A comparative study on parthenogenetic activation and embryo production from in vitro matured caprine oocytes

Melatonin improves in vitro maturation and subsequent embryo development of caprine oocytes*

The aim of the present investigation was to study the effect of melatonin on in vitro maturation and subsequent embryo development of caprine oocytes. In experiment 1, 384 in vitro matured oocytes were selected and randomly divided in to two groups, viz. group 1 (control) wherein oocytes matured in maturation media without supplementation for 27 h in humidified atmosphere at 38.5°C with 5% CO2 in CO2 incubator while in group 2 oocytes matured in maturation media with 30 ng/ml melatonin supplementation. After 27 h of culture, nuclear maturation was observed in both groups using Hoechst dye. In experiment 2, 1,336 oocytes were randomly divided into two groups, viz. group 1 (641) wherein oocytes were matured in maturation media without melatonin while in group 2 (n=695) oocytes matured in maturation media with 30 ng/ml melatonin supplementation. After 27 h, oocytes of both groups were then subjected to in vitro fertilization.The rate of nuclear maturation in group 2 (30 ng/ml melatonin) was significantly higher than that of group 1 (control). Similarly, the cleavage rate and blastocyst formation from in vitro matured goat oocytes were significantly higher in group 2 than that of group 1. In conclusion, the result indicated that the supplementation of 30 ng/ml melatonin in maturation media improves the nuclear maturation and subsequent cleavage rates and blastocyst production from caprine oocytes.

Effect of Ca Ionophore On Blastocyst Production Following Intracytoplasmic Sperm Injection in Caprine Oocytes

The aim of the present investigation was to study the effect of calcium ionophore activation on blastocyst production following intracytoplasmic sperm injection (ICSI) in in vitro-matured Caprine oocytes. A total of 470 in vitro-matured oocytes were selected and randomly divided in to three groups. Cumulus oocyte complexes (COCs) recovered by slicing the Caprine ovaries were matured in TCM199 supplemented with 10% foetal bovine serum (FBS) + 10% follicular fluid + FSH (5 μg/ml) + LH (10 μg/ml) + estradiol (1 μg/ml) + EGF (10 ng/ml) + BSA (3 mg/ml) for 27 h in humidified atmosphere at 38.5°C with 5% CO2 in CO2 incubator. After 27 h of culture, selected COCs (n = 470) were separated from cumulus cells by treating with 0.1% hyaluronidase enzyme and passing repeatedly through a fine pipette and randomly divided into three groups. In group 1, (n = 168) matured oocytes were injected with injection micropipette without sperm as control. In group 2, (n = 152) capacitated spermatozoa were injected into cytoplasm of in vitro-matured oocytes through injection micropipette. In group 3, (n = 150) capacitated spermatozoa were injected into cytoplasm of in vitro-matured oocytes through injection micropipette and then activated with 5 μm Ca ionophore for 5 min. The oocytes of all groups were then culture in RVCL media for embryo development. The cleavage rate was observed after 48-72 h of injection. The cleavage rate and blastocyst production in group 1, 2 and 3 were 0.00 and 0.00, 18.42 and 3.57 and 61.33% and 16.30%, respectively. The result indicated that mechanical activation failed to induce cleavage in in vitro-matured Caprine oocytes, whereas chemical activation of intracytoplasmic sperm-injected in vitro-matured Caprine oocytes showed significantly higher cleavage rate and blastocyst production as compare to non-activated oocytes.

Development of parthenote following in vivo transfer of embryos in Capra hircus

The aim of this study is to generate parthenogenetic embryos from chemically activated in vitro matured caprine oocytes and to study the in vivo developmental potency of such embryos. The parthenogenetic embryos (2-8 and 16 cells to morula stage) were surgically transferred in 26 recipients. Pregnancy in recipients following embryo transfer was monitored by ultrasonography. The recipient aborted a foetus on day 34 post transfer. Sexing of parthenogenetic foetus showed a single band of amelogenin gene indicating female cell DNA. Microsatellite analysis revealed that the recipient has not contributed genetically to the parthenogenetic foetus confirming the identity of aborted foetus of parthenogenetic origin. The authors believe that this is the first authentic report on in vivo development of parthenogenetic foetus in Capra hircus.