| dc.description.abstract |
Despite the role of melatonin in the regulation of the sleep-wake cycle and seasonal-reproduction, the
present study investigated, for the first time, the potential role of melatonin on testicular blood flow
(TBF) in goats. Twelve sexually mature male Shiba goats were exposed to a single s.c. injection of either
melatonin suspended in one ml of corn oil (melatonin group; 36 mg/goat; n ¼ 5) or one ml of corn oil
(control group; n ¼ 7). Monitoring the changes in TBF was done one week before (W-1), at the time of
injection (W0), and once a week for 8 weeks after injection using color-pulsed Doppler ultrasonography.
Concentrations of FSH, LH, inhibin, testosterone (T), estradiol (E2), and insulin-like growth factor-1 (IGF-
1) in plasma were determined by radioimmunoassay. Melatonin and nitric oxide (NO) concentrations
were measured using enzyme immunoassay kits. Moreover, semen collection and evaluation of some
sperm parameters were performed once a week. Results revealed decreases (P < 0.05) in the Doppler
indices (resistive index, pulsatility index) of the testicular arteries from W2 till W6 in the melatonin
group. FSH, LH, and inhibin concentrations did not change between the two groups, while T, E2, IGF-1,
NO, and melatonin concentrations increased (P < 0.05) in the melatonin group compared to the control.
Estradiol and NO concentrations increased (P < 0.05), coinciding with decreases in the values of
Doppler indices. Notable (P < 0.05) improvements in most parameters of semen quality were seen in the
melatonin group. In conclusion, melatonin induced a stimulatory effect on TBF in Shiba goats and
possibly, it could be a potential to improve male goats fertility |
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