Effect of follicle-stimulating hormone on nuclear and cytoplasmic maturation of sow oocytes in vitro

A series of experiments were conducted to evaluate the effects of FSH supplementation during IVM on porcine oocyte nuclear maturation, and subsequent fertilization, cleavage and embryo development. Cumulus–oocyte complexes (COCs) were cultured 40h without FSH (control), 40h with FSH (FSH 0–40h), or 20h with FSH followed by a 20-h culture period without FSH (FSH 0–20h). Nuclear stage of oocytes was assessed at intervals from 12 to 40h of IVM. Furthermore, oocytes were in vitro fertilized, fixed and stained to determine normally fertilized and polyspermic oocytes. Additionally, COCs were matured with FSH, fertilized and zygotes cultured in NCSU-23. The percentage of cleaved embryos and blastocysts were determined and the number of nuclei was counted.