by Heather Smith-Thomas

An Aid in Efficient Digestion and in Getting the Gut Back to Normal After Stress or Illness

Ruminants and horses have a unique type of digestion that enables them to process and utilize forages and plant material that cannot be digested by other animals—or humans—that rely on single stomachs. Microbes in the rumen of a cow and in the hindgut (cecum and colon) of a horse break down and ferment the fibrous portion of roughages so that this material can be utilized as food. This digestion results in the production of volatile fatty acids that serve as a significant energy source, vitamins, and many other nutrients that are essential to the well-being of the animal.

For a long time, scientists thought that bacteria were the key players in the rumen (or cecum) to facilitate this fermentation process, aided by protozoa. Then in 1975 a scientist named Colin Orpin discovered that some of the organisms earlier thought to be protozoa were actually fungi. Pioneering work by Orpin and others substantiated the importance of fungi and found that the action of rumen/hindgut fungi on fiber is crucial to the start of the breakdown/fermentation process. These fungi act as the “first attack” since they produce fiber-degrading enzymes and are positioned within the rumen fiber mat in strategic locations to break down the cellulose bonds of plant material. This allows the bacteria to better infiltrate this material and go to work. Without the increased available surface area, digestion of roughage is slower and less efficient.

The resident mix of bacteria, fungi and protozoa are responsible for breaking down fiber into usable nutrients, creating B vitamins in the process, and keeping harmful pathogens from becoming established in the digestive tract. In a healthy digestive tract the “good bugs” continually reproduce. Thus a thriving, healthy mix of rumen/cecum microbes in ruminants and horses keep the “bad bugs” from invading, because the population level of “good bugs” outnumber the bad ones and the “good bugs” produce fatty acids that keep the intestinal cells healthy. Anything that upsets this delicate balance, however, such as abrupt change in feed, severe stress or other factors that change the environment in the gut may inhibit the “good bugs” and create conditions in which the “bad bugs” can begin to multiply faster, adversely affecting digestion and the health of the animal. Therefore, during times of stress, strategies to enhance the growth of beneficial resident bacterial populations (the “good bugs”) are often used. This generally consists of administering probiotics or prebiotics to the animal, either via feed or in an oral force-fed preparation.

WHAT ARE PROBIOTICS AND PREBIOTICS?

Probiotic and prebiotic are the terms given to direct-fed microbial (DFM) products. Direct-fed microbials are products that claim to contain live microorganisms such as bacteria and/or yeast that are thought to aid digestion and digestive tract health. Nutritional science has been looking at these important factors for several decades. In 1974, R. B. Parker coined the term ‘probiotic’. The term is taken from the Greek words “for” and “life”. Parker defined the term as “organisms and substances which contribute to intestinal microbial balance” in his paper Probiotics, the other half of the antibiotic story (published in Animal Nutritional Health, volume 29:4-8). In 1979, R. Fuller modified the term probiotic to mean “a live microbial feed supplement which beneficially affects the host animal by improving its intestinal microbial balance” (as stated in his paper Probiotics in man and animals, published in the Journal of Applied Bacteriology, 66: 365-378).

This newer definition has been widely accepted in both human and animal nutrition fields, and probiotics are assumed to contain viable microbes. In 2001, Jergen Schrezenmeir and Michael de Vrese came up with a more complete definition describing probiotics as “a preparation of or a product containing viable, defined microorganisms in sufficient numbers which alter the microflora (by implantation or colonization) in a compartment of the host, and by that exert beneficial health effects in the host”. This definition was stated in their paper titled Probiotics, prebiotics and symbiotics—approaching a definition, published in 2001 in a supplement to the American Journal of Clinical Nutrition, number 73 (361S-364S).

The term prebiotic was first used in 1995 by G. R. Gibson and M. B. Roberfroid in their paper Dietary modulation of the human colonic microbiota: Introducing the concept of prebiotics, published in the Journal of Nutrition (125: 1401-1412). They defined a prebiotic as “a non-digestible food ingredient that beneficially affects the host by selectively stimulating the growth and (or) activity of one or a limited number of bacteria in the colon”, thus improving the health of the host animal. In this same paper, Gibson and Roberfroid came up with the term ‘symbiotic’ to describe the use of a combination of a probiotic and a prebiotic. In this type of combination product, the prebiotic helps support the probiotic’s viability and activity—giving the product more efficacy than if a probiotic is used by itself. To put it in very simple terms, a probiotic product contains the microbes (bacteria, fungi, yeasts, etc.) that naturally occur in the rumen or hindgut, and a prebiotic contains the enzymes that enhance the growth of these microbes.

PROBIOTICS

The most common early use of probiotics was to normalize digestion in animals that had suffered loss of the resident flora—especially calves or foals that had undergone antibiotic treatment, or any ruminant animal that had “lost its cud” due to illness or drastic feed changes. A long course of antibiotics in a sick animal, for instance, generally kills off the “good” bacteria as well as the bad ones that were targeted by the medication. Probiotics were a way to re-establish these “good” bacterial populations. Some of the first probiotics for calves, such as Lactobacillus cultures, were available in pill form (and had to be kept refrigerated to keep the microbes alive). Then pastes became a handier way to administer these products.

Animals with diarrhea or recovering from a long illness often benefit from administration of “good bacteria” such as Lactobacillus acidophilus and Streptococ-cus faecium, or use of live yeast cultures, such as those found in yogurt. Live yeast cultures (such as Aspergillis oryza and Saccharomyces cerevasiae) also come in paste, powder or liquid forms.

EARLY USE OF PREBIOTICS

Research in the 1960s and 1970s showed that fermentation extract from the fungus Aspergillus oryzae improved the fermentation and digestion of low quality roughages in ruminant animals. The original culture was a fermentation by-product from the production of grain alcohol used as aviation fuel. In experimental trials, chicks were fed the grain mash from which the alcohol had been taken, and showed significant improvements in growth.

Research continues to show the benefits of these products. In 1999, J. S. Chang and R. E. Calza reported that a fermentation extract of Aspergillus oryzae (as contained in Amaferm) accelerated both the rate and extent of fiber digestion through increased growth of a beneficial fungus (Neocallimastix frontalis EB188), thus functioning like a prebiotic in stimulating the activity of fungi that break the cellulose bonds—leading to enhanced bacterial digestion. The prebiotic effect of Amaferm stimulates the growth rate and enzyme activity of the naturally occurring microorganisms in the digestive tract of animals. As such, it does not compete with other DFM’s and may actually enhance their activities, as the modes of action are unique, according to Dr. Howard Jensen DVM, MS, Director of Technical Services at BioZyme. Jensen explains that this prebiotic may have synergistic capabilities rather than antagonistic, when used in conjunction with products that have different modes of action.

BENEFITS FOR HORSES

Even though Amaferm has been on the market for almost 40 years, most horse owners have never heard of it because it has mainly been used in premixes for cattle—to improve digestibility of forages and thus enhance growth and development of young animals, improve lactation and reproduction in adult cattle, etc. The company has also been making premixes for horses for 18 years, but since all the feeding trials and research have been done with livestock rather than horses, most veterinarians and horse owners are not aware of this product.

Dr. Jensen further explains that when you add Amaferm to the diet, there are visible changes in the digestive process. “There are 3 things that digest the fiber—bacteria, protozoa and fungi. The anaerobic fungi are the precursors for the others to do their work. The fungi go to work first and are essential to the effectiveness of the other microbes. Our extract stimulates these fungi. They attach to the fiber and grow down into it like a root system grows into the soil,” he says. This cracks apart the fiber, creating more surface space and attachment sites for the bacteria to enter and increase the breakdown.

“If you merely add the appropriate bacteria to the gut, this might help a little with digestion, if there are enough attachment sites. But if the attachment sites are the limiting factor, adding more bacteria won’t really help increase digestion,” says Jensen.

The addition of Amaferm stimulates the bacteria that are present but also does the most good by cracking apart the fiber, to create more attachment sites for them. This knowledge about how fermentation digestion works is fairly recent. “A lot of veterinarians and nutritionists are not aware of it, if they went to school more than about 12 years ago. They may have had only a few sentences about rumen fungi attachment sites in their nutrition classes,” he says.

Amaferm is a direct-fed microbial available in granular, pellet or liquid form, to be added to the feed of any kind of animal. Jensen explains that increasing digestibility can be a help to horses when feed supplies are short. “We’ve learned that increased digestibility can stretch your feed farther. If horsemen have ‘x’ amount of money to spend on hay and grain for the month, they often buy lesser quality hay because they can buy more of it (a more economical price). Research has shown that our products stimulate the anaerobic fungi in the hindgut—so the digestive process can derive more nutrients from lesser quality forage,” he says. This is similar to feeding cattle straw along with a good protein source (the protein feeds the rumen microbes and enables them to digest the straw and get more nutrients from it).

“We can increase the digestibility of straw, for instance, by up to 66 percent. If a cow can get that much nutrition from straw, or as many nutrients from half a bale as from 2/3 of a bale, this will stretch your feed and your budget farther.” Without this boost, the animal would get too much physical fill from the straw (not able to digest it fast enough to provide the necessary food value) and never get the same amount of nutrition as with just a half a bale of straw and Amaferm, he explains.

“The same effect works with horses. We can show that, on average, we can provide a horse with 10 percent more utilization from forage alone (not to mention the grain). In some cases, depending on the quality of hay, our research has shown that with Coastal Bermudagrass and orchardgrass we can get up to 38 percent more digestibility,” he says.

“Some boarding facilities and larger farms that are having problems getting rid of manure have found they don’t have nearly as much waste using Amaferm because there is more utilization of the forage. There’s not as much going on through as waste. The animals are using more of what is being eaten so it doesn’t take as much to meet their needs for body condition, performance, etc.,” explains Jensen.

Another plus in the improved digestion of roughages is that the horse is able to maintain his body condition, growth or energy levels (for athletic performance) with less grain or concentrates. This can help decrease the risk for digestive disturbances, colic and the musculoskeletal disorders that are associated with high levels of grain in the diet.

“Research shows that about 4.5 horses out of 100 have colic issues, and 90 percent of horses today have some kind of gastric or colonic ulcer issues. When you realize that about 75 percent of the horse’s digestion occurs in the hindgut, the health of the hindgut becomes a really big issue. Until recently, people mainly concentrated on the stomach and small intestine regarding ulcer problems and ignored the remaining 70 percent of the digestion issues,” he says.

Jensen also points out that about 30 to 80 percent of the horse’s energy for performance, reproduction, milk production, etc. comes from hindgut digestion. “If that digestion is not optimal, you are leaving a lot of unused nutrients on the table. Any time that we can increase feed utilization in the hindgut we are not only saving money but also doing better for the animal,” he says.

If feed utilization is increased, enabling horses to obtain the most nutritional benefit from their food, this may optimize good health and the ability to fend off disease. Some people who are using these products in high level performance horses, or any horses with high stress levels (or traveling frequently) or horses that have trouble keeping up their weight, feel that this just helps keep those animals healthier and doing better. Using these products in a grain ration may help ward off diarrhea or colic.

“Research has also shown that Amaferm stimulates two of the lactic acid utilizers in the hindgut. A lot of our customers use the product if they have horses that tend to have chronic colic or diarrhea, or tying up issues. Whenever grain goes on through to the hindgut (rather than being fully digested in the stomach and small intestine), this is when you get lactic acid buildup,” he says. This can lead to indigestion, colic, or laminitis.

“If the horse doesn’t have lactic acid utilizers in the hindgut to get rid of this buildup, then you end up with colic, acidosis or laminitis issues. What we’ve found with horses that have these situations is that they tend to have less of these digestive upsets when we increase the numbers of lactic utilizers in the hindgut. This reduces the colic and ulcer issues,” he says. The product is given daily, 2.5 ounces top dressed on grain or fed as a treat. It comes in pellet form and is very palatable; a horse will eat it out of your hand.

Most customers that start using the product will generally see a difference after 2 or 3 weeks of using it. “On a normal, healthy horse that is receiving Amaferm, you’ll find that you can cut back on your feed by about one-third. People that were feeding a horse 9 pounds of grain a day find they get as much response with just 5 to 7 pounds, and can also use a little less hay. This saves a little money on feed. When you add this up over a period of time, you will see a noticeable improvement in your checkbook,” he says.

USE OF PREBIOTICS AND PROBIOTICS TO AID RECOVERY IN SICK ANIMALS

“Amaferm can be used in conjunction with antibiotics, so you can replenish the microflora that are being killed off by the antibiotics,” says Jensen. “That’s when it’s used as a treatment in paste form. Otherwise, you just use a maintenance form that can be given daily as a top dress on feed. If you have a sick horse that’s not eating, that’s when the product needs to be given as a paste, to ensure that you get the proper amount into the horse—to get the gut functioning again. If we can get the horse to graze a little or nibble some good grass hay, this will get his digestion working again,” he says.

Vitalize (Amaferm Recovery Paste) is a three-in-one product that provides vitamins and protected minerals, the Amaferm fungal extract, and MOS (a yeast cell wall component that research has shown to be beneficial in walling off harmful pathogens and improving immune stimulation within the intestinal tract).

“We formulated the paste as a prebiotic. It can be successfully given in conjunction with antibiotics,” he says.

The probiotics that horse owners use—to try to combat negative effects associated with antibiotic treatment—are also negatively affected by antibiotics. “The drugs can’t choose between good and bad bugs, affecting the efficacy of the probiotics that are being given by equine owners to combat stress,” he explains.

“It’s during the recovery period that we need to optimize the performance of the digestive system to ensure that the horse is receiving the nutrients required to offset the challenge the body is encountering. When we restrict the nutrients by killing off the good bugs with the antibiotics, we are hindering the horse’s ability to heal,” explains Jensen.

For more information about prebiotic products, contact BioZyme at 800-821-3070 or check their website at www.biozymeproducts.com