The Role of Yeast Derivatives in Improving Animal Gut Health

Is there anything that replaces the antibiotics without actually replacing the results?
The answer to this is a single-celled organism known as yeast.
Brewer’s yeast, also known as Saccharomyces cerevisiae, has historically been an important contributor to food products and alcoholic beverages. In recent years, animal science and microbiology have identified even further functional capabilities of this yeast. The ability to transform the development, defense, and absorption processes within an animal’s gastrointestinal system by utilizing specific functional fractions present within the yeast.
These functional fractions such as yeast cell wall (YCW), beta-glucans, mannan-oligosaccharides (MOS), yeast nucleotides, and hydrolysed yeast are known collectively as yeast derivatives. Approximately ten years of research concerning yeast derivatives is currently available to support the previously mentioned claims of functional capabilities.
A meta-analysis published in 2023 in Frontiers in Veterinary Science included results from 47 trials related to poultry and swine and provided evidence that the use of MOS derived from yeast resulted in an increased height-to-depth ratio of intestinal villi (a key determiner of absorption capacity) and a reduction in pathogenic bacteria colonizing the intestine.
What Is Happening Inside the Gut?
The intestinal tract is more than a simple tube. The intestinal lining in broiler birds, for example, will experience a turnover approximately every 48–72 hours. Therefore, if the intestinal lining (gut) is fed and contained with adequate nutrients, the villi will grow tall and longer, which increases the total surface area of the intestinal lining and thus, the ability to absorb nutrients.
On the other hand, if the intestine is not fed an adequate diet or is allowed to be colonised by pathogenic organisms (such as Clostridium perfringens, or certain species of Salmonella), the villi will become shorter and blunted, which will result in a higher rate of mortality and reduced feed conversion ratios (FCR).
Yeast-derived products can assist the owner with a 2-fold mechanism of action:
1. Pathogen Exclusion using Mannan Oligosaccharides (MOS):
The mannan-oligosaccharides in yeast will physically attach to the fimbriae (attachment receptors) of harmful gram-negative pathogenic bacteria such as Salmonella spp and E. coli. While the pathogenic bacteria would normally adhere to the intestinal lining, by attaching to the MOS, the pathogenic bacteria are removed from the gastrointestinal tract when the yeast-derived MOS is consumed and digested. Research conducted at the University of Georgia in 2022 determined that the use of MOS in feed formulation (via 0.5 g/kg of feed) resulted in a 34% reduction in Salmonella colonisation of the intestinal tract of broiler birds over a 35-day time period.
2. Immune Modulation via Beta-Glucans:
Beta 1, 3/1, 6 glucans from yeast cell wall binds to pattern recognition receptors on Macrophages and Dendritic cells including Dectin-1, and primes the innate immune system without producing excessive inflammation in the process. Animal Feed Science and Technology in 2024 published research that demonstrated that beta-glucan supplementation applied to piglets after weaning resulted in lower levels of serum IL-6 and TNF-α (Inflammatory markers) and greater levels of both immunoglobulin A secretion in gut lumen. Therefore, will provide a better defence against immune challenges but with minimal collateral damage.
The Story of a Cattle
The attention moves back from the gut of ruminants to what is going on in the Rumen itself.
A stressed or dysbiotic Rumen leads to inefficient fibre fermentation, reduced production of volatile fatty acids and access to energy will be limited. This is where the saviour is; Live yeast and yeast cultures.
Studies published by the Journal of Dairy Science (2023) showed that during heat stress, the use of Saccharomyces cerevisiae supplemented to the diet of high producing dairy cows kept the rumen pH stable resulting in an up to 28% reduction in the incidence of subclinical ruminal acidosis.
How did this occur?
Yeast consumes any residual oxygen in the Rumen, thus producing a more deficient oxygen environment, which favours the growth of fibre digesting bacteria such as Fibrobacter succinogenes.
Improved rumen function is equal to improved milk production, improved body condition score and reduced culling rates.
Post-Antibiotic
The alteration of India’s Drug and Cosmetic Rules in 2021 when Class H1 was amended demonstrating growth promoters have moved away from being viewed solely as a regulation of how they will be used but rather an indication of how to address the urgent and non-negotiable nature of the global antibiotics resistance crisis.
The Global Yeast Derivative Market Value has been estimated to be $2.8 billion for the year ending 2023 and projected by Grand View Research to increase to $5.1 billion by 2030, the result of the animal nutrition industry’s movement away from its dependency on antibiotics.
Furthermore, it has been shown that while yeast derivatives will fill voids left by discontinued use of antibiotics as growth promoters yeast derivatives can also perform as well as or in many cases out perform (at least in 2 trial conditions), growth promoter antibiotics in long term gut morphology and microbiome diversity, as these are also two primary outcomes that have been routinely documented in prior studies as having been adversely affected by growth promoting antibiotic use.
From Research to Commercial Application
Precision is vital during the transition from research to commercialization. Dosing, processing method (autolysed vs. hydrolysed vs. dried yeast), and the ratio of beta-glucans to MOS in each product all impact the result. There is a great amount of difference among yeast derivatives and therefore the use of a generic product without taking into consideration which animal species is involved, which production phase they are in, and the amount of stress that they are experiencing can give varying results.
Therefore bio-based animal health companies are investing in fractionation technology to produce specific yeast fractions, rather than to produce crude or whole yeast products to standardise the use of specific fractions at specific concentrations for specific gut issues. The industry is moving from thinking about “yeast” as a category to how to categorise “which fraction, how much concentration, and what type of gut issue are we dealing with”.
A Gut Feeling Worth Trusting
Gut is where productivity starts and health is protected.
Yeast derivatives present an unusual option for addressing today’s challenges i.e. rising costs of feed, increased pressure from consumers to scrutinize the way animals are produced, and enhanced regulations by providing an option that is holistic, backed by science and able to be produced commercially.
From the Maharashtra poultry farm to dairies in Punjab to shrimp ponds in Andhra Pradesh, the invisible biology of yeast is becoming a key component for animal production today, and the science continues to develop further!
Frequently Asked Questions
Q1. What is the difference between live yeast and yeast derivatives?
Live yeast cells (e.g., live S. cerevisiae strains) are organisms that remain active after ingestion and positively impact rumen function in ruminants. In contrast, yeast derivatives are extracts of the yeast organism, including MOS, beta-glucan, or hydrolysed yeast, which no longer remain alive but contain particular biologically active components regulating immune response, excluding pathogens, and structuring the gut microflora. Live yeasts and derivatives perform different functions in animal nutrition.
Q2. Are yeast derivatives safe for all livestock species?
Yes, yeast derivatives are widely researched in relation to use in poultry, swine, ruminants, fishery, and pet animal species. They are GRAS in the USA, and their use is authorised across European and Asian countries. The most crucial thing about yeast derivatives is dosage and choosing the right fraction what is best for one animal can be different for another.
Q3. Can yeast derivatives fully replace antibiotic growth promoters?
Yes, in many cases where there is an effective hygiene management system, effective feed formulation and biosecurity practices, they can be used to entirely replace AGPs. Studies have proven that MOS and beta-glucans can perform better than AGPs in terms of improving FCR, reducing mortality rates and improving gut integrity. They cannot however be used to treat diseases; they will not cure diseases.
Q4. How quickly do yeast derivatives show results in production animals?
The improvement in gut morphology (villus height and crypt depth) takes about 7-14 days after starting the supplementation program. The effects on FCR and growth performance can be seen to be significantly improved after week 3-4 in broilers and after 6-8 weeks in cattle.