The current Doctoral Thesis studied the Influence of melatoninon the reproductive capacity of ovine
species in 3 different experimental work .The first experiment assessed the effect of increasing
concentration of melatonin during blastocyst post-warming culture on embryo’s ability to restore its
functions after cryopreservation. Thereafter, they were vitrified, warmed, and cultured in BSA plus
melatonin 10-3,10-6,10-9 M. The melatonin 10-9 M improve the re- expansion and hatching rates, the total
cell number and intracellular ATP concentration , with a low oxidative and apoptotic index. Thus, the dose
at which the embryos are exposed is pivotal to obtain the desiderate effect. In the second experiment o,
was to assess the effect of melatonin deprival on ovarian status and function in sheep. The pinealectomy
affect the extention of the breeding season,the mean area of corpus luteum, the progesterone plasma
concentration and caused fewer waves and caused during oestrus cycle.The third experiment assessed the
influence of melatonin implant in ram, during non-breeding season, in the plasma testosterone and
prolactin concentration,in the semen characteristics and in the cryopreservation. The melatonin implant
influence positivily the fertilization rate
