Effect of Omega-3 Fatty Acids on Equine Semen

The outermost component of a sperm cell, called the plasma membrane, relies upon polyunsaturated fatty acids (PUFAs) for optimal structure and function. In an attempt to improve plasma membrane fluidity of spermatozoa through dietary modification, stallions are sometimes fed PUFAs, including docosahexanoic acid (DHA), an omega-3 fatty acid. A study* conducted in Brazil evaluated the effect of this practice on the quality of fresh, cooled, and frozen semen from Mangalarga Marchador stallions.

Ten mature stallions were divided into two groups. Stallions in one group received 150 mL of omega-3 enriched linseed oil added to the daily grain ration. All stallions were fed hay plus water and a mineral mix, and stallions in the supplemented group were given slightly less grain to balance the increase in energy from the supplement. Semen was collected on days 0, 15, 30, 45, and 60 of the study period, and sperm motility, vigor, viability, morphology, acrosome integrity, and osmotic tolerance were evaluated on untreated, cooled, and frozen/thawed samples.

In this group of stallions, fresh and cooled semen showed no effect of dietary treatment, but frozen-thawed semen motility, vigor, and osmotic tolerance were higher in supplemented stallions. This result suggests that the addition of omega-3-enriched oil may be a way to improve semen quality by improving cell membrane integrity and functionality during cryopreservation processes.

EO-3, an excellent source of long-chain omega-3 fatty acids, was developed by Kentucky Equine Research as a palatable liquid supplement that can be fed to all classes of horses, including foals, breeding stock, and performance horses to improve the critical ratio of omega-3 to omega-6 in diets. The product contains the marine-derived long-chain fatty acids DHA and EPA, which are more efficiently used as precursors of local hormones than plant-based sources of omega-3 fatty acids.

*Cunha, I. Influence of omega-3 fatty acid-enriched diet on semen quality of Mangalarga Marchador stallions. Universidade Estadual do Norte Fluminense, Rio de Janeiro, Brazil.