Bioactive peptides: how they act in animal nutrition and performance

Date: 01/09/2026

The challenge facing today's formulations goes beyond meeting a nutrient requirement table. It also involves supporting gut health, sustaining feed intake, reducing nutrient losses, and maintaining productive performance across different species and life stages. For this reason, functional ingredients have increasingly been studied for what they offer beyond energy or protein supply.

In this article, you will learn:

What are bioactive peptides?

Bioactive peptides are amino acid sequences that, beyond contributing to nutrient supply, can perform specific biological functions in the body. Depending on their composition and structure, they are associated with mechanisms related to digestion, gut health, immune response, and nutrient utilization. Many of these sequences remain "hidden" within the structure of proteins and are released during digestion, fermentation, or industrial hydrolysis.

The amino acids that make up a peptide are joined by peptide bonds. Their composition and order determine the characteristics of the sequence, while their size influences how it is digested and absorbed.

Shorter chains may require fewer steps of enzymatic breakdown, but the biological activity of a peptide depends on preserving the sequence responsible for its function. When hydrolysis causes excessive fragmentation, this activity can be reduced or even lost.

Interest in these molecules reflects a shift in how protein ingredients are evaluated. While protein quality was previously assessed mainly by protein content and amino acid profile, today it is also considered how specific peptide fractions interact with the body.

In this context, molecular composition has come to be seen as a strategic attribute in the development of functional ingredients for animal nutrition. Beyond serving as amino acid sources, these ingredients are increasingly studied for their potential to provide peptide fractions capable of adding functional properties to formulations.

The relationship between molecular size and biological activity was discussed in a scientific review published in 2022, which compiled results from different studies on bioactive peptides. Among them, a study on corn gluten hydrolysate found greater antioxidant activity in peptides with a molecular mass between 500 and 1,500 Da (daltons) compared to smaller or larger fractions.

The other studies compiled by the authors indicate that excessive hydrolysis can reduce this activity by converting peptides into free amino acids. Although molecular size is an important factor, results vary depending on the protein source, the amino acid sequence, and the biological function assessed.

It is important to distinguish the role of each component in feed:

Component	What it is	Nutritional role
Amino acid	Basic unit that forms peptides and proteins	Participates in the synthesis of tissues, enzymes, hormones, and other molecules
Peptide	Chain of two or more amino acids	Can supply amino acids and, depending on the sequence, exhibit biological activity
Protein	Larger chain, organized into its own structure	Supplies amino acids and performs structural and metabolic functions

How are bioactive peptides produced?

In the production of hydrolyzed proteins, enzymes called proteases break specific bonds in the protein chain. Parameters such as enzyme type and concentration, pH, temperature, and reaction time are controlled to achieve a given degree of hydrolysis and molecular profile. The process can be summarized in the points listed below.

● Enzymatic hydrolysis: uses enzymes to break peptide bonds under defined conditions.
● Controlled protein breakdown: shortens long chains without relying on complete digestion in the gastrointestinal tract.
● Formation of di- and tripeptides: generates molecules with two or three amino acids, along with other peptides and free amino acids.
● Low molecular mass: concentrates smaller fractions, according to the process and product specification.
● Greater potential bioavailability: may make part of the nutrients more accessible, a result that needs to be confirmed for the specific diet and species of interest.

Enzymatic hydrolysis is often the preferred method because it takes place under milder conditions and offers greater control over the breakdown point than chemical methods. This reduces the risk of destroying sensitive amino acids and makes it easier to standardize the peptide profile.

A review on hydrolyzed proteins in animal nutrition compiled results from different studies and highlighted the advantages of enzymatic hydrolysis, such as greater control over the resulting molecular profile. At the same time, it showed that the responses observed depend on factors such as raw material, enzyme used, and processing conditions. For this reason, the performance of an ingredient is not determined solely by the use of hydrolysis, but by the combination of protein quality and process control.

How do bioactive peptides act in the animal body?

After being released from proteins, bioactive peptides can exert their effects in different ways. Some act locally in the gastrointestinal tract, while others may interact with cellular receptors or signaling molecules involved in immune response, oxidative stress, and other physiological processes. For this to occur, however, the bioactive sequence must remain intact until it reaches its site of action.

A peptide's ability to reach its site of action and exert its biological activity depends on its resistance to digestion and the way it is absorbed by the body. For this reason, understanding what happens to these molecules after ingestion is essential to understanding how their effects can be preserved and expressed.

After ingestion, digestive enzymes break down proteins into amino acids and peptides of different sizes. These molecules follow distinct absorption routes: free amino acids use specific transporters, while di- and tripeptides can enter the cells lining the intestine through PEPT1, the peptide transporter 1.

How does intestinal absorption occur (PEPT1)?

A study on intestinal PEPT1 in pigs identified the genetic material responsible for producing this transporter and confirmed its presence in the duodenum, jejunum, and ileum. To test how it functions, the researchers reproduced PEPT1 in laboratory-cultured cells and assessed its interaction with peptides of different sizes.

The tests showed that the transporter recognizes various chains formed by two or three amino acids, although affinity varies according to the composition of the sequence. The tetrapeptides tested, formed by four amino acids, were not transported. The study thus describes one of the routes through which the products of protein digestion cross the membrane of intestinal cells.

Entry through PEPT1 does not mean that all peptides reach the bloodstream intact. After absorption, most di- and tripeptides are broken down again inside enterocytes and enter circulation as free amino acids. Sequences that resist this breakdown may remain intact for longer, act locally on the intestinal mucosa, or reach other tissues, depending on their structure and stability.

Digestibility and bioavailability: what changes?

Nutrient utilization involves digestibility and bioavailability, which are different steps in this process. Digestibility estimates how much has been digested and absorbed up to a given point in the intestine. Bioavailability indicates how much of the absorbed portion can actually be used by the body. The study presented below examined only the first step, through apparent jejunal digestibility.

To assess how the form of amino acids affects apparent jejunal digestibility, a trial with 30 growing pigs, with an average initial weight of 33.7 kg, compared the effect of different feeding types. Over 14 days, the animals received one of the following three diets:

● intact protein from feather meal;
● free amino acids and small peptides obtained through extensive acid hydrolysis of feathers;
● a combination of purified free amino acids, formulated to match the profile of the hydrolyzed material.

In the evaluation, the amounts of feed, energy, and amino acids provided were controlled across treatments. After a meal containing non-digestible markers, the researchers collected content and tissue samples from different regions of the small intestine.

Both the diet with the hydrolysate and the one made up of free amino acids showed higher apparent jejunal digestibility than the intact protein diet. This indicator estimates how much of the ingested amino acids is no longer present in the intestinal content by the time it reaches the jejunum. The term "apparent" indicates that the calculation may also include amino acids from digestive secretions and the turnover of intestinal cells.

When comparing the hydrolysate with the free amino acids, the diet with small peptides showed significantly higher digestibility for cysteine, glycine, histidine, methionine, and proline. These differences may be related to the faster absorption of small peptides.

What are the benefits of bioactive peptides in animal nutrition?

The expected results do not come simply from the presence of short chains. They depend on peptides with active sequences, in adequate concentration, and preserved until they reach their site of action. Among the most studied effects are:

● Digestibility and nutrient utilization. Hydrolysis reduces chain length, favoring the action of digestive enzymes and intestinal absorption.
● Gut health. Certain sequences have been studied for their interaction with the intestinal mucosa, the microbiota, and local mediators.
● Immune response and antioxidant protection. Some peptides show immunomodulatory activity or neutralize reactive species in laboratory tests and animal trials.
● Palatability and intake. Peptides and free amino acids contribute to the flavor profile of the diet and can help make it more attractive. However, excessive hydrolysis can lead to bitterness.
● Feed conversion and performance. Better digestion, adequate feed intake, and intestinal integrity are directly related to the efficiency of nutrient use. As a result, these factors can contribute to improved feed conversion ratios and productive performance, provided they are combined with a balanced formulation and good management practices.

These mechanisms help explain why a functional ingredient can affect more than one indicator. Even so, there is no single answer that applies to all species.

An applied study, conducted in partnership with the Instituto de Pesca (Fisheries Institute), evaluated hydrolyzed chicken protein in diets for rainbow trout. According to the São Paulo State research agency, the ingredient enabled the complete replacement of fish meal in the tested formulation. These results point to possible uses, but transferring them to other species, systems, or diets requires defining the dose, running stability tests, and providing zootechnical follow-up.

In which segments are bioactive peptides used?

Bioactive peptides are supplied to diets mainly through hydrolyzed proteins. The application of these ingredients must take into account the digestive characteristics of each species, the stage of development, the amino acid profile of the feed, and the objective of the formulation. Among the main segments are aquaculture, pet food, and swine production.

Aquaculture

In feeds for fish and shrimp, hydrolyzed proteins supply free amino acids and low molecular mass peptides. They also show potential to increase feed attractiveness. The choice of ingredient and inclusion level should take into account the species, the production stage, nutritional balance, feed processing, and water stability.

Pet nutrition

In food for dogs and cats, these ingredients are often used in formulations that seek highly digestible proteins, good solubility, and a more controlled molecular profile. The presence of smaller peptides also supports the development of diets with specific nutritional purposes. Producing the formulation requires evaluating the degree of hydrolysis, the amino acid profile, palatability, digestive tolerance, and stool quality.

Swine production

In swine feeding, hydrolyzed proteins can be included in diets formulated to provide nutrients that are easily accessible to the digestive system. This is especially relevant after weaning, when piglets undergo dietary changes while their digestive capacity is still developing. The inclusion level should be adjusted to the production stage and to the contribution of other ingredients to energy, protein, and amino acids.

Other species

Application in poultry, ruminants, or other species requires its own evaluation. Differences in digestive physiology mean that recommendations defined for fish, shrimp, pets, or swine cannot simply be transferred to other animals. Before inclusion, it is necessary to confirm the product's intended use, its regulatory suitability, and its compatibility with the diet's nutritional matrix.

What is the relationship between hydrolyzed proteins and bioactive peptides?

An intact protein retains long chains and its three-dimensional structure. In hydrolyzed protein, some of the bonds have already been broken, forming a mixture of peptides of different sizes and free amino acids. This composition tends to reduce the digestive work needed to release nutrients, but its value depends on the amino acid profile, the quality of the raw material, and process control.

Hydrolyzed proteins are important sources of bioactive peptides, but the terms are not synonymous. "Hydrolysate" describes the ingredient obtained by partially breaking down a protein; a "bioactive peptide" is a specific sequence with a demonstrated biological effect. To support a functional claim, the fractions must be characterized and the effect validated under conditions compatible with the intended application.

Criterion	Intact protein	Hydrolyzed protein
Structure	Preserved, organized chains	Partially fragmented chains
Digestion	Depends on further breakdown in the gastrointestinal tract	Part of the bonds have already been broken
Composition	Predominance of higher molecular mass proteins	Mixture of peptides and free amino acids
Presence of bioactive peptides	May be hidden within the structure	May be released during hydrolysis
Functional outcome	Depends on digestion and protein quality	Depends on the resulting profile, dose, and species-specific validation

How does MBRF Ingredients apply bioactive peptide technology?

Bioactive peptides represent an advance in the development of protein ingredients because they broaden the analysis beyond crude protein content. Digestibility, molecular composition, interaction with the gut, and metabolic effects are now part of the technical decision.

When combined with a quality protein and a controlled process, these peptides have been associated with better nutrient utilization, immune response, feed conversion, and productive performance.

None of these results, however, should be assumed. Origin, standardization, degree of hydrolysis, species-specific evidence, and compatibility with the diet are essential criteria.

BioActio Health & Performance is a hydrolyzed chicken protein produced through enzymatic hydrolysis. The process generates free amino acids and low molecular mass peptides for use in aquaculture, swine production, and pet food. The technical proposition combines digestibility, palatability, and functional properties that should be evaluated according to the formulation and the production objective.

The BioActio line, from MBRF Ingredients, was developed based on research and trials conducted in partnership with recognized universities and institutes in the field. External validation came from the F3 Krill Replacement Challenge: in 2025, MBRF Ingredients was announced as one of the winners after a 12-week trial with Atlantic salmon that compared krill alternatives based on growth, feed intake, and survival. The solution featuring BioActio Health & Performance was among the ten finalists selected out of 40 entries.

Learn more about the BioActio Health & Performance line and discover how MBRF Ingredients' hydrolyzed protein technology contributes to high-performance formulations.

Frequently asked questions about bioactive peptides

What are bioactive peptides?

They are amino acid sequences that perform a biological activity beyond supplying nutrients. They can be present within the structure of a protein and be released through digestion, fermentation, or industrial hydrolysis. The effect depends on the sequence, the dose, stability, and the site of action.

What is the difference between bioactive peptides and hydrolyzed proteins?

Hydrolyzed protein is the ingredient obtained by partially breaking down a protein, resulting in a mixture of amino acids and peptides. A bioactive peptide is a specific sequence within that mixture that has a demonstrated biological effect. So a hydrolysate can contain bioactive peptides, but the two concepts are not equivalent.

How do bioactive peptides improve digestibility?

Hydrolysis shortens protein chains and makes small peptides and amino acids available for absorption. Di- and tripeptides can use the intestinal PEPT1 transporter. The gain in digestibility varies with the source protein, processing, species, production stage, and the diet's other components.

Which animals can benefit from bioactive peptides?

Research and applications exist for fish, shrimp, dogs, cats, swine, poultry, and cattle. The benefit is not the same across species or production stages. The choice should take into account nutritional needs, the objective of the formulation, ingredient quality, and evidence obtained under conditions comparable to actual use.

How do bioactive peptides influence feed conversion?

They can support digestion, absorption, and intestinal integrity, increasing the portion of the diet used for maintenance and production. Feed conversion also responds to nutritional balance, intake, health status, environment, and management. For this reason, the presence of peptides alone does not guarantee an improvement in this indicator.

How are bioactive peptides produced?

In industry, one of the main routes is enzymatic hydrolysis. Proteases break protein bonds under controlled pH, temperature, time, and enzyme concentration. The process forms peptides of different sizes and free amino acids; the final composition depends on the raw material and the parameters used.