Effects of Air Travel Stress on the Canine Microbiome: A Pilot Study

Behavior assessment is commonly used to identify canines that may have a higher threshold for environmental stress, but no work has established a connection between behavior (as indicated by search performance) and travel stress (as indicated by fecal scores and microbial stability). Six canines (aged 18 months to 8 years), trained according to the standard established by the Federal Emergency Management Agency (FEMA), were utilized to test the effects of airline travel stress on working canines. Our objectives were to test the hypotheses that: 1) working canines can overcome air travel stress with little or no impact on their performance; and 2) fecal score and microbial composition is impacted by airline travel stress. Two groups of dogs, (n=3 per group), were randomly selected from FEMA canine teams rostered in New York City, NY (CONTROL) and in Miami, FL (TRAVEL). TRAVEL dogs were flown in the cabin on a commercial airline to New York. Blood and fecal samples were collected each morning prior to travel (d0) and search work (d1-d3). Fecal bacterial DNA was extracted and 16S rRNA amplicon sequencing was completed using an Illumina MiSeq followed by analysis with QIIME 1.8.0. Fecal scores from TRAVEL were significantly higher (P = 0.01) than CONTROL indicating softer stool in the group that travelled. Pre- and post-travel blood samples for the TRAVEL group were compared and demonstrated significant decreases in lactate, bicarbonate, total carbon dioxide, and base excess (P < 0.05) following travel. However, these decreases were still within normal range, therefore, may not be biologically significant. In addition, blood samples from TRAVEL and CONTROL were compared on search days and increases were observed in the TRAVEL group for ionized calcium, bicarbonate, total carbon dioxide, base excess, creatinine, and blood urea nitrogen (P < 0.05). In contrast, blood glucose was decreased in the TRAVEL group (P < 0.05). Search behavior scores were not significant in TRAVEL compared to CONTROL. Principal coordinates analysis (PCoA) of UniFrac distances between samples based on their 97% OTU composition indicated that TRAVEL bacterial communities (P = 0.01) and bacterial community abundances (P = 0.02) were significantly different from CONTROL. These data demonstrate that airline travel of 2.5h impacts the working canine gut microbiota and some blood metabolites, but has no observed effect on working canine performance.