Effects of oral and intravenous dimethylglycine treatment on hematobiochemical profiles and total oxidant/antioxidant status in low-intensity exercised horses

Dimethylglycine (DMG) may help delay muscle fatigue and prevent exercise-induced muscle damage in athletic animals. This study investigated the effects of intravenous and oral DMG on physiological, hematological, biochemical, blood gas, and oxidative stress parameters in exercising horses. In this study, 30 Turkish Arab saddle horses were randomly divided into three groups. Group A horses were injected intravenously with 15 mL (1500 mg) of a 10 % DMG twice daily for three days. Group B horses received 1500 mg DMG powder orally twice daily for three days, and group C (control) horses were injected with 15 mL 0,9 % NaCl solution twice daily for three days. Following the last dose, all horses were subjected to aerobic exercise, including 30 min of cantering, with a 15-minute warm-up and a 15-minute walking cool-down. Vital and hematobiochemical parameters were evaluated at −2 h (pre-exercise), immediately after exercise (0 h), and at 2, 4, and 6 h post-exercise. Heart rate (HR), respiratory rate (RR), and rectal temperature (RT) were measured to exclude exercise-induced heat stress. Total oxidative status (TOS), total antioxidant status (TAS), and their ratio, the oxidative stress index (OSI), were used to evaluate oxidative stress at rest and after exercise. Other routine blood parameters used to exclude subclinical infection and muscle damage included white blood cell count (WBC), aspartate aminotransferase (AST), creatine kinase (CK), lactate dehydrogenase (LDH), creatinine, and urea. None of these parameters suggested the presence of subclinical disease. As expected, heart rate (HR), respiratory rate (RR), and rectal temperature (RT) showed mild increases following exercise; however, there was no evidence of exercise-induced heat stress. Blood gas parameters remained within physiological limits, and DMG treatment appeared to stabilize post-exercise lactate levels at 0, 2, and 4 h compared to controls. TOS levels were significantly decreased in both treatment groups compared to controls (p < 0.05), particularly following IV administration immediately after exercise (0 h). TAS levels were also lower in DMG-treated horses, likely reflecting greater antioxidant utilization during exercise. However, OSI values did not differ significantly between groups. These findings suggest that DMG, especially when administered intravenously, may help balance oxidative stress and reduce markers of muscle damage in exercising horses, without compromising physiological homeostasis. However, further studies are required to better understand its role and long-term benefits.