Markers of Inflammation in Arthritic Horses Fed Omega-3 Fatty Acids

Sixteen mature horses with arthritis in the knee, fetlock, hock, or stifle joints were blocked by severity of arthritis, affected joints, and age, and randomly divided into 2 groups. The control group (n = 8) received a commercial 12% CP feed at 1% BW per day. Treated horses (n = 8) received the same mixed feed with the addition of 2 n-3 fatty acid supplements to supply an additional 15 g/d of eicosapentaenoic acid and 19.8 g/d of docosahexaenoic acid. Both groups had access to coastal bermudagrass hay at approximately 1.3% of BW. Horses received respective dietary treatments for 90 d. Synovial fluid was collected from at least one affected joint of each horse on d 0, 30, 60, and 90. Blood samples were collected every 15 d beginning on d 0. Compared with control horses, treatment horses experienced a greater decrease (P< 0.05) in synovial fluid white blood cell concentration and plasma prostaglandin E2 A trend (P = 0.076) toward lower normalized plasma fibrinogen concentration was observed in treated horses compared with control horses throughout the entire trial. When data were analyzed from d 30 through 90, fibrinogen concentrations between groups were significantly different (P < 0.05). Force plate data from 7 horses were obtained to determine potential changes in weight distribution. No significant increase in weight placed on arthritic limbs (P = 0.12) was seen. These data provide further evidence that supplemental long-chain n-3 fatty acids in the equine diet could be advantageous for horses with existing arthritis.