Effects of synbiotic intake on the gut microbiota analyzed by PCR-DGGE and Real-Time PCR

The human gastrointestinal tract harbours a diverse community of microorganisms which serve numerous important functions for the host wellbeing. Functional foods (pre-, pro- and symbiotics) are commonly used to modulate the composition of the gut microbiota contributing to the maintenance of health or prevention of disease. 16S rRNA-based techniques represent eligible approaches to investigate the biodiversity of the gut ecosystem and specific responses to diet supplements. In the present study we evaluated the influence of a 30-days intake of a symbiotic food (0,5 g FOS, 10E9 CFU B. longum, 10E9 CFU L. helveticus) on faecal microbiota composition in 20 healthy volunteers. PCR-DGGE with universal primers for Eubacteria was employed to determine changes in the distribution of the dominant bacterial species. Cluster analysis of DGGE profiles showed higher inter-individual variation than that among the different time-points of the trial, suggesting a stabilising impact of the symbiotic food on the microbiota. Real-time PCR with B. longum and L. helveticus species-specific primers allowed to assess the intestinal colonization of the probiotic strains included in the symbiotics.