Development of In Vivo-Matured Porcine Oocytes Following Intracytoplasmic Sperm Injection

The objective of this study was to assess the development of porcine ova fertilized by intracytoplasmic sperm injection (ICSI). Allyl trenbolone (Regumate) was used to synchronize estrus in 13 postpuberal gilts. Gilts were superovulated with pregnant mare serum gonadotropin and hCG. Ova were aspirated from 5- to 8-mm follicles at 36 h after hCG. Cumulus cells were removed by blunt dissection and pipetting in Beltsville embryo culture medium (BECM) supplemented with 0.1% hyaluronidase. Sperm were washed and resuspended in BECM + 8% polyvinylpyrrolidone. Ova (n = 237) that exhibited a polar body were centrifuged at 15 000 × g for 6 min and injected with a single spermatozoon. One hundred fifty-four ova were cultured in NCSU-23 medium in a 5% CO2 in air environment for 168 h. Ova were fixed in acetic acid/ethanol and stained with 1% orcein. Sixty-nine ICSI ova were cultured for 24 h and transferred (mean = 23) to three recipients. Eighty-one ova (69%) that survived ICSI cleaved within 48 h. Thirty-eight percent (31/81) of these ova became blastocysts (mean ± SEM = 24.7 ± 1.1 cells). One recipient gave birth to three pigs. These results demonstrate that porcine embryos derived from ICSI can develop into live pigs.