Naturally occurring prebiotic oligosaccharides in poultry feed mixtures.

The presence of raffinose series oligosaccharides (RSO) was determined by an enzymic method in three commercially available chicken feed mixtures. All feed mixtures contained RSO at a concentration of 2.1-2.2%. Soya meal was identified as the exclusive source of RSO. Subsequently, the bifidogenic effect of stachyose (main soya bean RSO) was also assigned on the growth of poultry intestinal bifidobacteria. Bifidobacteria were counted in chicken intestinal tract using cultivation and FISH methods. Four out of 6 bifidobacterial strains tested grew significantly better on stachyose than on glucose. It can be thus concluded that chicken feed mixtures naturally contain prebiotic oligosaccharides in the form of RSO in higher levels (>2%) compared with the concentration (usually up to 1%) recommended for artificially added prebiotics. Our results therefore indicate that there is no reason for the supplementation of chicken feed mixtures with prebiotics with bifidogenic properties.