Germany/Australia Index of Sperm Sex Sortability in Elephants and Rhinoceros

Abstract

Flow cytometric sexing of spermatozoa followed by application in artificial insemination or in vitro fertilization provides a unique opportunity to predetermine the sex of offspring and might enhance the conservation management of endangered species in captivity such as the elephant and rhinoceros. To obtain an indication of the sortability of spermatozoa from these species, the relative DNA differences between X and Y chromosome bearing spermatozoa (fresh, frozen thawed, epididymal) from three rhinoceros species [white (Ceratotherium simum), black (Diceros bicornis), Indian (Rhinoceros unicornis)] and both elephant species, the Asian and the African elephant (Elephas maximus, Loxodonta Africana), were determined through separation of spermatozoa into X and Y chromosome bearing populations, using a modified high speed flow cytometer. The head profile areas of spermatozoa from all five species were measured using light microscopy. By multiplying the relative DNA differences and the head profile areas, the sperm sorting indices were calculated to be 47, 48 and 51 for white, black and Indian rhinoceros respectively. The calculated sorting index for the Asian elephant was 66. In the African elephant, we determined the highest sorting index of 76. These results indicate the practicability of flow cytometric sex sorting of spermatozoa from the tested rhinoceros species and both elephant species. The lower sorting indices in rhinos indicate that sex sorting of spermatozoa from the rhinoceros will be more challenging than in elephants.

Feasibility of sex-sorting sperm from the white and the black rhinoceros (Ceratotherium simum, Diceros bicornis)

“…Considering the sperm-sorting index of the rhinoceros, general sortability sits in the range between the human and the stallion, consistent with the medium degree of resolution of X-and Ychromosome-bearing sperm populations [13]. However, sorting rates in the rhinoceros were low in the current study, with a maximum of 700 cells/sec compared with a mean of 3500 to 4500 cells/sec in the stallion [40], and only 30% (incubation at 37 8C) and 60% (incubation at 15 8C) of stained sperm samples were separable into Xand Y-chromosome-bearing sperm populations.…”

“…Whereas a theoretical sex-sorting index for rhinoceros spermatozoa has been established [13], the development of a sperm-sorting protocol for this species remains in its infancy. Spermatozoa of domestic species such as sheep and cattle have benefited from almost two decades of sex-sorting protocol optimization and diluent development in an effort to maximize protection against the myriad of stressors to which they are exposed [14,15].…”

The Effects of Hoechst 33342 Staining and the Male Sample Donor on the Sorting Efficiency of Canine Spermatozoa

“…Similarly, results regarding the influence of ejaculate quality on spermatozoa sortability have been described for elephants and rhinoceroses (Behr et al. ). Therefore, the results obtained herein can most likely be explained by the fact that two of the males included in the study had spermatozoa populations with higher FDA+ values, thereby determining a lower proportion of properly oriented spermatozoa and resulting in lower sorting rates, which compromised the efficiency of the sorting process.…”

Genome Banking for Vertebrates Wildlife Conservation

“…This technique has been tested in various wildlife species such as elephants, rhinoceros, dolphins and non-human primates O'Brien & Robeck, 2006;Behr et al, 2009a;Behr et al, 2009b;Hermes et al, 2009a). Sperm sorting machines, however, are very expensive, scarce and usually situated far away from where the sperm donor and recipient are located.…”