Infant formula with galacto-oligosaccharides (OM55N) stimulates the growth of indigenous bifidobacteria in healthy term infants

The objective of the study was to investigate whether an infant formula supplemented with galacto-oligosaccharides (GOS; OM55N) was able to stimulate the growth of indigenous bifidobacteria and to establish microbiota similar to that of breastfed infants. A randomised, double-blind, placebo-controlled trial was performed using 35 healthy term infants (31-54 days of age; 42 +/- 6 days) to determine whether infant formula with 0.3 g/dl GOS (OM55N) stimulated the growth of bifidobacteria in the infants' guts. At the trial onset and 2 weeks after, the infants' faecal samples were examined for microbiota composition (bacterial abundance and alpha-diversity) and faecal characteristics. Among the 35 infants, 5 were withdrawn and 8 were excluded from the final evaluation before breaking the blinding since the indigenous bifidobacteria were not detected at the trial onset. After 2 weeks, the abundance of Bifidobacteriaceae was significantly increased in the GOS feeding group compared to the control (+11.6 +/- 24.1% vs -3.9 +/- 13.0%; P=0.043). The Shannon index, which accounts for both abundance and evenness of the present species, was significantly decreased with GOS supplementation (-0.1 +/- 0.4 vs +0.4 +/- 0.4; P=0.014). Faecal characteristics such as pH and organic acids were similar in both groups, with no statistical differences. No adverse side effects related to the formula consumption were reported. Although the concentration of GOS was relatively low, the infant formula with GOS increased the abundance of bifidobacteria and resulted in a reduced a-diversity of the microbiota.