Abstract
Mammalian ovaries contain a large number of oocytes, most of which degenerate either before or during the various stages of growth. To utilize these potential female gametes stored in the ovary, it is essential to develop a culture system that can provide a suitable alternative environment for oocytes to achieve full growth and competences to undergo meiotic maturation, fertilization, and embryonic development. In this review, the culture systems developed for bovine and porcine oocyte–granulosa cell complexes, at approximately the late mid-growth stage, are discussed. The culture systems are broadly divided in two types, the sphere system and substratum-adhering system. In the former system, a matrix such as collagen is utilized to maintain the 3-D structure of the follicles/oocyte–granulosa cell complexes. The latter system is characterized by the use of high concentrations of polyvinylpyrrolidone (molecular weight: 360,000), which positively affects the growth and competence of the oocytes. The quality and competence of the oocytes grown in these systems are discussed.
