Intestinal Microbiota Structure of Xichuan Black-Bone Chickens and Preliminary Evaluation of a Probiotic-Based Fecal Microbiota Substitute.

In this study, we aimed to explore the intestinal microbiota structure of Xichuan black-bone chickens (XBCs) and evaluate the effect of fecal microbiota substitute transplantation (FMST) by comparing it with traditional fecal microbiota transplantation (FMT). Metagenomic sequencing was used to analyze the microbiota composition and diversity of different intestinal segments (duodenum, jejunum, ileum, cecum, and rectum) of adult XBCs. Probiotic strains were subsequently isolated and screened from the cecal contents under anaerobic conditions to prepare FMST preparations. In total, 90 1-day-old XBCs were randomly divided into the FMT group, FMST group and control group (CK) for the transplantation experiment. The results revealed that the cecum had the highest species richness among all intestinal segments, with a mean species number of 7593.2. Three probiotic strains, namely, Lactobacillus crispatus, Weissella paramesenteroides and Bacillus amyloliquefaciens, were successfully screened and identified. In the transplantation experiment, the FMT group exhibited optimal α diversity of the cecal microbiota, while compared with the FMT group, the FMST group had significantly reduced expression of pro-inflammatory cytokines (IL-6, TNF-α, and IL-1β) and increased expression of intestinal tight junction proteins (claudin-1 and ZO-1). In conclusion, the cecum of XBCs has the most abundant microbial resources. Under the short-term intervention model tested herein, the custom FMST formulation delivers superior intestinal protective effects and shows promising potential as a standardized alternative to conventional FMT, which is highly important for the standardized application of fecal microbiota transplantation in poultry production.