Melatonin promotes superovulation in sika deer (Cervus nippon)

Area of Science:

• Reproductive biology
• Endocrinology
• Veterinary science

Background:

• Melatonin plays a crucial role in regulating seasonal reproduction in various species.
• Understanding melatonin's impact on superovulation is vital for improving deer breeding programs.

Purpose of the Study:

• To investigate the effects of exogenous melatonin administration on superovulation in female sika deer.
• To analyze the impact of melatonin on key reproductive hormones: FSH, LH, and PRL.

Main Methods:

• Subcutaneous implantation of two different melatonin doses (40 or 80 mg/animal) in sika deer prior to the breeding season.
• Monitoring of serum hormone levels (melatonin, FSH, LH, PRL) at various reproductive stages.
• Evaluation of superovulatory response by counting corpora lutea and assessing embryo numbers.

Main Results:

• Melatonin treatment significantly increased serum FSH levels at insemination.
• Elevated LH levels were sustained from insemination to embryo recovery in treated deer.
• The 80 mg melatonin group showed significantly lower PRL levels, and a significant increase in corpora lutea count compared to controls.

Conclusions:

• Exogenous melatonin administration positively influences superovulation in sika deer, primarily by modulating FSH and LH secretion.
• While melatonin increases the number of corpora lutea, it may also lead to delayed embryonic development, warranting further investigation.