A horse's digestion is based on extensive and sensitive microbial fermentation, where efficient use of fiber is especially key. This is precisely why yeasts and yeast-based products have been used in equine feeding for a long time—and why they have also been studied extensively. Based on research, the interest in yeasts is linked to the fact that they help create intestinal conditions in which fiber can be utilized as efficiently as possible. In this article, yeasts are examined in a practical way: what they are, why they are used, and what research has found.
What Is Meant by Yeasts in Equine Feeding?
In equine feeding, yeasts used are most commonly based on Saccharomyces cerevisiae yeast strains. They may be:
- live yeasts
- yeast cultures
- products derived from yeast
Yeasts do not replace the horse's own gut microbiota. Instead, they influence the conditions in which the intestinal microbes function.
Put simply: yeasts do not do digestion on behalf of the horse. They help the gut operate under more favorable conditions.
Yeasts and Fiber Utilization – Why Is This Important?
Multiple studies have found that the use of yeast products is associated with more efficient fiber fermentation, better fiber digestibility, and the activity of microbial fermentation in the hindgut.
In practice, this means that feed does not merely pass through the horse. Instead, fiber is better utilized in the horse's digestive process.
In studies, the effects of yeasts are seen specifically in how well a fiber-based feeding program functions, not in the absorption of individual nutrients.
Impact on the Digestive Environment – "Working Conditions" in the Gut
For gut microbes to break down fiber efficiently, conditions in the hindgut must be suitable. In research, yeasts have been linked particularly to:
- maintaining a low-oxygen environment in the hindgut
- the steadiness and stability of fermentation
- supporting the operating conditions of microbes
In other words, yeasts help keep the gut's working environment calm and functional, which is a prerequisite for normal microbial fermentation.
Glade (1991) and later studies have shown that yeast use is associated with overall feeding efficiency when the functioning of the entire digestive tract is considered.
Yeasts and Hindgut Fermentation
The hindgut is the center of the horse's digestion. According to research, yeasts are connected to hindgut microbial activity, they participate in regulating fermentation, and they influence the efficiency of fiber breakdown.
Graham-Thiers & Bowen (2011) showed that yeast supplementation can improve parameters of fiber digestibility. This highlights the role of yeasts as part of a balanced, well-functioning overall feeding strategy.
Yeast-Derived Products, MOS, and Beta-Glucans – What Does This Mean in Practice?
Some yeast products contain compounds derived from the yeast cell wall, such as:
- mannan oligosaccharides (MOS)
- beta-glucan chains
These are not live microbes. They are fiber-like structures that pass through the digestive tract and interact with the gut environment.
In studies:
MOS compounds have been examined due to their role in interactions between bacteria and the gut
beta-glucans are known as structural carbohydrates that the body recognizes biologically
These compounds are considered as part of a nutritional whole, not as medicinal substances.
Summary – Why Are Yeasts Used in Equine Feeding?
Based on research, the use of yeasts in equine feeding is linked especially to the fact that they:
- support efficient utilization of fiber
- promote normal microbial fermentation in the hindgut
- help maintain stability in the intestinal environment
- are part of a functional and long-term feeding approach
Yeasts are not a quick fix. They are part of a nutritional strategy aimed at supporting normal, balanced digestive function in the horse.
References
- Glade, M. J. (1991). Yeast culture supplementation improves feed digestibility and performance in horses.
- Medina, M. et al. (2002). Effect of yeast culture supplementation on digestion in horses.
- Graham-Thiers, P. & Bowen, L. (2011). Impact of yeast supplementation on fiber digestibility in horses.
- Respondek, F. et al. (2008). Prebiotic potential of yeast-derived products in horses.
- Wagner, A. et al. (2015). Effects of prebiotics and yeast products on equine gastrointestinal health.
