Influence of melatonin implantation on sperm quality, biochemical composition of the seminal plasma and plasma testosterone levels in rams

Influence of the melatonin implantation on sperm quality, plasma testostero ne levels and biochemical composition of the seminal plasma was evaluated i n rams in the breeding and non-breeding season. Melatonin administration du ring the non-breeding season improved progressive motility and morphologica lly normal sperm rates. The mean plasma testosterone level was significantl y higher in melatonin treated animals compared to untreated ones. Fructose, sodium, calcium, magnesium levels, and aspartate aminotransferase and lact ate dehydrogenase activity in the seminal plasma were similar in melatonin treated and control rams. In contrast, melatonin administration during the breeding season did not enhance spermatologic parameters and plasma testost erone levels. Biochemical composition of the seminal plasma was also compar able in melatonin treated and untreated control groups. In conclusion, melatonin administration during the breeding season did not influence sperm quality, plasma testosterone levels and biochemical paramet ers evaluated in this study.