Equine Gut Health Explained: Prebiotics, Probiotics and Postbiotics

Why Gut Health and the Microbiome Matter in Horses

Gut health is one of the most important factors influencing a horse’s overall wellbeing, performance and immune system. The gastrointestinal tract is not only responsible for nutrient absorption but is also considered the largest immune organ in the body, contributing up to 70% of total immunity.

Modern equine management practices—such as intensive training, frequent travel, prolonged stabling and dietary changes—can negatively impact the gut microbiome. As a result, digestive support supplements are increasingly used to maintain balance and health.

The most important groups include:

• Prebiotics
• Probiotics
• Postbiotics

Prebiotics for Horses – Feeding the Good Bacteria

Prebiotics are non-digestible ingredients that stimulate the growth and activity of beneficial bacteria in the gut.

In simple terms:

They act as food for good bacteria.

Common equine prebiotics:

• MOS (mannanoligosaccharides)
• FOS (fructooligosaccharides)
• Inulin

Benefits:

• Support gut microbiota balance
• Improve digestion
• Strengthen immune function

Where to find them on the label?

Under Composition

Probiotics for Horses – Live Microorganisms

Probiotics are live microorganisms that provide health benefits when consumed in adequate amounts.

In Europe, only one probiotic is approved for horses:

Saccharomyces cerevisiae (live yeast)

Benefits:

• Improves feed digestibility
• Supports stable gut function

Important:

If there is no CFU (colony forming units) listed, it is NOT a probiotic

“Brewer’s yeast” = inactive yeast (not a probiotic)

Where to find them on the label?

Under Additives

Postbiotics – The New Generation of Gut Support

Postbiotics are the metabolic by-products of microbial fermentation.

They are already “active compounds,” meaning the horse can use them immediately.

Key components include:

• Volatile fatty acids (VFAs) – energy source
• B vitamins (e.g. biotin B7, niacin B3)
• Amino acids and peptides

Benefits:

• Support energy metabolism
• Improve gut function
• Enhance immune response

Important:

Synthetic vitamins or amino acids are not postbiotics

Postbiotics must come from microbial fermentation

Where to find them?

Listed as “Yeast products” under Composition

Microbiota vs Microbiome

These terms are often used interchangeably, but they are not identical.

Microbiota

The microorganisms themselves (bacteria, yeast, protozoa, fungi)

Microbiome

The entire microbial environment:

• Microorganisms
• Genetic material
• Metabolites (VFAs, vitamins, peptides)

Probiotics support microbiota

Probiotics + postbiotics support the microbiome

When Should You Use Gut Health Supplements?

Digestive health affects many aspects of performance and wellbeing. Consider using pre-, pro- and postbiotics in the following situations:

• Loose droppings or digestive upset
• Weight loss
• Poor coat condition
• Reduced performance
• Travel and stress
• High-performance horses
• After deworming
• After antibiotic treatment
• Moving to a new yard

How to Choose the Right Product

Look for:

• Prebiotics – MOS, FOS
• Probiotics – Saccharomyces cerevisiae + CFU
• Postbiotics – Yeast products

Source

Based on material by:

Kate Hore, Head Nutritionist, RNutr (Animal), R.Anim.Technol (Cert), BSc (Hons)