Research & Insights
Brewer’s Yeast in Sea Bass and Barramundi Feed: What the Trials Show
Published
Brewer’s yeast has one of the better-documented records among alternative proteins in sea bass feed. In European sea bass, it replaced up to half of the fish meal protein without loss of growth. In Asian seabass, also sold as barramundi, dried brewer’s yeast replaced 20 to 47% of fish meal in two 60-day trials with no significant change in growth or feed conversion. At 1 to 2% of the diet, it improved weight gain in hybrid striped bass.
This guide sets out what those trials tested, where the limits sit, and how to evaluate brewer’s yeast in your own sea bass or barramundi formula.
Why look at brewer’s yeast for sea bass feed?
Sea bass are carnivorous. Their feeds carry high protein and a large share of fish meal, which leaves them exposed to fish meal price and supply. Plant proteins are the usual substitute, but carnivorous fish often eat less as plant protein rises. In Asian seabass, defatted soybean meal at 20% of the diet reduced feed intake and growth, a result Sorphea et al. (2019) cite from earlier work.
Dried brewer’s yeast sits between fish meal and soybean meal. In the Asian seabass trial below, the analysed yeast contained 46.8% crude protein in dry matter, against 62.2% for the fish meal and 46.2% for defatted soybean meal. Its fat was 1.7% and its lysine 2.74% of dry matter.
What do sea bass trials show?
The table groups the trials we reviewed. Read the level column first: some trials use yeast as a main protein source, others add a small amount to a complete diet.
| Study | Species and length | Yeast product and level | Main result |
|---|---|---|---|
| Oliva-Teles and Gonçalves (2001) | European sea bass, juveniles | Dried brewer’s yeast replacing fish meal protein | Up to 50% of fish meal protein replaced without loss of growth |
| Sorphea et al. (2019) | Asian seabass, 22 to 44 g fingerlings, 60 days, tanks and hapas | Dried brewer’s yeast at 20 to 47% of the diet, replacing 20, 37 and 47% of fish meal | No significant difference in growth or FCR; survival 90 to 97%, with a trend toward higher survival on yeast diets |
| Li and Gatlin (2003) | Hybrid striped bass | Dried brewer’s yeast, 1 to 4% added to the diet | Up to 20% more weight gain at 1 to 2%; better resistance to bacterial challenge at 2 to 4% |
| Tulli et al. (2005) | European sea bass juveniles, 84 days | Nucleic acid nitrogen from dried brewer’s yeast, 1.0 to 4.2% of total nitrogen | Growth unaffected; nitrogen retention fell at the highest levels |
Replacement level or supplement level?
The trials answer two different questions. Oliva-Teles and Gonçalves (2001) and Sorphea et al. (2019) used brewer’s yeast as a protein source and asked whether growth holds as fish meal falls. Li and Gatlin (2003) added 1 to 4% to a diet that already met requirements and asked whether growth or health improves.
These results do not transfer across levels. A gain response at 2% inclusion says nothing about a diet with 30% yeast, and a neutral result at 47% replacement does not mean a small addition has no effect.
What limits brewer’s yeast in sea bass diets?
Methionine. In the Sorphea et al. diets, methionine fell from 1.05% to 0.74% of dry matter as yeast replaced fish meal, while lysine stayed level. At high replacement, supplement methionine to keep the amino acid profile balanced.
Nucleic acids. Yeast is rich in nucleic acids, and their nitrogen is not used like protein nitrogen. Tulli et al. (2005) found that sea bass grew normally on diets with up to 4.2% of nitrogen from yeast nucleic acids, but retained less nitrogen at the top level.
Digestibility. In both Asian seabass experiments, the highest yeast diets showed slightly higher FCR, though the differences were not significant. The authors suggest yeast protein may be slightly less digestible than fish meal protein.
Product consistency. Protein, ash and moisture vary between yeast sources and drying methods. A trial result holds only for a product with a similar analysis.
How to test brewer’s yeast in a sea bass or barramundi formula
- Decide the question first: protein replacement, typically 10 to 30% of the diet, or a supplement at 1 to 4%.
- Formulate on digestible amino acids and add methionine as the yeast level rises.
- Keep the diets isonitrogenous and isoenergetic, and check pellet quality on your own production line.
- Run at least 8 weeks with three or more replicates per diet. Record feed intake, FCR and survival, not weight alone.
- Ask the supplier for the analysis of the sample you test, and confirm that later deliveries match it.
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 other species, read brewer’s yeast in catfish and pangasius feed and brewer’s yeast in tilapia feed.
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
- Oliva-Teles, A. and Gonçalves, P. (2001). Partial replacement of fishmeal by brewers yeast (Saccaromyces cerevisae) in diets for sea bass (Dicentrarchus labrax) juveniles. Aquaculture 202: 269–278.
- Sorphea, S., Lundh, T., Lindberg, J.E., Da, C.T., Barnes, A.C. and Kiessling, A. (2019). Effect of dietary replacement of fishmeal with spent brewer’s yeast on growth performance of Asian seabass (Lates calcarifer) in Cambodia coastal aquaculture. Livestock Research for Rural Development 31(9).
- Li, P. and Gatlin, D.M. III (2003). Evaluation of brewers yeast (Saccharomyces cerevisiae) as a feed supplement for hybrid striped bass (Morone chrysops × M. saxatilis). Aquaculture 219: 681–692.
- Tulli, F. et al. (2005). Growth and nitrogen metabolism of sea bass fed graded levels of nucleic acid nitrogen from yeast or RNA extract as partial substitute for protein nitrogen from fish meal. FAO AGRIS record.
Frequently asked questions
How much fish meal can brewer’s yeast replace in sea bass feed?
In the trials reviewed here, up to half of fish meal protein in European sea bass and up to 47% of fish meal in Asian seabass, with no significant loss of growth. Confirm the level in your own diet before scaling up.
Is Asian seabass the same as barramundi?
Yes. Both names refer to Lates calcarifer, farmed widely across Southeast Asia and Australia.
Does brewer’s yeast improve sea bass survival?
The evidence is suggestive, not settled. Survival trended higher on yeast diets in Asian seabass, but the difference was not significant. In hybrid striped bass, 2 to 4% dried brewer’s yeast improved resistance to bacterial challenge.
Can brewer’s yeast replace all fish meal in sea bass feed?
None of the trials reviewed here supports full replacement. Above roughly half of fish meal protein, amino acid balance, nucleic acid load and digestibility become the limiting factors.