Research & Insights
Brewer’s Yeast for Catfish and Pangasius Feed: What the Trials Show
Published
Brewer’s yeast has a small but useful record in catfish feed. In channel catfish, 1 to 2% dried brewer’s yeast improved weight gain and feed efficiency over an all-plant diet, and 1% matched a diet with 5% fish meal. Pangasius data are thinner and mostly test other yeast products, so formulators should read each result by product type.
This guide sorts the catfish and pangasius trials by the yeast product used, explains why that matters, and sets out how to test yeast in your own formula.
Why does yeast matter in catfish and pangasius feed?
Catfish and pangasius are omnivores. Practical diets for them are often built mostly on plant protein, with little fish meal. That makes the formulation question specific: can a small share of yeast lift growth and feed efficiency in a low fish meal, high soybean meal diet?
Pangasius farming is one of Vietnam’s largest aquaculture sectors, and its feed is priced tightly. A protein that adds performance at 1 to 2% of the diet is worth more to these formulas than one that needs 20% inclusion to show an effect.
Dried brewer’s yeast also brings what plant proteins lack. Feedipedia lists dehydrated brewer’s yeast at 48.9% crude protein in dry matter, with lysine at 6.3% of protein and 13.1 g phosphorus per kg of dry matter.
What do catfish trials show?
The table groups the published trials we reviewed. Read the product column first: the results do not transfer from one product to another.
| Study | Species and length | Yeast product and level | Main result |
|---|---|---|---|
| Li, Oberle and Lucas (2011) | Channel catfish, 9.1 g juveniles, 8 weeks | Dried brewer’s yeast, 1% and 2% of diet | Better weight gain and feed efficiency than the all-plant diet; 1% yeast matched the 5% fish meal diet |
| Journal of the World Aquaculture Society (2007) | Channel catfish juveniles, 4 weeks plus 2 weeks on control feed | Whole-cell S. cerevisiae, two β-glucan products and one MOS product, at suppliers’ recommended levels | No effect on growth, blood values or immune function; survival after Edwardsiella ictaluri challenge 5 to 17.5% higher, but not significant |
| Aquaculture Reports (2022) | Channel catfish, 12 weeks | S. cerevisiae yeast culture, 2% of diet | Higher weight gain; higher survival after an Aeromonas challenge |
| Boonanuntanasarn et al. (2019) | Striped catfish (Pangasianodon hypophthalmus), 120 days | Microencapsulated probiotic S. cerevisiae, 106 and 108 CFU/g | Better growth and feed conversion; higher lysozyme, total immunoglobulin and complement activity; taller villi in the anterior intestine |
Two patterns emerge. Low inclusion is enough: none of these trials used yeast above 2% of the diet to get a growth response. And results vary by product and by trial. The 2007 study found no growth effect from any of four yeast products, which is a useful check on expectations.
For pangasius hybrids, a study by Pongpet and colleagues in Aquaculture Nutrition (vol. 22) tested partial replacement of fish meal by brewer’s yeast in Thai Panga. Formulators working on pangasius should read the full paper for its levels and results.
Whole brewer’s yeast or a yeast derivative?
Catfish research uses several yeast products under similar names. They are made differently and do different jobs.
| Product | What it is | Main role in catfish feed |
|---|---|---|
| Whole-cell dried brewer’s yeast | Inactivated, dried yeast cells from beer fermentation | Protein, amino acids, B vitamins and palatability, plus the cell wall it contains |
| Yeast culture | Yeast fermented on a growth medium, dried with the medium | Fermentation metabolites; used at low levels |
| Probiotic live yeast | Viable yeast cells, dosed in CFU | Live microbial additive, not a protein source |
| β-glucan and MOS | Fractions extracted from the yeast cell wall | Functional additives at very low levels |
Whole-cell brewer’s yeast contains its own cell wall, so it supplies some β-glucan and mannan along with protein. Extracted β-glucan or MOS concentrates those fractions but adds little protein. Live probiotic yeast must stay viable, while feed-grade brewer’s yeast is deliberately inactivated. TBESBY supplies whole-cell dried brewer’s yeast only. It does not sell yeast culture, probiotic yeast or cell wall extracts.
What limits brewer’s yeast in catfish diets?
- Nucleic acids: RNA can carry up to about a third of yeast nitrogen. This is one reason trials keep inclusion moderate.
- Live yeast: fresh or live yeast can ferment and spoil. Feedipedia recommends inactivated product for feed.
- Methionine: yeast is low in methionine and cystine, so it does not fix a sulphur amino acid gap in a soybean-based diet.
- Processing: yeast fines can change expansion and pellet water stability in floating feed. Check this on the extruder before the growth trial.
How to test brewer’s yeast in a catfish or pangasius formula
- Start low. Test 1% and 2% of the diet, the range used in the channel catfish trial, before going higher.
- Replace one ingredient. Take the yeast from soybean meal or fish meal, keep the diet isonitrogenous, and rebalance lysine and methionine.
- Run the extruder test. Check expansion, floatability and water stability of the pellets.
- Feed long enough. Eight weeks was the shortest trial with a clear growth response.
- Measure what pays. Weight gain, feed conversion, survival and feed cost per kilogram of fish.
Related reading: brewer’s yeast in sea bass and barramundi feed.
Source TBESBY dried brewer’s yeast for aquafeed
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, with a 12-month shelf life.
Request a sample and the full analysis, see TBESBY brewer’s yeast for aquafeed, or check the product specification. For related species, read brewer’s yeast in tilapia feed and our guide to brewer’s yeast in aquaculture.
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 vs fish meal in shrimp feed
Sources
- 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
- Immune response and resistance to stress and Edwardsiella ictaluri challenge in channel catfish fed yeast or yeast subcomponents. Journal of the World Aquaculture Society (2007)
- Effects of dietary Saccharomyces cerevisiae on growth, intestinal and liver health, intestinal microbiota and disease resistance of channel catfish (Ictalurus punctatus). Aquaculture Reports (2022)
- Boonanuntanasarn, S. et al. (2019). Effects of microencapsulated Saccharomyces cerevisiae on growth, hematological indices, blood chemical, and immune parameters and intestinal morphology in striped catfish. Probiotics and Antimicrobial Proteins 11: 427–437
- Pongpet, J., Ponchunchoovong, S. and Payooha, K. Partial replacement of fishmeal by brewer’s yeast in the diets of Thai Panga. Aquaculture Nutrition 22(3): 575–585
- Feedipedia: Brewers yeast (INRAE, CIRAD, AFZ and FAO)
Frequently asked questions
How much brewer’s yeast can I use in catfish feed?
Published catfish trials showing a growth response used 1 to 2% of the diet. Higher levels have less direct evidence in catfish, so test them in your own formula first.
Does brewer’s yeast help pangasius disease resistance?
The striped catfish study that measured immune markers used a live probiotic yeast, not dried brewer’s yeast. Those results show research findings for that product and should not be read as a health claim for whole dried yeast.
Can brewer’s yeast replace fish meal in pangasius feed?
It can replace part of it. In channel catfish, 1% yeast matched a 5% fish meal diet for growth and feed efficiency. Full replacement has not been shown in these trials.
Is yeast culture the same as brewer’s yeast?
No. Yeast culture is yeast dried together with its fermentation medium. Dried brewer’s yeast is the yeast cell mass from beer fermentation, used mainly as a protein.