Comparison of gut microbiota between slow- and fast-growing broiler chickens

Gastrointestinal tract (GIT) microbiome plays an important role in the metabolism, immune competence, and growth performance of broiler chickens. It has been shown that interaction between the microbial population and host genetics affects the nutritional, immunological, and physiological status of the host. The aim of this study was to compare ileal and cecal microbiome between slow- (SGB) and fast-growing (FGB) broiler chickens. Three SGB (Athens Canadian Random Breed, ACRB; Longenecker Hatchery Heritage breed, LHR; Red-bro, RB) and 3 FGB (Ross 708, Cobb500 and Hubbard H1, HH1) broiler breeds were raised from hatch to d 35 post-hatch (PH) in a floorpen setting with ad libitum access to the same feed and water. Ileal and cecal digesta and epithelial scrapings were collected −2, 0, 7, 14, 21, 28, and 35 d PH for microbiome analysis. Microbiota was determined by sequencing of the V3-V4 region of bacterial 16S rRNA and analyzed using Qiime2. Body composition of birds were determined by DEXA. Significant differences (P < 0.05) in body weight and feed intake were observed between breads Cobb500 was characterized by the highest body weight, followed by Ross708 and HH1, LHR and RB and ACRB. Similar pattern was observed for feed intake. FGB were characterized by the lowest FCR (P < 0.05) while ACRB had the highest FCR (P < 0.05). Significant differences (P < 0.05) in body composition (bone mineral density and content, and percentage of lean mass and fat) were observed between SGB and FGB. Overall, no differences (P > 0.05) in α and β diversity in bacterial populations of ileum and cecum were observed between different broiler breeds. However, significant (P < 0.05) effect of breed or breed by age interaction were detected on bacterial composition at every taxonomic level in all 4 microbial populations (luminal and mucosal populations of ileum and cecum). These results indicate possibility of host genetic-specific microbiome interaction that could be involved in some of the performance differences seen between breeds.

Key Words: slow-growing chicks, fast-growing chicks, gastrointestinal tract, microbiome, 16S.

Presented at the Symposium on Gut Health in Production of Food Animals 2019 in St. Louis, USA.