INVESTIGATING MITOCHONDRIAL UNCOUPLING PROTEIN 1 IN THE INTERPLAY OF METABOLIC ADAPTATION AND INFLAMMATORY RESPONSE OF DAIRY COWS DURING THE PERIPARTUM PERIOD

Homeostasis is a finely coordinated regulation of bodily functions that is crucial for maintaining a stable physiological state. Some conditions, even physiological ones, place a strain on homeostasis, requiring the body to undergo metabolic and physiological adaptations to restore balance (1). One such condition is the peripartum period in mammals. In this regard, dairy cows undergo significant changes in energy during the peripartum phase (2). Mitochondrial uncoupling protein (UCP1) plays an important role in regulating metabolism and energy balance through its effect on adipose tissue. Furthermore, especially during the peripartum period, it plays a key function in the interaction between lipid metabolism and inflammation in cows by the promotion of T-helper 1 responses and mediating the production of proinflammatory interleukins such as tumor necrosis factor-α (TNFα), interleukin (IL)-1, IL-2 and IL-6. In view of the above, the present study explored key metabolic markers and inflammatory responses in 10 cows during the peripartum period. Blood samples were collected at various stages surrounding calving, and plasma concentrations of mitochondrial uncoupling protein 1 (UCP1), glucose, non-esterified fatty acids (NEFA), triglycerides, total cholesterol, interleukin (IL)-1β, IL-6, and tumor necrosis factor α (TNFα) were measured. The results showed a decline in UCP1 levels from prepartum to calving (p < 0.05), followed by an increase up to three weeks postpartum. IL-6 peaked at -7 days (p < 0.05), while TNFα was elevated at -21 and -7 days compared to calving and subsequent days (p < 0.05). Glucose levels were higher at -21 and -7 days, and NEFA increased from -21 until calving, then decreased (p < 0.05). Total cholesterol was lower at calving and one day post-partum compared to earlier and later measurements. Triglycerides were elevated prepartum but decreased at calving. UCP1 values were negatively correlated with NEFA and positively correlated with total cholesterol (p < 0.05). The changes observed in plasma UCP1, glucose and lipids levels of peripartum cows reflect the hormonal and metabolic adaptations that occur during late pregnancy and lactation. These adaptation are crucial to meet the energy demands of ovaries, placenta, and mammary glands and, thereby help protect cows from negative energy balance. Specifically, the lower plasma levels of UCP1 may play a role in counteracting energy loss associated with pregnancy demands and milk production.This study contributes the undestanding of the dynamic changes in energetic balance and inflammatory state in dairy cows during the peripartum period.