Uncategorized
Brewer’s Yeast Nutrient Profile vs Fish Meal, Soybean Meal and DDGS
Published
Last updated: November 2026
Quick answer: Dried brewer’s yeast typically contains 40–50% crude protein, with lysine at about 6–7% of protein, close to soybean meal and below fish meal. Compared with corn DDGS, it carries nearly twice the protein and far more lysine per unit of protein. It also brings B-vitamins, nucleotides and cell-wall β-glucans and mannans that the other protein sources do not.
This page compares the reference composition of dried brewer’s yeast with three protein ingredients formulators most often weigh it against: fish meal, soybean meal and corn DDGS. Reference values come from Feedipedia (INRAE, CIRAD, AFZ and FAO) and university extension data; TBESBY values are our published specification.
Protein and amino acid comparison
| Ingredient | Crude protein | Lysine (% of protein) | Methionine (% of protein) | Crude fibre | Basis and source |
|---|---|---|---|---|---|
| Brewers yeast, dehydrated | 48.9% (range 39–57%) | 6.3 | 1.5 | 1.8% | Dry matter, Feedipedia |
| TBESBY dried brewer’s yeast | 40–46% | Lysine 30.5 g/kg product | – | – | As fed, TBESBY specification |
| Fish meal, type 65 protein | 70.7% | 7.5 | 2.7 | 0% | Dry matter, Feedipedia |
| Soybean meal, type 48 | 52.6% | 6.2 | 1.4 | 6.8% | Dry matter, Feedipedia |
| Corn DDGS | 23–29% | about 2–3 | – | about 8–9% | As fed, SDSU and University of Illinois extension |
Dry-matter and as-fed values are not directly comparable. Dried brewer’s yeast is usually around 93–94% dry matter, so as-fed protein is a few points lower than the dry-matter figure.
What brewer’s yeast adds beyond protein
- Palatability. Nucleotides, glutamic acid and peptides give a savoury taste that pets and young animals accept readily.
- B-vitamins. Brewer’s yeast is a natural source of thiamine (B1), riboflavin (B2) and niacin (B3).
- Cell-wall components. β-glucans and mannans in the yeast cell wall are widely used to support gut and immune health.
- Low fibre. Crude fibre is under 2% of dry matter, well below soybean meal and DDGS.
Formulation notes
- Against fish meal: brewer’s yeast has less protein and lysine, but partial replacement is common in shrimp and fish feed, where its attractant effect helps intake.
- Against soybean meal: the lysine share of protein is similar. Brewer’s yeast adds palatability and cell-wall components, and contains no soybean anti-nutritional factors.
- Against DDGS: DDGS lysine is low and sensitive to heat damage. University of Illinois guidance is to avoid DDGS with a lysine-to-crude-protein ratio below 2.80%. Brewer’s yeast sits well above that range.
- Nucleic acids: part of yeast nitrogen is nucleic acid rather than true protein, which is one reason inclusion rates are moderate: typically 1–3% in pet food, 2–5% in aquafeed and 2–8% in livestock feed.
Request our full specification and Certificate of Analysis on the product page, or see bulk supply terms.
Sources
- Feedipedia: Brewers yeast, dehydrated
- Feedipedia: Fish meal, type 65 protein
- Feedipedia: Soybean meal, type 48 and similar
- University of Illinois: Recommendations for feeding DDGS to swine
- South Dakota State University Extension: Use of DDGS in swine diets (ExEx2035)
Frequently asked questions
How much protein does dried brewer’s yeast contain?
Reference data average about 49% crude protein on a dry-matter basis, with a range of roughly 39–57%. TBESBY dried brewer’s yeast is specified at 40–46% crude protein as fed.
Is brewer’s yeast a good lysine source?
Yes. Lysine averages about 6.3% of protein in reference data, similar to soybean meal (6.2%) and well above corn DDGS.
Can brewer’s yeast replace fish meal?
Partly. It has less protein and lysine than fish meal, so it is used as a partial replacement, especially in aquafeed where its palatability supports intake.