Dietary Energy Sources Affect Cecal and Fecal Microbiota of Healthy Horses.
Authors: Brandi Laura A, Nunes Alanne T, Faleiros Camila A, Poleti Mirele D, Oliveira Elisângela C de M, Schmidt Natalia T, Sousa Ricardo L M, Fukumasu Heidge, Balieiro Julio C C, Brandi Roberta A
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Energy Sources Shape Equine Microbiota Composition Researchers at the University of São Paulo investigated how three distinct dietary energy approaches—forage alone, forage with added starch and sugar, and forage with fiber and oil supplements—influence the bacterial populations inhabiting the cecum and colon of healthy horses. Using high-throughput genetic sequencing on samples from five horses, the team not only characterised microbial community structure but also measured fermentation byproducts (short-chain fatty acids), pH, and buffering capacity across both sites. Whilst the starch-supplemented diet produced subtle shifts in cecal buffering capacity and the oil-based diet increased fecal microbial diversity, each energy source drove distinct compositional changes: starch diets favoured potentially problematic taxa like *Desulfovibrio* and *Streptococcus*, whilst fibre-oil diets promoted beneficial genera including *Prevotella* and *Akkermansia*. Notably, these microbial compositional shifts occurred without dramatic alterations to pH or fermentation patterns, suggesting the diets tested did not provoke acute dysbiosis in these healthy individuals. For practitioners formulating performance diets, these findings support the role of fibre and oil as microbiota-modulators that maintain favourable bacterial profiles, whilst highlighting the need for caution with high-starch inclusions—particularly given that long-term effects and responses in horses with compromised gastrointestinal health remain unexplored.
Read the full abstract on PubMed
Practical Takeaways
- •Diet choice (hay alone vs. supplemented with starch/sugar or fiber/oil) meaningfully shifts gut bacterial populations in horses; practitioners should recognize these differences may affect long-term digestive health and consider individual horse responses
- •While the study found no immediate negative effects on fermentation under these conditions, the differential shifts in bacterial populations suggest dietary choices have specific microbiota signatures worth monitoring in practice
- •Small sample size (n=5) limits generalizability; obtain additional research before making broad recommendations, but results suggest fiber/oil supplementation may promote potentially beneficial bacteria (Akkermansia, Prevotella) compared to high-starch diets
Key Findings
- •Hay diet associated with highest fecal pH and lower alpha diversity in feces compared to supplemented diets
- •Starch and sugar diet increased Desulfovibrio, Lachnospiraceae AC2044, and Streptococcus in cecum; Streptococcus and Prevotellaceae UCG-001 in feces
- •Fiber and oil diet increased Prevotella, Prevotellaceae UCG-003, and Akkermansia in cecum; Rikenellaceae RC9 gut group and Ruminococcus in feces
- •Different energy sources altered microbiota composition and fecal diversity without significantly affecting fermentation processes (pH, short-chain fatty acids, buffer capacity)