The BioRescue project develops and pioneers advanced assisted reproduction technologies (aART) for conservation in the face of the imminent extinction of most rhino species and subspecies. In a new scientific analysis published in the journal “Reproduction”, the team evaluated 65 aART procedures comprising hormonal ovarian stimulation, ovum pick-up (OPU), in-vitro oocyte maturation and in-vitro fertilisation (IVF), embryo culture and cryopreservation conducted from 2015 to 2022. The evaluation showed that aART is safe for the donor females with no detrimental health effects, and successful in that it yielded 51 embryos. In fact, regular OPUs benefited the reproductive health of individual female rhinos by improving ovarian function, increasing follicle numbers and instigating the regression of pathological structures such as ovarian cysts.
As most rhino species and subspecies face impairment of natural reproduction and are threatened with extinction, new approaches to their conservation are required. A most promising new approach is the application of advanced assisted reproduction technologies (aART) such as ovum pick-up (OPU) – the retrieval of immature egg cells (oocytes) from ovaries – and in-vitro fertilisation (IVF). These technologies enable the creation of embryos in the lab that can later be transferred into surrogate mothers to carry gestation to term.
The application of aART is the only option to create offspring for the northern white rhinoceros, a subspecies with only two individuals known to be alive – two females that cannot become pregnant anymore to carry out their own embryos. The BioRescue project, led by the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW), develops and pioneers these technologies to enhance the breeding success of southern white rhinos in human care and to save the northern white rhino from extinction. The consortium takes animal safety and welfare, quality control and ethical risk assessment seriously and constantly evaluates its new scientific and veterinary procedures.
BioRescue has performed 65 aART procedures from 2015 to 2022 and now published an evaluation of these data in the scientific journal “Reproduction”. The team of authors around Prof Thomas Hildebrandt, Dr Frank Göritz, Dr Susanne Holtze (from the Leibniz-IZW), Dr Silvia Colleoni and Prof Cesare Galli (from Avantea srl.) analysed animal health and health effects of the procedures, age and seasonality, subspecies and origins of individuals, hormonal status and cyclicity as well as the effects of the stimulation protocol in relation to OPU and IVF success rates with 20 southern and two northern white rhino females. Their most important findings are:
BioRescue emphasises how important it is to put these newly developed technologies into practice without delay, whilst at the same time to learn from the results of these analyses and improve the procedures. The regular evaluation and ethical risk assessment will continue to be a pivotal element of the BioRescue mission on the edge of what is technologically possible in conservation. The successful generation of the embryos – in particular the northern white rhino embryos – underlines the importance of the technology and its potential to address one of the most pressing global problems of our time, the dramatic loss of biodiversity. This decline causes an incalculable disturbance of crucial ecosystem services while simultaneously fostering the emergence of novel pathogens, which undermines the basis of our very existence.
Hildebrandt TB, Holtze S, Colleoni S, Hermes R, Stejskal J, Lekolool Isaac, Ndeereh D, Omondi P, Kariuki, L. Mijele, D, Mutisya, S, Ngulu S, Diecke S, Hayashi K, Lazzari G, de Mori B, Biasetti P, Quaggio A, Galli C, Goeritz F (2023): In vitro fertilization (IVF) program in white rhinoceros. Reproduction 166/6, 383–399. DOI: 10.1530/REP-23-0087