Characterizing the chicken gut colonization ability of a diverse group of bacteria

The development of probiotics for chick-ens is a rapidly expanding field. The main approach to probiotics is to administer the probiotic strain through-out the bird's life, usually through incorporation in the feed. However, probiotics which would utilize bacterial strains capable of permanently colonizing the gut after a single exposure are likely to have a greater impact on the developing gut community as well as on the host, would simplify probiotic use and also reduce costs in an industrial setting. Finally, very limited and conflicting information about the colonization ability of different bacterial strains has been reported. Here we report 2 col-onization experiments using 14 different bacterial strains from diverse phylogenetic groups. In both experiments, groups of chicks were orally inoculated on the day of hatch with different bacterial strains that had been pre-viously isolated from adult heavy breeders. In the first experiment, colonization of the bacterial strains in broiler chicks was determined 7 d after treatment. In the second experiment, colonization was followed in layer chicks until d 17. Ten of the bacterial strains, including Lactobacillales and Bacteroidales strains, were able to colonize chicks after a single exposure for the duration of the experiment. For a few of these strains, exposure had little effect compared to non -treated chicks due to natural background colonization. Only 4 strains failed to colonize the chicks. Moreover, it is shown that fecal samples are useful to identify and provide a dynamic view of colonization. We further analyzed the effects of artificial colonization on micro -biota composition. Some of the strains used in this research were found to reduce Enterobacteriaceae fam-ily abundance, implying that they might be useful in reducing relevant pathogen levels. To conclude, our results show that the development of single exposure based probiotics is possible.

Automated summary

The development of probiotics for chickens is a rapidly growing field. The current main approach is to administer probiotics through the bird's life, usually through feed incorporation. This study reports two colonization experiments using 14 different bacterial strains, and finds that some strains are able to colonize chicks after a single exposure. Fecal samples are shown to be useful for identifying and understanding colonization dynamics.