KER | Horse Racing Free Tips

Antioxidants For GGT Syndrome In Training Racehorses

Blood analyses of Thoroughbred racehorses can reveal elevations in the enzyme gamma-glutamyl transferase (GGT). In what appear to be otherwise healthy horses, the significance of these high GGT values remains unclear. Using advanced metabolomic, viral and chemistry techniques, veterinarians suggest that “GGT syndrome” in fit racehorses could be related to oxidative stress.

“The horse's body produces excess GGT in the face of liver, pancreatic, and kidney disease, particularly injury to the bile duct. Concomitant increases in other liver enzymes, however, usually do not occur, suggesting that primary liver disease does not explain elevated GGT levels seen in racehorses,” explained Peter Huntington, B.V.Sc., M.A.C.V.Sc., director of nutrition, Kentucky Equine Research.

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Elevated GGT levels may be caused by:

Hypoxia (decreased oxygen reaching tissues);
Infection;
Toxicity (e.g., pyrrolizidine alkaloids from toxic plants);
Liver injury;
Hepatic glycogen depletion and repletion;
Overtraining; and
Oxidative stress associated with inadequate selenium or glutathione

Previous studies show that GGT levels tend to increase with racing frequency and cumulative training load and then decrease with recovery. This trend in GGT raises the possibility that oxidative stress and oxidative depletion play a role in the syndrome.

In a recent study, veterinarians collected blood samples from Thoroughbred racehorses.^* GGT values were analyzed, as were other liver values, selenium levels, viral load, and metabolomics. Comparisons were made between horses that did and did not have elevated GGT.

“Many of the potential causes of GGT syndrome were ruled out based on this testing, including viral hepatitis. One particularly interesting finding was that while selenium concentrations in horses with high GGT levels were within normal limits, they were significantly lower than selenium levels in horses with normal GGT,” noted Huntington.

These low selenium levels were reported in earlier studies and may reflect reduced antioxidant capacity related to oxidative stress. That said, one investigation found that selenium supplementation did not prevent increased levels of GGT in racehorses in training. In contrast, supplementation with the powerful antioxidant coenzyme Q10, such as Nano-Q10, can increase serum coenzyme Q10 levels.

“Racehorses in training with higher coenzyme Q10 levels had significantly lower GGT levels in one study. In addition, supplementation with EO-3, a marine-derived omega-3 fatty acid supplement, was associated with a significant reduction in GGT levels in horses in training,” Huntington said.

Overall, GGT syndrome is likely multifactorial rather than a result of a single mechanism, including oxidative stress. But, according to Huntington, there are some nutritional strategies that may be used to manage it, such as supplementing the horse's diet with antioxidants.

^*Mann, S., J.D. Ramsay, J.J. Wakshlag, T. Stokol, S. Reed, and T.J. Divers. 2021. Investigating the pathogenesis of high-serum gamma-glutamyl transferase activity in Thoroughbred racehorses: A series of case-control studies. Equine Veterinary Journal:13435.

Reprinted courtesy of Kentucky Equine Research. Visit ker.com for the latest in equine nutrition and management, and subscribe to Equinews to receive these articles directly

The post Antioxidants For GGT Syndrome In Training Racehorses appeared first on Horse Racing News | Paulick Report.

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The Hindgut: Understanding Its Role In Equine Digestive Health

Horses rely on fermentation for optimal digestion of feedstuffs and energy production. Hindgut digestion, which occurs in the cecum and large colon, progresses most efficiently when horses are allowed continual access to forage and limited access to feedstuffs that could upset the pH of the cecum, including large grain meals.

Fermentation is achieved through the machinations of billions of protozoa, fungi, and bacteria. Together, these microbes convert carbohydrate-based contents, essentially plant-based fiber, into volatile fatty acids (VFA), which provide energy to the horse. If soluble carbohydrates, such as those found in large supply in grain meals, find their way into the hindgut, some lactate might be produced.

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An overproduction of lactate can shift the pH of the hindgut to a more acidic state, which may cause problems. When a drop in pH occurs, called hindgut acidosis, some of the beneficial fiber-digesting microbes die off. Digestive efficiency drops as a result. In many horses, this manifests as poor appetite, crabby disposition, recurrent colic, and onset of certain stable vices, such as stall-walking and cribbing.

To offset this, horse owners should scrutinize feeding management. Hindgut acidosis is rarely caused by what is fed but rather how it is fed. Here are three strategies to ward off hindgut acidosis:

Good-quality forage should be offered at all times, so the hindgut is continually in “processing mode.” Forage may be pasture, hay, or hay-based products such as cubes or pellets. Forage selection should be based largely on the nutrient needs of the horse.
Concentrate meals should not exceed approximately a half-pound per 100 pounds of body weight (5 pounds for a 1,000-pound horse).
If a horse requires more than 5 pounds of concentrate per day, divide total daily allotment into separate meals. Feeding three or four concentrate meals, evenly spaced throughout the day, is more beneficial to the horse than huge meals.

Some horses, especially those that are asked to perform intense exercise, must consume large grain meals to fuel performance. Hindgut acidosis can be curbed by feeding EquiShure, a time-released buffer that raises the pH of the hindgut and eliminates signs of acidosis.

Gastric Ulcers In Horses: Search For Biomarkers, Treatments Continues

Are you considering having your horse's stomach scoped again? Is there any other way to verify the presence of gastric ulcers? Right now, there isn't, but researchers are working on noninvasive ways to diagnose and monitor horses with equine gastric ulcer syndrome (EGUS).

Many performance horses have gastric ulcers, which are defects in the surface of the stomach lining that occur in either the glandular or nonglandular (squamous) regions. Thought to be largely due to management factors—stress due to training or competition, social isolation, diets high in concentrates or low in forages—gastric ulcers often cause poor performance, decreased appetite, and weight loss.

After diagnosing and grading ulcers via gastroscopy, veterinarians typically recommend treatments geared to decreasing the acidity of the stomach. Treatment plans for EGUS typically include diet modifications, management changes, and medications such as omeprazole, sucralfate, and ranitidine. Nutritional supplements designed to control the pH within the stomach could also be included.

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“Triacton supports gastric health by moderating acidity using ingredients shown to have greater buffering capacity. Those include a seaweed-derived source of calcium and several other highly bioavailable minerals,” said Catherine Whitehouse, M.S., a nutritionist for Kentucky Equine Research. “The form of calcium in Triacton offsets the negative effects of omeprazole on calcium digestibility compared to other commonly used sources of calcium in feeds and supplements.”

Because gastroscopies play a key role in ulcer management, repeated procedures are a necessary evil as horses may be resistant to treatment or the ulcers may return rapidly following cessation of pharmaceutical treatments like omeprazole.

Veterinary researchers recently suggested that identifying blood or salivary markers, or perhaps a combination of both, could help create a diagnostic panel for EGUS. This tool would screen patients for EGUS and monitor response to treatment, which would limit the frequency of gastroscopy.^*

Blood collected from eight mature geldings with gastric ulcers was evaluated for total antioxidant capacity. A moderate but significant correlation between blood and salivary antioxidant capacity was identified, potentially indicating that oxidative stress decreases as ulcers heal.

“The role of oxidative stress and antioxidants in EGUS requires further exploration, but these very preliminary findings suggest that antioxidants may play a role in the future management of this condition,” said Whitehouse.

While horse owners wait for this research to advance, Whitehouse suggested using diagnostics and treatments, including gastrointestinal buffers, currently recommended by veterinarians.

^*Svagerko, P., W. Bridges, E. Jesch, S. Pratt-Phillips, and K. Vernon. 2021. Equine gastric ulcers; a pilot study: Associated biomarkers and polysaccharide supplementation as a solution. Journal of Equine Veterinary Science 100:103518.

Reprinted courtesy of Kentucky Equine Research. Visit ker.com for the latest in equine nutrition and management, and subscribe to Equinews to receive these articles directly

The post Gastric Ulcers In Horses: Search For Biomarkers, Treatments Continues appeared first on Horse Racing News | Paulick Report.

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Tempting Tastebuds: How Taste Preference Is Measured Among Horses

How do feed manufacturers know horses will readily eat the products they produce? If the manufacturer works with Kentucky Equine Research, more than 30 years of palatability research is taken into consideration.

In this video, research coordinator Michael Sandwick explains the two-choice preference test and how it relates to product development. In these tests, horses are given two feed options in matching buckets, which are rotated daily. Initially, the horse is allowed to smell but not taste the feeds. The handler then turns the horse away from the buckets before releasing it to consume its preferred choice for three minutes. A scribe notes how many times the horse returns to the bucket, lifts its head, or gets distracted by outside factors. After three minutes, the leftover portions are weighed to measure how much of each feed was consumed.

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Sandwick got her start with the company as a summer intern. She is currently finishing her master's degree at Kansas State University while working at the Kentucky Equine Research Performance Center in Ocala.

Learn more about product development at Kentucky Equine Research.