Characterization and comparison of the bacterial microbiota in different gastrointestinal tract compartments in horses.

This research examines and compares the bacterial profiles found in different parts of the horse’s digestive system. Using high-throughput sequencing technology, the study found significant variations in bacterial populations across different digestive compartments, with the presence of specific bacterial species in each part due to the various environmental factors such as pH levels, digestive enzymes, and anaerobiosis. The results also indicate that fecal samples might provide a reliable representation of changes in the distal gut.

Understanding the Bacterial Microbiota in Horses’ Digestive Tract

• This study uses new sequencing technologies to examine the complex microbial communities habiting different compartments of horses’ intestinal tract.
• The presence of intense environmental filters such as the low pH, anaerobic conditions and digestive enzymes along the digestive tract result in the selection and survival of unique species of bacteria in each compartment.
• Understanding the different bacterial communities across these compartments is crucial due to their impact on the overall health of the horse.

Methodology and Findings

• The researchers leveraged high throughput sequencing to study and compare the bacterial profiles for different compartments of the intestinal system in 11 horses that were scheduled for euthanasia for reasons not related to any gastrointestinal problems.
• The compartments showed significant differences even at higher taxonomic levels. However, Firmicutes were found to be the dominant bacterial phylum across all compartments.
• In the stomach, Lactobacillus spp. and Sarcina spp. were found to be dominant, while there was a marked increase of Streptococcus spp. in the duodenum, the initial section of the small intestine.
• In the ileum (last part of the small intestine), the most abundant genera were Actinobacillus and Clostridium sensu stricto, while the large colon through feces was dominated by a genus from the Subdivision 5 class of Verrucomicrobia called ‘5 genus incertae sedis’.

Significance of the Findings

• There was a remarkable increase in the diversity of bacterial populations towards the distal (or terminal) part of the gut.
• At the class level, similar bacterial profiles were identified from the cecum (a pouch that forms the first part of the large intestine) through the feces.
• From these observations, the study concludes that the bacterial composition varies significantly across different compartments of the horses’ intestinal tract.
• Moreover, it points out that fecal samples could be a useful indicator of changes and alterations happening in the distal compartments of the horse’s intestinal system.