Background: Excretion of fecal short-chain fatty acids (SCFAs) may indicate changes in colonic or colonocyte metabolism. The aim of this study was to detect the influence of gestational age and feeding practices on SCFA concentrations and profiles in healthy preterm infants.
Methods: A total of 198 fecal samples (28 infants) were collected from 8 to 21 days of age from 3 groups of preterm infants born at 33 to 37 weeks of gestation and fed either breast milk (group I) or Nutramigen, a lactose-free formula (group II), and extremely preterm infants born before 33 weeks of gestation and fed breast milk (group III). Total SCFA concentrations and SCFA profiles were analyzed using a gas chromographic (GC) procedure.
Results: Total fecal SCFA excretion did not differ significantly between group I (mean, 24.0 micromol/g; range, 1.3 to 118.8 micromol/g) and group II (mean, 23.0 micromol/g; range, 3.0 to 73.3 micromol/g). Conversely, differences occurred between SCFA profiles and became significant after day 17. The main differences were a significant increase in the butyric acid concentration (12% versus 30%) with group II. Compared with group I, fecal SCFA concentrations were 3.2-fold lower (7.4 micromol/g; range, 0.3 to 37.4 micromol/g) in group III with no significant changes in the profiles.
Conclusions: Fecal SCFA excretion may vary in absence of any digestive disease. During this study, in terms of gestational age, total SCFA concentrations were significantly lower in extremely premature infants compared with infants born less premature, despite their known higher deficiency in intestinal lactase activity. In terms of diet, the absence of lactose did not lead to a decrease in colonic fermentation and induced changes in SCFA patterns. These new baseline data may offer clues to further development of milk formulas.