An analysis of threats, strategies, and opportunities for African rhinoceros conservation

The impact of induced pluripotent stem cells in animal conservation

It is widely acknowledged that we are currently facing a critical tipping point with regards to global extinction, with human activities driving us perilously close to the brink of a devastating sixth mass extinction. As a promising option for safeguarding endangered species, induced pluripotent stem cells (iPSCs) hold great potential to aid in the preservation of threatened animal populations. For endangered species, such as the northern white rhinoceros (Ceratotherium simum cottoni), supply of embryos is often limited. After the death of the last male in 2019, only two females remained in the world. IPSC technology offers novel approaches and techniques for obtaining pluripotent stem cells (PSCs) from rare and endangered animal species. Successful generation of iPSCs circumvents several bottlenecks that impede the development of PSCs, including the challenges associated with establishing embryonic stem cells, limited embryo sources and immune rejection following embryo transfer. To provide more opportunities and room for growth in our work on animal welfare, in this paper we will focus on the progress made with iPSC lines derived from endangered and extinct species, exploring their potential applications and limitations in animal welfare research.

High-Throughput Sequencing Reveals a Dynamic Bacterial Linkage between the Captive White Rhinoceros and Its Environment

Soil is an essential part of the animal habitat and has a large diversity of microbiota, while the animal body was colonized by a complex bacterial community; so far, the relationship between the animal host microbial community and the soil microbial ecosystem remains largely unknown. In this study, 15 white rhinoceros from three different captive grounds were selected and the bacterial community of the gut, skin, and environment of these rhinoceros were analyzed by 16S rRNA sequencing technology. Our results showed that Firmicutes and Bacteroidota were the predominant phyla in the gut microbiome, whereas skin and environment samples share similar microbiome profiles and are dominated by the phyla of Actinobacteriota, Chloroflexi, and Proteobacteria. Although the bacterial composition of the gut differs from that of the skin and environment, the Venn diagrams showed that there were 22 phyla and 186 genera shared by all the gut, skin, and environmental microbes in white rhinoceroses. Further cooccurrence network analysis indicated a bacterial linkage based on a complex interaction was established by the bacterial communities from the three different niches. In addition, beta diversity and bacterial composition analysis showed that both the captive ground and host ages induced shifts in the microbial composition of white rhinoceroses, which suggested that the bacterial linkage between the captive white rhinoceros and its environment is dynamic. Overall, our data contribute to a better understanding of the bacterial community of the captive white rhinoceros, especially for the relationship between the environment and animal bacterial communities. IMPORTANCE The white rhinoceros is one of the world's most endangered mammals. The microbial population plays a key role in animal health and welfare; however, studies regarding the microbial communities of the white rhinoceros are relatively limited. As the white rhinoceros has a common behavior of mud baths and thus is in direct contact with the environment, a relationship between the animal microbial community and the soil microbial ecosystem appears possible, but it remains unclear. Here, we described the characteristics and interaction of bacterial communities of the white rhinoceros in three different niches, including gut, skin, and environment. We also analyzed the effects of captive ground and age on the composition of the bacterial community. Our findings highlighted the relationship among the three niches and may have important implications for the conservation and management of this threatened species.

Comparison of Hematocrit and Biochemical Analytes among Two Point-of-Care Analyzers (EPOC and i-STAT Alinity v) and a Veterinary Diagnostic Laboratory in the African Savanna Elephant (Loxodonta africana) and the Southern White Rhinoceros (Ceratotherium simum simum)

This study compared hematocrit measured with the EPOC and i-STAT Alinity v point-of-care analyzers and manual measurement of packed cell volume in managed African savanna elephants (Loxodonta africana) and southern white rhinoceros (Ceratotherium simum simum). Biochemical analytes were also measured with the EPOC, i-STAT Alinity v, and a veterinary diagnostic laboratory in the same animals. Analytes assessed included blood urea nitrogen, chloride, creatinine, glucose, ionized calcium, potassium, and sodium. There were no differences for hematocrit values for African savanna elephants or southern white rhinoceros (p ≤ 0.05). In African savanna elephants, there were no differences between the EPOC and i-STAT Alinity v analyzers for any measured analytes except ionized calcium. When compared to a veterinary diagnostic laboratory, there were differences for a majority of the biochemical analytes measured on the EPOC and i-STAT Alinity v analyzers in African savanna elephants. In southern white rhinoceros, there were differences for a majority of analytes among all three analyzers. While differences existed among the portable analyzers and a veterinary diagnostic laboratory for biochemical analytes in both species, these numerically small differences are unlikely to be clinically significant. For routine health care of African savanna elephants and southern white rhinoceros, these point-of-care analyzers may be a useful alternative to commercial analyzers for the parameters evaluated.