Effects of Crude Rice Bran Oil and a Flaxseed Oil Blend in Young Horses in Training

Rice bran oil and a flaxseed oil contain omega-3 fatty acids with the potential to reduce post-exercise inflammation and muscle damage. This study observed body fat and muscle parameters, heart rates, and plasma lactate, glucose, interleukin-1β, creatine kinase, and fatty acid profiles in lightly worked young horses undergoing a 16 min incremental exercise test (IET; 16.1, 19.3, 22.5, and 25.7 kph) after 60-d of oil inclusion. Horses received their energy requirement as 40% from concentrate and 60% from hay, with oil replacing 25% of concentrate calories. Treatments consisted of CON (n=4), which received no oil, FLAX (n=4), which received a flaxseed oil blend, and RICE (n=4), which received crude rice bran oil. Blood was obtained pre-exercise, 1 min, 30 min, 24 h, 48 h, and 72 h post-IET. Data were analyzed by repeated measures ANOVA. All treatments increased (P < 0.05) in body fat and muscle parameters after 30-d of the study. Plasma lactate and glucose concentrations were greater (P < 0.05) 1 min post exercise in all treatment groups, and all treatment groups exhibited heart rates greater than 150 beats per min (bpm), indicating anaerobic exercise. Plasma creatine kinase activity was not different in CON during the study, greater (P < 0.05) in RICE from pre-exercise to 30 min post exercise overall, and lesser (P < 0.05) in FLAX at 30 min post exercise on day 30 compared to day 0. Plasma interleukin-1β was greater (P < 0.01) in CON on day 60, but no differences were shown in FLAX and RICE throughout the study. Plasma alpha-linolenic and linoleic acids were highest (P < 0.05) in FLAX after 30-d of inclusion, while CON horses had greater (P < 0.05) EPA overall and DHA after 60-d. These results indicate that 30 to 60-d of inclusion of crude rice bran oil or a flaxseed oil blend may benefit lightly worked young horses by reducing training program related increases in interleukin-1β, while only the flaxseed oil blend reduced exercise induced increases in creatine kinase. Results also indicate that neither oil induces loss of muscle mass nor increase in body fat. Additionally, the flaxseed oil blend has the potential to increase plasma omega-3 and omega-6 fatty acids.