Adverse effects of stress on microbiota

Authors: MIR, RAIES - Orise Fellow; KLEINHENZ, MICHAEL - Iowa State University; Kudva, Indira; COETZEE, JOHANN - Kansas State University; Allen, Heather

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/27/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The complex communities of microorganisms that colonize the gastrointestinal tract impact the health status of an animal. The health of an animal as well as production traits are also affected by exposure to stress. The aim of present study was to evaluate the effects of dehorning stress on the gut microbiota of dairy calves. Dehorning is a stressful procedure performed on over 90 percent of dairy farms, and analgesics like flunixin meglumine (FLU) are given at the time of dehorning to reduce pain. We analyzed fecal microbiota of 24 weaned male calves of 6-8 weeks’ age for changes in the microbiota due to dehorning and flunixin meglumine treatment. The calves were randomly assigned to one of three treatment groups of: 1) topical flunixin and dehorning (FLU, analgesic and dehorned); 2) topical flunixin and sham dehorn (SHM, analgesic but no dehorning); and 3) placebo and dehorn (PLB, no analgesic but dehorned). For data analysis calves were grouped based on their body weights (light and heavy). Fecal samples were collected from rectum immediately prior to dehorning or analgesic treatment (day 0) and at 72 hours post-dehorning (day 3). Dehorning was performed using an electrocautery dehorner applied to the horn for 10 seconds. The results show that the alpha diversity measures (Chao 1 bias-corrected species richness, Shannon entropy and Simpson’s index) are significantly higher in SHM group (no dehorning) compared to dehorned groups (FLU and PLB) at day 3, indicating that the stress caused a decrease in the diversity of the calf gut microbiota. This decrease was more pronounced in the lower weight calves. Between the two weight groups (small vs heavy) in all dehorned calves, the negative effect of dehorning (stress) on the microbiota was less pronounced in heavy weight animals receiving the analgesic, flunixin meglumine, compared to small weight animals and animals receiving placebo (PLB). The future studies are aimed at elucidating the association with other stressful conditions like castration, the temporal changes in the bovine gut microbiota, and the potential resilience of the microbiota of heavier compared to lighter calves. This work is important for elucidating potential modulation points in the microbiota of food-producing animals to improve animal health and food safety.