Changes in faecal bacteria associated with concentrate and forage-only diets fed to horses in training.
Authors: Willing B, Vörös A, Roos S, Jones C, Jansson A, Lindberg J E
Journal: Equine veterinary journal
Summary
# Editorial Summary Training horses on high-energy concentrate diets has long been standard practice to meet their increased metabolic demands, yet these grain-rich rations are implicated in various gastrointestinal disturbances linked to shifts in the hindgut microbiota—changes that remain poorly characterised. Willing and colleagues fed six Standardbred geldings under training either a forage-only diet or a traditional forage-concentrate diet in a crossover design lasting 29 days per period, collecting faecal samples at multiple timepoints and analysing bacterial communities using molecular techniques (16S rRNA gene sequencing) alongside direct culture of lactic acid bacteria and enterobacteria. The forage-only diet produced a more stable microbial ecosystem with significantly lower counts of cultivable lactic acid bacteria, particularly Streptococcus bovis/equinus complex members; in contrast, the concentrate diet consistently harboured motile Lactobacillus ruminis and prompted increases in Clostridiaceae alongside reductions in certain Bacteroidales groups. These findings suggest that concentrate feeding—whilst meeting energy requirements—disrupts microbial balance in ways that could compromise intestinal health, indicating potential merit in developing forage-based feeding strategies for working horses, though the specific clinical significance of these microbial shifts warrants further investigation to establish causative links with documented digestive disorders.
Read the full abstract on PubMed
Practical Takeaways
- •Feeding high-energy forage-only diets to performance horses may promote more stable and healthier gut microbiota compared to traditional concentrate-supplemented diets, potentially reducing gastrointestinal disorders
- •Concentrate feeding drives proliferation of potentially problematic bacteria (Streptococcus bovis/equinus) that may contribute to digestive disturbances in training horses
- •Consider forage-based feeding strategies as a management tool to support intestinal health and welfare in horses in training, though energy requirements must still be met
Key Findings
- •Forage-only diet resulted in more stable microbial composition between sampling periods compared to forage-concentrate diet
- •Forage-concentrate diet significantly increased cultivable lactic acid bacteria and Streptococcus bovis/equinus complex members (P < 0.05)
- •Motile and swarming Lactobacillus ruminis was present in all horses on concentrate diet but absent in forage-only diet horses
- •Forage-concentrate diet increased Clostridiaceae cluster III members and reduced unknown Bacteroidales groups (P < 0.05)