Brewer’s Yeast vs Fish Meal in Shrimp Feed

Dried brewer’s yeast can replace part of the fish meal in shrimp feed, but not all of it. Published trials with Litopenaeus vannamei kept growth, survival and FCR in line with fish meal diets at moderate inclusion, and saw weight gain slip at the highest level tested. The practical result for formulators is a cheaper, steadier protein that also helps feed intake, used alongside fish meal rather than instead of it.

This guide compares the two ingredients, summarises what the research shows, and sets out a simple way to run your own replacement trial.

Why look beyond fish meal?

Fish meal is still the benchmark protein in shrimp feed. It is digestible, palatable and well balanced in essential amino acids. The problem is supply: it depends on wild catch, its price moves with fishing seasons and quotas, and every shrimp feed producer in the region competes for the same tonnage. Brewer’s yeast comes from a different supply chain, the brewing industry, so it adds a second protein source whose price does not follow the fish meal market.

How do the two ingredients compare?

Because yeast carries less protein per kilogram, replacing fish meal is never one-for-one. Formulators usually rebalance with a second plant or animal protein and check methionine and lysine after the swap.

What does the research show in shrimp?

Two lines of work are useful for L. vannamei.

• Replacement at percent levels. A trial at Auburn University fed a high-protein dried brewer’s yeast product at 0, 6, 12, 18 and 24% of the diet, replacing fish meal or soybean meal. Biomass, survival and FCR did not differ significantly from the control. In a confirmation trial, weight gain at 24% was lower than on the high fish meal diet, so the authors’ working range sits below the top level tested.
• Low-level functional use. A 2018 study added brewer’s yeast at 1% of the diet. Shrimp grew better, showed stronger innate immune markers and coped better with ammonia stress than shrimp on the control diet.

Fish trials point the same way. In Nile tilapia, yeast replaced fish meal at up to 15% of the diet without hurting feed conversion, while growth fell at 30% and 40%.

Two cautions apply. The Auburn product had a higher protein content than standard dried brewer’s yeast, so expect to adjust the inclusion level for a 40–46% product. And trial results depend on the base formula, so the numbers above are a starting point, not a recipe.

Where does brewer’s yeast fit in a shrimp formula?

• Partial fish meal replacement. Moderate inclusion lowers fish meal use while keeping protein targets, once amino acids are rebalanced.
• Feeding response. Yeast’s free amino acids and nucleotides help shrimp find and eat the pellet, which matters most in grower and finisher feeds with less fish meal.
• Gut and immune support. Cell-wall β-glucans and mannans are widely studied for their role in shrimp health; low-level inclusion is often used for this reason alone.

How to run a replacement trial

1. Fix the target. Decide what you are testing: cost per tonne at equal growth, or a lower fish meal share at equal FCR.
2. Get the analysis first. Ask for protein, moisture and the amino acid profile of the exact yeast you will buy, and formulate on those numbers rather than book values.
3. Step the levels. Test at least three levels against your current diet, for example a low, middle and high replacement, and keep everything else equal.
4. Rebalance amino acids. Correct methionine and lysine at each level so you are testing the ingredient, not an amino acid gap.
5. Check the pellet. Confirm water stability and durability at the plant before the growth trial.
6. Measure what pays. Record weight gain, FCR, survival and feed cost per kilogram of shrimp, not growth alone.

What to ask a brewer’s yeast supplier

• Guaranteed crude protein and moisture, and a recent full analysis
• Whether the yeast is inactivated and from brewing (not molasses-grown or ethanol yeast)
• Packing that suits your intake system: 25 kg bags or 600–1,200 kg jumbo bags
• Shelf life and storage conditions
• Documents for your import market: Certificate of Analysis, certificate of origin, health certificate

Related reading: brewer’s yeast in tilapia feed, brewer’s yeast in sea bass and barramundi feed and the brewer’s yeast nutrient profile vs fish meal, soybean meal and DDGS.

Sources

• Guo J, Qiu X, Chaturanga GAHS, Davis DA. High-protein dried brewer’s yeast (DBY50) in Pacific white shrimp diets. World Aquaculture Society meeting abstract 75490
• Jin M et al. (2018). Fish & Shellfish Immunology 82: 121–129
• Ozório ROA, Portz L, Borghesi R, Cyrino JEP (2012). Animals 2(1): 16–24 (yeast replacing fish meal in Nile tilapia diets)
• Feedipedia. Brewers yeast