Selection of potential probiotic bifidobacteria and prebiotics for elderly by using in vitro faecal batch cultures

The gut microbiota plays an important role in host health. The ageing process affects this microbial community, and therefore, the use of functional foods to restore the microbiota of elderly constitutes an interesting strategy. To this end, probiotics and prebiotics targeted at correcting the specific microbiota alterations occurring during senescence are needed. We performed an in vitro selection of bifidobacterial strains and prebiotic substrates on the basis of their ability to counterbalance the specific microbiota aberrancies previously identified in the elderly population. Batch cultures of faeces from elderly were carried out adding different strains of Bifidobacterium or prebiotics. The effects of these strains/prebiotics upon gut microbiota were assessed by quantitative PCR and the concentrations of short chain fatty acids determined by gas chromatography-FID/MS. The target-specific selection process applied in this study allowed the preliminary selection of two Bifidobacterium strains and a prebiotic fructooligosaccharide on the basis of their specific properties for the modulation of the microbiota of elders. Overall, this study identifies potentially probiotic strains and prebiotic substrates for the development of functional foods specifically targeted to the senior population.