The European Equine Health & Nutrition Congress was held in March 2006, at the Veterinary Faculty of the University of Ghent in Belgium. The Congress included five full-length feature presentations and several shorter communications and work shops. These presentations included two given by our veterinary editor, Dr. Eleanor Kellon, and we’d like to share the highlights from the convention with you.
Pre- And ProBiotics
Veronica Julliand, head of the Laboratory of Nutrition of Monogastric Herbivores from the Higher National School of Agronomy in Dijon, France, discussed the use and status of probiotics and prebiotics in horses.
Prebiotics are defined as selectively fermented (food) ingredients that allow specific changes in the composition and/or activity in the gastrointestinal flora. In Europe, probiotics are defined as live organisms that, when administered in adequate amounts, confer a health benefit on the host.
Interestingly, prebiotics are prohibited from using any medical/health claims, while probiotics, because their definition includes a health claim, must prove they’re of benefit to be licensed. Because of these rigid requirements, Saccharomyces yeast is licensed specifically for pregnant and lactating mares, for young growing horses, to improve fiber digestibility (on mixed grain and hay rations).
Julliand presented the findings of two studies that looked at the benefit of oligofructose (aka fructans) as a prebiotic in horses. In both studies, it was found that the incidence of colic decreased and the level of putrefactive (lost to digestion and undergoing breakdown in the colon) compounds decreased in the manure. She was careful to point out fructans are safe at these dosages, since the amount that has been used experimentally to produce laminitis is 100 times higher than the prebiotic dose. Look for fructan-containing equine prebiotics in the near future.
Mineral Bioavailability in Horses
Prof. Ellen Kienzle, Chair of Animal Nutrition and Dietetics at the Institute of Animal Physiology of the Veterinary Faculty at Ludwig-Maximilians University in Munich, Germany, reviewed what is known about the bioavailability of minerals in horses.
She said that, while it is valuable to use data from other species as a starting point, the horse is not a ”rat with hooves” and equine-specific studies are needed. Bioavailability means how easily the horse’s body can utilize a given mineral.
The superiority of chelated minerals versus inorganic mineral salts has not been proven in horses. In the few studies that have looked at organic versus inorganic forms (e.g. zinc), sulfates are absorbed just as well as the organic form.
In addition, she stated, blood levels of a mineral are not a reliable way to determine status or absorption because the mineral may be tightly regulated or the animal may be deficient and rapidly clearing the mineral into the tissues.
Glycemic Index/Blood Glucose and Feeding
Dr. Ingrid Vervuert, from the Institute for Animal Nutrition, University of Veterinary Medicine in Hannover, Germany, spoke about factors influencing the glycemic index of feeds for horses. The glycemic index is a measure of how high blood glucose goes after eating, which is extremely important for horses with insulin resistance.
We already know that grain produces the largest increase in blood glucose, but there’s conflicting information about whether how much is fed, the type of grain fed, or if it’s fed with hay makes any difference.
One thing that does seem to be clear is that the more processed a grain is (smaller particle size, heat treatments), the more rapidly its starch is digested and the higher the glucose level becomes in the horse’s blood.
Gynostemma (Jiaogulan) and Spirulina in Horses
Dr. Eleanor Kellon, private nutritional consultant and veterinary editor of Horse Journal, spoke on the use of Gynostemma pentaphyllum (Jiaogulan) and Spirulina platensis in horses. She first described how herbal and natural substances are now being studied scientifically, and how it is possible to research safety data in other species and the actual pharmacology of how these substances work before deciding if they may be of use in horses.
Horse Journal readers already know about Jiaogulan for laminitis and Spirulina in the treatment of allergies, and many readers have written to tell how well Spirulina, especially, has worked for their horses. Jiaogulan is also helpful with bronchospasm and can be combined with Spirulina to help control lung allergies/obstructive lung disease.
Electrolytes and Control of Blood pH
Prof. Donald Topliff, Head of Agricultural Research at Texas A&M, gave a presentation on electrolytes, detailing how the respiratory system, kidneys and electrolytes contribute to keep the pH of the body and blood normal. He focused on how DCAD — dietary cation and anion difference — is a major determinate of the body’s pH. We’ll discuss the impact of this in a upcoming article, but the take-home message for now is the effect of the types of electrolyte used on the exercising horse.
Transportation and Probiotic Use
Dr. David vanDoorn, of the Department of Nutrition, Faculty of Veterinary Medicine at Utrecht University in the Netherlands, presented a paper on the effect of transportation on the digestive tract of horses and whether pretreatment with probiotics has any beneficial effect.
They found that transport did cause a significant jump in cortisol, but there were no significant changes in fecal pH or consistency in either the treated or untreated ponies. However, both groups of ponies did show changes in one specific group of bacteria. While the probiotic used did not influence this transport-induced change, they found it may have produced changes in two other groups of bacteria.
The conclusion was that the probiotic strains used had no influence on the transport-induced alterations in gut bacteria , so more study is needed to identify exactly what those strains are and how they might be protected. The fact they did see changes in two other groups of bacteria when horse were given probiotics indicates they do influence gut micro-organisms, but more work is needed to find out which ones.
Iron Overload and Insulin Resistance
Dr. Eleanor Kellon gave another presentation on the connection between iron status and insulin resistance (IR) in horses. In humans, IR has been linked to iron overload in several studies. Iron can be both a risk factor for the development of insulin resistance and occur as a consequence of IR.
Kellon looked at the iron status in insulin-resistant horses a nd compared this to normal controls in the study as well as published normals. It was found that insulin resistant horses on diets that were not mineral balanced had greatly elevated indices of iron burden compared to both normal horses and IR horses on correctly mineral balanced diets. This shows that the same relationship between iron burden and IR as occurs in people also occurs in horses, and controlling iron burden may be a way to help control IR.
Energy Requirements High Intensity Exercise
Dr. vanDoorn also discussed a study that looked at the predicted energy (calorie) requirements of Standardbreds in interval training at a highly successful private stable in Italy vs. how much feed it actually took to maintain normal body condition. The message here is to feed your horse according to body condition, not ”by the book.”