Research & Insights
Brewer’s Yeast in Weaned Piglet Diets: What the Trials Show
Published
Weaning is the hardest feeding transition a pig makes, and nursery diets are where protein choice matters most. Dried brewer’s yeast has a modest but useful record here. In one trial, 4% dried brewer’s yeast in place of soybean meal improved daily gain and feed efficiency in the first nursery phase. In another, 3% had little effect on growth but raised some immune markers. Yeast hydrolysates show stronger responses, but they are a different product.
This guide sorts the weaned piglet trials by yeast product, explains why the product type matters, and sets out how to test brewer’s yeast in a nursery formula.
Why consider brewer’s yeast in nursery diets?
In the days after weaning, feed intake drops and the young gut is still adapting to solid feed. Soybean meal contains antigenic proteins that newly weaned pigs tolerate poorly, which is why nursery diets lean on costlier proteins such as fish meal, plasma and processed soy.
Dried brewer’s yeast offers protein with little fat. One analysed sample contained 46.8% crude protein and 1.7% fat in dry matter, with lysine at 2.74% of dry matter. Whole yeast also carries cell wall mannans and β-glucans and a high nucleotide content, the components most often studied for gut health in weaned pigs.
What do weaned piglet trials show?
The table groups the trials we reviewed. Read the product column first: results from a hydrolysate do not transfer to whole dried yeast.
| Study | Pigs and length | Yeast product and level | Main result |
|---|---|---|---|
| LeMieux et al. (2010) | Creep feeding from day 5, weaning at about 21 days, then nursery | Dried brewer’s yeast, 4%, replacing soybean meal | No effect before weaning; higher daily gain and gain:feed in nursery phase 1, and higher overall daily gain |
| White et al. (2002) | Weaned at 22 days, 28 days | Dried brewer’s yeast, 3%, alone or with 2% citric acid | Minimal effect on growth, gut microbes and intestinal traits; some serum immune traits improved |
| Hu, Park and Kim (2020) | Weanling pigs, 8.15 kg, 6 weeks, LPS challenge | Brewer’s yeast hydrolysate, 1% | Higher feed intake in weeks 2 to 4 and better gain:feed overall; may reduce diarrhoea |
Whole dried yeast or a yeast derivative?
Whole-cell dried brewer’s yeast is a protein ingredient used at a few percent of the diet. A hydrolysate has been broken down to release peptides and nucleotides, and is used at lower levels with a functional aim. Yeast cell wall products concentrate the mannans and β-glucans. Live yeast is a probiotic and works through a different mechanism again.
The two whole-yeast trials above point to a growth benefit that is real but modest and not guaranteed. Price whole dried yeast as a protein that can also bring gut-health value, and judge it on growth and cost per kg of gain. For the differences between products, see brewer’s yeast vs yeast extract and yeast cell wall vs brewer’s dried yeast.
What limits brewer’s yeast in piglet diets?
Palatability. Feed intake drives nursery performance, and untreated brewer’s yeast can carry bitter hop compounds. Check intake closely in the first week. See what debittered brewer’s yeast means.
Inconsistent response. The 4% trial improved gain; the 3% trial did not. Health status, weaning age and the basal diet all change how much a young pig benefits.
Nucleic acids. Yeast is rich in nucleic acids, which supply nucleotides but add nitrogen that is not used like protein. Published nursery trials have stayed at low inclusion.
Product consistency. Protein, ash and moisture vary between yeast sources. A trial result holds only for a product with a similar analysis. Our guide on how to read a brewer’s yeast CoA covers the numbers to check.
How to test brewer’s yeast in a nursery formula
- Start at 3 to 4% of the diet in phase 1, replacing soybean meal on a digestible lysine basis.
- Keep the control and test diets equal in digestible amino acids and net energy.
- Feed from weaning through at least phase 1 and phase 2, and record daily gain, feed intake, gain:feed and faecal scores.
- Use enough pens per diet to detect a 3 to 5% difference in gain; single-pen comparisons mislead.
- 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 swine feed
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 livestock and poultry, or check the product specification. For the wider picture, read our guide to brewer’s yeast in swine 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 DDGS in livestock feed
Sources
- LeMieux, F.M., Naranjo, V.D., Bidner, T.D. and Southern, L.L. (2010). Effect of dried brewers yeast on growth performance of nursing and weanling pigs. The Professional Animal Scientist 26(1): 70–75.
- White, L.A., Newman, M.C., Cromwell, G.L. and Lindemann, M.D. (2002). Brewers dried yeast as a source of mannan oligosaccharides for weanling pigs. Journal of Animal Science 80: 2619–2628.
- Hu, J., Park, J.W. and Kim, I.H. (2020). Effect of dietary supplementation with brewer’s yeast hydrolysate on growth performance, faecal microbial counts, diarrhoea score, blood profile, rectal temperature in weanling pigs challenged with lipopolysaccharide. Journal of Animal Physiology and Animal Nutrition.
- Sorphea, S. et al. (2019). Analysed composition of dry brewer’s yeast, Table 1. Livestock Research for Rural Development 31(9).
Frequently asked questions
How much brewer’s yeast can I use in weaned piglet diets?
The whole-yeast trials reviewed here used 3 to 4% of the diet. The 4% level, replacing soybean meal, improved gain in the first nursery phase with no negative effects.
Does brewer’s yeast reduce post-weaning diarrhoea?
The clearest signal comes from a hydrolysate at 1%, not from whole dried yeast. Treat diarrhoea claims as product-specific and test them in your own herd.
Can brewer’s yeast replace plasma or fish meal in nursery feed?
No trial reviewed here tested that directly. The evidence supports brewer’s yeast as a partial replacement for soybean meal at low inclusion.
Is brewer’s yeast the same as a live yeast probiotic?
No. Dried brewer’s yeast is inactive and works as a nutrient source. Live yeast products are dosed by colony-forming units and act as probiotics.