Characterization of Chicken Cecal Microbiome During Acute and Chronic Heat Stress

The gut microbiome has garnered attention in the recent years for its contribution toward host response to stress.  For production chickens, both broilers and layers, heat stress has a significant negative impact on production traits and overall well-being of the birds.  The gut microbiome of chickens under heat stress is poorly understood.  In this study, we characterized the chicken cecal microbiome during a 4 week heat stress experiment with layer hens during active egg production in order to detect any noticeable differences from heat stress.

A group of 80 egg-layers were randomly split into 2 groups: heated and not heated.  Eight birds from each group were euthanized to harvest samples at 5 time points during heat treatment:  day 1 (acute), and weekly in weeks 1 through 4 (chronic).  Bacterial DNA were isolated from cecal digesta, and the V1-V3 region of the 16S rRNA gene was amplified.  The barcoded amplicons were pooled and sequenced on the Illumina MiSeq.  The sequences were analyzed with QIIME using the Greengenes reference database.

We identified changes in the microbial community during the 4 week heat stress experiment.  The microbial community was first summarized based on taxonomic information assigned to OTUs for the 5 time points.  Next, alpha diversities were calculated and summarized as alpha rarefaction plots.  Finally, beta diversities were calculated between heated and not heated groups within the 5 time points and summarized as principal coordinates analysis plots.

Support for this work is from an USDA-NIFA-AFRI grant and Hatch project #5358.