Isolation, growth on prebiotics and probiotic potential of novel bifidobacteria from pigs

Bifidobacteria were isolated from the faeces of pigs of various ages and examined for their potential use as probiotics in combination with di- and oligosaccharides. Ninty-six per cent of the isolates were found to have characteristics in common with Bifidobacterium boum, B. thermophilum and B. choerinum. B. thermophilum was most commonly isolated from sows, whereas most of the other strains were isolated from piglets. A few strains of each species were able to grow in the presence of air. A microplate assay was modified to allow comparison of growth on different substrates. Di- and oligosaccharides considered to promote bifidobacteria were screened for their ability to support growth of selected isolates in vitro. Growth on these substrates varied within and between species. Of the fructose oligosaccharides tested, Actilight P supported the best growth of the widest range of strains. The strains which grew best on the disaccharide lactulose were related to B. choerinum and some of these strains grew on xylo-oligosaccharides. It seems that prebiotic di- and oligosaccharides may have both a species and intra-species/strain selective effect. B. choerinum appeared to be well adapted to the gut of pre-weaned piglets.