Влияние на размера на фоликулите и средите за култивиране върху ин витро матурацията на ювенилни свински ооцити

Abstract

In vitro maturation (IVM) of oocytes is a critical step in the assisted reproductive technologies performed in pigs. The aim of the present study was to determine what effect the use of a particular maturation medium has on the maturation of oocytes from follicles of different sizes. The results of SF and LF oocytes cultured in medium containing FCS after 0, 28 and 46 h of IVM were compared. Before the start of culture (0 h), 92% of oocytes from both classes of follicles were in the GV stage and after the first half of IVM (28 h). At the end of culture (46 h), both groups of oocytes completed meiosis at MII, with only 83.0% of oocytes from SF compared to 94.0% from LF reaching this stage. The results of oocytes, cultured in medium containing PVA, after 0, 28 and 46 hours of IVM were compared. Before culture (0 h), 94% of oocytes from small follicles and 92.0% of those from large follicles were in the GV stage. After 28 hours, 90.0% (SF) and 92.0% (LF) of oocytes were in the Metaphase I stage of nuclear maturation. The majority of oocytes from both groups (SF 94.0%, LF 92.0%) underwent meiosis to Metaphase II after 46 h. The present study shows that oocytes from smaller follicles with deficiencies in meiotic competence have problems with cytoplasmic maturation that are potentiated by the use of a certain medium. It was found that COCs from SF under the influence of FCS showed stronger luteinization compared to COCs from LF, but this could be compensated by using serum-free maturation medium.