Effect of collection techniques on cumulus oocyte complexes (COCs) recovery, in vitro maturation and fertilization of goat oocytes
The experiment was undertaken to study the effect of collection techniques on cumulus oocyte complexes (COCs) recovery, in vitro maturation (IVM) and in vitro fertilization (IVF) of goat oocytes. COCs were collected by three techniques viz. puncture, slicing and aspiration of goat ovaries obtained at slaughterhouse. It was observed that, the total number of COCs/ovary as well as the number of abnormal COCs/ovary were significantly higher (p < 0.01) in puncture (4.22 and 2.38, respectively) and slicing (4.14 and 2.22, respectively) followed by aspiration (3.28 and 0.80, respectively) technique. In contrast, the number of normal COCs/ovary was significantly higher (p < 0.01) in aspiration (2.48) followed by slicing (1.91) and puncture (1.85) techniques. Only normal quality COCs were cultured in TCM-199 supplemented with 2.5% bovine serum albumin (BSA) plus 10% goat follicular fluid (gFF). The matured COCs were then fertilized in BO medium with fresh buck semen. The results showed that the rates of COCs that reached the maximum cumulus cell expansion (level-3) were 64.14, 65.93 and 65.73%; metaphase-II (M-II) stage were 57.75, 58.23 and 58.57%; normal fertilization (formation of male and female pronuclei) were 34.43, 35.03 and 34.65% in puncture, slicing and aspiration techniques, respectively; there were no significant differences among these rates. The results revealed that the collection techniques have no significant effect (p > 0.05) on in vitro maturation and fertilization of goat oocytes as long as normal quality COCs was used.
Key words: Collection techniques, cumulus oocyte complexes (COCs), in vitro maturation (IVM), in vitro fertilization (IVF).