The horse gut bacteriome and anaerobic mycobiome are influenced by seasonal forages and small intestinal starch digestibility.

The research article explores how the populations of bacteria and anaerobic fungi in the gut of horses are affected by different dietary conditions and the availability of starch in the small intestine.

Objectives and Methodology

• The aim of this investigation was to explore the diversity of bacteria and anaerobic fungi (organisms that thrive in conditions without oxygen) in the hindgut of horses, and how this diversity changes with seasonal differences in diet.
• Sample collection and analysis involved gathering faecal samples from 48 horses, and studying these samples using long-read amplicon sequencing, a technique used to identify variations in genetic material.
• The researchers collected samples from two groups of horses: racehorses who are on high-concentrate diets, and wild-foraging horses who graze on different pastures through the seasons.

Findings

• The study showed that the bacterial profiles in the horses’ guts differed greatly, and these differences were strongly influenced by the seasons.
• In the racehorses, whose diet is developed to reduce the availability of starch in the hindgut, fibrolytic or fibre-digesting bacteria such as Roseburia were promoted while the amylolytic or starch-digesting bacteria such as Lactobacillus were reduced.
• The community of anaerobic fungi, although generally stable across different diets and seasons, exhibited differences between the two groups of horses. Certain fungi, Piromyces and Khoyollomyces, were more commonly associated with the wild-foraging horses, while Caecomyces was more common in the racehorse group.

Conclusion

• These results highlight how the diverse microbiome in the gut of horses is impacted by the shifting components of the diet.
• The authors suggests that future research combining different types of biological data will further improve our understanding of the functionality of the gut microbiome, helping develop strategies to optimize horse gut health.