Hindgut Microflora of Laminitic, Nonlaminitic Horses Compared

Hindgut Microflora of Laminitic, Nonlaminitic Horses Compared

Researchers expected to see decreased bacterial diversity in the laminitic group, but instead discovered a significantly higher bacterial diversity.

Photo: Christy M. West

Could your laminitic horse's poop be harboring secrets about his health? According to new study results obtained by Texas A&M University (TAMU) researchers, it's a possibility. The team examined the DNA of fecal microflora (bacterial population of intestine) from laminitic and nonlaminitic horses and found some surprising differences between the two groups.

While research in other species suggested researchers might find decreased bacterial diversity in laminitic horses, it was the healthy horses that had lower bacterial diversity in the current study.

"The microflora within the gastrointestinal system directly affects energy metabolism, digestive function, mucosal immune system development, and disease pathogenesis," the researchers explained in the study.

"Most of the published literature (in other species) suggests that disease states are associated with a decrease in bacterial diversity," relayed Samantha Steelman, MS, PhD, USDA postdoctoral fellow at TAMU College of Veterinary Medicine Department of Veterinary Integrative Biosciencesand lead researcher on the study. The TAMU researchers worked with David Hood, DVM, PhD, of the Hoof Diagnostic and Rehabilitation Clinic, in Bryan, Texas, on the current study.

Nine healthy horses and seven horses with chronic laminitis were housed separately but fed a nearly identical diet of a pelleted concentrate, coastal bermudagrass, and limited alfalfa hay. Using technology known as "next generation sequencing," the researchers mapped out the bacterial DNA strands extracted from the horses' fecal samples.

To the researchers' surprise, findings from the current study differed from that of most previous published literature on the topic. They expected to see decreased bacterial diversity in the laminitic group, but instead discovered a significantly higher bacterial diversity. They noted that further research regarding changes in bacterial communities is still needed to fully understand the phenomenon.

Other key findings included:

  • Considerable individual variation in bacterial populations among all horses (likely influenced by external factors, researchers said);
  • Samples from the laminitic group contained greater abundance of two unknown bacteria than control horses; and
  • The majority of abundant bacteria found were anaerobic (able to survive with little to no oxygen) fermenters, which the researchers said suggested that the hindgut microflora are specialized for breaking down plant material.

The team concluded, "Our data provide a foundation for future investigations of hindgut bacterial factors that may influence the development and progression of chronic laminitis."

The study, "Pyrosequencing of 16S rRNA genes in fecal samples reveals high diversity of hindgut microflora in horses and potential links to chronic laminitis," will appear in an upcoming issue of BMC Veterinary Research. The abstract can be viewed online.

About the Author

Casie Bazay, NBCAAM

Casie Bazay holds a bachelor of science degree in education from Oklahoma State University. She taught middle school for ten years, but now is a nationally certified equine acupressure practitioner and freelance writer. She has owned Quarter Horses nearly her entire life and has participated in a variety of horse events including Western and English pleasure, trail riding, and speed events. She was a competitive barrel racer for many years and hopes to pursue the sport again soon.

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