The Roles of Probiotics, Prebiotics, and Postbiotics in Patient Health

Written by Tonya Cooksey, DVM

Published on April 19, 2023

It is pertinent to understand the important differences between probiotics, prebiotics, and postbiotics when practicing within the realm of microbiome medicine. All three are scientifically proven to provide health benefits for a range of animal health conditions. Know the unique attributes and specific applications in which they are useful to make informed decisions about patient therapy.


Prebiotics are non-digestible food ingredients that selectively stimulate the growth or metabolite-producing activity of beneficial bacteria within the gut. By feeding the beneficial bacteria, prebiotics support immune function, improve gut barrier integrity, and increase the production of short-chain fatty acids (SCFAs).3 Butyrate is one of the most important SCFAs produced by the fermentation process of prebiotics because it is the key energy source for enterocytes and colonocytes.

Each type of prebiotic will influence the gut in a different method, depending on its chemical structure and which bacteria can properly use it for metabolism. Soluble fiber is the most common prebiotic additive to veterinary diets to enhance overall gut health. Other common prebiotics include fructo-oligosaccharides (FOS), xylo-oligosaccharides (XOS), psyllium, and inulin.


Probiotics are living organisms, typically bacteria or yeast in origin, that when administered in adequate amounts, improve gut health by restoring balance to the microbiome, promoting the growth of beneficial bacteria, and reducing levels of pathogenic bacteria. This balance within the gut microbiome allows for improved immune system function, decreased production of pro-inflammatory cytokines, and overall improvement in digestion and absorption. Learn more here.

Most bacterial probiotics in veterinary medicine contain strains of Lactobacillus or Bifidobacterium, as these are found to be part of a normal healthy human gut microbiome and are based on human studies. However, these microbes are not part of feline and canine healthy gut reference sets, indicating a need for more research on species-specific strains. When restoring the bacterial content of the gut microbiome, lyophilized fecal material in our FMT Gut Restore Supplement provides species-specific microbes necessary for the health of the patient. Learn more here.

Saccharomyces boulardii is a yeast-based probiotic that is shown to be beneficial in both cats and dogs. It supports the gut while also decreasing levels of pathogenic Clostridium species, including Clostridium difficile, and protects against antibiotic-associated diarrhea.1,2 In general, the efficacy of probiotics depends on several factors, including the strain of probiotic used, the dosing and the duration of therapy.


Postbiotics are the metabolic by-products produced by beneficial microbes during the fermentation process. These by-products can include SCFAs, enzymes, bacteriocins, and organic acids. Postbiotics, like the Saccharomyces cerevisiae fermentate in our Skin and Coat Relief Supplement, improve gut health and produce overall health benefits in patients. They can increase the production of immunoglobulins within the immune system, regulate and reduce intestinal inflammation and inhibit the growth of pathogenic microbes in the gut microbiome.4

Cited Literature

[1] Kelesidis T, Pothoulakis C. Efficacy and safety of the probiotic Saccharomyces boulardii for the prevention and therapy of gastrointestinal disorders. Therap Adv Gastroenterol. 2012;5(2):111-125.

[2] Ehrhardt S, Guo N, Hinz R, Schoppen S, May J, Reiser M, et al. Saccharomyces boulardii to Prevent Antibiotic-Associated Diarrhea: A Randomized, Double-Masked, Placebo-Controlled Trial. Open Forum Infect Dis. 2016;3(1):ofw011.

[3] Holscher HD. Dietary fiber and prebiotics and the gastrointestinal microbiota. Gut Microbes. 2017;8(2):172-184.

[4] Lin CY, Alexander C, Steelman AJ, Warzecha CM, de Godoy MRC, Swanson KS. Effects of a Saccharomyces cerevisiae fermentation product on fecal characteristics, nutrient digestibility, fecal fermentative end-products, fecal microbial populations, immune function, and diet palatability in adult dogs1. J Anim Sci. 2019;97(4):1586-1599.


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