While prebiotics and probiotics are often confused or thought of as one and the same, their commonalities end with their stint in the intestine.
Prebiotics are fiber that feeds the beneficial microorganisms residing in the intestine. Probiotics are live microorganisms that when ingested, can enhance intestinal microbial balance.
Prebiotics have been used in pet foods for decades, probably without pet owners even knowing it. But probiotics’ delicate handling needs means they’re sold in sachets and capsules. They are in something of a state of hibernation, according to Grace Long, DVM, MS, MBA, director of veterinary technical marketing for Nestlé Purina PetCare in St. Louis. The microorganisms become active when they enter the intestine.
“Probiotics are heat and moisture sensitive, so it would be very difficult to incorporate them directly into the kibble,” Dr. Long says.
“The most effective way of keeping probiotics alive in the packaging process is in a cool, dry environment away from air exposure. Not all probiotics sold in the veterinary market have evidence to support their claims, so veterinarians should make sure that the levels of microorganisms are guaranteed and that the manufacturer can provide support of efficacy.”
Label accuracy concerns prompted J. Scott Weese, DVM, DVSc, Dipl. ACVIM, associate professor in the department of pathobiology at Ontario Veterinary College, University of Guelph, in Ontario, Canada, to evaluate labels and bacterial contents of commercial probiotics marketed for use with animals.
In Dr. Weese’s study, 25 animal-marketed probiotics were purchased, labels were evaluated and bacterial contents were counted. Weese found that 21 products listed specific microorganisms. Expected bacterial numbers were listed for 15 products. To add to the suspicion of questionable probiotic efficacy, one or more organisms were misspelled on the labels of seven products.
Only four of 15 products tested met or exceeded their labels’ claims. Only two of these also had a label that properly described the contents, Weese says. He concluded that deficiencies in veterinary probiotic quality remain.
“Veterinary probiotics are less regulated than drugs,” says Joseph Bartges, DVM, PhD, Dipl. ACVIM, Dipl. ACVN, professor of medicine and nutrition at the University of Tennessee in Knoxville. “There’s less confidence that you are getting what the label claims. I believe in using probiotics in animals but I prefer to use one called VSL#3 marketed for human use because it contains 450 billion live bacteria per packet. This probiotic is manufactured by VSL Pharmaceuticals Inc.”
Animal food and supplement manufacturers interested in providing efficacious and effective probiotics perform in-house tests, sometimes evaluating hundreds of beneficial bacteria species before deciding which to use.
“We deal with one strain of bacteria in our probiotic,” says Amy Dicke, DVM, technical services veterinarian for P&G PetCare in Cincinnati. “After looking at 500 species and three clinical trials, bifidobacterium animalis AHC7 met our requirements for Prostora Max.”
In a Purina study, Enterococcus faecium SF68 (FortiFlora) minimized the incidence of diarrhea in a naturally occurring outbreak in kittens. While 60 percent of kittens fed the control diet developed diarrhea severe enough to be treated, only 9.5 percent of the kittens eating SF68 required treatment.
| Bifidobacterium animalis AHC7
Photo courtesy of P&G PetCare
“Using probiotics proactively can help reduce the risk of situations that tend to spur gastrointestinal upset in certain situations, like boarding or post antibiotic use,” Long says. “Animal shelters are using probiotics more and more because of the stress dogs and cats feel. Traveling with a pet and diet changes can also create an intestinal microflora upset, which probiotics can help to minimize.”
Probiotics are considered nutritional supplements as opposed to drugs. Although some veterinarians prefer to use medication to control diarrhea in patients, probiotics can be used in conjunction with medication or alone. Probiotics are finding their way into the standard protocol for managing dogs and cats with diarrhea.
“We are also encouraging veterinarians to recommend that clients keep a proven probiotic on hand for diarrhea, especially if their pets are prone to GI upset,” Long says.
Long points out that probiotics can even be used as a regular part of an animal’s diet to help support a good immune system. This is especially important in the young, the elderly and any pet with compromised health.
Probiotics are considered a nutritional supplement rather than a drug. Although some veterinarians prefer medication for controlling patients’ existing diarrhea issues, probiotics can be used in conjunction with medication or alone.
“We are trying to communicate to veterinarians that keeping a proven probiotic on hand for diarrhea is just like keeping Imodium in the cupboard,” Long says.
“Sometimes it’s hard for a veterinarian to develop a new habit when you are used to treating a condition in a certain way. When considering treatment for a patient with diarrhea, sometimes medicine can be faster, but probiotics can be used with drugs like Metronidazole.”
Long points out that probiotics can even be used to help support a good immune system.
“FortiFlora is packaged to be effective on any-sized animal,” Long says. “The only exception might be a veterinary recommendation to use two packets on a very large dog like a great Dane.”
Veterinarians and veterinary nutritionists say giant breed dogs generally have a poorer stool quality when compared to smaller breed dogs, making larger dogs another target group to benefit from probiotics.
“Large and giant breed dogs have decreased digestibility compared to small- and medium-size dogs,” says Brent Mayabb, DVM, manager of education and development of Royal Canin U.S. in St. Charles, Mo.
“About 7 percent of a small or medium dog’s weight is its GI tract, whereas a large or giant breed dog’s GI tract is only 2.5 percent of its entire weight, so it doesn’t have the same ratio as other dogs and generally has looser stools.
“Junctions between large-breed dogs’ intestinal cells allow minerals to pass back into the intestinal lumen after absorption. The minerals draw water with them, resulting in loose stools. A probiotic and a healthy diet containing prebiotics can help all dogs, and especially larger, dogs have better quality stools, in turn having a healthier GI tract.”
Dr. Mayabb says clients continue to ask their veterinarians about diet options and brand advice, which means veterinarians will be expected to be able to relay nutrition information to serve a variety of patient needs.
“Nutrition talk isn’t done enough during veterinary visits,” Mayabb says.
“In part, I think it’s because in the past, nutrition wasn’t a large part of veterinary school curriculum. Nutrition would be talked about in correlation with helping with certain diseases, but that’s about it. Now new grads focus more on preventive care, in which nutrition plays a huge role. I think we’ll see more of a shift in veterinary interest and subsequent owner interest in a healthy GI tract.”
“Think of prebiotics as functional food,” Dr. Dicke says.
“The right prebiotic will be resistant to digestive juices, selectively increase the number and activity of good bacteria and provide a health benefit. Prebiotics also have to stay in the intestine long enough for the bacteria to break it apart, basically attacking and fermenting it. This process releases short-chain fatty acids.
“Prebiotics are key components for intestinal cells, which create a barrier in the intestinal tract. This lining is important because it helps to keep bacteria in the intestinal tract and doesn’t allow it to travel to other areas of the body.”
While most everyone in the industry is optimistic about what probiotics can offer veterinary patients, there isn’t a consensus about the parameters.
For Kittens and Puppies
Nutramax Laboratories Inc., in Edgewood, Md., which markets Proviable–DC (capsules) and Proviable-KP (paste) for dogs and cats, says it learned that even puppies in the same litter had different microflora.
“Since different microflora is found even within the same litter of puppies, some may benefit from one bacteria while others benefit from another, so we use seven types of bacteria in our probiotic,” says Robert Devlin, DVM, senior director of the veterinary sciences division, Lancaster, S.C. “We have used our probiotic every day for 21 days in studies and found no change in bloodwork that shows a negative effect.”
The company also markets Bactaquin, an over-the-counter digestive health supplement for dogs that contains one bacteria strain.
“Everyone has a price-point,” Dr. Devlin says. “With inflated fuel prices and the bad economy, owners might make cutbacks. But effective probiotics that deliver 2 billion bacteria can be given for about 50 cents a day.”
Dicke says using puppy and kitten formulations containing prebiotics is an important part of ensuring a healthy GI tract from the beginning.
“Kittens’ and puppies’ intestinal bacterial balance begins forming when their mom licks them,” Dicke says. “The bacteria accumulated in the first couple of weeks of an animal’s life can ultimately affect their long-term bacteria colonization. When animals are orphaned or even when they have loose stools, a probiotic can help remedy the situation.”
Probiotics have an immune-boosting effect that is often discussed secondarily to their benefits in treating diarrhea, Long says.
“Very young animals have a fragile immune system and it’s not uncommon for them to have soft stools,” Long says. “Diarrhea can be very dangerous for young animals and providing a probiotic can help stablize the GI tract.”
Joseph Wakshlag, DVM, PhD, Dipl. ACVN, Dipl. ACVSMR, assistant professor of clinical nutrition at Cornell University College of Veterinary Medicine in New York, says that because little research exists about using probiotics in pediatric animals, veterinarians have to turn to research conducted in human medicine to make assumptions.
“Pediatric literature suggests that transdermal migration can cause sepsis in children who have used probiotics,” Dr. Wakshlag says.
“There hasn’t been documentation of this in veterinary medicine to date, but it just means it’s not impossible that there can be a negative to probiotic use. There’s been much more evidence to support the use of prebiotics than probiotics. But even there, some manufacturers throw everything but the kitchen sink in their products and pet owners may think that makes it a good food when it doesn’t. Manufacturers sometimes have ingredients in their foods that naturally contain prebiotics, but they add more like fructooligosaccharides and mannanoligosaccharides because owners are looking for that on the ingredients list.”
Dr. Bartges says additional evidence from human medicine suggests that asthma and other immune disease symptoms may decrease with probiotic use.
“No one knows for sure why or how probiotics help immune diseases aside from its role in changing GI tract bacteria,” Bartges says. “It’s possible the benefit comes from the immune system’s reaction and the systemic response.”
Manufacturers say ongoing research continues to improve existing products, broaden uses and enhance benefits. They say using proven products now will be an asset to any veterinarian’s tool box.
“We’re all still in the learning process with probiotics and how they can help with skin allergies and other issues that spur an inflammatory response,” Dicke says. “Certain probiotics or symbiotic combinations may be more effective on different medical conditions, but work is being done to find new ways to feed pets and use probiotics.”