In vitro fertilization in the pigtailed macaque (Macaca nemestrina)

The objective of this study was to investigate the possibility of collecting oocytes and semen from pigtailed macaques (Macaca nemestrina) and to establish a protocol for the production of viable embryos that would be suitable for transfer into surrogate females. A total of 82 oocytes were collected from a total of four females (on 2 d with two females each). Semen was collected from the same male on both occasions with respective ejaculate volumes of 0.55 and 0.1 mL containing 2 × 109 and 6.6 × 108 sperm/mL. Following insemination and after 48 h in culture, 42 (51.2%) of the oocytes had cleaved. Of these, 21 were selected based on developmental stage and their morphology and cryopreserved. The remainder was kept in culture for an additional 5 d, at which time three had reached the expanded blastocyst stage. A total of five transfers were performed with frozen-thawed embryos; two of these resulted in pregnancies and the birth of infants. The results of this study demonstrated that oocytes can be retrieved from pigtailed macaques and that such oocytes can be inseminated and cultured in vitro to the blastocyst stage and give rise to viable offspring after transfer into surrogate females.