Ampika Thongphakdee

Assisted reproductive technologies (ART) provide opportunities for conservation of endangered wildlife, but their use is still limited by species-specific reproductive physiology, variable gamete competence, cryoinjury, and lack of validation of new approaches. This narrative review covers ART, biobanking, somatic cell nuclear transfer (SCNT), induced pluripotent stem cells (iPSCs), in vitro gametogenesis (IVG) and conservation genomics in vertebrates. Key molecular barriers include oxidative and mitochondrial damage, aberrant embryonic genome activation, incomplete epigenetic reprogramming, nuclear-mitochondrial incompatibility and defective germ-cell differentiation. Technological readiness is used to evaluate the evidence and separate demonstrated reproductive outcomes from experimental proof of concept, and indirect findings from domestic or laboratory models. Semen cryopreservation and artificial insemination are established in selected species, while embryo-based interventions remain species-dependent and stem-cell-derived reproductive approaches require functional validation. We propose an integrated decision framework linking reproductive diagnosis, biobanking, genomic donor selection, technological readiness, animal welfare, and resource allocation with reproductive and population-level outcomes. Importantly, laboratory milestones alone cannot demonstrate conservation success without sustained genetic contribution across multiple subsequent generations. Successful translation depends on species-specific protocols, standardized endpoints, and evidence of genetically valuable offspring survival, reproduction, and contribution to long-term population viability.

Induced pluripotent stem cell (iPSC)-based in vitro gametogenesis (IVG) provides a possible route from cryobanked or collected somatic cells to functional gametes and, ultimately, offspring. However, full offspring-level proof of concept has so far been largely demonstrated in mice. In livestock, non-human primates and threatened species, iPSC-based IVG remains prospective, with most studies restricted to derivation of pluripotent cells, specification of primordial germ cell-like cells or partial germline development. If successfully developed, this technology could increase the representation of founders in threatened populations, recover genetic contributions from non-reproductive or deceased animals, and potentially support shorter generation intervals and targeted trait introgression in livestock. Here, we critically evaluate the biological and translational requirements for iPSC-based IVG. These include reprogramming quality, germline specification, epigenetic reprogramming, imprint erasure, meiosis, sex-specific gonadal niches, gamete maturation, embryo development and long-term offspring assessment. iPSC-based IVG should be integrated with cryobanking, population-genetic management, assisted reproduction, animal welfare and habitat recovery for conservation. In livestock, applications include management of genetic diversity, recovery of rare breeds, shorter generation intervals, and targeted trait introgression. The current evidence shows that it is research and protocol development, not commercial deployment. A stage-gated validation framework and a cross-species roadmap are proposed. Reproductive application should require evidence from genomics, epigenomics, cytology, function, development, and multiple generations.

The hippopotamus, commonly known as the hippo, is classified into two extant species: the common hippopotamus (Hippopotamus amphibius) and the pygmy hippopotamus (Choeropsis liberiensis). Pygmy hippos are fascinating creatures native to the forests and swamps of West Africa. Their survival is increasingly threatened by habitat loss resulting from agricultural expansion and urban development. As the population declines, zoological institutions play a crucial role in conservation by acting as genetic reservoirs and promoting public awareness of wildlife and environmental protection. “Moo Deng”, a pygmy hippo, whose name in Thai has gained international recognition, represents a notable success story of the Zoological Park Organization of Thailand’s conservation breeding program. This initiative aims to sustain the population of this endangered species. This article focuses on the biology, reproduction, and conservation of the pygmy hippo under human care. It explores the reproductive biology of the species, with a detailed look into Moo Deng’s life. Topics addressed include mating behavior, gestation, and parental and veterinary managements.

Cat Induced Pluripotent Stem Cells have been previously established using viral vectors integrating into the host genome to deliver reprogramming factors. To aid wild felid conservation using stem cell technology, in this study we utilized non-integrative Venezuelan Equine Encephalitis-based self-replicating RNA (srRNA) to carry the reprogramming factors. This approach induced cat somatic cells towards pluripotency without genomic modification, supporting the future use of srRNA in wild felid cells. The srRNA expressing human OCT4, SOX2, KLF4, CMYC, and GLIS1 (OSKMG) could induce the formation of cat iPSC colonies after 4 rounds of transfections. Different species-specific Leukemia Inhibitory Factor (LIF) could capture the induced cells maintaining pluripotency. A combination of feline and human LIFs, could maintain cat iPSC in a pluripotent state, that was different from those seen in human or mouse embryonic stem cells (ESCs). The cat iPSCs also exhibited spontaneous differentiation towards ectodermal, mesodermal, and endodermal lineages upon the removal of LIF from the culture medium. This work demonstrates the utility of srRNA containing human reprogramming factors to induce reprogramming in somatic cat cells in the presence of serum and LIF. Further investigations into the maintenance of cat iPSC will aid in inducing wild felid stem cells for long-term conservation.