207 Ovarian stimulation, transvaginal, ultrasound-guided oocyte retrieval, ICSI and blastocyst production in sequential media in the western lowland gorilla (Gorilla Gorilla Gorilla)

Abstract

Two young (ages: 15 and 16 yr;; studbook # 947 and # 939, respectively) parous female gorillas were initially primed with daily oral monophasic estrogen/progesterone treatment (Ovcon 35: Bristol-Myers Squibb Co., Princeton, NJ, USA) for 3 mo to synchronize their menstrual cycles. After withdrawing treatment, urine was tested daily for occult blood (Hemastix;; Baxter Healthcare Corp., Deerfield, IL, USA). On days 3-10 following the onset of menses (Day 1), ovarian activity was stimulated with 225 IU human FSH im (Repronex;; Ferring Pharmaceuticals, New South Wales, Australia). Then on Days 6-8 this treatment was combined with 25�mg GnRH antagonist im (Antagon;; Organon, West Orange, NJ, USA) to prevent premature endogenous LH release. Final oocyte maturation was stimulated 36�h after the last FSH/GnRH treatment with 10,000�IU hCG im (Profasi;; Serono Lab., Hingham/Rockland, MA, USA) and oocyte retrieval was performed 36�h post-hCG administration in sternal recumbency (knee-chest) using a 3-6�mHz probe, 17-ga needles and 87�mm�Hg (VMAR-5000 Regulated Vacuum Pump;; Cook Veterinary Products). Both gorillas displayed a thickened endometrium, and approximately 6 (# 947) to 10 (# 939) maturing follicles (10-15�mm) were detected in each animal. In female # 947, one oocyte was collected but peritoneal fluid and pathology (hydrosalpinx) were also diagnosed and the right ovary showed no follicular development. A total of 3 oocytes were recovered in highly viscous follicular fluid containing massive amounts of cumulus cells. They were transported in a HEPES-buffered transport medium in a portable incubator (CryoLogic, Mulgrave, Victoria, Australia) at 37�C by airline immediately from Brownsville to Dallas, TX, USA, and within 6-h post-retrieval were fertilized by ICSI using cryopreserved sperm collected by rectal probe electrostimulation (age: est. 40�yr ; studbook # 268). The fertilized oocytes were cultured in Gardner's Sequential Medium at 37�C in 6% CO2 all three cleaved and developed to blastocysts by 115�h post-ICSI. One high-quality expanding blastocyst was transported back to Brownsville, TX, and transferred transcervically into the oocyte donor (studbook # 939), and two fair-quality blastocysts were transported overnight to Omaha, NE, and transferred into a synchronized gorilla recipient (age: 29�yr; studbook # 543/91). Weekly urine samples from the two embryo transfer recipients are being tested for pregnancy diagnosis using OvuQuick test strips (Quidel, San Diego, CA, USA). Acknowledgments: This research was supported in part by the Morris Animal Foundation (Ruth Morris Keesling Animal Health Study).