Exposure of different bacterial inocula to newborn chicken affects gut microbiota development and ileum gene expression

The transition from a sterile gut environment to the development of microbiota in the newborns is not fully understood. The objective of this study was to investigate the impact of exposure to bacterial communities on the development of gut microbiota in the newly hatched chicken. A total of 90 as-hatched chicks were divided into three groups. Groups A and B were treated with inocula of the cecal origin, whereas group C was fed with sterile water. The major bacteria in Inoculum-I to treat group A included Bacteroides (20.7%), Lachnospiraceae (17.2%) and unclassified Ruminococcaceae (16.1%), whereas group B was introduced with Inoculum-II composed of Prevotella (37.9%), Acidaminococcus (16.1%) and Dorea (12.6%). Analyses of the ileal and cecal contents over a period of 15 days showed that Inoculum-I resulted in a higher rate of colonization than Inoculum-II, but the colonization was predominantly in the cecum. The influence of Inoculum-II on group B was similar to that of water on group C, showing only a marginal effect on colonization. Microarray analysis showed that each group presented a distinct pattern of gene expression in the ileum. In group A, the most obvious changes were noted in genes controlling the function of ion transport, cell cycle and chromosome maintenance, suggesting that the inocula influenced gene expression. Our findings indicate that initial exposure to different bacterial communities could lead to the development of distinct microbiota and gene expression in the gut. It is possible to manipulate the gut microbiota by feeding to a proper bacterial composition at an early age. The ISME Journal (2010) 4, 367-376; doi:10.1038/ismej.2009.128; published online 3 December 2009