Digestive health in puppies and kittens

By Gemma Vardy, Senior Category Specialist, Select from NVS

The neonatal period of life for kittens and puppies is marked by rapid physiological, immunological, and microbiological development¹. The digestive system is at the centre of this transformation, playing a pivotal role not only in nutrient absorption but also in immune system education and protection against infectious disease. As veterinary professionals, understanding and supporting this process is essential to ensuring the health and vitality of our youngest patients.

Maturation of the digestive tract

At birth, the gastrointestinal (GI) tract of puppies and kittens is structurally formed but functionally immature. The stomach produces limited acid, enzyme activity is reduced, and intestinal permeability is high, making neonates especially vulnerable to pathogens and digestive disturbances. Over the first weeks of life, gastric acidity increases, pancreatic enzymes become more active, and the epithelial barrier gradually strengthens. This functional maturation is essential for efficient digestion, nutrient assimilation, and microbial defence.¹

During this critical period, any disruption – such as early weaning, poor colostrum intake, environmental stress, or dietary changes – can impair development and predispose animals to acute or chronic GI issues. This makes early nutritional support a crucial aspect of veterinary care.

The role of the microbiome

The gut microbiome is now recognised as a vital organ in its own right, influencing digestive function, immune development, and resistance to disease³. In neonates, the GI tract is initially sterile but is rapidly colonised by microorganisms from the dam, littermates, and the environment. The balance and diversity of these early microbial populations are fundamental to gut and the development of the immune system².

A stable and diverse microbiome contributes to the maturation of gut-associated lymphoid tissue (GALT), modulates inflammation, enhances mucosal barrier function, and aids in pathogen exclusion. Conversely, dysbiosis during early life has been associated with increased susceptibility to diarrhoea, allergies, and even behavioural changes later in life⁴.

As such, supporting microbial balance through optimal neonatal care is essential. Good husbandry is paramount, as is the health of the mother. Ensuring neonates consume enough colostrum in their early hours and days is key, as is maintaining the dam’s nutritional and hydration status throughout the period when her young are so dependent on her. There are however, times when additional support is needed and carefully selected probiotics, prebiotics, and bioactive nutrients can be a powerful strategy to promote resilience and wellbeing³.

Digestive health and immune function

The gut acts as both a nutrient-processing organ and a critical training ground for immune tolerance and defence. It is the largest immune organ in the body, containing over 65% of all immune cells and over 90% of all Ig-producing cells². In young animals, this interface between the GI tract and immune cells is where the foundation of lifelong immunity is established.

Healthy gut function helps prime the immune system to distinguish between harmful pathogens and harmless antigens, reducing the risk of chronic inflammation and inappropriate immune responses⁵.

Importantly, immune cells in the gut produce high levels of free radicals and are particularly sensitive to oxidative stress, making antioxidant support another cornerstone of immune health in puppies and kittens.

Nutritional strategies to support GI and immune development

In situations where a dam or the young are compromised, or in need or some additional nutritional support, modern nutritional science offers several tools to help bridge the gap during this vulnerable period:

• Bovine colostrum provides immunoglobulins, growth factors, and bioactive peptides that directly interact with immune cells in the gut. Studies show it can enhance the immune response to vaccination in both kittens and adult dogs, and improve resistance to GI pathogens^7,8.
• Probiotics, such as Enterococcus faecium, have been shown to support immune development and help stabilise the intestinal microbiota during times of stress or transition⁹.
• Nucleotides, derived from yeast, play a key role in rapidly dividing tissues like the intestinal lining and in the synthesis of antibodies³.
• Hydrolysed plasma supplies easily digestible proteins, peptides, and immunoglobulins that can improve intestinal health and reduce inflammation⁹.
• Antioxidant nutrients, including vitamins E, C, protect immune cells from oxidative damage and support optimal response to immunological challenges².

These ingredients work synergistically to fortify the gut barrier, promote microbiome balance, and modulate immune responses.

A stronger start with Duostart

While some innate immunity is transferred via the placenta, the immediate postnatal period is critical for the acquisition of passive immunity and immune system education. The neonatal gut is uniquely primed to absorb and respond to bioactive molecules in the hours following birth, making early intervention particularly effective.

Duostart is a newly launched oral paste formulated to support digestive and immune health in newborn puppies and kittens. Presented in a 15 ml dosing syringe, with a recommended dose of 1 ml daily, Duostart delivers a concentrated blend of functional ingredients including:

• Bovine colostrum
• Enterococcus faecium
• Yeast-derived nucleotides
• Hydrolysed plasma
• Vitamins C, E, and A

Together, these components work to protect the vulnerable neonatal gut, encourage the establishment of beneficial microbiota, and enhance immune competence during the critical early weeks of life. Whether used for large litters, orphaned neonates, or simply as a proactive support strategy, Duostart offers a convenient and scientifically grounded approach to early-life care.

References:

1. Casal, M. (2010). Chapter 15. In BSAVA manual of canine and feline reproduction and neonatology (pp. 135–146). British Small Animal Veterinary Association. https://doi.org/10.22233/9781905319541.15
2. Satyaraj, E. (2011). Emerging paradigms in immunonutrition. Topics in Companion Animal Medicine, 26(1), 25–32.
3. Lappin, M., et al. (2017). Effect of a commercially available probiotic on immune responses in healthy dogs. ACVIM Abstract NM05.
4. Benyacoub, J., et al. (2003). Supplementation of food with Enterococcus faecium SF68 stimulates immune function in young dogs. Journal of Nutrition, 133, 1158–1162.
5. Datz, C. A. (2010). Noninfectious causes of immunosuppression in dogs and cats. The Veterinary Clinics of North America: Small Animal Practice, 40(3), 459–467.
6. Jean-Philippe, C. (n.d.). Beneficial effects of dietary colostrum supplementation in kittens. Scientific Update of Feline Nutrition, Issue 4, 1–8.
7. Satyaraj, E., et al. (2013). Supplementation of diets with bovine colostrum influences immune function in dogs. British Journal of Nutrition, 110(12), 2216–2221.
8. Veir, J. K. (2007). Effect of supplementation with Enterococcus faecium (SF68) on immune function in cats. Veterinary Therapeutics, 8(4), 229–238.
9. Bosi, P., Han, I. K., Jung, H. J., Heo, K. N., Perini, S., Castellazzi, A. M., Casini, L., Creston, D., & Gremokolini, C. (2001). Effect of different spray dried plasmas on growth, ileal digestibility, nutrient deposition, immunity and health of early-weaned pigs challenged with E. coli K88. Asian-Australasian Journal of Animal Sciences, 14(8), 1138-1143. https://doi.org/10.5713/ajas.2001.1138