Equine insulin resistance—a condition in which cells fail to respond normally to the hormone insulin—requires careful dietary management to prevent laminitis and other complications from developing. So it’s no surprise that both veterinarians and horse owners are on the lookout for new ways to help manage this disorder.

Case in point: Researchers from Colorado State University (CSU) recently tested the effects of n-3 polyunsaturated fatty acids, or n-3 PUFAs, on glucose and insulin dynamics in horses. Previous research in other species showed that n-3 PUFAs can improve insulin sensitivity, and n-3 PUFAs from marine sources, such as fish or algae, appeared to improve glucose transport from the blood into the cells.

For the current study the researchers, led by Tanja M. Hess, MV, MSc, PhD, assistant professor of equine sciences at CSU, employed 21 nonpregnant mares of mixed stock horse breeding. The mares consumed a diet of free-choice alfalfa/bromegrass hay for one month before the researchers grouped the horses by age, body weight (BW), and body condition score (BCS) and randomly assigned them to one of three treatments:

  • CON—These horses consumed a control diet, consisting of rolled barley and alfalfa/bromegrass hay, containing no supplemental PUFAs.
  • MARINE—These horses consumed a control diet supplemented with a commercial algae/fish oil pellet to provide 38g of n-3 PUFAs.
  • FLAX—These horses consumed a control diet supplemented with ground flaxseed to provide 38g n-3 PUFAs.

The team housed the horses in drylots for the duration of the 90-day treatment period and recor