What Each Probiotic and Prebiotic Strain in ImmunoGut Does for Your Dog's Gut

Educational content only. Shop Healthy Pets supplements are not intended to diagnose, treat, cure, or prevent disease; always talk to your veterinarian about your dog's digestive health.

ImmunoGut's probiotic blend packs 7 billion CFU across 11 distinct bacterial strains, plus two prebiotic fibers that feed them. Rather than one generic “probiotic,” each strain plays a specific, researched role in gut health. Here's what the science says about each one.

Key Takeaways

• ImmunoGut's probiotic blend spans 4 bacterial genera: Lactobacillus, Bifidobacterium, Bacillus, and Streptococcus.
• Probiotic benefits are strain-specific — research on one strain doesn't automatically apply to a different strain of the same species (Segui-Perez et al.).
• Inulin and FOS aren't bacteria themselves — they're prebiotic fibers that feed the probiotic strains already living in the gut (Garcia-Mazcorro et al.).
• A canine-derived Lactobacillus acidophilus strain has shown probiotic potential specifically in dogs, not just in lab or human studies (Zhao et al.).

The Lactobacillus Strains

Lactobacillus acidophilus — One of the most studied probiotic species in both humans and dogs. Canine-derived strains have shown the ability to support immune regulation, strengthen the intestinal barrier, help balance the broader gut microbiota, and reduce populations of less desirable bacteria in the gut (Zhao et al.).

Lactobacillus plantarum — Studied for supporting healthy digestion and a balanced inflammatory response in the gut. Some research associates this species with better colon wall integrity and reduced antibiotic-related diarrhea.

Lactobacillus casei — Lives in the gut's mucus lining and has been studied in connection with easing diarrhea, constipation, and other digestive upset. As part of the broader gut-brain axis, this species is also of interest for its potential connection to mood and behavior.

Lactobacillus salivarius — A natural resident of a healthy gut microbiome. This species helps break down undigested protein and has been studied for its ability to help keep less desirable bacteria in check.

Lactobacillus rhamnosus — Known for being unusually stable across a range of temperatures and pH levels, which helps it survive the trip through the stomach. Widely studied for its role in gut inflammation and hypersensitivity responses.

Lactobacillus brevis — Common in fermented foods and studied for its influence on gut microflora balance and inflammatory signaling in the gut.

The Bifidobacterium Strains

Bifidobacterium lactis — One of the most recognized Bifidobacterium species used in probiotic research, valued for fermenting carbohydrates into short-chain fatty acids that feed colon cells.

Bifidobacterium bifidum — Research on probiotic B. bifidum strains has shown they can strengthen the intestinal epithelial barrier and interact directly with the gut's protective mucus layer (Segui-Perez et al.).

Bifidobacterium longum — Alongside B. bifidum, this species helps promote a balanced gut microbiome by supporting beneficial bacteria and helping crowd out less desirable ones.

As a genus, Bifidobacterium species are considered colon specialists — they primarily ferment complex fibers into short-chain fatty acids like acetate and lactic acid, which nourish colon cells and support the gut barrier.

Bacillus subtilis

Bacillus subtilis is a hardier strain than most Lactobacillus and Bifidobacterium species, able to survive the trip through the GI tract particularly well. In a randomized, placebo-controlled trial, a Bacillus subtilis strain (DE111) increased anti-inflammatory immune cell response and supported fecal and salivary markers tied to immune defense (Freedman et al.). It's also studied for supporting enzyme production that aids digestion and for helping crowd out less desirable organisms in the gut.

Streptococcus thermophilus

Streptococcus thermophilus produces lactase, the enzyme that breaks down lactose, which is part of why it's associated with easier digestion of dairy-containing ingredients. Research shows its effect on gut microbiota is strain-specific, and it's also studied for anti-inflammatory activity in the digestive tract (Yu et al.).

The Prebiotics: Inulin and Fructooligosaccharides (FOS)

Unlike the 11 probiotic strains above, inulin and FOS aren't living bacteria — they're prebiotic fibers. They pass through the upper digestive tract undigested and reach the colon, where beneficial bacteria like Lactobacillus and Bifidobacterium ferment them into short-chain fatty acids (SCFAs) such as acetate, propionate, and butyrate (Garcia-Mazcorro et al.). Those SCFAs feed intestinal cells, help regulate inflammation, and support a healthy gut lining. In other words, the prebiotics in ImmunoGut are food for the probiotics in ImmunoGut — the two work as a team rather than working separately.

Frequently Asked Questions

Why does ImmunoGut use 11 different probiotic strains instead of just one or two?
Because probiotic benefits are strain-specific, not just species-specific — different strains support different aspects of gut and immune health, so a broader blend is designed to cover more ground than a single-strain product (Segui-Perez et al.).

What's the difference between a probiotic and a prebiotic?
Probiotics are live bacterial strains; prebiotics like inulin and FOS are fibers that feed those bacteria once they're in the gut (Garcia-Mazcorro et al.).

Are these the same probiotic strains found in human supplements?
Many of the species overlap with human research, but some ImmunoGut strains — like the canine-derived L. acidophilus research referenced above — have been studied specifically in dogs (Zhao et al.).

This article is for general educational purposes and is not veterinary advice. Consult your veterinarian about your pet's specific digestive or immune health needs.

Works Cited

Freedman, Kimberley E., et al. “Examining the Gastrointestinal and Immunomodulatory Effects of the Novel Probiotic Bacillus subtilis DE111.” International Journal of Molecular Sciences, vol. 22, no. 5, 2021, article 2453, doi:10.3390/ijms22052453.

Garcia-Mazcorro, Jose F., et al. “Molecular Assessment of the Fecal Microbiota in Healthy Cats and Dogs Before and During Supplementation with Fructo-Oligosaccharides (FOS) and Inulin Using High-Throughput 454-Pyrosequencing.” PeerJ, vol. 5, 2017, e3184, doi:10.7717/peerj.3184.

Segui-Perez, C., et al. “Probiotic Bifidobacterium bifidum Strains Desialylate MUC13 and Increase Intestinal Epithelial Barrier Function.” Scientific Reports, vol. 15, 2025, article 8778, doi:10.1038/s41598-025-92125-2.

Yu, Peng, et al. “Influence of Lactose Supplementation on Regulation of Streptococcus thermophilus on Gut Microbiota.” Nutrients, vol. 15, no. 22, 2023, article 4767, doi:10.3390/nu15224767.

Zhao, Mengdi, et al. “Developing Gut-Healthy Strains for Pets: Probiotic Potential and Genomic Insights of Canine-Derived Lactobacillus acidophilus GLA09.” Microorganisms, vol. 13, no. 2, 2025, article 350, doi:10.3390/microorganisms13020350.