In vitro production of a caprine embryo from a preantral follicle cultured in media supplemented with growth hormone

The objective was to evaluate the effects of growth hormone (GH) on the survival, growth, maturation, and fertilization of oocytes derived from caprine preantral ovarian follicles cultured in vitro. Preantral follicles were isolated from the cortex of caprine ovaries and individually cultured for 18 d in the absence (control) or presence of bovine GH at concentrations of 10 or 50 ng/mL (GH10 and GH50, respectively). Follicle development was evaluated on the basis of survival, antral cavity formation, diameter increase, and the presence of healthy cumulus-oocyte complexes and mature oocytes. After culture, oocytes were subjected to in vitro maturation (IVM) and in vitro fertilization (IVF). The rate of antrum formation after Day 6 of culture was higher in both GH10 and GH50 than in the control (81.0, 92.7, and 47.6%, respectively, P < 0.05). Percentages of grown oocytes that were acceptable for IVM were also higher (P < 0.05) in GH-treated groups than in the control (54.8, 48.8, and 11.9% for GH10, GH50, and Control). A higher percentage of oocytes in the GH50 treatment underwent meiotic resumption (50.0%), produced mature oocytes, and enabled production of an embryo after IVF than in the control group (0.0%; P < 0.05). In conclusion, GH promoted in vitro growth and maturation of goat preantral follicle oocytes and enabled production of an embryo. Furthermore, this study was apparently the first to produce a caprine embryo by in vitro fertilization of oocytes derived from preantral follicles grown in vitro.