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External supporting research SCFAs, gut barrier & inflammation Peer reviewed EXT-S01

Short-Chain Fatty Acids & Colic in Horses — 2025 Review

Independent peer-reviewed research from Lincoln Memorial University reviews how short-chain fatty acids — particularly acetate, propionate and butyrate — support the equine gut barrier, energy metabolism and immune regulation, and how disruption of SCFA production may contribute to gastrointestinal dysfunction and colic risk.

Original study title

The Role of Short-Chain Fatty Acids (SCFAs) in Colic and Anti-Inflammatory Pathways in Horses

Short-chain fatty acids Butyrate Colic Gut barrier Inflammation Hindgut microbiome Diet
Study at a glance
Year 2025
Study type Narrative review
Publication Peer-reviewed review article
EquiNectar tested? No
Peer reviewed Yes
Open access Yes
Relationship External supporting research
Research question

What did the researchers want to understand?

What roles do short-chain fatty acids play in equine gastrointestinal health, intestinal barrier function and inflammatory regulation, how might disruption of SCFA production relate to colic, and what nutritional or microbiome-based strategies may support healthy SCFA production?

Researchers

Study authors

Nathan Schank


Lincoln Memorial University

Ashley Cottone


Lincoln Memorial University

Michelle Wulf


Lincoln Memorial University

Keely Seiter


Lincoln Memorial University

Brinley Thomas


Lincoln Memorial University

Lynda M. J. Miller


Lincoln Memorial University

Stacy L. Anderson


Lincoln Memorial University

Amal Sahyoun


Lincoln Memorial University

Amal Sahyoun


Lincoln Memorial University

Modar Kassan


Lincoln Memorial University

Ashutosh Verma


Lincoln Memorial University
Research organizations

Research institutions

Lincoln Memorial University

University
United States
Methodology

How the study was conducted

Study design

This was a peer-reviewed narrative review of published scientific literature.

The authors critically examined evidence concerning the production and biological functions of short-chain fatty acids in horses, with particular emphasis on acetate, propionate and butyrate.

The review considered relationships between diet, the hindgut microbiome, epithelial barrier integrity, inflammation and colic, together with potential strategies for supporting SCFA production.

Both equine-specific evidence and relevant mechanistic findings from other species were considered, with the authors explicitly identifying areas where direct equine evidence remains limited.

What was measured

No new animals, samples or experimental data were measured in this study.

The authors reviewed and synthesized published evidence concerning equine short-chain fatty-acid production, gut microbial ecology, intestinal barrier integrity, immune and inflammatory signaling, hindgut acidosis and colic.

The review also examined nutritional and microbiome-directed approaches proposed to support SCFA production, while assessing the limitations of the current equine evidence base.

Study findings

Key results

• Acetate, propionate and butyrate are major short-chain fatty acids produced through microbial fermentation in the equine hindgut.

• SCFAs provide an important source of energy and contribute to intestinal barrier integrity, motility and immune regulation.

• Butyrate is particularly important as an energy source for colonocytes and is involved in maintaining epithelial tight junctions and mucus production.

• High-starch and low-fiber dietary patterns can alter microbial communities and reduce populations associated with fiber fermentation and SCFA production.

• Reduced SCFA availability is associated with impaired barrier function, increased intestinal permeability and inflammatory signaling.

• Altered SCFA profiles have been observed in horses with gastrointestinal disease and experimental hindgut disruption.

• The authors emphasize that the causal relationship between SCFA depletion and colic remains incompletely understood.

• More longitudinal, controlled and mechanistic equine studies are needed before SCFA-targeted interventions can be translated into firm clinical recommendations.

Interpretation

What do the findings mean?

The review places short-chain fatty acids at an important intersection between diet, the equine microbiome, intestinal barrier function and immune regulation.

Acetate, propionate and butyrate are produced largely through microbial fermentation of dietary fiber. Among them, butyrate is particularly important because it supplies energy to colonocytes and contributes to maintenance of epithelial tight junctions and mucus production.

The authors propose that disruption of normal microbial fermentation can reduce SCFA availability, weaken intestinal barrier function and contribute to inflammatory processes associated with gastrointestinal disease.

However, the review does not establish that increasing a particular SCFA will prevent colic, nor does it demonstrate efficacy for any specific nutritional product. Its principal contribution is to bring together the growing mechanistic evidence linking microbial metabolism with equine gastrointestinal resilience.

In practice

Why this research matters

Horses depend heavily on microbial fermentation in the hindgut to extract energy from dietary fiber. Acetate, propionate and butyrate are among the principal short-chain fatty acids produced during this process.

The review describes these metabolites as having functions that extend beyond energy production. In particular, butyrate provides an important energy source for cells lining the colon and is involved in maintaining epithelial barrier integrity, mucus production and regulation of inflammatory signaling.

Diet strongly influences this microbial environment. The authors describe how forage-rich diets support fibrolytic microbial communities, while greater starch exposure can favor lactate-producing organisms and disrupt the balance of fermentation.

This reinforces the importance of feeding and management strategies that support stable hindgut fermentation rather than focusing on any single bacterial species or supplement.

Research transparency

Study limitations

This is a review article and did not generate new experimental data.

Although substantial evidence supports important biological roles for short-chain fatty acids, the authors emphasize that equine-specific research remains limited. Much of the detailed knowledge concerning SCFA signaling, immune regulation and therapeutic applications has been derived from human, rodent or other animal research.

Associations between altered SCFA profiles, dysbiosis and colic do not establish whether reduced SCFA production is a cause of gastrointestinal disease, a consequence of disease, or both.

Colic is also a multifactorial clinical syndrome with many different causes, and SCFA biology represents only one component of its pathophysiology.

The authors therefore call for longitudinal and mechanistic studies in horses to determine how diet, microbiome composition, SCFA production and gastrointestinal disease interact over time.

EquiNectar context

How this research relates to EquiNectar

This research did not test EquiNectar and was conducted independently of Tharos Ltd.

Its relevance to EquiNectar is mechanistic. The review identifies short-chain fatty acids — particularly acetate, propionate and butyrate — as important microbial metabolites involved in energy supply, intestinal barrier integrity and regulation of inflammatory pathways within the equine gut.

This independently supports the biological relevance of findings from published EquiNectar research. In the 2024 Waring, Dagi & Hunter horse study, mean total fecal short-chain fatty acids increased from 1,376 ppb before supplementation to 2,077 ppb after eight weeks of EquiNectar, including increases in mean acetate, propionate and butyrate.

The Schank review does not validate EquiNectar itself. Rather, it provides independent scientific context explaining why the SCFA changes measured in EquiNectar research may be biologically important.

Tharos / EquiNectar involvement

None. This review was conducted independently by researchers at Lincoln Memorial University. EquiNectar and Tharos Ltd were not evaluated in the paper and were not involved in the research, authorship or publication.

EquiNectar evaluated No
Transparency

Funding & competing interests

Funding statement

Ashutosh Verma was supported by Lincoln Memorial University institutional grants 25MKA001, 24AV001 and 25AV001. Ammaar H. Abidi was supported by Lincoln Memorial University institutional grant 25SKM001 and the Naserdean Foundation. Modar Kassan was supported by institutional grant 25MKA001, the Naserdean Foundation and the American Heart Association grant 5TPA1482496.

Competing interests

The authors declared no conflicts of interest. The published paper states that the funders had no role in study design, data collection, analysis or interpretation, preparation of the manuscript, or the decision to publish.

Source record

Publication details

Journal
Animals
Publisher
MDPI
Year
2025
Volume
15
Issue
23
Pages / article
3482
DOI
10.3390/ani15233482
PMID
41375540
Species
Horse
License
CC BY 4.0
View original source ↗ Read full text ↗
Recommended citation

Schank N, Cottone A, Wulf M, Seiter K, Thomas B, Miller LMJ, Anderson SL, Sahyoun A, Abidi AH, Kassan M, Verma A. The Role of Short-Chain Fatty Acids (SCFAs) in Colic and Anti-Inflammatory Pathways in Horses. Animals. 2025;15(23):3482. doi:10.3390/ani15233482.

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