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Section: Immunology, Health, and Disease
Session: Student Competition: Immunology, Health, and Disease
Format: Orals
Day/Time: Monday 11:45 AM–12:00 PM
Location: Crystal J2

# 55
Natural environmental selection differentially modulates the diversity of gut microbes and innate immune responses of feral and modern broiler chickens.
Ricardo Hayashi*2, Celia Garcia3, Eben Gering1, Alexandra Smith4, Thomas Rehberger4, Isaac Cann3, Elizabeth Santin2, Roderick Mackie3, 1Michigan State University, East Lansing, MI, 2UFPR, Curitiba, PR, Brazil, 3University of Illinois, Urbana-Champaign, IL, 4Agro Biosciences, Wauwatoosa, WI.

Feralization occurs when a domestic population recolonizes the wild, escaping its previous restricted environment, and has been considered as the reverse of domestication. Modern broiler chickens have been selected on growth characteristics that could adversely affect innate immune competence leaving chickens more susceptible to diseases. Understanding the feral chicken’s gut microbiota and its relation with immunity may provide insights to enhance performance and the microbiological safety of poultry products. Ileal and cecal contents of 20 adult feral chickens from Bermuda and 12 Cobb broiler chickens 42 d of age from the UIUC Poultry Farm were collected. Genomic DNA was then extracted and amplified based on primers targeting the V4 region of 16S rRNA. Sequencing of amplicons was performed using the Illumina MiSeq V3 platform with paired end reads (2x300) to ensure recovery of the integral V4 region. The single reads were merged by PEAR software and subjected to phylogenetic analysis and taxonomic assignments using QIIME package configured for constructing OTUs with 97% of identity and assigning taxonomy based on the Greengenes reference database. We also compared the expression profiles of chicken toll-like receptors (TLR) genes in liver and ileum using RT-qPCR. The microbial communities in the feral birds were more diverse in comparison with the broiler communities (ileal P = 0.008 and cecal P ≤ 0.001). Potentially pathogenic bacteria such as Enterobacteriaceae, Pasteurellaceae, Pseudomonaceae in ileum were elevated in feral chickens as well as populations of beneficial bacteria such as Lactobacillales and Bifidobacterium (P ≤ 0.05). Conventional broilers showed a higher abundance of Staphylococcus sp. in the ileum and Clostridiales in the cecum compared with feral chickens (P ≤ 0.05). Feral birds presented higher expression of TLR 3, 4, 5, 15 and 21 in ileum than broilers (P ≤ 0.05). However, gene expression of TLR 1, 2, 3, 5, 15 and 21 in the liver from feral chickens was lower compared with broilers (P ≤ 0.05) which may be related to the higher bacterial diversity in the ileum of feral birds. The TLR results suggest difference in innate immune response from the feral birds compared with broilers, which could be due to microbiota diversity and environmental challenges. Rearing broiler chickens in more natural type of environments might improve genetic selection, reduce enteric diseases without reliance on subtherapeutic antibiotics leading to safer food supply.

Key Words: 16S rRNA, feralization, gut microbiota, next-generation sequencing, toll-like receptors

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