Your pet’s gut is home to trillions of microorganisms working behind the scenes to support digestion, immunity, and overall well-being. Scientists have discovered that postbiotic bacteria —non-viable bacterial cells that retain their structure and functional properties— can help maintain this internal ecosystem, especially during stressful events like antibiotic treatment or dietary changes. Here’s what the latest research reveals about these shelf-stable, science-backed ingredients for pet gut health.
Global Category Manager
Lallemand Animal Nutrition
The next time you look at your dog, your cat, or even yourself in a mirror, think of this: each of us is currently hosting trillions of microorganisms. This inner world, called the microbiome, is a complex collection made up mostly of bacteria, but also includes viruses, fungi and other microbes. For the most part, we coexist harmoniously with this second internal world. Most of our microbiome lives in our gut, where it performs a variety of functions like helping us digest food, producing vitamins and neurotransmitters, supporting our immune systems, and even influencing our moods. As science continues to explore the gut microbiome, we learn more about its significant impact on our physical and mental health.
If a balanced gut microbiome helps keep us healthy, it is important to remember that what we (and our pets) eat impacts the ability of our microbiome to do its job.
FEEDING THE “GOOD GUYS”: PREBIOTICS AND PROBIOTICS
Nutritionists recommend a high-fiber diet for many reasons, but for the microbiome the crucial one is the introduction of prebiotics. Prebiotics fuel the beneficial bacteria in our gut, helping them thrive. When they do, they support our overall health from the inside out.
Another aspect of our gut microbiome is the balance of “good” and “bad” bacteria. This balance can be disrupted by many factors, including dietary changes, stress, infections, and antibiotics. When disrupted, the imbalance can cause acute or chronic diarrhea, vomiting, or loss of appetite, ultimately impairing digestion and nutrient absorption.
Probiotics are live bacteria and yeasts that can help restore the healthy balance of bacteria and digestion. Probiotics have additional complex benefits. Current understanding of their properties includes providing immune support by helping stimulate the immune system, outcompeting “bad” bacteria, and initiating host-microbiome crosstalk that can have a positive impact on the intestinal barrier.
POSTBIOTICS: PRESERVING THE BENEFITS, ENHANCING THE PRACTICALITY
The introduction of live probiotic organisms has been shown to be beneficial for some medical conditions. However, working with live organisms presents practical challenges, including stringent regulatory requirements and maintaining viability throughout the production, storage, and distribution process.
Recent research set out to investigate if the benefits of probiotics could be obtained without those risks, by using heat treatment to inactivate bacteria and yeast, and then evaluating if the remaining components could be beneficial without harm to the host. These inactivated microbial fractions are called postbiotics. The researchers theorized that selected bacteria strains, made non-viable before administration, could be valuable functional ingredients to enhance pet food and pet supplement products.
Lallemand’s researchers selected three strains of bacteria based on their known immunomodulatory properties: Lactobacillus helveticus HA-122, L. paracasei HA-108 and L. plantarum HA-119. They then used a strain-specific, gentle, heat-treatment process that:
• enabled preservation of the cell membrane and cell structure of the bacteria strains while inhibiting their capacity to replicate, and
• ensured the production of microbiologically non-viable, shelf-stable, yet functionally active microbial cells.
While all three strains underwent this careful preparation, the following studies zoom in on L. helveticus HA-122 and L. plantarum HA-119 to demonstrate the postbiotic approach in depth.
After the bacteria were heat treated, they were examined in depth. The researchers observed that the cell membrane and cellular structure were preserved, retaining their structural integrity and bioactive components.
The research then progressed to the next critical step: an in vivo proof-of-concept study. This marked the second phase of a rigorous three-step research program designed to validate the postbiotics’ efficacy—first, strain characterization to preserve bacterial structure and function; second, effect characterization using a phenotyping model; and third, validation in the target species.
THE REMARKABLE MAMMALIAN MODEL: THE ZEBRAFISH
To validate the functional activity of the heat-treated strains, researchers first turned to the zebrafish—a well-recognized model for studying mammalian gut and immune biology. Although obviously not a mammal, the zebrafish offers key advantages: a fully sequenced genome, rapid reproduction, cost-effective maintenance, and strong physiological parallels with mammals, particularly in gut structure, nutrient metabolism, and immune pathways.
For the first part of the study, adult zebrafish were divided into four groups. All were fed a standard diet, and some received a diet enriched with either live L. helveticus HA-122, heat-treated L. helveticus HA-122, or heat-treated L. plantarum HA-119. After five weeks, fish receiving heat-treated bacteria showed clear improvements in gut barrier integrity and immune responsiveness—evidence that the postbiotics retained beneficial activity even without live cells.1
The second part of the study focused on whether these postbiotics helped to strengthen the animals’ natural defenses against a viral challenge. After three weeks on the dietary treatments, L. plantarum HA-119 showed the strongest effect, and fish receiving the heat-treated form exhibited significantly elevated immune gene expression.2
Combined, these studies showed strong evidence that postbiotics could help strengthen gut barrier integrity and natural defenses in the zebrafish model, paving the way for validation in dogs.
FROM FISHBOWL TO PET BOWL: TESTING DIGESTIVE RESILIENCE IN DOGS
While model organisms help us uncover mechanisms, the real evidence emerges when we test these ingredients in the animals we care for. Building on the encouraging zebrafish data, researchers from Lallemand zoomed in exclusively on L. helveticus HA-122 for validation in dogs—the studies that really count. After all, findings in a model become even more meaningful when they are confirmed in the target species we are aiming to support.
The research team designed two studies addressing scenarios familiar to veterinarians and pet owners alike.
The first in-vitro study focused on antibiotic-induced dysbiosis—a common complication when dogs require antibiotic treatment. Using an advanced bioreactor system that replicates the canine gut environment, researchers administered a five-day course of broad-spectrum antibiotics known to disrupt gut microbial balance.3 One bioreactor was infused with heat-treated L. helveticus HA-122 concurrently with the antibiotic treatment. The critical phase came next: monitoring gut microbiota recovery over the following weeks. The results showed that the heat-treated L. helveticus HA-122 accelerated the re-establishment of microbial balance compared with controls.
The second in-vivo study involved 40 healthy adult dogs and examined another common digestive stressor: dietary transitions. Whether upgrading nutrition or managing sensitivities, food changes can challenge gut stability. Dogs received either their standard diet or the same food supplemented with the postbiotic. All dogs then transitioned to a high-protein formula to assess digestive adaptation.
The results demonstrated consistent benefits compared to control animals:
• Improved digestive function: Stool quality normalized more rapidly in supplemented dogs, indicating quicker resolution of dietary stress.
• Enhanced gut barrier support: Measurements of fecal calprotectin and secretory IgA revealed beneficial trends, suggesting the postbiotic helped reinforce intestinal defenses during periods of stress.
• Better tolerance of dietary changes: During food transitions, dogs receiving supplementation demonstrated smoother adaptation and more stable fecal consistency.
• Improved skin and coat health: Dogs showed measurable enhancements in skin condition and in microbiota composition and diversity, supporting the gut–skin axis hypothesis.
WHY THESE FINDINGS MATTER
These weren’t artificial scenarios with abstract endpoints. The studies tested real challenges—antibiotic treatment and diet changes—that companion animals routinely face. Heat-treated L. helveticus HA-122 consistently supported digestive stability during these predictable stressors.
For veterinarians and pet owners seeking evidence-based approaches to immune support and gut health, these findings offer practical validation: a scientifically substantiated way to support overall health and well-being when dogs encounter unavoidable challenges.
THE NEXT GENERATION OF GUT HEALTH SUPPORT
As more people look for ways to support their pets’ health naturally, nutraceuticals—foods with functional health benefits—are gaining momentum. Among them, postbiotics emerge as a practical and effective addition to premium pet food and supplements.
Postbiotics offer distinct advantages: they don’t require refrigeration, remain stable throughout the pet food manufacturing process, and their shelf stability makes them easy to incorporate into daily feeding. Equally important, robust research demonstrates their ability to promote gut integrity, support immune balance, and help restore microbial equilibrium after antibiotic use or dietary changes.
When we feed our pets, we’re nourishing more than just our companions—we’re also supporting a complex microscopic ecosystem that plays a vital role in their overall well-being. Thanks to science-backed innovations like postbiotics, we’re better equipped than ever to care for that hidden world inside them.
References
1Rawling, et al. 2023. “Modulation of Zebrafish (Danio rerio) Intestinal Mucosal Barrier Function Fed Different Postbiotics and a Probiotic from Lactobacilli.” Microorganisms 11(12): 2900. https://doi.org/10.3390/microorganisms11122900
2Apper, et al. 2023. “The Zebrafish (Danio rerio) Model: An Accurate Model to Screen the Effect of Heat-Inactivated Lactobacillus Strain on Immune Responses.” Paper presented at the 27th Congress of the European Society of Veterinary & Comparative Nutrition (ESVCN), Vila Real, Portugal, September 7–9, 2023.
3Deschamps, C. 2023. “Impact of Body Weight and Antibiotic Disturbance on Canine Gut Microbiota: In Vitro Simulation and Restoration Strategies.” Microbiology and Parasitology. Université Clermont Auvergne.
About Dr. Francesca Susca
As the Global Category Manager for Pet at Lallemand Animal Nutrition, Dr. Francesca Susca is dedicated to advancing the company’s mission of optimizing animal health and well-being through carefully selected natural microbial solutions. Prior to this, Susca spent 10 years at Nestlé Purina, where she held various roles in Product Development, Regulatory Affairs and Compliance within the PetCare and Pet Food sectors.
She earned a Doctorate in Veterinary Medicine from the University of Milan, followed by a PhD in Animal Feed and Food Safety. Her doctoral research focused on the effects of dietary nutrient supplementation on the metabolism and performance of dairy ruminants, though her professional career has been dedicated to pets.
