The Horse

MAR 2019

The Horse:Your Guide To Equine Health Care provides monthly equine health care information to horse owners, breeders, veterinarians, barn/farm managers, trainer/riding instructors, and others involved in the hands-on care of the horse.

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32 March 2019 The Horse | omega-3 as a percentage of total fat. No published research using them in equine diets exists, however, making it difficult to determine their acceptability and digest- ibility as an omega-3 source. Flaxseed is produced by the flax plant, commonly grown in cool north- ern climates such as Canada, Montana, and North Dakota. On average, flaxseed is 40% fat with about 58% of the total fat coming from omega-3s. Horses can consume flaxseed oil or whole flaxseed, but to obtain its nutrients they should eat it ground (due to the seed's hard outer coating). Marine Sources The most concentrated and biologically effective omega-3 fatty acid sources come from the sea. Algae and plankton can produce DHA and EPA, which marine animals then accumulate by consuming these organisms. Fish oil is mainly derived from cold-wa- ter oily fish such as menhaden, herring, cod, or salmon, which serve as rich, pure sources of these omega-3s fats. Research conducted at the University of Kentucky revealed that adding fish oil to exercising horses' diets resulted in lower heart rates, plasma glycerol, free fatty acids, and cholesterol during an exercise test than adding corn oil, a source of omega-6 fatty acids (O'Connor et al., 2004). Algae Depending on the manufacturer or source, omega-3 fatty acids from algae can be derived from the whole-cell form (the dried microalgae itself) or oils ex- tracted from the microalgae biomass. The species and culturing conditions are what influence the fatty acid composition, says Lori Warren, PhD, associate professor of equine nutrition at the University of Florida's Department of Animal Sciences, in Gainesville. Manufacturers can further customize the composition for various purposes (e.g., to emphasize EPA or DHA or the proportion of each) during the oil extraction and blending process. "It's important to note manufacturers are using microalgae (microscopic algae) of marine origin, which is different from the algae most of us know (such as that growing in a pond or a dirty water tank)," says Warren. "Although the specifics re- main proprietary, companies use different microalgae species and may co-culture them with various yeasts and bacteria to enhance biomass growth." In Warren's lab, she and her colleagues fed broodmares a microalgae supplement during the last three months of gestation and first two months of lactation. "We evaluated reproductive performance of the mare, foal viability after parturition (birth), passive transfer of immunity, foal behavior, and at two months of age we evaluated foal learning using operant conditioning (target training)," she says. They continued their evaluations of memory and learning when the foals were 6 to 8 months old (after weaning) and when they were 1 and 2. The result- ing data suggest that supplementing pregnant broodmares with a relatively low amount of DHA via an algae supple- ment can increase DHA transferred to the foal, improve innate and social behaviors in nursing foals, and potentially improve long-term memory recall in yearlings and 2-year-olds (Adkin et al., 2013, 2015). In 2018 Tanja Hess, DVM, PhD, as- sociate professor in equine sciences at CSU, released information from a study performed in her lab showing that add- ing 10 grams of DHA helped moderate post-exercise inflammation as measured by interferon gamma and interleukin-10 (two proteins produced by the immune system) in moderately working polo horses. Choosing a Supplement With a slew of commercially available supplements available from a variety of sources, how do you choose the best omega-3 for your horse? Consider the form of supplement. Most omega-3 fatty acid supplements come as meal, pellets, or oil, says Hess. Canola and soybean oil exist only in liquid form. Flaxseed can be fed as an oil or a meal (ground). Owners find plant-based ingre- dients to be palatable to most horses. Marine-based PUFAs can be found as oils, powders, or pellets, but palatabil- ity can be an issue due to their "fishy" aroma. Most fish and algae supplements include odor- and flavor-masking ingredi- ents, such as peppermint, to help prevent smell and taste issues with horses. The omega-3 source you feed also depends on your goals: ■ Does your horse's coat need some TLC? A diet deficient in essential fatty acids can sometimes cause dry, flaky skin, particularly in frequently stalled horses or during winter when pasture isn't as available. If, indeed, diet is the cause, supplying any form of omega-3s (ALA, EPA, or DHA) should do the trick. ■ Does he have allergies or asthma? When horses with sweet itch con- sumed 1 pound of flaxseed per day, they experienced a significant decrease in reactivity to a Culicoides (a genus of biting midges) extract used during intradermal allergy testing (O'Neill et al., 2002; In another study common equine asthma symptoms (e.g., coughing) and lung function improved within one week of DHA supplementation. Researchers concluded that feeding a DHA-rich product as part of a low-dust diet to horses with chronic airway disease for eight weeks was equivalent to administering a three-week course of the anti-inflammatory medication dexamethasone with a non-low-dust diet (Nogradi et al., 2015). ■ Need support for insulin resistance? In research Hess performed on insulin- resistant mares, those receiving marine and flaxseed supplements were more sensitive to insulin than control mares and showed a "trend for reduction in insulin resistance," she says ( TheHorse. com/116465). ■ Are you managing a chronic NUTRITION Flaxseed (top, ground) and chia seed (bottom) are among the plant-based omega-3 fatty acid sources available.

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