Consequences of Gonadotropin Administration on Fertilization and Early Embryonic Development in the Domestic Cat and the In Vitro Fertilization of Feline Follicular Oocytes
UNIFORMED SERVICES UNIV OF THE HEALTH SCIENCES BETHESDA MD
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The purpose of this research was to 1 investigate effects of an exogenous gonadotropin on embryo recovery, quality and developmental potential in the domestic cat and 2 study factors associated with in vitro fertilization of gonadotropin-stimulated domestic and leopard cat follicular oocytes and ejaculated, homologous spermatozoa. In Study 1, females treated with follicle stimulating hormone 2.0 mg FSH-P for 5 days, IE group and mated produced more corpora lutea and unovulated, cystic-appearing follicles than mated, natural estrus NE animals P0.05. IE cats also produced more P0.01 poor quality embryos 51.6 and unfertilized ova 24.4 than the NE group 21.6 and 2.4, respectively. Additionally, IE females demonstrated lower circulating estradiol-17beta levels and a premature rise in serum progesterone. Transfer of NE and IE embryos to FSH-P treated recipients resulted in three pregnancies and two litters of kittens. In Study 2, females were treated with pregnant mares serum gonadotropin PMSG, 150 IU followed 72 or 80 hours later with 100 or 200 IU human chorionic gonadotropin hCG. After laparoscopic collection, follicular oocytes were inseminated with ejaculated, processed spermatozoa, cultured in vitro 37 C, 5 C02 and examined for evidence of fertilization. Selected two- to four-cell stage embryos were transferred to the oviducts of four original oocyte donors. Naturally mated and oocyte donor cats were subjected to laparoscopy and blood sampling to assess corpora lutea function. After 22 to 30 hours of culture, more degenerate oocytes were observed in the 200 20.6 than the 100 IU hCG group 8.2 , regardless of the PMSG-hCG interval. Fertilization 48.1 and cleavage 35.8 rates were greatest following an 80 hour PMSG-hCG interval combined with 100 IU hCG. Three of four queens receiving embryos became pregnant and produced litters of four, one and three kittens, respectively.
- Anatomy and Physiology