Oral Melatonin Supplementation During Transition Period Reduces Systemic Inflammation and Enhances Oocyte Quality in Dairy Cows

Background: Metabolic and inflammatory stress during the transition period harms ovarian function in negative ways, causing delays in the restoration of cyclicity and fertility. Melatonin is known for its anti-inflammatory and antioxidant actions. However, the effect that melatonin might have on transition cattle oocyte competence is not previously well understood. This study therefore sought to investigate its ability to modulate inflammation. Methods: Thirty multiparous Holstein cows were randomly allocated to melatonin (۱۵) or control (۱۵) groups. Melatonin-treated cows received melatonin (۱۰ mg/head/day) orally mixed in their Total Mixed Ration (TMR) from -۲۱ days to ۲۱ days postpartum. Blood samples for serum levels of TNF-alpha, IL-۶, malondialdehyde (MDA), and total antioxidant capacity (TAC) determination were taken weekly. Oocyte aspirates by ovum pick-up procedure on Day ۳۰ postpartum were evaluated morphologically. conception rate at the first service was evaluated by ultrasonography on Day ۳۰ post-AI. Results: Melatonin decreased TNF-α by ۳۵% (P < ۰.۰۱) and IL-۶ by ۲۸% (P < ۰.۰۵) compared to controls. Serum MDA was lower (P < ۰.۰۱), but the levels of TAC rose (P < ۰.۰۱). Cows treated with melatonin showed an increase in grade I oocytes (۶۲% compared to ۴۱%; P < ۰.۰۵). Conception rate for the first service was higher in melatonin-treated cows (۶۶.۷% compared to ۳۳.۳%; P = ۰.۰۳). Conclusion: Oral melatonin administration during the transition period reduced the adverse effects of systemic inflammation on the redox state and oocyte quality, thereby increasing the rate of conception. Melatonin might provide an effective tool in improving the reproductive performance in high yielding dairy cattle.

کلیدواژه ها:

Melatonin ، Inflammation ، Oocyte quality ، Transition cows ، Fertility improvement