Fish Oil and Corn Oil Supplementation Affect Red Blood Cell and Serum Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA) Concentrations in Thoroughbred Horses

Horses require both omega-3 and omega-6 fatty acids in their diets. Long-chain omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are intermediate in the formation of eicosanoids that have been shown to reduce inflammatory responses, support immune function, and enhance fertility. This study was conducted to compare the effect of supplementation with oil high in EPA and DHA (fish oil) or low in EPA and DHA (corn oil) on red blood cell (RBC) and serum EPA and DHA.

Twelve Thoroughbred geldings were supplemented for 127 days with 60 ml of either fish oil (EO-3) or corn oil. Blood samples were taken at days 0, 29, 57, 92, and 127 and analyzed for EPA and DHA. By day 29, horses receiving fish oil had an average increase in serum EPA and DHA of 3.7-fold and 17.9-fold, respectively. In horses receiving corn oil, serum EPA decreased 1.5-fold from baseline at day 57 and fourfold by day 92. By day 127, RBC DHA concentrations in the fish oil supplemented horses was over 1.9-fold greater than baseline, while there was no significant difference observed in RBC DHA from horses receiving corn oil. In the fish oil supplemented group, RBC EPA increased 11.5-fold by day 127. Corn oil supplemented horses had significantly lower than baseline RBC EPA at 57, 92, and 127 days.

Results of this study showed that 60 ml/d of fish oil supplementation (EO-3) significantly increases both serum and RBC EPA and DHA in horses. Corn oil supplementation resulted in a significant decrease in RBC EPA, which may affect RBC membrane fragility.

This research was published in Proceedings of the Australasian Equine Science Symposium, 2010.