Molecular profiling of Lactobacillus, Streptococcus, and Bifidobacterium species in feces of active racehorses.

This study analyzed the types and abundance of three groups of bacteria found in the feces of professional racing horses. The research indicates that the gut microbiome of these horses is consistent over a three month period and contains some species unique to horses.

Study Method and Species Found

• The researchers focused on three groups of bacteria in the horse’s feces: Lactobacillus, Streptococcus, and Bifidobacterium. They used laboratory methods, PCR-denaturing gradient gel electrophoresis (DGGE) and real-time PCR, to identify and quantify the different species within these groups.
• Among the Lactobacillus group, Lactobacillus equi, Lactobacillus johnsonii, a relative of Lactobacillus salivarius, a relative of Lactobacillus gastricus, and Weissella confusa were most commonly found.
• Within the Streptococcus group, Streptococcus bovis/Streptococcus equinus were the predominant species.
• The Bifidobacterium group was not identified by the initial PCR test, but a few atypical species were found in 3 out of 6 horses tested by nested-PCR.

Bacteria Abundance

• Analysis found that lactic acid bacteria, which encompass both Lactobacillus and Streptococcus groups, were predominant in the feces sample.
• On the other hand, bifidobacteria, which belong to Bifidobacterium group, were minor contributors.
• These results emphasize the unique composition of bacteria in horses– they harbor a specific set of bacterial species and have a low proportion of the Bifidobacterium group.

Stability of Bacteria Composition

• Tests performed over a 3 month period showed that horse gut microbiome, particularly the Lactobacillus, Streptococcus, and Bifidobacterium groups of bacteria, are largely stable over time.