Embryo production by in vitro fertilization in wild ungulates: progress and perspectives – A Review

Abstract

Wild ungulates are of fundamental importance for balancing ecosystems, as well as being the species of economic interest. Increasing concern over the accelerated population reduction of these species has resulted in the development of assisted reproduction techniques, such as in vitro fertilization (IVF), as a tool for conservation and multiplication. In the present scenario, IVF protocols were developed based on the methodologies used for domestic ungulates. Nevertheless, owing to the physiological and reproductive differences among the species, several factors associated with IVF and its relationship with the characteristics of the species of interest require clarification. In vitro conditions for the collection and selection of female and male gametes, oocyte maturation, sperm capacitation, co-incubation of gametes, and embryonic development can influence IVF results. Therefore, the present review considers the main advances in the methodologies already used for wild ungulates, emphasizing the strategies for improving the protocols to obtain better efficiency rates. Additionally, we discuss the conditions of each IVF stage, with emphasis on aspects related to in vitro manipulation and comparability with the protocols for domestic ungulates.

Short- and Long-Term Storage of Non-Domesticated European Mouflon (Ovis aries musimon) Cumulus–Oocyte Complexes Recovered in Field Conditions

“…Reproductive biotechnologies, including artificial insemination (AI), embryo transfer (ET), in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), somatic cell nuclear transfer (SCNT), generation of induced pluripotent stem cell (iPSCs), and cryopreservation of gametes and embryos with gene banking procedures, can be utilized in the conservation of these species and to counteract their numerical reduction as well as genetic disappearance. However, the development of suitable reproductive biotechnology protocols for use in non-domesticated animals is of greater importance because of the lower knowledge of reproductive anatomy, physiology, and endocrinology and limited number of available gametes to evaluate efficacy when using these technologies [ 1 , 2 , 3 ]. Therefore, the use of common and suitable taxonomically related animals can be useful in initial studies particularly to validate experimental protocols which will be subsequently applied to rare non-domesticated animals [ 1 , 3 ].…”

“…However, the development of suitable reproductive biotechnology protocols for use in non-domesticated animals is of greater importance because of the lower knowledge of reproductive anatomy, physiology, and endocrinology and limited number of available gametes to evaluate efficacy when using these technologies [ 1 , 2 , 3 ]. Therefore, the use of common and suitable taxonomically related animals can be useful in initial studies particularly to validate experimental protocols which will be subsequently applied to rare non-domesticated animals [ 1 , 3 ].…”

“…In particular, the preservation of wild female germplasm is a promising biotechnological approach to conserve animal species [ 2 ]. However, the collection of in vivo matured oocytes is difficult in non-domesticated animals, because adequate and standardized ovarian stimulation protocols still do not exist to provide optimization of oocyte collections from preovulatory follicles in such animals [ 1 , 3 ]. Therefore, a more feasible approach is the collection under field conditions of reproductive material (ovaries, fragments of ovarian tissue or immature cumulus–oocyte complexes, COCs) performed after ovariectomy, animal culling, or unexpected mouflon death [ 3 ].…”

“…However, the collection of in vivo matured oocytes is difficult in non-domesticated animals, because adequate and standardized ovarian stimulation protocols still do not exist to provide optimization of oocyte collections from preovulatory follicles in such animals [ 1 , 3 ]. Therefore, a more feasible approach is the collection under field conditions of reproductive material (ovaries, fragments of ovarian tissue or immature cumulus–oocyte complexes, COCs) performed after ovariectomy, animal culling, or unexpected mouflon death [ 3 ]. To achieve this, it is necessary to develop suitable short- and long-term storage strategies for the preservation of collected reproductive tissue during transfer from the collection sites to the specialized laboratories, which will ensure oocyte viability and functionality such as maintenance of meiotic arrest without loss of developmental competence, and will allow further successful laboratory procedures [ 8 , 9 , 10 ].…”

Different Methods for Seminal Plasma Removal and Sperm Selection on the Quality and Fertility of Collared Peccary Sperm

“…However, an effective method for seminal plasma (SP) removal and sperm selection has not been established for collared peccaries. While there are many studies on pigs and ruminants, the ART protocols used in domestic species cannot be applied to wild animals without prior evaluation [ 14 ].…”