Essential Fatty Acids and the Equine Diet
Dr. Martin Adams, Equine Nutritionist for Southern States
You’ve probably noticed lots of ads for omega-3 supplements for horses, usually containing flaxseed meal or oil, or fish oil. Studies in humans have found many health benefits with supplementation of omega-3 fatty acids in the diet. While research benefits for horses have not been as numerous, omega-3 supplementation shows potential to provide some healthy results. The following information is to provide you with an understanding of essential fatty acids and how you may improve the diet and health of your horse with their use.
Each molecule of fat or oil consists of three fatty acid molecules and one glycerol molecule. The horse needs a certain amount of fat in its diet, and all fats contain omega-3 and omega-6 fatty acids. Horses require these two types of polyunsaturated fatty acids, the major ones are linoleic acid (an omega-6 fatty acid) and alpha-linolenic acid (an omega-3 fatty acid). These fats are termed essential fatty acids (EFA) because the horse’s metabolism can’t synthesize them; they must be consumed in the diet to be provided. Although the exact EFA requirements for horses have not been established, they have been demonstrated as necessary for all animals and humans for many normal body functions. Deficiency of EFA in humans and animals includes hair loss, skin problems, and impaired immune function.
Pasture grasses and hay, although containing only 2% to 3% fat, have greater concentrations of omega-3 than omega-6 fatty acids. Cereal grains, such as corn and oats, contain much higher levels of omega-6 than omega-3 fatty acids in reference to their total fat content. Both rice bran and soybean oils are higher in omega-3 and lower in omega-6 content than corn oil. And oils from sunflower, flax, and canola seeds contain the largest amount of omega-3’s, with higher levels of omega-3 than omega-6 fatty acids. Flaxseed oil is the most concentrated plant source of omega-3 fatty acids or alpha-linoleic acid, also known as ALA. Fish oil is the greatest source of omega-3 fatty acids, with the highest ratio of omega-3:omega-6, and contains the omega-3’s eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA). Horses can convert ALA into DHA and EPA in their body tissues, which are used in various physiological functions, so these are not required.
The horse needs a balance of omega-3’s and omega-6’s to function at an optimal level, but the exact amounts or ratio of omega-3:omega-6 is not known. Research has focused on adding more omega-3’s, which increases the dietary ratio of omega-3:omega-6 fatty acids in the equine diet. Studies in animals and humans have shown that high concentrations of omega-6 fatty acids increase inflammatory processes by increasing the formation of prostaglandins. And the addition of omega-3 fatty acids has been shown to reduce inflammatory processes by decreasing prostaglandin formation. For example, a study with reining horses found that supplementation with soybean oil compared to corn oil had reduced inflammatory response when they were exercised.
Generations of horse owners have fed flaxseed oil or flaxseed meal and observed improved hair coat condition in their horses. Two recent studies have demonstrated the beneficial effects of omega-3 fatty acids in this regard. A Canadian study showed reduction in skin lesions of horses with a demonstrated Culicoides gnat allergy fed flaxseed meal when injected with Culicoides gnat extract compared to a control group without flaxseed supplementation. And significant correlations between high blood plasma ratios of omega-3:omega-6 fatty acids and good hair coat condition, and low blood plasma ratios of omega-3:omega-6 fatty acids and poor hair coat condition were reported in a study with thoroughbreds.
Other equine research studies with omega-3 supplementation have had mixed results. Breeding stallions supplemented with DHA have shown increased sperm concentration and motility in several studies conducted at Colorado State University. Several equine supplementation studies with sources of ALA, DHA and EPA have shown increased levels of omega-3 fatty acids in blood plasma and red blood cells. Omega-3 supplementation of pregnant mare diets using flaxseed oil and fish oil resulted in a change the milk fatty acid composition (ratio of omega-3:omega-6 increased) but there was no immunity advantage for foals (no increase in number of antibodies in colostrum, milk or foal blood serum). The change in the fatty acid profile of blood or tissue (higher omega-3:omega-6 in the cell membranes) is the mechanism that allows anti-inflammatory, immune-enhancing or other physiological effects to occur. Research examining the effect of DHA supplementation on racehorses with exercise induced pulmonary hemorrhage (EIPH) found no reduction in airway inflammation or severity of EIPH.
Studies in humans have demonstrated beneficial effects of omega-3 supplementation and negative effects of high levels of dietary omega-6 fatty acids. However, significant results in human studies are more likely due to the relatively high fat content of the human diet (30%) compared to the equine diet (usually less than 5%). Future research in horses will certainly continue to investigate higher levels of omega-3 supplementation. The benefits of boosting the immune system and reducing inflammatory responses would be beneficial for horses that are aged, involved in intense exercise, or affected with allergic reactions (hives), emphysema or heaves, degenerative joint disease and laminitis.
There is not enough known about the effects of omega-3 supplementation to recommend that every horse requires supplementation or the exact amount required for a beneficial result. Certainly horses on high-grain diets and horses with allergic skin conditions and poor hair coat would likely benefit from higher levels of omega-3 fatty acids. All Southern States horse feeds (RelianceÒ, LegendsÒ and Triple CrownÒ) use soybean oil as the source of fat, which provides increased amounts of omega-3’s compared to feeds using corn oil. Also, all Triple CrownÒ horse feeds contain added flaxseed, and all Triple CrownÒ feeds except Lite contain added rice bran, and both of these ingredients increase the omega-3 content of these feeds. Triple CrownÒ Rice Bran Oil Plus contains a combination of rice bran oil, flaxseed oil and corn oil to provide a high level of omega-3 fatty acid supplementation. Triple CrownÒ Rice Bran and LegendsÒ Pelleted Rice Bran contain high levels of fat and can increase the omega-3 content of the equine diet.
