The science behind species-specific probiotics.

Probiotics for dogs are intended to help maintain digestive health and hasten recovery from diarrhea and other illnesses (including antibiotic-associated diarrhea).

However, commercially available formulations for dogs generally use probiotics of human origin. Since probiotic bacteria can evolve host-specific traits, and because the gastrointestinal tracts of humans and canines have unique anatomical, physiological and biochemical differences, we aimed for a higher standard: the pursuit of species-specific probiotics for dogs.


For this research, we worked with Dr. Jake Burlet of CanBiocin. Together, we developed a process to investigate the viability, bioavailability, and survival rates of canine-specific probiotics.

We specifically isolated Gram-positive bacteria (Lactobacilli) from freshly-voided healthy canine feces and used the appropriate tests to eliminate duplicate isolates. The probiotic candidates were subjected to a series of evaluations including (but not limited to): tolerance to simulated gastric and intestinal conditions; production of antibacterial substances; host immune modulation capabilities (using two canine cell lines); antibiotic resistance testing; and strain stability.

We isolated 11 distinct Gram-positive, rod-shaped bacteria that were subsequently identified as Lactobacillus spp. The isolates were assigned the designation K9-1 and K9-2 for differentiation. By subjecting these isolates to the experiments in the paragraph above, we eliminated strains from the list based on their unique properties.

Ultimately, we were left with two unique microbial isolates (K9-1 and K9-2) that have promising immune modulation capabilities and excellent stability. We thus chose to pursue a strain cocktail to encompass the positive attributes of both K9-1 and K9-2 in one formulation. Additional testing was done to determine Section Shelf Life and Survival in simulated gastric and intestinal conditions.


Shelf life is an important element when including probiotics in formulations for administration to dogs (and other companion animals). The ability to confer positive outcomes in the target species is a function of probiotic organism viability as well as the accompanying prebiotics and postbiotic metabolites. Prebiotics help provide fuel for the growth of species-specific probiotics and foster their ability to colonize in the intestinal tract. Postbiotics include metabolites which have specific functions as well as inanimate organisms.

Viability over time decreases for non-spore-forming probiotic organisms. Viability can be enhanced with micro-encapsulation as well as careful attention to recommendations regarding handling and storage. One to two log reductions in live cell viability over time are well documented and to be expected. We recognized the importance of an integrated approach to formulation, taking into consideration the synergies of prebiotics, probiotics and their postbiotic metabolites.


Cytokines are small proteins that help control the activity of other immune system cells. Cytokines direct the immune system to do its job.

DH82 (canine macrophage-like cell line) or MDCK (canine epithelial cell line) cells were co-incubated with K9-1 or K9-2. Cell lysates were analyzed for their cytokine expression levels by qRT-PCR.

The results showed that CanBiocin species-specific probiotics were associated with increased cytokine production within the intestinal lumen. Intestinal epithelial M cells become stimulated to transport pathogens (bad bacteria) as well as inflammatory antigens out of the intestinal lumen to the sub-epithelium. Within the sub-epithelium, macrophages and other immune cells process and “dispose” of the pathogens and antigens.


Together with Dr. Burlet, our goal is to continue developing host-specific probiotic products with supportive natural formulas for canines, felines, and equines. We all agree that current probiotics have a genuine foothold when it comes to the health and well-being of our companion animals, but with this exciting new research showing the postbiotic metabolites and the immune modulation of these species-focused bacterial strains, we’ve been able to reinforce their far-reaching effects in comparison to the strains we have been using in practice to date. Combining these strains with prebiotics that are geared towards specific species produces a synergy that aids in the healing of the mucosal lining, supports the chelation of toxins, provides anti-inflammatory properties, and creates a diverse gut ecosystem that builds the pillars of a balanced, healthy body.


Julie Anne Lee, DCH, has over 25 years of clinical practice, and opened the first licensed holistic veterinary hospital in Canada. A primary focus for Julie has always been the microbiome. She regularly lectures at veterinary conferences and universities worldwide. Julie is the owner and formulator of Adored Beast Apothecary.


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