Independent EquiNectar-related research Microbiome & metabolomics Peer reviewed EQN-S01

Racehorse Microbiome & Metabolome Study

Peer-reviewed research in Thoroughbred racehorses found marked changes in the fecal volatile metabolome after six weeks of EquiNectar supplementation, alongside measurable changes in microbial community structure.

Original study title

Characterisation of the faecal metabolome and microbiome of Thoroughbred racehorses

Microbiome Metabolome Volatile organic compounds Starch digestion Racehorses

Study at a glance

Year 2014

Study type Intervention study

Sample 8 horses at baseline; 6 available for paired post-supplementation analysis

Duration 6 weeks

Population Castrated male Thoroughbred racehorses aged 4–6 years in active flat-race training

Publication Peer-reviewed journal article

EquiNectar tested? Yes

Peer reviewed Yes

Open access Yes

Relationship Independent EquiNectar-related research

8 → 6

Horses sampled at baseline → available after six weeks

81 / 28

VOCs identified / present in more than 50% of samples

1,200–3,000

Verifiable microbial OTUs per individual

P < 0.05

Significant reduction in fecal acetic and propanoic acid

Research question

What did the researchers want to understand?

Two complementary approaches were used.

The fecal volatile metabolome was characterized using thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). Volatile organic compounds were identified using AMDIS software and comparison with the NIST mass-spectral database.

The fecal microbiome was characterized by sequencing 16S rRNA gene amplicons using 454 pyrosequencing. Sequence data were processed using QIIME and bacterial operational taxonomic units were classified and compared between pre- and post-supplementation samples.

This allowed the researchers to examine both microbial community structure and the metabolic products associated with microbial fermentation.

Researchers

Study authors

Christopher Proudman

University of Surrey

John O. Hunter

Professor

Tharos Ltd
Addenbrooke's Hospital

A. C. Darby

University of Liverpool

E. E. Escalona

University of Liverpool

C. Batty

Open University

C. Turner

Open University

Research organizations

Research institutions

University of Surrey

University
United Kingdom

Addenbrooke's Hospital

Hospital
United Kingdom

University of Liverpool

University
United Kingdom

Open University

University
United Kingdom

Methodology

How the study was conducted

Study design

Eight privately owned castrated male Thoroughbred racehorses aged 4–6 years were studied while in active flat-race training. All were housed at the same premises, managed by the same trainer and fed a standardized diet.

Fecal samples were collected before supplementation. The horses then received EquiNectar for six weeks, providing a total of 200 g per day divided between morning and evening feeds, with 70% of the daily amount provided in the larger evening feed.

Six horses were available for repeat sampling after six weeks; two were lost from the study because of orthopedic injury.

There was no separate untreated control group. Pre- and post-supplementation samples were compared using metabolomic and microbiome analyses.

Sampling and metadata collection were conducted under University of Liverpool ethics approval RETH000363 with the trainer's informed consent.

What was measured

Two complementary approaches were used.

This allowed the researchers to examine both microbial community structure and the metabolic products associated with microbial fermentation.

Study findings

Key results

• 81 different volatile organic compounds (VOCs) were identified; only 28 were present in more than 50% of samples.

• Fecal VOC profiles differed substantially between pre- and post-supplementation sampling.

• Acetic acid and propanoic acid abundance were significantly reduced after supplementation (p<0.05).

• The fecal microbiome was highly diverse, with approximately 1,200–3,000 verifiable operational taxonomic units (OTUs) per individual.

• Significant differences were detected in several lower-abundance bacterial taxa after supplementation.

• Changes in overall bacterial community structure were relatively small and inconsistent between individual horses despite marked changes in the metabolome.

• The authors concluded that the intervention primarily induced metabolic adaptation within existing microbial communities rather than a dramatic change in overall community structure.

Interpretation

What do the findings mean?

The strongest change observed after supplementation was functional rather than a wholesale restructuring of the microbial community.

Fecal volatile-organic-compound profiles changed markedly, including statistically significant reductions in acetic and propanoic acid. In contrast, overall changes in microbial community structure were smaller and varied between individual horses.

The authors concluded that the intervention appeared to produce metabolic adaptation within existing bacterial communities rather than dramatic replacement of those communities.

They considered the reduction in fecal products of carbohydrate fermentation to be consistent with enhanced pre-caecal starch digestion, leaving less carbohydrate available for hindgut fermentation. However, the study did not directly measure small-intestinal starch digestion or the cecal environment, so this remains a mechanistic interpretation rather than a direct measurement.

In practice

Why this research matters

Racehorses commonly receive relatively high-energy, concentrate-based diets. The amount and digestibility of carbohydrate reaching the hindgut can influence microbial fermentation and the metabolites produced there.

In this study, EquiNectar supplementation was associated with substantial changes in the fecal volatile metabolome. The authors considered the reduction in several products of carbohydrate fermentation to be consistent with enhanced pre-caecal starch digestion and therefore less carbohydrate becoming available for microbial fermentation in the hindgut.

The study also demonstrated that individual horses differed in their microbial response, reinforcing the complexity and individuality of the equine hindgut microbiome.

Research transparency

Study limitations

This was a small study involving eight Thoroughbred racehorses from a highly homogeneous population managed at the same premises by the same trainer.

Only six horses were available for post-supplementation sampling because two were lost from the study following orthopedic injury.

There was no untreated control group, no crossover design and no repeated control sampling over the same period. The authors therefore acknowledged that unmeasured changes over time could potentially have contributed to differences between the two sampling points.

Fecal samples were used as a practical proxy for the intestinal environment, but fecal microbial communities are not identical to those within the cecum and more proximal large colon.

The highly standardized population helped reduce within-study variation but limits how confidently the findings can be extrapolated to horses managed under different conditions.

EquiNectar context

How this research relates to EquiNectar

This study directly evaluated EquiNectar in Thoroughbred racehorses.

After six weeks of EquiNectar supplementation, researchers identified substantial changes in the fecal volatile metabolome alongside smaller changes in microbial community structure.

The findings provide direct evidence that EquiNectar supplementation can influence downstream microbial fermentation and metabolic activity within the equine digestive system.

Tharos / EquiNectar involvement

No involvement by Tharos Ltd is stated in the published paper. The study evaluated dietary supplementation with amylase-rich malt extract. Sequencing work was funded independently through a Bluesky Research grant from the Royal College of Veterinary Surgeons Charitable Trust.

EquiNectar evaluated Yes

Transparency

Funding & competing interests

Funding statement

Sequencing work was funded by a Bluesky Research grant from the Royal College of Veterinary Surgeons Charitable Trust.

Competing interests

No competing interests were declared.

Source record

Publication details

Journal

Equine Veterinary Journal

Publisher

Wiley

Year

2014

Volume

Issue

Pages / article

580–586

DOI

10.1111/evj.12324

PMID

25041526

Species

Horse

Population

Castrated male Thoroughbred racehorses aged 4–6 years in active flat-race training

Sample

8 horses at baseline; 6 available for paired post-supplementation analysis

Duration

6 weeks

Setting

Single Thoroughbred flat-racing yard, with all horses managed by the same trainer

License

Wiley self-archiving terms — non-commercial use

View original source ↗ Read full text ↗

Recommended citation

Proudman CJ, Hunter JO, Darby AC, Escalona EE, Batty C, Turner C. Characterisation of the faecal metabolome and microbiome of Thoroughbred racehorses. Equine Veterinary Journal. 47(5):580–586. doi:10.1111/evj.12324.

Racehorse Microbiome & Metabolome Study

What did the researchers want to understand?

Study authors

Christopher Proudman

John O. Hunter

A. C. Darby

E. E. Escalona

C. Batty

C. Turner

Research institutions

University of Surrey

Addenbrooke's Hospital

University of Liverpool

Open University

How the study was conducted

Key results

What do the findings mean?

Why this research matters

Study limitations

How this research relates to EquiNectar

Funding & competing interests

Funding statement

Competing interests

Publication details

Related research

EquiNectar Racehorse Fecal pH Study

Related practical resources

Hindgut Acidosis in Horses: Signs, Causes & Management