Repeated hormonal treatment and laparoscopic ovum pick-up followed by in vitro embryo production in goats raised in the tropics

In vitro production of small ruminant embryos: latest improvements and further research

This review presents the latest advances in and main obstacles to the application of invitro embryo production (IVEP) systems in small ruminants. This biotechnology is an extremely important tool for genetic improvement for livestock and is essential for the establishment of other biotechnologies, such as cloning and transgenesis. At present, the IVEP market is almost non-existent for small ruminants, in contrast with the trends observed in cattle. This is probably related to the lower added value of small ruminants, lower commercial demand and fewer qualified professionals interested in this area. Moreover, there are fewer research groups working on small ruminant IVEP than those working with cattle and pigs. The heterogeneity of oocytes collected from growing follicles in live females or from ovaries collected from abattoirs remains a challenge for IVEP dissemination in goats and sheep. Of note, although the logistics of oocyte collection from live small ruminant females are more complex than in the bovine, in general the IVEP outcomes, in terms of blastocyst production, are similar. We anticipate that after appropriate training and repeatable results, the commercial demand for small ruminant invitro -produced embryos may increase.

Effect of Continuous Administration of Enalapril Maleate on the Oocyte Quality and In Vitro Production of Parthenote Embryos in Nulliparous and Multiparous Goats Undergoing Serial Laparoscopic Ovum Pick-Up

The aim of this work was to determine the effect of enalapril maleate administration, during oocyte recovery by serial laparoscopic ovum pick-up (LOPU), on the ovarian response and in vitro embryo production (IVP). Twenty cross-bred goats were allocated equally into two groups: Nulliparous and Multiparous. In each group, five animals were selected to receive daily doses of enalapril maleate during the hormonal protocol. Estrus was synchronized by a PGF2α analog, followed 48 h later by insertion of an intravaginal device with progesterone. Forty-eight hours after, a single dose of FSH/eCG was administered. The FSH/eCG doses were repeated three times, on every four day. Oocytes were recovered by LOPU 24 h after each FSH/eCG dose. Viable oocytes were matured in vitro, to be parthenogenetically activated and cultured for 72 h to the cleavage stage. The drug treatment increased the proportion of total follicles observed at LOPU (p < 0.01) in multiparous goats. In both parity groups, enalapril administration had no effect on the proportion or quality of oocytes recovered. Furthermore, the number of embryos cleaved was similar between the groups. Thus, enalapril maleate affected the ovarian response in multiparous animals only and had no effect on the oocyte quality or IVP.

In Vitro Culture of Embryos from LOPU-Derived Goat Oocytes

A high oocyte quality is the prerequisite for in vitro embryo production. Goat cumulus-oocyte complexes (COC) are mainly collected from slaughterhouse ovaries or by laparoscopic ovum pickup (LOPU) from live animals. Several features can influence the availability of good quality oocytes recovered by the LOPU technique. Interestingly, slaughterhouse and LOPU oocytes have different in vitro maturation kinetics and requirements, and thus, the IVP system must be adapted regarding the oocyte origin. Overall, the use of undefined media in the different steps makes interpretation of results more difficult, hampers their reproducibility, and introduces a sanitary risk. Thus, there is an effort worldwide to use simpler conditions for goat IVP. Although the success of IVP rates is relatively high, in vitro embryos differ from in vivo-derived ones in many aspects, resulting in lower viability. Therefore, strategies to improve in vitro embryo quality are crucial, such as the use of oviductal epithelium cells for coculture. Here we describe the main steps and culture media which can be utilized to produce embryos in vitro from LOPU or slaughterhouse oocytes in goats.