Research & Insights
Brewer’s Yeast vs DDGS in Livestock Feed: Composition, Use Levels and Risks
Published
Brewer’s yeast and DDGS both come out of fermentation, but they do different jobs in a diet. Corn DDGS is a bulk energy and fibre ingredient with about 30% crude protein and weak lysine. Dried brewer’s yeast is a concentrated protein with about three times the lysine per kilogram. Formulators use DDGS at 10 to 30% and yeast at 1 to 5%.
This guide compares the two on composition, use levels by species and the risks a buyer should check. All figures come from Feedipedia and peer-reviewed trials listed under Sources.
What is the difference between brewer’s yeast and DDGS?
DDGS (distillers dried grains with solubles) is what is left of the grain after ethanol production. The starch is fermented away, so protein, fibre, fat and minerals are concentrated about threefold. Most of the product is grain residue. Ethanol yeast is present, but only as a small share.
Dried brewer’s yeast is the yeast itself. It is the Saccharomyces cerevisiae biomass recovered after beer fermentation, then inactivated and dried. There is no grain residue in it, which is why fibre and fat are low and protein is high.
So the two are not substitutes in the strict sense. DDGS replaces part of the corn and soybean meal. Brewer’s yeast replaces part of the soybean meal, fish meal or other high-quality protein.
How do they compare on nutrients?
The table uses Feedipedia average values on a dry matter basis. The amino acid rows are calculated from the protein content and the amino acid profile reported for each feed.
| Nutrient (dry matter basis) | Corn DDGS | Dehydrated brewer’s yeast |
|---|---|---|
| Crude protein, % | 29.5 | 48.9 |
| Lysine, g/kg | 8.9 | 30.8 |
| Threonine, g/kg | 10.9 | 21.5 |
| Methionine, g/kg | 5.9 | 7.3 |
| Tryptophan, g/kg | 2.4 | 5.4 |
| Ether extract (fat), % | 11.1 | 2.4 |
| NDF, % | 34.2 | 8.8 |
| Ash, % | 5.4 | 7.0 |
| Phosphorus, g/kg | 7.9 | 13.1 |
Three points stand out. Lysine is the main gap: yeast carries about 3.5 times more per kilogram of dry matter. DDGS brings fat and fibre, which give it energy value but also limit how much a young animal can take. Methionine is the closest row, so neither ingredient fixes a methionine shortfall on its own.
Digestibility widens the lysine gap further. In the swine review by Stein and Shurson, standardized ileal digestibility of lysine in corn DDGS averaged 60.6%, and lysine was the most variable amino acid between sources. Heat damage during drying is the usual cause.
How much of each can you use?
Typical inclusion levels from the same sources are shown below. They are starting points for formulation, not fixed limits.
| Species | Corn DDGS | Dried brewer’s yeast |
|---|---|---|
| Nursery pigs | Up to 30% from 2 to 3 weeks after weaning | 2 to 5% of the diet |
| Growing-finishing pigs | Up to 30%; pork fat iodine value may be unacceptable above 20% in finisher diets | 2 to 5%; one study saw lower intake above about 12% |
| Gestating sows | Up to 50% | 2 to 5% (general pig guidance) |
| Broilers | About 6% in starters, 12 to 15% in growers and finishers | 2 to 5%; dried yeast replaced fish meal up to 9.3% without loss of growth |
| Laying hens | About 15% | 2 to 5% (general poultry guidance) |
| Dairy cows | About 15% of diet DM well supported; about 20% as a general maximum | Up to 20% of diet DM with no effect on intake or performance |
One trial shows the contrast neatly. In juvenile channel catfish fed for 8 weeks, a diet with 1% brewer’s yeast and a diet with 30% DDGS each supported the same growth and feed efficiency as a diet with 5% fish meal (Li, Oberle and Lucas, 2011). The same result took thirty times more DDGS than yeast.
What risks should buyers check?
Each ingredient has its own weak points. Knowing them makes the specification and the supplier questions sharper.
DDGS
- Mycotoxins: Feedipedia notes that mycotoxins can be about three times more concentrated than in the original grain.
- Sulphur: sulphuric acid use in ethanol production leaves 0.5 to 1.7% sulphate in DM. Cattle diets above about 0.56% sulphur risk polioencephalomalacia.
- Soft fat in pigs: the unsaturated oil raises the iodine value of pork fat. Withdrawing DDGS for the last 3 to 4 weeks before slaughter reduced it in the cited studies.
- Variability and heat damage: composition varies between ethanol producers. A dark, coffee-like colour signals overheating and lower lysine availability.
Dried brewer’s yeast
- Nucleic acids: RNA can carry up to about a third of total yeast nitrogen. Non-ruminants cannot use this nitrogen, which is one reason inclusion stays moderate.
- Live yeast: fresh yeast spoils quickly and can ferment in the gut. Feedipedia recommends inactivated, dried product.
- Bitterness: hop residues can make yeast bitter at high inclusion. Debittered or well-washed yeast avoids most of this.
- Moisture: dried yeast must stay dry in storage to keep its shelf life.
How to choose between them
- Name the nutrient gap. If the diet is short on energy and you want to cut corn, look at DDGS. If it is short on digestible lysine or high-quality protein, look at yeast.
- Check the animal’s age. Young pigs, chicks and fish tolerate fibre poorly. Yeast suits starter diets better than high DDGS levels.
- Price on the nutrient, not the tonne. Compare cost per kilogram of digestible lysine and per point of protein, not price per tonne.
- Use both where it pays. They are not exclusive. A grower diet can carry DDGS for energy and a small share of yeast for protein quality.
- Ask for the right analysis. For DDGS: mycotoxins, sulphur, fat and colour. For yeast: crude protein, moisture, ash, lysine and a certificate of analysis.
Source TBESBY dried brewer’s yeast
TBESBY is whole-cell dried brewer’s yeast made from fresh brewer’s yeast from leading international breweries in Vietnam. The published specification is crude protein 40 to 46%, moisture below 10%, ash below 6%, fat max 0.5%, fibre max 1.5% and lysine 30.5 g/kg. It ships in 25 kg bags or 600 to 1,200 kg jumbo bags, with a 12-month shelf life.
Request a sample and the full analysis, see TBESBY brewer’s yeast for livestock and poultry, or check the product specification. For species detail, read our guides to brewer’s yeast in swine feed and brewer’s yeast for dairy cows.
Free: Brewer’s Yeast Formulation Kit
Inclusion levels by species, the five spec numbers to check, a supplier checklist and storage notes in one 6-page PDF.
Download the kit · Request a sample
Related reading: Brewer’s yeast for poultry
Sources
- Feedipedia: Corn distillers grain (INRAE, CIRAD, AFZ and FAO)
- Feedipedia: Brewers yeast (INRAE, CIRAD, AFZ and FAO)
- Stein, H.H. and Shurson, G.C. (2009). Board-invited review: The use and application of distillers dried grains with solubles in swine diets. Journal of Animal Science 87: 1292–1303
- Li, M.H., Oberle, D. and Lucas, P. (2011). Evaluation of corn distillers dried grains with solubles and brewers yeast in diets for channel catfish Ictalurus punctatus. USDA ARS publication record
Frequently asked questions
Is DDGS the same as brewer’s yeast?
No. DDGS is mostly fermented grain residue from ethanol production. Brewer’s yeast is the yeast cell mass from beer brewing, with much higher protein and lysine and much less fibre and fat.
Can brewer’s yeast replace DDGS in a diet?
Not tonne for tonne. DDGS supplies energy and bulk at 10 to 30% of the diet. Yeast is a concentrated protein used at a few percent, so it replaces soybean meal or fish meal rather than DDGS.
Which has more lysine, DDGS or brewer’s yeast?
Brewer’s yeast. On Feedipedia averages it carries about 30.8 g lysine per kg of dry matter, against about 8.9 g in corn DDGS.
Does DDGS contain yeast?
Yes, some. Ethanol yeast stays in the product after fermentation, but grain residue makes up most of DDGS. Its composition is driven by the grain, not the yeast.