1101±190g, 3/7 infants born by Caesarean section) were analyzed. The microbiome showed wide variation during the first weeks of life. SCFA production was low in the first stool (mean 4.4±1.5 days) and did not increase until time point 4 (mean 29.1±0.5 days). scGOS/lcFOS (p<0.01) increased total SCFA, mostly acetate, in the stool from 2 weeks after birth and CAX (p=0.04) from 3 weeks after birth. SCFA production was positively influenced by vaginal delivery and negatively influenced by longer initial antibiotic course. Bifidobacteria were correlated with acetate production.Conclusion: The fecal microbiome in preterm infants were highly variable in the first weeks of life. SCFAs production was very low but increased, mainly due to acetate, after two weeks if dietary fibers, especially scGOS/lcFOS, were added. C-section delayed SCFA production by intestinal microbiota even in the presence of dietary fibers.