Oligofructose contributes to the protective role of bifidobacteria in experimental necrotising enterocolitis in quails

Bifidobacteria are dominant in the gut of full-term infants, although colonisation by them is often delayed in preterm neonates. Bifidobacteria are recognised to have beneficial effects on digestive disorders and they might prevent neonatal necrotising enterocolitis (NEC), a gastrointestinal disease that predominantly affects premature infants. They have been shown to protect gnotobiotic quails against NEC-like lesions when the birds were inoculated with faecal flora from preterm infants, decreasing the clostridial population. The present study was designed to investigate whether oligofructose, which stimulates the activity of bifidobacteria, may enhance their protective role. Experiments were done in eight groups of germ-free quails for 28 days. The groups differed as to their bacterial status, diet and environment. Quails were inoculated with one of two flora from premature twins. The first flora included Bifidobacterium pseudo-catenulatum, Escherichia coli and no clostridia. The second flora included clostridial species and was associated with B. infantis-longum. Caecal bacterial population and metabolism changes were investigated with a lactose (6%) diet versus a lactose-oligofructose (3%-3%) diet, either in a gnotobiotic environment or in an ordinary environment permitting post-colonisation by exogenous bacteria. In both environments and with both flora, oligofructose significantly increased the level of bifidobacteria and this was associated with a decrease of E. coli or C. perfringens and C. ramosum. The bacterial changes in the ordinary environment depended on the initial composition of the microflora and the colonisation resistance against exogenous bacteria was more efficient with the flora that included B. pseudo-catenulatum. The changes in caecal pH and short-chain fatty acids were minimal. It was demonstrated that, irrespective of the environmental conditions, the use of oligofructose helped to prevent the overgrowth of bacteria implicated in necrotising enterocolitis in preterm neonates.