Why worry about probiotics for animals? The bacteria that reside in the small intestine and colon of the dog and cat play an important role in their overall health. These bacteria constitute a metabolically active system that acts as a significant barrier to infection by pathogenic microorganisms.
DNA-based microbiology that has identified and enumeration these microorganisms provides insight as to how the bacteria that live in the gut prevent disease affect nutrient absorption and impact the immune systems of our pets.
The gastrointestinal (GI) tract is the body’s number one barrier against disease. The bacteria that reside within the gut can be classified as either protective or potentially harmful. The balance of these bacteria is critically important to the overall health of all animals.
The GI tract of the dog and cat is essentially a long unsterile tube that runs from one end of the animal to the other. It is also the largest immune reactive surface in your pet’s body. How we feed our pets and the various stresses we place on them can alter the balance between the good gut microflora and those that can cause disease. It can also alter the defense mechanisms that occur in the lining of the GI tract.
Diet can either cause or eliminate inflammation. It can increase or decrease gut permeability, thereby altering nutrient absorption and overall health. When your dog or cat’s GI tract is healthy, it allows for the absorption of amino acids, vitamins and minerals, while at the same time preventing the entry of disease-causing substances.
Maintaining Balance in the Gut
It is said that our dogs and cats have more intestinal bacteria than cells in their body. Symbiosis is when the good bacteria are in balance with the potentially bad ones resulting in optimum gut health.
There are a number of conditions that can cause the good bacteria to decrease in numbers thereby allowing the potentially harmful ones to over-populate. They are:
- Poor Diet
- Intestinal Parasites
The Microflora of the Dog and Cat
The complex microflora of the carnivore GI tract has been studied in both the dog and cat. By understanding what bacteria are present, in what numbers, and the specific role that each plays has allowed us the opportunity to develop products capable of maintaining gut microflora balance.
The most significant aspect of the canine microflora is the large number of lactobacillus species and the much lower level of bifidobacteria found in canines compared to other animals.
The feline colonic flora is even less well characterized. Lactobacilli levels predominate and the bifidobacteria levels are even lower than in canines. In fact, bifidobacteria are only intermittently isolated from felines.
Dietary Management of Intestinal Bacteria
Probiotics for Animals
Probiotics for animals (good bacteria) have been investigated as a dietary management tool for many years. The concept evolves around the ingestion of beneficial bacteria leading to colonization within the gut.
One recent study investigated the application of Lactobacillus acidophilus in canines. When fed to 15 healthy dogs it resulted in a significant increase in the population of recoverable lactobacilli in the feces with a concomitant decrease in the clostridia population. The animals displayed no significant changes in blood biochemistry, body temperature, or fecal quality. Immune-function studies showed no significant changes in haptoglobin level or white blood cell count but significant increases in serum IgG, monocytes, and neutrophils demonstrated how GI bacteria can affect the immune system.
In addition, significant decreases in plasma nitric oxide levels and the osmotic fragility of red blood cells were observed. The researchers concluded that feeding of the probiotic resulted in positive changes in the gut microbiology and in systemic effects that suggested immune system stimulation.
An alternative to feeding probiotics to animals is the use of prebiotics. A prebiotic is a non-digestible food ingredient that is selectively metabolized by the indigenous probiotic bacteria in the gut. Using prebiotics is attractive; because they are stable to heat treatment where Probiotics can be fairly unstable and are more expensive.
Available Prebiotics for Animals:
- Other Oligosaccharides
There is relatively little published research on the use of prebiotics in companion animals. What there is has focused on lactosucrose and Fructooligosaccharides (FOS).
Studies on lactosucrose in dogs resulted in statistically significant desirable changes to the gut microflora. Decreases were seen in harmful Clostridia numbers, toxin levels and fecal odor. Lactosucrose was also fed to healthy cats, which resulted in a significant increase in favorable lactobacilli numbers and an increase in the incidence of recovery of bifidobacteria. Significant decreases were seen with levels of clostridia and Enterobacteriaceae. Toxin levels and fecal odor were also reduced.
Several studies are available on FOS consumption in companion animals. In dogs, statistically significant increases in bifidobacteria and lactobacilli numbers were seen together with a small but significant decrease in clostridia level. Increases were seen in lactate and butyrate quantities but increases were also observed in ammonia, isovalerate, dimethylsulfide, and hydrogen sulfide levels.
A study in cats using FOS for 12 weeks resulted in a significant increase in lactobacilli numbers and a single isolation of Bifidobacterium species. Significant decreases in clostridia and Escherichia coli numbers and an increase in Bacteroides were also noted.
Combining probiotics with a prebiotic to support its viability and activity against specific harmful bacteria in a given species is now possible. This concept was attempted for the first time in a Labrador retriever. Five candidate lactobacilli, L. acidophilus, L. murinus, L. reuteri, L. mucosae, and L. rhamnosus were isolated and evaluated for their activity against Salmonella and enteropathogenic E. coli. The research data was positive and shows that certain prebiotics are even more effective when used in conjunction with specific probiotics.
Dietary-management tools, therefore, exist in the shape of probiotic microorganisms, prebiotic oligosaccharides, and synbiotic mixtures of the two.