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Journal of veterinary internal medicine2021; 35(5); 2437-2448; doi: 10.1111/jvim.16206

The effects of signalment, diet, geographic location, season, and colitis associated with antimicrobial use or Salmonella infection on the fecal microbiome of horses.

Abstract: The fecal microbiome of healthy horses may be influenced by signalment, diet, environmental factors, and disease. Objective: To assess the effects of age, breed, sex, geographic location, season, diet, and colitis caused by antibiotic use (antimicrobial-associated diarrhea [AAD]) and Salmonella infection on fecal microbiota. Methods: Healthy horses (n = 80) were sampled from nonhospital environments across multiple geographical locations in the United States. Horses with AAD (n = 14) were defined as those that developed diarrhea secondary to antimicrobial use. Horses with Salmonella infection (n = 12) were presented with spontaneous onset of colitis and subsequently tested positive on Salmonella quantitative polymerase chain reaction. All horses were >1 year of age and stratified by a dietary scale that included forages (pasture and hay) and concentrates grouped by percentage of fiber and amount. Methods: Illumina sequencing of 16S rRNA genes was performed on fecal DNA. Results: Healthy horses fed higher amounts of grain clustered separately from those fed lower amounts of grain (analysis of similarities [ANOSIM], R = 0.356-0.385, Q = 0.002). Horses with AAD and Salmonella had decreased richness and evenness compared to healthy horses (P < .05). Univariable analysis of the 3 groups identified increases in Bacteroidetes (Q = 0.002) and Protebacteria (Q = 0.001) and decreases in Verrucomicrobia (Q = 0.001) in AAD horses whereas Salmonella horses had less Firmicutes (Q = 0.001) when compared to healthy horses. Conclusions: Although the amount of grain in the diet had some impact on the fecal microbiome, colitis had a significantly larger influence. Horses with ADD have a more severe dysbiosis than do horses with Salmonella.
© 2021 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.
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Publication Date: 2021-07-16 PubMed ID: 34268795PubMed Central: PMC8478058DOI: 10.1111/jvim.16206Google Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research explores the impact of various factors such as dietary intake, environment, and specific diseases on the fecal microbiome of horses, concluding that while diet can affect the fecal microbiome, an encounter with diseases like colitis has a more significant influence.

Introduction and Objectives

  • The study’s broad objective is to evaluate how variables such as age, breed, sex, location, changing seasons, and diet, along with diseases such as antimicrobial-associated diarrhea (AAD) and salmonella infection influence the fecal microbiota of horses.
  • The research particularly focuses on healthy horses, horses suffering from AAD (diarrhea caused by the use of antibiotics), and those infected with Salmonella.

Methodology

  • The sample consisted of 80 healthy horses from various geographical locations in the U.S., 14 horses affected by AAD, and 12 horses exhibiting spontaneous colitis and tested positive for Salmonella infection.
  • The horses were all above one year old and their diets were classified on a scale including forages (pasture and hay) and differentially fibered and portioned concentrates.
  • DNA was extracted from the fecal matter and subjected to Illumina sequencing of 16S rRNA genes to identify the gut microbiota present.

Results

  • Findings show that changes in the microbiome were observed in healthy horses depending on the grain diet they were fed: those fed higher amounts of grain had different clusters of bacteria than those fed lower amounts.
  • AAD and Salmonella-infected horses had reduced “richness and evenness” of fecal microbiota in comparison to healthy horses.
  • In AAD horses, there was an increased prevalence of Bacteroidetes and Proteobacteria and a decrease in Verrucomicrobia. Salmonella-infected horses, however, had lesser Firmicutes when compared to healthy horses.

Conclusions

  • The outcomes suggest that dietary factors do impact the horse’s fecal microbiome, particularly the quantity of grain consumed.
  • However, the research concludes that the presence of diseases like colitis has a much more substantial impact on the fecal microbiome.
  • It was further observed that the impact on microbiome was more severe in horses with ADD as compared to those infected with Salmonella.

Cite This Article

APA
Arnold CE, Pilla R, Chaffin MK, Leatherwood JL, Wickersham TA, Callaway TR, Lawhon SD, Lidbury JA, Steiner JM, Suchodolski JS. (2021). The effects of signalment, diet, geographic location, season, and colitis associated with antimicrobial use or Salmonella infection on the fecal microbiome of horses. J Vet Intern Med, 35(5), 2437-2448. https://doi.org/10.1111/jvim.16206

Publication

Journal of veterinary internal medicine
ISSN: 1939-1676
NlmUniqueID: 8708660
Country: United States
Language: English
Volume: 35
Issue: 5
Pages: 2437-2448

Researcher Affiliations

Arnold, Carolyn E
  • Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
Pilla, Rachel
  • Department of Small Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
Chaffin, M Keith
  • Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
Leatherwood, Jessica L
  • Department of Animal Science, Texas A&M University, College Station, Texas, USA.
Wickersham, Tryon A
  • Department of Animal Science, Texas A&M University, College Station, Texas, USA.
Callaway, Todd R
  • Department of Animal and Dairy Science, University of Georgia, Athens, Georgia, USA.
Lawhon, Sara D
  • Department of Veterinary Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
Lidbury, Jonathan A
  • Department of Small Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
Steiner, Joerg M
  • Department of Small Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
Suchodolski, Jan S
  • Department of Small Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, USA.

MeSH Terms

  • Animals
  • Anti-Bacterial Agents / adverse effects
  • Colitis / chemically induced
  • Colitis / veterinary
  • Diet / veterinary
  • Feces
  • Horse Diseases
  • Horses
  • Microbiota
  • RNA, Ribosomal, 16S / genetics
  • Salmonella Infections
  • Seasons

Grant Funding

  • The Donley Family
  • The Paula and Michael Gaughan Fund

Conflict of Interest Statement

Authors declare no conflict of interest.

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