Functional Ingredients In Horse Feeds
By: Dr. Bill Vandergrift
Many horse feeds and supplements include probiotics, prebiotics, yeast cultures, digestive enzymes, organic minerals, and/or botanicals. Why these ingredients are included in equine nutritional products and what benefits they provide to your horse will be the focus of this article.
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A probiotic is a live micro-organism (primarily bacteria) that promotes normal digestion and fermentation in the digestive system. Beneficial bacteria (probiotic) and disease causing bacteria (pathogenic) exits in all parts of the digestive system including the mouth, stomach, small intestine and large intestine. While most probiotics elicit their greatest effect in the horse’s large intestine, their beneficial effects in the stomach and small intestine should not be dismissed.
Recent University research and clinical evidence indicates that in order for a probiotic to be effective it must be fed or dosed at a minimum of 1 billion colony forming units (CFU’s) per day. Even if a feed or supplement contains multiple strains of probiotics that all add up to more than 1 billion CFU’s total, research has demonstrated that this “probiotic cocktail” will not be as effective as a single probiotic strain provided at 1 billion CFU’s or more per day. Different probiotic strains provide different benefits to the digestive system; for example Lactobacillus acidophilus helps maintain desired pH in the large intestine and thereby promotes the proliferation of other desired bacteria strains which in turn results in healthy and normal fermentation while also inhibiting the proliferation of pathogenic bacteria. Lactobacillus reuteri orEnterococcus faecium are often used to reduce problems associated with diarrhea. Calculating probiotic intake:
Compare the following two products –
At first glance, Product A looks like it might provide more beneficial probiotic effects due to the inclusion of more probiotic strains compared to Product B. However, now that you know that there is a minimum number of colony forming units (CFU’s) for each individual probiotic strain that needs to be provided for efficacy, you should recognize that Product B would actually be expected to provide greater probiotic and digestive benefits. In fact, only 1 pound of Product B would be needed to provide the desired minimum number of CFU’s of either probiotic strain it contains, whereas 20 pounds of Product A would be required to provide at least 1 billion CFU’s of either Lactobacillus acidophilus, Enterococcus faecium orLactobacillus reuteri. Even worse is the fact that 28.6 pounds would need to be fed to provide at least 1 billion CFU’s of either Lactobacillus casei or Bacillus subtilis.
Research has also demonstrated conclusively that combining probiotics with prebiotics significantly increases the efficacy of both. Therefore, when evaluating the probiotic package of a nutritional product always look for the inclusion of both probiotic and prebiotic ingredients.
Prebiotics are functional ingredients that promote the growth and proliferation of beneficial bacteria (probiotics) in the digestive system. Prebiotics often provide additional benefits to the horse by stimulating normal immune activity by intestinal tissues. The most common prebiotics found in animal diets include mannan-oligosaccharides, inulin, fructan-oligosaccharides (which is a derivative of inulin) and yeast cultures. When reading the ingredient list on a feed or supplement tag you may not see manna-oligosaccharide or fructan-oligosaccharide listed, instead these ingredients will sometimes be listed as “hydrolyzed yeast” since they are actually derived from yeast cell walls. Yeast culture is not the same as mannan- or fructan-oligosaccharide; yeast cultures act as a food source for many beneficial bacteria and are therefore considered a prebiotic, however, since they are a live micro-organism and can directly affect digestion and fermentation they are sometimes considered a probiotic as well.
The inclusion of probiotics and prebiotics together in a nutritional product has been proven to increase the overall digestibility of your horse’s diet, reduce susceptibility to pathogenic bacteria, and improve the function of your horse’s immune system. These benefits combined result in reduced susceptibility to digestive disorders such as colic or diarrhea, improved metabolic profiles such as reduced insulin resistance and improved immune profiles such as reduced susceptibility to allergies and more effective responses to vaccinations.
University research has demonstrated the inclusion of digestive enzymes in equine diets is beneficial in regard to diet digestibility and nutrient utilization. Even though one would assume that horses will produce an adequate amount of digestive enzymes on their own to break down and digest their diet this is not always the case for individual horses. Horses most likely to demonstrate efficacy to digestive enzyme inclusion in their diet include horses that are “hard keepers”, horses presenting with pars pituitary intermedia dysfunction (PPID or Cushing’s), and horses that colic easily or horses with chronically loose manure. Horses that do not need an addition of digestive enzymes in their diet will also benefit from their inclusion, however, they will not benefit enough for the addition of digestive enzymes to be noticeable.
Organic minerals are minerals that are bonded (chelated) to an organic compound such as an amino acid, peptide or carbohydrate. Not all minerals that are required by the horse can be bonded to organic compounds, therefore, it should be recognized that only a portion of the minerals required by the horse can be presented in organic form. The primary minerals that are available in organic form include zinc, iron, copper, manganese and selenium. For those of you that are “chemically minded” you will notice that these minerals are all found in the same section of Periodic Table of Elements which means they share similar chemical properties. By bonding these minerals to an organic compound their availability for digestion and absorption increases and their utilization by the horse’s body once absorbed also increases. Horses that benefit the most from the inclusion of organic minerals in their diet include horses with poor hoof quality, horses with poor immune function such as horses with allergies or horses that appear to get sick easily, horses with poor stamina during performance, and horses susceptible to stress due to transportation and/or showing. When examining the ingredient list of a nutritional product look for the words “proteinate” or “amino acid chelate or complex”; example: zinc proteinate or copper proteinate.
Selenium is a little different in that you will usually find organic selenium listed on the label as selenium yeast. This is because organic selenium is produced by growing yeast in a selenium rich media facilitating the uptake of selenium by the yeast cell in the form of seleno-methionine. Seleno-methionine is the form of selenium that is actually utilized by the body which easily explains why selenium yeast is not only more available but is also less toxic compared to inorganic selenium sources such as sodium selenite.
The benefits of different botanical ingredients are varied and far reaching. Any botanical ingredient found in an animal feed must be listed as GRAS (Generally Regarded As Safe) by the American Association of Feed Control Officials (AAFCO). Examples of some of the more common botanicals found in horse feed products include kelp, anise, fenugreek, algae, spearmint, and lecithin. Several different herbs can also be found in nutritional products for horses but care should be taken to ensure that they are not banned by your respective horse show association for being considered performance enhancing; (yucca and valerian are two examples of common herbs found in equine nutrition products that are banned by certain horse show associations).
Kelp is used to provide minerals required by the horse in very small quantities such as boron and vanadium. Many horse owners report improvements in hair and skin quality as well as overall temperament when these minerals are supplied in their horse’s diet. Anise and fenugreek have been used for centuries to improve appetite and digestion and reduce complications associated with gastric ulcers. Algae is a good source of DHA, an omega-3 fatty acid. Spearmint is not only known to improve appetite but also provides excellent anti-oxidant properties. Lecithin improves the digestion of fat, therefore, any feed containing added fat should benefit from the inclusion of lecithin; lecithin is also know to speed up the rate of gastric ulcer healing.
The list of functional ingredients that can safely be added to equine nutrition products is long and varied. We have listed a few of the more common functional ingredients and provided a brief explanation why you would want your horse to receive these ingredients. Not all horses will benefit from these functional ingredients, but for those that do, these ingredients can make a huge difference in an individual horse’s appearance, health and general attitude.
Dr. Bill Vandergrift obtained his PhD in animal nutrition from Texas A&M University in 1980. He held a tenure track faculty position at the University of Georgia and has served as director of equine nutrition for regional and national feed manufacturers. Dr. Vandergrift founded EquiVision in 1992 to provide independent equine nutrition consulting services to breeders, trainers and riders and has had the good fortune of working with some of the best sport, breeding, racing and performance horses throughout the world during the past 30 years. He has been the consulting nutritionist for Triple Crown since 1992 and has formulated all the Triple Crown feed products.