Formulating Pet Food for Gut Health: A Practical Guide to Using Prebiotics and Postbiotics

What you will learn in this article

• The differences and definitions of prebiotics, probiotics, and postbiotics
• The main types of ingredients used in pet food, typical inclusion levels, and the risks of side effects
• Why postbiotics are attracting attention in OEM manufacturing, especially in terms of processing stability
• The latest insights into combining prebiotics and postbiotics in product design
• Practical considerations for claims, labeling, and selecting an OEM factory

The human “gut health” boom has now extended into the pet world as well. One reason more Japanese pet owners are becoming interested in the gut health of their dogs and cats is the broader trend of “pet humanization,” in which pets are increasingly treated as members of the family and their health is managed accordingly.

This shift represents a significant opportunity for the pet food market. The global functional pet food market was estimated at approximately USD 2.8 billion in 2024 and is projected to reach around USD 5.8 billion by 2033, growing at a CAGR of 8.5% (Straits Research, 2024). Within this market, gut health-related ingredients are drawing particular attention as one of the fastest-growing categories, with an estimated CAGR of 10.9% from 2024 to 2030.

Demand for premium and functional pet food is also steadily increasing in Japan. According to Grand View Research (2024), the Japanese pet food market is expected to reach approximately USD 6.4 billion in 2025, with premium products and categories offering specific health-related benefits acting as key growth drivers.

At the same time, we frequently hear practical questions from brand owners and product developers who want to position their products around gut health: “What is the difference between prebiotics and postbiotics?” “Which ingredients should we use, and at what inclusion level?” “Will they survive the manufacturing process?” This article addresses those real-world questions from both a scientific and manufacturing perspective.

Why “gut health” claims are gaining momentum in the pet food market

Why is interest in pet food containing gut health ingredients growing so rapidly right now? Several factors are driving this trend.

First, consumers are becoming more informed. As interest in the human gut microbiome has grown rapidly in nutrition science, more pet owners want to apply the same thinking to their pets. Terms such as probiotics and prebiotics are becoming increasingly familiar to consumers.

Second, the pet population is aging. In Japan, the proportion of senior dogs and cats is increasing, creating demand for products that address age-related declines in digestive function and shifts in immune health. Supporting gut health is considered an important approach for maintaining quality of life in older pets.

Third, the market is becoming more premiumized. Claims such as “made with health-supporting ingredients” and “based on scientific evidence” have become important differentiators that influence purchase decisions. The global pet prebiotics market was valued at approximately USD 120 million in 2024 and is expected to expand to around USD 250 million by 2035 (Meta Tech Insights, 2025). This growth is being driven primarily by premium product categories.

Clarifying three commonly confused terms

When designing a pet food product positioned around gut health, it is essential to correctly understand the differences between prebiotics, probiotics, and postbiotics. These three terms are often confused because they sound similar, but their mechanisms of action and manufacturing characteristics differ significantly.

Prebiotics: non-digestible ingredients that feed beneficial gut bacteria

Prebiotics are substances that are not digested by the host but are selectively utilized by beneficial microorganisms in the gut, thereby conferring a health benefit to the host. Typical examples include fructooligosaccharides (FOS), inulin, and mannan oligosaccharides (MOS).

These ingredients pass through the small intestine without being digested or absorbed and reach the large intestine, where they promote the growth of beneficial bacteria such as Bifidobacterium and Lactobacillus. During this process, short-chain fatty acids such as butyrate, propionate, and acetate are produced. These compounds serve as energy sources for colonic epithelial cells and are known to contribute to maintaining intestinal barrier function.

According to the website of ISAPP (the International Scientific Association for Probiotics and Prebiotics), applications in dogs and cats have also shown improvements in gut microbiota balance, stool quality, and immune modulation in multiple studies (ISAPP, 2025). In addition, the study PMC5398277 reported changes in gut flora and improvements in short-chain fatty acid profiles in healthy dogs and cats supplemented with FOS and inulin.

Because prebiotics are not live microorganisms, they also offer a practical advantage: they are relatively resistant to heat and pressure during manufacturing.

Probiotics: supplementation with live microorganisms, but with manufacturing challenges

Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. Representative strains include Lactobacillus, Bifidobacterium, Bacillus, and Saccharomyces cerevisiae (PMC12524077).

The biggest challenge in pet food formulation is manufacturing stability. Because probiotics are live organisms, they may lose a substantial portion of their activity during processing steps such as extrusion and high-temperature drying. To guarantee viable counts (CFU) through shelf life, additional manufacturing steps and quality control costs are often required, such as coating technologies or post-process application by spraying.

Postbiotics: inactivated microorganisms and/or their components

In 2021, ISAPP published a consensus statement in Nature Reviews Gastroenterology & Hepatology formally defining postbiotics as “a preparation of inanimate microorganisms and/or their components that confers a health benefit on the host” (Salminen et al., 2021).

Whereas probiotics require live microorganisms, postbiotics consist of inactivated microorganisms or their bioactive components, such as cell wall fragments, metabolites, enzymes, and short-chain fatty acids. The fact that these microorganisms do not need to remain alive represents a major innovation from a manufacturing perspective.

Practical formulation of prebiotics

Main ingredient types and their characteristics

The prebiotic ingredients most commonly used in pet food generally fall into the following three categories.

FOS (fructooligosaccharides)

FOS are short-chain fructans typically derived from chicory or sugar beet. They are rapidly fermented in the proximal colon and preferentially promote the growth of Bifidobacterium. Multiple studies have confirmed their ability to reduce putrefactive compounds such as indoles and phenols in feces (Fermentation, 2023).

Inulin

Inulin is a longer-chain fructan, usually derived from chicory. Because it ferments further down the colon, it can influence a broader portion of the gut microbiota than FOS alone. In study PMC5398277, inulin supplementation increased beneficial bacteria in dogs and improved short-chain fatty acid profiles.

MOS (mannan oligosaccharides)

MOS are derived from yeast cell walls, primarily Saccharomyces cerevisiae. Unlike FOS and inulin, which directly stimulate beneficial bacteria, MOS are characterized by their ability to physically block the adhesion of pathogenic bacteria to the intestinal wall through binding and exclusion mechanisms. Research has also shown that combinations of FOS and MOS may improve gut microbiota while enhancing both local and systemic immune function (Fermentation, 2023).

Appropriate inclusion levels and the risks of overuse

As a general guideline, ISAPP recommends that in most commercial pet foods, prebiotic inclusion levels should remain below 0.5% of the total formula (ISAPP, 2025).

This is because excessive use of prebiotics may lead to over-fermentation in the large intestine, which can cause digestive issues such as diarrhea, loose stools, and flatulence. For products using these ingredients for the first time, it is advisable to start with low inclusion levels and monitor responses through feeding trials.

Species-specific responses in dogs and cats

Dogs are generally considered more tolerant of higher prebiotic inclusion levels than cats. Responses may also vary depending on body weight, age, and health status. In particular, the following groups may benefit from prebiotics, although careful digestive consideration is required (ISAPP, 2025):

• Senior dogs and senior cats, whose gut microbial diversity tends to decline
• Animals currently taking antibiotics or recovering from antibiotic use, where the gut flora may be disrupted
• Animals at higher risk of digestive disorders

Cats generally tend to be more sensitive to prebiotics than dogs, so greater care is required when selecting both ingredient type and dosage.

The potential of postbiotics in OEM manufacturing

Processing stability: a decisive practical advantage

The biggest reason postbiotics are gaining attention in pet food OEM development is their manufacturing stability.

Because probiotics are live organisms, they may not withstand standard processing conditions such as extrusion, retort sterilization, or high-temperature drying. Ensuring survival through shelf life may require post-heat application methods such as coating technology or even dedicated production lines, which increases both cost and operational complexity.

Postbiotics, by contrast, do not depend on microbial viability because the microorganisms are already inactivated. Industry reports indicate that they can remain stable through extrusion, retorting, long-term storage, and transportation, especially in hot and humid Asian markets (PetfoodIndustry.com, 2024). This makes them suitable for use in virtually all product formats, including dry kibble, wet food, treats, and powdered toppers.

Main functions: supporting the gut barrier, immune modulation, and anti-inflammatory activity

Current scientific literature suggests the following major functions of postbiotics.

Strengthening intestinal barrier function

Postbiotics may enhance the expression of tight junction proteins between intestinal epithelial cells, thereby reducing the risk of pathogens and harmful substances penetrating into the body.

Immune modulation

They have been reported to suppress inflammatory cytokines such as TNF-α and IL-6 while increasing the anti-inflammatory cytokine IL-10. They may also be involved in mucosal immunity by promoting the production of secretory IgA (sIgA) (PMC12299376).

Antioxidant activity

Some studies have reported that postbiotics may help reduce oxidative stress by scavenging reactive oxygen species (ROS) and activating antioxidant enzyme systems.

The current evidence base and how to communicate it responsibly

An important point is that high-quality studies on postbiotics in dogs and cats remain limited.

A 2025 systematic review and meta-analysis (Bonel-Ayuso et al., 2025) reported that in some cases, the meta-analysis did not find statistically significant effects of postbiotics in dogs.

The authors attributed this partly to small sample sizes and heterogeneity in strains and preparations, concluding that further high-quality research is needed. Although efficacy has been reported in other animal species such as poultry and swine, and similar functions are expected in dogs and cats, the current evidence still suggests a stage of “potential benefit” rather than definitive proof.

With this in mind, product communication should avoid definitive therapeutic claims. More cautious language such as “may help support the maintenance of gut health” or “formulated with digestive health in mind” is more appropriate from both a regulatory and ethical standpoint.

Designing combinations of prebiotics and postbiotics

One of the most interesting recent developments is the combination of prebiotics and postbiotics. This can be viewed as an evolution of synbiotic design, and several studies suggest that it may produce stronger synergistic effects than either component used alone.

In study PMC11971633 (Gómez-Gallego et al., Journal of Animal Science), dogs with a tendency toward soft stools were given a blend of prebiotics and postbiotics. The results showed significantly greater improvement in the gut microbiota compared with prebiotics alone or postbiotics alone.

The mechanism can be summarized as follows:

1. Prebiotics serve as a food source for beneficial bacteria already present in the gut
2. These beneficial bacteria produce short-chain fatty acids such as butyrate through fermentation, which are postbiotic components
3. Supplemented postbiotics can act immediately on the gut barrier and immune system
4. The beneficial bacteria promoted by prebiotics may then produce even more postbiotic compounds

This cycle is believed to sustain and amplify the overall effect on the gut environment more effectively than using either approach alone.

In addition, study PMC12184448 reported the safety of a combination product containing prebiotics, probiotics, and postbiotics when administered to healthy dogs and cats. No abnormalities were observed in blood cell counts or blood biochemistry results. This suggests that combined formulations can be considered reasonably safe, although appropriate dosage design remains essential.

Five key design points for product development and OEM practice

When developing a gut health-focused pet food product through OEM manufacturing, we recommend clarifying the following five points at the design stage.

① Match the ingredient to the intended purpose

Define the gut health issue you want to address before selecting ingredients. If the goal is to promote beneficial bacteria, FOS or inulin may be suitable. If the aim is to reduce adhesion of pathogenic bacteria, MOS may be more appropriate. If the main objective is to support intestinal barrier function, postbiotics may be the better option.

② Confirm compatibility with the product format

Because probiotics are highly vulnerable to manufacturing conditions, incorporating them into extruded products is technically demanding. Prebiotics and postbiotics, on the other hand, are more tolerant of heat and pressure, making them easier to use across dry food, wet food, and treat formats.

③ Set inclusion levels with clinical plausibility in mind

For prebiotics, a level below 0.5% is a common benchmark. When multiple ingredients are combined, interactions and total inclusion levels must be considered. It is important to work closely with the OEM factory’s nutrition team and raw material suppliers to confirm recommended usage levels supported by data.

④ Design claims and labeling carefully

For products sold in Japan, pet food is subject to regulations governing feed for companion animals, and medicinal or drug-like efficacy claims are not permitted. Phrases such as “improves gut flora” or “normalizes the intestinal environment” may stray into a regulatory gray zone. Expressions such as “formulated to support the maintenance of gut health” or “made with ingredients selected with digestive health in mind” are generally more appropriate. A compliance review by a qualified specialist should always be conducted before launch.

⑤ Confirm the OEM factory’s handling experience

It is important to choose a factory that has actual experience working with prebiotics and postbiotics. Postbiotics are still a relatively new ingredient category, so the factory’s technical knowledge, experience, and access to appropriate suppliers should all be verified. More overseas OEM factories, especially in Thailand, are becoming capable of handling these functional ingredients, but their experience should still be confirmed during the formulation and trial stage.

Conclusion

To summarize the key points of this article:

• Market background: The functional pet food market is growing at more than 8.5% annually, and gut health ingredients are among the fastest-growing categories. In Japan as well, demand for premium and functional products continues to rise.
• Clarifying the three terms: Prebiotics feed beneficial bacteria, probiotics are live microorganisms, and postbiotics are preparations of inactivated microorganisms and/or their components (ISAPP, 2021). From a manufacturing stability perspective, prebiotics and postbiotics offer clear advantages in OEM formulation.
• Formulation practice: FOS, inulin, and MOS are the main prebiotic ingredients, and an inclusion level below 0.5% is a common benchmark. Because dogs and cats respond differently, formulation should be tailored according to species, age, and health status.
• Potential of combination design: Combined use of prebiotics and postbiotics has been suggested to provide stronger gut health benefits than either alone. However, high-quality evidence in dogs and cats is still limited, so definitive claims should be avoided.
• Practical development points: Clarifying the five key points—ingredient selection, product format compatibility, inclusion level, claim design, and factory selection—at the planning stage will improve the chances of successful OEM development.

A gut health positioning can be an effective strategy for both product differentiation and lead generation. At the same time, long-term brand trust depends on being scientifically responsible and fully compliant with labeling and regulatory requirements.

For companies considering original OEM pet food development

Our company supports the planning, manufacturing, and import of pet food products formulated with functional ingredients by leveraging a network of overseas OEM factories, including in Thailand. We also welcome inquiries regarding the development of products containing prebiotics and postbiotics. Please feel free to contact us.