Utilizzo dell'ultrasonografia nei piccoli ruminanti per la caratterizzazione della dinamica follicolare al fine di identificare fattori ovarici in grado di influenzare la qualità dell'oocita

The current Doctoral Thesis studied the effect of the ovarian status, as evaluated by ultrasonography, on oocyte developmental competence in small ruminants. The first experiment assessed differences in oestrus cycle characteristics, follicle growth in response to exogenous FSH administration, hormonal milieu and oocyte quality in aged and adult sheep. Results obtained evidenced that aging in the sheep is accompanied by alterations in follicle functions, but fertility seems to be maintained, as evaluated by oocytein vitrodevelopmental competence after FSH stimulation. The second experiment examined the effects of melatonin on ovarian follicular growth patterns and on in vitro oocyte developmental competence in anestrous goats. Melatonin treatment prior to oocyte collection hastened dominant follicle growth phase, thus increasing ovarian follicle turnover, and improved oocyte quality. The third experiment determined influence of the glucogenic supply on follicular growth patterns and oocyte developmental competence in Sarda sheep. Short-term energy inputs modified the growth dynamics of ovarian follicles by increasing both their recruitment and development to larger categories, and improved oocyte developmental competence. In conclusion, this study evidenced the strong link existing between follicle function and oocyte developmental competence and set the basis for the development of new protocols aimed at improving oocyte quality in small ruminants.