The puppy gut microbiome
When we bring a new puppy home, our aim is to help them become confident, happy dogs. But there’s a hidden community inside every puppy that quietly shapes how they feel and learn to cope with the world around them: their gut microbiome.
The gut microbiome is recognised as a major contributor to digestion and a key factor in nutrition, development, immune function and other aspects of host physiology that contribute to physical and mental health and overall wellbeing[1].
A happy microbiome will help our young dogs thrive. Not only will it contribute to growth, development and learning in early life; it can also reduce the risk of gastrointestinal conditions when they are older.
Studies have shown that there is an interplay between nutrition, the gut microbiome and health. Dietary choices during puppyhood and adolescence are modifiable factors which might lessen or increase chronic enteropathy (CE) in later life[2]. This gives us a chance to act proactively and have an impact on our dog’s health.
Robust microbiome
Canine studies show that establishing microbial diversity is crucial for development in puppies and young dogs and likely to affect the immune system and health in the future. That being the case, our aim is to achieve a robust gut ecosystem at an early age.
A robust microbiome helps to:
- Develop immune tolerance, reducing the risk of allergies and inflammatory conditions later in life.
- Maintain gut barrier integrity, preventing pathogens from crossing into the bloodstream.
- Contribute to the production of key metabolites like short-chain fatty acids, which influence gut-brain communication, potentially affecting mood and behaviour.
It doesn’t need to be complicated. The study referenced above found that even just feeding a non-processed meat-based diet and giving the dog human meal leftovers and table scraps during puppyhood (2–6 months) and adolescence (6–18 months) were protective against CE later in life[3]. (I would add a caveat that it’s not good to give ALL table scraps – but sensible dog owners know that.)
It’s a fact that health literacy isn’t great among pet owners. But the more literate we are, the more able we are to make informed decisions.
SO – what do we need to know?
Influence of early-life factors
The very first step in modulating the puppy’s gut may even occur during gestation[4]. Although microbiota at the time of birth are relatively sparse, colonization occurs rapidly: the microbiome is already richer in species at 21 and 42 days of age than at 2 days of age[5].
Weaning to solid food is an important milestone. The transition to new types of food stimulates the abundance and activities of certain bacteria[6] and, as the diet expands, the microbiome diversifies from the early, simple communities to a stable and more complex microbiome.
Age-related shifts
The puppy’s gut microbiome remains dynamic, continuing to develop and mature until around one year of age.The gut is colonised by crucial bacteria before the puppy reaches adulthood [7][8]. This development is supported by a healthy, varied diet and the maturing of the puppy’s own immune system.
A well-developed and stable gut microbiome will influence:
· Digestive efficiency. A well-developed gut microbiome helps break down food more effectively, so puppies can access energy, proteins, vitamins and minerals from their diet.
· Nutrient availability. Certain gut bacteria improve nutritional status by producing or helping to release vitamins, like B vitamins and vitamin K, and other compounds.
· Immune function. A balanced microbiome helps train the immune system to tolerate food proteins and beneficial microbes while resisting pathogens, which is essential for healthy growth. It can also affect the development of systemic autoimmune disorders[9].
· Growth and development. Puppies with a well-nourished gut and balanced microbiome tend to grow steadily, have better learning abilities and cognitive function and exhibit fewer mood-related behavioural problems[10].
Nutritional needs and microbiome health
It is generally accepted that dogs of any age that are given a varied diet of fresh ingredients will have a more diverse and balanced gut microbiome than those on a more restricted diet. Diet also has a key role in the equilibrium of the gut environment (eubiosis) in puppies, influencing the microbiome, gut barrier and immunity.
Puppies require higher levels of energy, protein and certain minerals to fuel growth and development than adult dogs. For around the first year, half of their food will fuel growth and development and half will be used for ‘maintenance needs’[11].
Differences between puppy food and adult dog food include:
- More protein: A minimum of 22.5% protein is recommended for dry puppy food, compared to 18% for adult dog maintenance food (AAFCO).
- Higher calories: A minimum of 8.5% fat for dry puppy food compared to 5.5% for adult dog food (AAFCO).
- More calcium: A minimum of 1.2% calcium in dry puppy food compared to 0.5% for adult dog food (AAFCO).
- DHA (docosahexaenoic acid): Important for eye and brain development, this nutrient can be found in fish oil. A study[12] showed that puppies fed a DHA rich diet with higher concentrations of vitamin E, taurine, choline and l-carnitine performed significantly better in task learning, memory and visual discrimination than puppies fed a lower DHA diet.
Diets with adequate fermentable fibres, high-quality (and easily digestible) proteins and balanced fat profiles help beneficial bacteria thrive and produce metabolites like short-chain fatty acids, which nourish gut cells and regulate inflammation[13].
External influences
Early colonization depends not just on physiology; it is also subject to multifaceted influences including dietary, social and environmental factors. Disruption can be caused by things like exposure to polluted water, chemicals and even some medications.
Social factors, such as changes in environment or routine, can also contribute to stress in puppies, disrupting the delicate balance of their gut microbiome and potentially leading to digestive issues and even influencing mood-regulating neurotransmitters.
Setting a course for a healthy gut
“It is reassuring for owners to know that they themselves can have an impact on their dog’s health.”[14].
The gut microbiome is more than the sum of its parts – it’s a living, dynamic system. Enhancing gut health from the earliest days can have a positive impact on health and wellbeing well into later life. For working dogs in particular, a resilient gut microbiome can also mean better cognitive function and performance. By understanding the dietary and environmental factors that shape this process, we can help set our puppies on the path to success.
References:
[1] Hand D, Wallis C, Colyer A, Penn, C.W. Pyrosequencing the Canine Faecal Microbiota: Breadth and Depth of Biodiversity. January 2013. https://doi.org/10.1371/journal.pone.0053115.
[2] Vuori, K.A., Hemida, M., Moore, R. et al. The effect of puppyhood and adolescent diet on the incidence of chronic enteropathy in dogs later in life. Sci Rep 13, 1830 (2023). https://doi.org/10.1038/s41598-023-27866-z
[3] Vuori, K.A., Hemida, M., Moore, R. et al. The effect of puppyhood and adolescent diet on the incidence of chronic enteropathy in dogs later in life. Sci Rep 13, 1830 (2023). https://doi.org/10.1038/s41598-023-27866-z
[4] Maja Zakošek Pipan, Leonida Kajdič, Anja Kalin, Tanja Plavec, Irena Zdovc. Do newborn puppies have their own microbiota at birth? Influence of type of birth on newborn puppy microbiota, Theriogenology,
Volume 152, 2020, Pages 18-28, ISSN 0093-691X,
[5] Guard BC, Mila H, Steiner JM, Mariani C, Suchodolski JS, Chastant-Maillard S. Characterization of the fecal microbiome during neonatal and early pediatric development in puppies. PLoS ONE. (2017) 12:e0175718. doi: 10.1371/journal.pone.0175718
[6] Masuoka H, Shimada K, Kiyosue-Yasuda T, Kiyosue M, Oishi Y, Kimura S, et al. Transition of the intestinal microbiota of dogs with age. Biosci Microbiota Food Health. (2017) 36:27–31. doi: 10.12938/bmfh.BMFH-2016-021
[7] Front. Vet. Sci., 02 September 2022. Sec. Animal Nutrition and Metabolism. Volume 9 – 2022 https://doi.org/10.3389/fvets.2022.964649
[8] Garrigues Quentin , Apper Emmanuelle , Chastant Sylvie , Mila Hanna. Gut microbiota development in the growing dog: A dynamic process influenced by maternal, environmental and host factors. Frontiers in Veterinary Science, Volume 9 – 2022.DOI: 10.3389/fvets.2022.964649
[9] Wu HJ, Wu E. The role of gut microbiota in immune homeostasis and autoimmunity. Gut Microbes. 2012 Jan-Feb;3(1):4-14. doi: 10.4161/gmic.19320. Epub 2012 Jan 1. PMID: 22356853; PMCID: PMC3337124.
[10] Kiełbik P, Witkowska-Piłaszewicz O. The Relationship between Canine Behavioral Disorders and Gut Microbiome and Future Therapeutic Perspectives. Animals (Basel). 2024 Jul 12;14(14):2048. doi: 10.3390/ani14142048. PMID: 39061510; PMCID: PMC11273744.
[11] https://www.markmorrisinstitute.org/sacn5_download.html
[12] Zicker, S. C., Jewell, D. E., Yamka, R. M., & Milgram, N. W. (2012). Evaluation of cognitive learning, memory, psychomotor, immunologic, and retinal functions in healthy puppies fed foods fortified with docosahexaenoic acid–rich fish oil from 8 to 52 weeks of age. Journal of the American Veterinary Medical Association, 241(5), 583-594. Retrieved Jun 8, 2025, from https://doi.org/10.2460/javma.241.5.583
[13] Guard BC, Mila H, Steiner JM, Mariani C, Suchodolski JS, Chastant-Maillard S. Characterization of the fecal microbiome during neonatal and early pediatric development in puppies. PLoS ONE. (2017) 12:e0175718. doi: 10.1371/journal.pone.0175718
[14] Hemida Manal , Vuori Kristiina A. , Moore R. , Anturaniemi J. , Hielm-Björkman A. Early Life Modifiable Exposures and Their Association With Owner Reported Inflammatory Bowel Disease Symptoms in Adult Dogs. Frontiers in Veterinary Science Volume 8 – 2021. Doi.org/10.3389/fvets.2021.552350