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| Staff Writer |
Building on a strong tradition of performing cutting-edge equine nutrition and exercise physiology research studies, the nutritionists at Kentucky Equine Research published a study titled “66 Type of Polyunsaturated Fatty Acid Supplementation Affects Red Blood Cell Fatty Acid Composition in Exercised Thoroughbreds.” This study was conducted to determine the effect of feeding different chain length omega-3 and omega-6 polyunsaturated fatty acids on red blood cell fatty acid composition in exercised horses, and was first presented at the 2023 Equine Science Society Symposium in Grapevine, Texas.
The Equine Science Society promotes quality research in many fields of study and establishes effective communication among researchers, teachers, extension, and production personnel. The society’s signature event is its biennial symposium, which features professionals and students from multiple countries, many of whom report the latest scientific advances. Kentucky Equine Research has contributed to nearly every symposium since it began 35 years ago.
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The published abstract of this study is as follows:
Omega-3 and omega-6 polyunsaturated fatty acids are essential nutrients for horses. Short-chain polyunsaturated fatty acids (<20 carbon) include α-linolenic acid (ALA, n3), linoleic acid (LA, n6), and gamma-linolenic acid (GLA, n6), while long-chain polyunsaturated fatty acids (≥20 carbon) include eicosapentaenoic acid (EPA, n3), docosahexaenoic acid (DHA, n3), dihomo-gamma-linolenic acid (DGLA, n6), and arachidonic acid (AA, n6). Eicosanoids produced from AA tend to be pro-inflammatory while DGLA, EPA, and DHA give rise to lipid mediators that are anti-inflammatory.
This study was conducted to determine the effect of feeding different chain length omega-3 and omega-6 polyunsaturated fatty acids on red blood cell fatty acid composition in exercised horses. Thirteen fit Thoroughbred horses (age 4.1 ± 1.9 y, BW 496.0 kg ± 36.5 kg; mean ± SD) were split into two groups balanced for age, gender, and body weight. The horses received either 35 mL per day of a corn oil-flax oil supplement (LA-ALA) (n = 6) or 60 mL per day of a high-GLA safflower oil-fish oil supplement (GLA-EPA-DHA) (n = 7).
The LA-ALA supplement provided 8.0 g LA and 10.2 g ALA per day. The GLA-EPA-DHA supplement provided 2.5 g LA, 5.4 g GLA, 0.3 g AA, 4.4 g EPA, 0.8 g DPA, and 3.8 g DHA per day. Each supplement provided a similar amount of total omega-6 and omega-3 per day.
The horses were fed 4.9 ± 1.4 kg/d (mean ± SD) of a textured horse feed along with 1.0–1.5% BW/d of timothy hay and 60 g loose salt. The basal diet provided about 140 g/d LA and 62 g/d ALA. For 90 days before the start and during the study, the horses were exercised three times per week on a racetrack and walked three days per week on a mechanical walker. For 90 days before the study, the horses were fed the same basal ration. Twenty-four individual fatty acids were measured at monthly intervals in red blood cells over the 3-month supplementation period.
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Differences related to time and treatment were analysed using a 2-way ANOVA. Red blood cell fatty acid did not change in the LA-ALA group during the supplementation period. RBC GLA, DGLA, EPA, and DHA increased over time in the GLA-EPA-DHA group (P < 0.01) and were higher than with LA-ALA supplementation after one, two, and three months of supplementation (P < 0.01).
Red blood cell AA increased over time in the GLA-EPA-DHA group (P < 0.05). These increases in GLA and long-chain polyunsaturated fatty acids were primarily offset by decreases in red blood cell oleic acid (18:1n9), LA, and ALA. The ratio of red blood cell AA to (DGLA+EPA+DHA) was 3.9 times higher in the LA-ALA supplemented group compared with the GLA-EPA-DHA group (P < 0.01). This study found that horses fed a high LA intake and supplemented with ALA did not efficiently elongate ALA to EPA and DHA, but that horses did elongate GLA to DGLA.
Kentucky Equine Research is an international equine nutrition, research, and consultation company serving horse owners and the feed industry. The company advances the industry's knowledge of equine nutrition and exercise physiology, applies that knowledge to produce healthier, more athletic horses, and supports the nutritional care of all horses throughout their lives. Research is our key ingredient. Learn more at ker.com.