Research into the benefits of omega-3 fatty acids in equine diets is increasing. In many species, the health benefits of feeding omega-3 fatty acids are widely accepted. Improving fertility, reducing the inflammatory response, and enhancing immunity are just some of the proven benefits of a diet high in omega-3 fatty acids. Fat as a source of dietary energy for horses is now widely accepted, and its nutritional advantages are irrefutable. Substitution of starch with fat can help relieve painful muscle conditions such as tying up, modify behavior, and control metabolic conditions such as insulin resistance. Scientists are further exploring how certain types of fats help horses.
Researchers have focused their attention on two distinct families of fatty acids: the omega-3 family and the omega-6 family. Significant members of the omega-3 family are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Interestingly, the horse’s body can convert alpha-linolenic acid (ALA), a short-chain omega-3 fatty acid, to EPA and DHA when sufficient quantities of ALA are consumed, although this process is not entirely efficient. The lack of EPA and DHA in equine diets is understandable, as these two fatty acids are found almost exclusively in fish. The fish, namely cold water species, are at the top of a food chain based largely on algae that manufacture EPA and DHA. ALA, on the other hand, is found predominantly in leafy plants, more traditional components of equine diets then fish by-products (fish meal or fish oil). Flaxseed (linseed) oil is also a rich source of omega-s fatty acids, however a even better source is camelina sativa seed oil as it is naturally high in Vitamin E which acts as a natural antioxidant providing an excellent shelf life of a minimum of two years. The primary source of omega-6 fatty acids in the diet is linoleic acids (LA) derived from the oils of seeds and grains. Corn, sunflower, and safflower oil contain abundant quantities of omega-6.
Omega-3 and omega-6 fatty acids must be balanced within the body in order for both to be effective. Each fatty acid is necessary for the production of prostaglandins. The prostaglandins that evolve from consumption of omega-3 and omega-6 fatty acids have different effects on inflammatory processes in the body. In addition to their effects on inflammatory responses, omega-3 and omega-6 fatty acids aid in the maintenance of cell membrane stability, development and function of central nervous system tissue, oxygen transfer and immune functions.
Scientists have not pinpointed the optimal ratio of omega-3 to omega-6 fatty acids for horses. Even without an exact ratio, general knowledge of omega-3 and omega-6 fatty acids and typical equine management practices uncover some potentially undesirable trends. The natural diet of horses–primarily fresh and dried forages–contains more omega-3 fatty acids than diets consisting of a mixture of forage and cereal grains. Domesticated horses are often fed concentrated sources of energy in the form of grain meals. Grains possess more omega-6 fatty acids then forages, creating a balance of omega-3 to omega 6 fatty acids that may be inappropriate, especially when diets are high in grain. Horses that must expend high levels of energy–hard working equine athletes such as racehorses, for example–are typically fed high-grain diets. Lactating broodmares determined to be hard keepers might also fit into this category. Such diets may not include the myriad benefits of one abundant in omega-3 fatty acids.
Of all the health benefits associated with omega-3 fatty acids, the one perhaps most relevant to the performance horse industry is the positive effect on inflammation, specifically inflammation involved in musculoskeletal diseases. Dietary supplementation of omega-3 fatty acids can help offset the inflammatory response, but the response is not immediate. They must be supplemented for at least 28 days before they have any effect on the inflammatory cascade. However with that said we have noticed differences with Excel EQ as soon as 14 days in some horses.
Omega-3 fatty acids have direct anti-inflammatory actions that can be useful for the treatment of osteoarthritis and lameness. Inflammation is characterized by pain, swelling, heat and loss of use. One of the most important mediators of inflammation is prostaglandin, which is produced from fatty acids in cell membranes. The usual mediators of inflammation are produced from omega-6 acids. Dietary supplementation of omega-3 fatty acids can offset the inflammatory response in several ways. Increased concentrations of omega-3 fatty acids compete with omega-6 fatty acids to produce prostaglandins. The end products produced from omega-3 fatty acids have less inflammatory effects than those usually produced from omega-6 fatty acids. Phenylbutazone (bute), flunixin, and corticosteroids are routinely prescribed to block different steps in this same pathway that creates inflammation. Omega-3 fatty acids are safe, natural, and will not affect testing for anti-inflammatory medications.
A recent study involving 109 dogs with radiographically confirmed osteoarthritis of the hip or stifle investigated the effects of omega-3 fatty acid supplementation for 12 weeks on the dose of carprofen required to control the dogs level of pain (Fritsch et al., 2010). Carprofen is a nonsteroidal anti-inflammatory drug often prescribed by veterinarians as a supportive treatment for relief of arthritic symptoms in dogs. The results of the study indicated that the required dose of carprofen to improve lameness decreased significantly faster in dogs supplemented with omega-3 fatty acids.
A study of 16 horses with confirmed arthritis of the knee, fetlock, stifle, or hock investigated the effects of omega-3 fatty acid supplementation for 90 days (Manhart et al., 2009). Arthritics was confirmed using radiography and forceplate analysis, which detects weight-bearing differences on each hoof. Joint fluid was collected monthly for 90 days from at least one arthritic join in each horse. Horses supplemented with omega-3 fatty acids had a significant and continuing reduction in joint fluid white blood cell concentration beginning at 30 days after supplementation and persisting until the end of the 90 days. Supplementation with omega-3 fatty acids also significantly decreased plasma concentrations of prostaglandin E2, an important inflammatory mediator. Force-plate analysis revealed a trend for horses to bear more weight on their lame limb, but this was not statistically significant.
Osteoarthritis is a common and potentially career-ending ailment of horses. Treatment of osteoarthritis involves rest and anti-inflammatory drugs such as phenylbutazone, corticosteroids, hyaluronic acid, or polysulfated glycosaminoglycans. Nonsteroidal anti-inflammatory drugs such as phenylbutazone can have serious adverse effects in some horses such as renal disease and gastric or colonic ulcers.
Omega-3 fatty acids have been shown to have some beneficial effects to reduce musculoskeletal pain in humans, dogs, and horses. Studies in arthritic horses supplemented with omega-3 fatty acids have reported improvement in stride length, decreased numbers of white blood cells in joint fluid, and decreased concentrations of inflammatory mediators in blood. Further research is needed to determine how omega-3 fatty acids can benefit lame horses or if their use will allow the dose of nonsteroidal anti-inflammatory drugs to control lameness to be reduced and better avoid possible adverse effects.
Fritsch, D.A., T.A. Allen, C.E. Dodd, D.E. Jewell, K.A. Sixby, P.S. Leventhal, J. Brejda, and K.A. Hahn. 2010. A multicenter study of the effect of dietary supplementation with fish oil omega-3 fatty acids on carprofen dosage in dogs with osteoarthritis. Journal of the American Veterinary Medical Association 236:535-539.
Manhart, D.R., B.D. Scott, P.G. Gibbs, J.A. Coverdale, E.M. Miller, C.M. Honnas, and D.M. Hood. 2009. Markers of inflammation in arthritic horses fed omega-3 fatty acids. Professional Animal Scientist 25:155-160