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Can plant protein hydrolysates be used in pet food and aquafeed?
Beyond Biopharma | Plant Protein Peptide FAQ
Short answer: Yes. Hydrolyzed plant proteins are used in pet food, specialty feed and aquafeed, mainly for palatability, digestibility and free amino acid supply. Feed-grade specifications are different from food grade: they are written around nutrition, contaminants and process performance rather than around human-food labeling, so the grade has to match the intended use and the feed rules of the market.
Why hydrolysates are used in feed
Animals respond to short peptides and free amino acids in ways that intact protein cannot always deliver. Hydrolysis breaks a large protein into smaller, more accessible fragments, which raises the speed of absorption in young or compromised animals and reduces the antigenic load that can trigger adverse reactions to a native protein. In practice, feed formulators use plant hydrolysates for three reasons: they are a source of highly digestible nitrogen, they carry taste-active compounds that attract animals to the feed, and they can be produced with a consistent profile that other plant protein forms cannot match.
Palatability and digestive support
Palatability is often the commercial reason a hydrolysate is chosen. Small peptides and free amino acids contribute to the savory, brothy notes that cats, dogs and many farmed fish find attractive, and a liquid or spray-dried hydrolysate can be coated onto a kibble or pellet to raise intake. On the digestive side, a controlled degree of hydrolysis is linked to faster gastric emptying and easier absorption, which matters in weaning, recovery and diets for animals with a sensitive gut. Where a hydrolysate is used in an elimination diet, the protein source and the hydrolysis conditions have to be selected carefully and the claim supported by the diet design rather than by the ingredient name alone.
Aquafeed specifics
In aquaculture, hydrolysates often act as feed attractants and as a transition ingredient for larvae and fry, where digestive capacity is still developing. Key practical points include water stability, because a soluble hydrolysate can leach out of the pellet before it is eaten, and inclusion rate, because an excess of free amino acids can depress growth rather than support it. Fish meal and fish hydrolysate are the traditional references, and plant hydrolysates are usually evaluated as a partial replacement within a balanced formula rather than as a like-for-like swap.
Feed grade compared with food grade
| Point | Food grade | Feed grade |
|---|---|---|
| Specification focus | Nutrition, taste, clarity and human-food labeling | Nutritional value, contaminants and process performance |
| Microbiology | Tight limits aligned to food safety rules | Feed-oriented limits, with pathogen control still essential |
| Contaminants | Heavy metals and residues per food limits | Heavy metals, mycotoxins and residues per feed limits |
| Labeling | Ingredient and allergen declarations for people | Feed ingredient declarations for the target species |
What to check before using one
- Target species and life stage - a profile suited to a weaning piglet is not automatically suited to a shrimp or a senior dog.
- Local feed rules - permitted ingredients, maximum inclusion levels and registration duties differ by market, so confirm them before formulation.
- Documentation - request the certificate of analysis, the source statement, the allergen status and the process description, and keep them with the feed file.
- Performance data - intake and digestibility trials in the real matrix, because palatability cannot be predicted from a specification sheet.
Related reading
For more detail, see how bitterness in plant peptides is prevented, whether peptides survive UHT and retort processing and how novel food status is judged in the EU.
