Probiotics for Dogs: Science on Benefits

Probiotics for Dogs

Probiotics for Dogs

Are probiotics for dogs necessary? Do they help only with dog’s digestive system, or are there any more benefits to them? What about side effects? Let’s discuss and see what current research has to say about probiotics for dogs.

Everyone is all abuzz about the different ways that you can incorporate probiotics into your daily diet. Supplement pills, special yogurts and even baby formula are packed full of the stuff. But what are probiotics for dogs and are they beneficial at all?

What are probiotics for dogs?

Probiotics are live “good” bacteria that when ingested in high sufficient numbers can improve the health of your dog [1]. The bacteria in the gut is commonly known as “intestinal flora.”

Probiotics vs Prebiotics

Prebiotics are non-digestible substances that help stimulate and potentiate the benefit of probiotics. They can consist of fibers and sugars, such as fructans and galactooligosaccharides [2, 3].

Prebiotics are sometimes marketed with probiotics in the same supplement or package. These are also known as synbiotics [1].

Are probiotics an essential nutrient for my dog?

No, probiotics are not an essential nutrient for dogs in any way.

How does it work for my dog?

While they are not technically ‘essential’, probiotics are beneficial for your dog’s immune system and digestion. 70% of the dog’s immune system lies in and adjacent to its gut [7].

Dogs and other animals with improper or absent “good” intestinal bacterial flora have underdeveloped immune systems and abnormal intestinal structure [2, 4, 5].

These “good” bacteria in your dog’s intestines help to prevent “bad” bacteria (such as Clostridia or Proteus species) from taking over and causing problems in your dog’s gut [6].

Probiotic species such as Lactobacilli and Bifidobacteria produce helpful amounts of lactic and acetic acids. These acids in the dog’s gut in turn inhibit the growth of “bad” bacteria [7].

Probiotic species also help the dog to digest foodstuffs that their body can’t break down alone, such as during the production of short-chain fatty acids either from supplements or foods like fatty fish. These fatty acids in turn help to feed the cells of the dog’s colon and help to maintain water and sodium balance in canines [8].

Why should my dog take probiotics?

Your dog’s digestive tract, like yours, is teaming with helpful bacteria that aid our digestion and immune system. We could not thrive without them. Sometimes, bad bacteria, inflammation and other infections can cause health problems in the gut. This is where probiotics step in to support your dog’s health and treat the problem at hand.

A number of ailments may be treated or improved by the use of probiotics for dogs [1, 2, 9, 10, 14]:

  • Diarrhea
  • Inflammatory Bowel Disease
  • Cancer
  • Exocrine pancreatic insufficiency
  • Skin disease
  • Reduce inflammation

Can probiotics be used to prevent disease?

Yes, it is possible. Probiotics can be used to boost your dog’s immune system, reduce inflammation and prevent colonization of “bad” bacteria [1, 11].

However, there have not been enough studies in dogs to say that probiotics can without a doubt prevent certain diseases.

My dog is taking antibiotics, can he still take probiotics?

Yes! Antibiotics are used to kill “bad” bacteria, but they can kill the “good” bacteria in your dog’s system too.

Sometimes veterinarians will treat intestinal infections with an antibiotic called metronidazole. Certain strains of probiotics are resistant to metronidazole, which can help replenish your dog’s intestinal bacterial flora. An example of a metronidazole-resistant probiotic is Nestle Purina’s FortiFlora.

My dog’s food contains probiotics, are they helping him?

Probiotics in your dog’s food is never a bad thing, but it can have questionable benefit. A large number of bacterial cells must be ingested for them to be beneficial to your dog’s system. Studies have shown that many cell counts in these dog foods fall short [12].

Veterinarians, however, still recommend giving a separate supplement even if your dog eats these foods.

What are some trusted sources of probiotics for dogs?

Always consult with your veterinarian about what probiotics for dogs are the best specifically for your canine’s case.

Trusted probiotic brands for dogs include:

  • Vetri-Science Probiotic BD
  • Vetri-Science Fast Balance GI Paste
  • Nutramax Proviable DC
  • Nestle Purina FortiFlora

These companies guarantee that their product contains a live culture of multiple beneficial species. Note that none of these have been tested for label accuracy or bioviability of the product.

Can I simply give my dog some yogurt?

Yogurt can contain useful bacterial cultures for humans but these cultures have questionable benefit for dogs. No studies have shown that yogurt contains enough bacterial cell counts to alter the intestinal bacterial flora in dogs [13].

It is best to give a more concentrated probiotic supplement to your dog daily or as directed by your veterinarian.

The bottom line

If your dog is normal and healthy, a digestive supplement like probiotics and/or prebiotics may not be necessary. Some of these may have benefits and certain supplements may prevent medical problems in the future, but so far, this would be guesswork as we have no hard data to conclude that probiotics for dogs are truly necessary in a general sense.

If your dog has endocrine, immune, digestive, skin or urinary tract disease, a probiotic can be very helpful in treating their condition. Remember to talk to your veterinarian for more information about what probiotic is right for him or her.

Food for thought on probiotics for dogs

Billions of bugs

The normal “flora” of the dog’s digestive tract is made up of hundreds of different types of beneficial bacteria. It is helpful to keep in mind that probiotic supplements only provide a handful of these beneficial bugs. In the future, “fecal transplants” may be the best way to treat chronic digestive problems, such as inflammatory bowel disease and infections with pathologic Clostridium [16]:

“Clostridium perfringens is commonly recognized as a cause of diarrhea with mucus and blood in the dog. The purpose of this study was to determine if fecal transplantation could be used to cure Clostridium perfringens infections that were not cured by treatment with metronidazole and amoxicillin trihydrate/clavulanate potassium.

Eight dogs who tested positive for Clostridium perfringens on RealPCRTM panels by IDEXX Laboratories and whose infections were not cured with antimicrobial therapy alone underwent fecal transplants from an infection-free donor dog.

Donor stool was mixed with saline in a blender and given as an enema on an outpatient basis in an unsedated patient. Eight out of eight dogs had immediate resolution of their diarrhea and six out of eight dogs were negative on follow-up PCR panels for Clostridium perfringens alpha toxin gene expression. Dogs had between one and three fecal transplants.

To the authors’ knowledge, this is the first report of fecal flora transplantation in the dog for refractory Clostridium perfringens infections. This treatment plan is an option for dogs failing antibiotic therapy and also reduces antibiotic use.

Atopic dermatitis

You probably thought that probiotics for dogs would only work on their digestive health. But did you know that they can potentially help prevent or treat your dog’s skin allergy dermatitis? A study in 2012 showed that [14]:

Probiotics modulate the immune response and may have protective effects against atopic dermatitis (AD). Clinical trials using dogs with spontaneous disease are limited by confounding factors such as different diets, environments and sensitizations while a more controlled evaluation is possible using experimental models. A validated model of canine AD showed that early exposure to Lactobacillus rhamnosus GG (LGG) significantly decreases allergen-specific IgE and partially prevents AD in the first 6 months of life.

This study is a follow-up three years after discontinuation of LGG. Clinical signs were evaluated after allergen challenge with ragweed, timothy, Dermatophagoides farinae. Allergen-specific IgE, IL-10 and TGF-β were measured on the 1st day of challenge, before allergen exposure. Normal dogs were included as controls. Analyses included seven dogs in the non-probiotic and nine in the probiotic litter. For clinical scores, a 2-Group × 9-Time Analysis of Variance showed significant effects of group (p=0.0003, probiotic<controls), time (p<0.0001) and group × time interaction (p<0.0001). IL-10 for all allergens was significantly higher in the control group than probiotics-exposed dogs.

Allergen-specific IgE and TGF-β did not differ between litters. Early exposure to probiotics has long-term clinical and immunological effects in this model and larger studies using dogs with spontaneous disease are needed.

This is very exciting for veterinarians and dog owners alike. Many dogs suffer from allergies to environmental substances like pollen and even food sources like chicken proteins. With further research and clinical use, some atopic dogs may benefit from daily, long-term probiotic usage.

Some breeds, like the Golden retriever, are more prone and ‘at risk’ to developing atopic dermatitis than other breeds. It may be worthwhile to supplement young ‘at-risk’ puppies with probiotics in order to prevent allergies. Science has not fully explained if probiotics for dogs really will help, but it may be a benign preventative measure for some pet owners to try.

Urinary tract infections and probiotics for dogs

Some women with urinary tract infections benefit from oral probiotic supplementation. This is because the vaginal vault of women is colonized by Lactobacillus species. Could similar probiotic supplementation for dogs be helpful? It is possible, but the “jury is still out.”

Dr. Shelly Vaden, a board-certified veterinary internist, says this about using probiotics for dogs to prevent UTI in canines [10]:

Because most UTIs in dogs are believed to be ascending infections, maintenance of a healthy microbial population of the vestibule and vagina may be important in female dogs. In most women, the vaginal microbiota is remarkably similar with lactobacilli being the most dominant colonizer. Although it is uncertain if outliers from this normal population are always at increased risk of UTI, women with recurrent UTI have been reported to have a high incidence of bacterial vaginosis.

Probiotic lactobacilli are believed to improve urogenital health in women through immune modulation, pathogen displacement, and creation of a niche less favorable for pathogenic bacterial proliferation. Probiotics may help replenish the normal microbes, displacing pathogens and leading to a return to the lactobacilli-dominated state found in healthy women, preventing ascending UTI. In one study of 120 children who were given either Lactobacillus sp. or trimethoprim/sulfamethoxazole prophylaxis for one year, there was no difference in the incidence of recurrent UTI. The use of probiotics in prevention of UTIs in dogs probably warrants further study.

One study in 2013 showed that the vaginal vault of dogs is not colonized by these beneficial bacteria [15]:

Recurrent urinary tract infections (UTIs) are often difficult to treat. Vaginal colonization with lactic acid-producing bacteria (LAB) is associated with reduced frequency of recurrent UTIs in women. Oral probiotics might help increase the prevalence of vaginal LAB and decrease the frequency of recurrent UTIs in dogs. HYPOTHESIS: Administration of an oral probiotic supplement containing Lactobacillus, Bifidobacterium, and Bacillus species will increase the prevalence of LAB in the vagina of dogs. ANIMALS: Thirty-five healthy, spayed female dogs without history of recurrent UTIs. METHODS: Prospective, controlled study.

Enrolled dogs received an oral probiotic supplement for 14 or 28 days. A vaginal tract culture was obtained from each dog before and after oral probiotic administration. Twenty-three dogs received the oral probiotic supplement daily for a period of 14 days and 12 dogs received the oral probiotic supplement daily for a period of 28 days. RESULTS: Lactic acid-producing bacteria were isolated from 7 of 35 dogs prior to probiotic administration. After the treatment course, 6 of 35 dogs had LAB isolated. Only one of these dogs had LAB (Enterococcus canintestini) isolated for the first time.

Enterococcus canintestini was the most common LAB isolated from all dogs in this study, although it was not included in the probiotic supplement. CONCLUSIONS AND CLINICAL IMPORTANCE: Lactic acid-producing bacteria are not a common isolate from the vaginal vault of dogs. Administration of this oral probiotic supplement for a 2- or 4-week period did not increase the prevalence of vaginal LAB in dogs.


[toggle title=”References”]
  1. Sanderson, S. They’re Not Just for Diarrhea Anymore. Student American Veterinary Medical Association Symposium Proceedings. 2013. Veterinary Information Network.
  2. Swanson, K. Microbiota: How the Gut Flora Affects Health and Disease in Dogs and Cats. ACVIM Proceedings 2011. Veterinary Information Network.
  3. Patra, A. Responses of feeding probiotics on nutrient digestibility, faecal microbiota composition and short-chain fatty acid concentrations in dogs: a meta-analysis. September 2011;5(11):1743-50. [study]
  4. Thorbecke G. Ann NY Acad Sci 1959;78:237.
  5. McCracken V, Gaskins H. Probiotics: A Critical Review 1999;85.
  6. Wortinger, A. Prebiotics & Probiotics: What Can They Do For the Dog & Cat, ACVIM Proceedings 2010. Veterinary Information Network.
  7. Kelly M. The role of probiotics in GI tract health. Nestle Purina PetCare Company. 2006
  8. Pan X, Chen F, Wu T, Tang H, Zhao Z. Prebiotic oligosaccharides change the concentrations of short-chain fatty acids and the microbial population of mouse bowel. Journal of Zhejiang University Science B. 2009 10(4); 258-263. [study]
  9. Rossi, G. et. al, Comparison of microbiological, histological, and immunomodulatory parameters in response to treatment with either combination therapy with prednisone and metronidazole or probiotic VSL#3 strains in dogs with idiopathic inflammatory bowel disease. PLoS ONE. 2014;9(4):e94699. DOI: 10.1371/journal.pone.0094699
  10. Vaden, S. Can We Prevent UTI? ACVIM Proceedings 2011. Veterinary Information Network.
  11. Benyacoub J, Czarnecki-Maulden GL, Cavadini C, Sauthier T, Anderson RE, Schiffrin EJ, von der WT. Supplementation of food with Enterococcus faecium (SF68) stimulates immune functions in young dogs. J Nutr. 2003;133:1158. [study]
  12. Weese, JS, Arroyo L. Bacteriological evaluation of dog and cat diets that claim to contain probiotics. Canadian Veterinary Journal  44, March 2003. [paper]
  13. Fascetti, A. Nutritional Management of Gastrointestinal Disease. Western Veterinary Conference Proceedings. 2004. Veterinary Information Network.
  14. Marsella, R. et al, Early exposure to probiotics in a canine model of atopic dermatitis has long-term clinical and immunological effects. Vet Immunol Immunopathol. April 2012;146(2):185-9. doi: 10.1016/j.vetimm.2012.02.013
  15. Hutchins, R. et al, The effect of an oral probiotic containing lactobacillus, bifidobacterium, and bacillus species on the vaginal microbiota of spayed female dogs. J Vet Intern Med. 2013 Nov-Dec;27(6):1368-71. doi: 10.1111/jvim.12174
  16. Murphy, T, Chaitman, J, Han, E. Use of Fecal Transplant in Eight Dogs with Refractory Clostridium perfringens-Associated Diarrhea. ACVIM 2014 Proceedings. Veterinary Information Network.

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