From itchy skin and digestive problems to anxiety and behaviour, new scientific research highlights just how important the gut microbiome is to your dog's overall health.
When we think about keeping our dogs healthy, we often focus on their diet, exercise and general wellbeing. But inside every dog's digestive system lives an extraordinary community of trillions of microorganisms that influence far more than simply how food is digested.
A major scientific review published in the Journal of Animal Science and Biotechnology in 2025, titled Understanding the Diversity and Roles of the Canine Gut Microbiome, brings together research examining how gut bacteria influence canine digestion, immunity, metabolism, skin health and even behaviour.
The findings reinforce something we focus on every day at Biome4Pets: understanding the bacterial communities living in your dog's gut can provide valuable insights into their health.
1. Your Dog's Gut Does Much More Than Digest Food
The gut microbiome is a complex ecosystem of bacteria and other microorganisms living throughout the digestive tract.
These microorganisms help to:
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Break down food and extract nutrients.
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Produce beneficial compounds called short-chain fatty acids (SCFAs).
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Support the intestinal lining and gut barrier.
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Regulate immune responses and inflammation.
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Influence metabolism and energy balance.
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Communicate with the brain through the gut–brain axis.
When these microbial communities are functioning well together, the gut is considered to be in a state of eubiosis, or microbial balance.
When this balance is disrupted, a condition known as dysbiosis can develop.
Dysbiosis may involve the loss of beneficial bacteria, reduced microbial diversity or excessive growth of particular bacterial groups. Research increasingly associates these changes with digestive problems and conditions affecting other parts of the body.
2. Not All Gut Bacteria Are Bad — Many Are Essential
One of the most important messages from the research is that bacteria should not simply be classified as good or bad.
A healthy canine gut contains several major bacterial groups, including Firmicutes, Bacteroidetes, Fusobacteria, Proteobacteria and Actinobacteria.
Each contributes different functions.
For example:
Clostridia and Faecalibacterium include important butyrate-producing bacteria. Butyrate helps nourish intestinal cells, maintain the gut barrier and regulate inflammation.
Prevotella helps break down dietary carbohydrates and fibre, contributing to the production of beneficial fermentation products.
Bacteroides plays an important role in breaking down complex carbohydrates and polysaccharides.
Fusobacterium is a normal component of the canine microbiome and participates in protein and amino acid metabolism.
However, the abundance of these bacteria matters. A bacterial group that contributes positively to gut function at one level may become associated with imbalance when particular species proliferate excessively.
This is why understanding the overall microbiome is more useful than simply looking for the presence or absence of individual bacteria.
3. Your Dog's Diet Has a Powerful Influence on Gut Bacteria
The review identifies diet as one of the most consistent influences on the canine gut microbiome.
Different foods encourage the growth of different bacterial communities.
Dogs consuming high-protein or raw-meat diets often have increased populations of Fusobacteria, reflecting their role in protein metabolism.
Diets containing more fermentable carbohydrates and fibre tend to encourage bacteria involved in carbohydrate fermentation, including Prevotella.
Importantly, research also highlights the benefits of prebiotic fibres, including inulin and fructooligosaccharides, which can encourage beneficial bacteria such as Bifidobacterium and Faecalibacterium.
These bacteria contribute to the production of SCFAs, helping support intestinal health.
The key message is that feeding the dog also means feeding the microbiome.
The type and balance of nutrients reaching the gut can determine which bacterial populations thrive.
4. Antibiotics Can Affect the Microbiome for Weeks
Antibiotics are sometimes necessary, but research shows they can significantly disrupt the intestinal microbial community.
The review discusses studies involving antibiotics such as metronidazole, enrofloxacin and tylosin.
These treatments can reduce beneficial bacterial populations, including Faecalibacterium and Clostridium hiranonis, while also reducing overall microbial diversity.
In one study, the microbiome had not returned to its original composition even 56 days after antibiotic treatment.
Other research found evidence of dysbiosis persisting for several weeks after antibiotics were discontinued.
This is particularly relevant for dogs experiencing repeated digestive problems or receiving multiple courses of antibiotics.
Supporting microbial recovery following treatment may therefore be an important part of restoring gut balance.
5. Could Your Dog's Itchy Skin Be Connected to Their Gut?
One of the most interesting areas of research involves the relationship between the gut microbiome and skin health, often called the gut–skin axis.
Studies discussed in the review found that dogs with atopic dermatitis frequently had different gut bacterial populations compared with healthy dogs.
These differences included:
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Reduced microbial diversity.
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Lower levels of certain beneficial bacteria.
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Increased populations of Escherichia and Shigella.
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Changes in bacteria involved in immune regulation.
The gut microbiome interacts closely with the immune system, and disruption of this relationship may contribute to inflammatory responses affecting the skin.
Although an altered microbiome does not necessarily mean it is the cause of itching or allergies, the findings suggest that gut health deserves consideration when investigating persistent skin problems.
For dogs experiencing recurring paw licking, itchy skin or other inflammatory skin conditions, understanding the gut microbiome may provide another useful piece of the puzzle.
6. The Gut–Brain Connection: Can Gut Bacteria Influence Behaviour?
The relationship between gut bacteria and behaviour is another rapidly developing area of canine microbiome research.
The gut and brain communicate through a complex network involving the nervous system, immune system, hormones and microbial metabolites.
This communication pathway is known as the gut–brain axis.
The review highlights research showing that stressed dogs can have:
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Reduced populations of Clostridia.
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Increased Proteobacteria.
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Lower overall microbial diversity.
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Changes in bacterial populations associated with inflammatory responses.
Researchers have also identified differences in the gut microbiomes of dogs displaying aggression, fear and anxiety.
Certain gut bacteria may influence signalling pathways involving neurotransmitters such as serotonin and GABA, which are involved in emotional regulation and stress responses.
This does not mean that dysbiosis is responsible for every behavioural problem. However, the findings suggest that the microbiome may be one of several factors influencing how dogs respond to stress.
7. Why Microbial Diversity Matters
A healthy gut is not simply about having large quantities of beneficial bacteria.
It is also about maintaining a diverse and functioning microbial ecosystem.
Different bacterial groups perform different jobs, from breaking down fibre and protein to producing metabolites that support the intestinal environment.
When diversity declines, some of these functions may become less resilient.
The review reports reduced microbial diversity in dogs with inflammatory bowel disease, atopic dermatitis and certain stress-related conditions.
Age also influences diversity. The microbiome develops during puppyhood, generally becomes more established in adulthood and may undergo changes as dogs grow older.
This makes microbial diversity an important consideration when assessing gut health, alongside the abundance and functions of individual bacterial groups.
8. Can We Help Restore a Disrupted Gut Microbiome?
The research discusses several approaches to supporting microbial balance.
These include dietary adjustments, prebiotic fibres, probiotics, synbiotics and, in selected circumstances, faecal microbiota transplantation (FMT).
Prebiotics provide substrates that encourage the growth and activity of beneficial bacteria.
Probiotics introduce specific live microorganisms that may support gut function, depending on the strains used.
FMT introduces a community of microorganisms from a healthy donor and is being investigated as an intervention for dogs with persistent dysbiosis and chronic gastrointestinal conditions.
The review highlights the potential of these approaches, although their effectiveness depends on the individual dog, the microbial imbalance involved and the intervention used.
There is no single solution that is appropriate for every microbiome.
9. Why Testing Your Dog's Gut Microbiome Can Be Valuable
Two dogs may experience similar symptoms but have very different bacterial populations.
For example, one dog may have reduced levels of important butyrate-producing bacteria, while another may have an excessive abundance of bacteria associated with protein fermentation or inflammatory conditions.
This is why a personalised approach to gut health is so important.
At Biome4Pets, our canine gut microbiome test uses 16S rRNA sequencing to identify and measure bacterial populations within a dog's faecal sample.
The results provide information about:
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Microbial diversity and bacterial composition.
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The relative abundance of key bacterial groups.
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Potential bacterial imbalances.
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Changes in the microbiome when comparing an original test with a later retest.
By examining the bacterial community as a whole, rather than focusing on a single organism, we can develop a more informed approach to supporting microbial balance.
Microbiome testing does not diagnose allergies, behavioural disorders or specific diseases, but it can provide useful information about the intestinal ecosystem.
10. A Healthier Gut Starts With Understanding What's Happening Inside
The message from this scientific review is clear: the canine gut microbiome is a fundamental part of health, not simply a collection of bacteria involved in digestion.
Its influence extends to immune regulation, intestinal barrier function, metabolism, skin health and communication with the brain.
The research also demonstrates that the microbiome is highly individual and influenced by diet, age, breed, medication, stress and environment.
For dogs experiencing persistent digestive difficulties, skin problems or other health concerns, understanding the composition of their gut bacteria may help identify imbalances worth addressing.
At Biome4Pets, we believe that understanding the microbiome is the first step towards supporting a healthier gut.
Rather than guessing which bacteria may be missing or overrepresented, microbiome analysis provides a clearer picture of the bacterial ecosystem and how it may be changing over time.
Because when we understand what's happening inside the gut, we can make more informed decisions about how to support it.
Discover What's Happening in Your Dog's Gut
Is your dog experiencing recurring digestive problems, itchy skin or unexplained changes in wellbeing?
Our Biome4Pets Gut Microbiome Test provides a detailed analysis of your dog's gut bacteria, helping you better understand their microbial balance and identify areas that may benefit from nutritional support.
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Scientific Reference
Kim, H., Chae, Y., Cho, J.H. et al. (2025). Understanding the diversity and roles of the canine gut microbiome. Journal of Animal Science and Biotechnology, 16, Article 95.
https://doi.org/10.1186/s40104-025-01235-4
This article summarises findings from a scientific review of published research. Associations between gut bacteria and health conditions do not necessarily establish cause and effect.
