Chromatin and cytoplasmic characteristics of equine oocytes recovered by transvaginal ultrasound-guided follicle aspiration are influenced by the developmental stage of their follicle of origin.

Dynamic follicular changes occur during the equine estrus cycle, but little is known about their impact on the properties of recovered oocytes. The aim of this study was to characterize the cytoplasmic and chromatin status of equine oocytes in relation to the time of recovery during the follicle wave. Transvaginal ultrasound-guided follicle aspiration was performed two times in relation to the follicle wave: estrus-subordinate, from the subordinate follicles of mares in estrus, 24 hours after human chorionic gonadotropin stimulation of a dominant preovulatory follicle, and new-wave, from the follicles of the subsequent induced follicular wave, at the time of dominant follicle divergence (largest follicle 23 mm diameter).

Incidence of apoptosis and transcript abundance in bovine follicular cells is associated with the quality of the enclosed oocyte.

The close contact and interaction between the oocyte and the follicular environment influence the establishment of oocyte developmental competence. Moreover, it is assumed that apoptosis in the follicular cells has a beneficial influence on the developmental competence of oocytes. The aim of this study was to investigate whether bovine oocytes with varied developmental competence show differences in the degree of apoptosis and gene expression pattern in their surrounding follicular cells (cumulus and granulosa cells).

Sperm migration in pigs after deep intrauterine and intraperitoneal insemination.

Deep intrauterine insemination in pigs allows sperm deposition only into one uterine horn, but bilateral fertilization of oocytes occurs. How the sperm reach the contralateral oviduct remains disputable. The aim of this experiment was to study possible transperitoneal and/or transuterine sperm migration ways.

Mitochondrial aggregation patterns and activity in in vitro cultured bovine oocytes recovered from early antral ovarian follicles.

The low developmental competence seen in in vitro cultured oocytes collected from early antral follicles may be related to their mitochondrial status. The aim of this study was to examine the chromatin configuration, pattern of mitochondrial aggregation and mitochondrial activity of non-cultured and in vitro-cultured bovine oocytes originating from early antral ovarian follicles. Cumulus-oocyte complexes with adjacent granulosa cells (COCGs) were recovered from early antral follicles of 0.

Occurrence of polyovular follicles in mouse lines selected for high fecundity.

The aim of this study was to evaluate the prevalence of follicles with more than one oocyte (polyovular follicles, POFs) in mouse lines selected for high fecundity. The ovaries of 18 mice, 6 each from 3 different lines, were examined to evaluate the number of POFs and the follicular histology. Polyovular follicles were observed in the two high fecundity breeds, FL1 and FL2, as well as in the unselected control line, DUKsi.