Characterization of ultramicroscopic parameters of rusa deer (Rusa Timorensis) spermatozoa

Abstract

The rusa deer (Rusa timorensis) is a tropical species native to Asia, now found in Brazil, Malaysia, Thailand, New Caledonia, Australia, and Mauritius. Reproductive studies, including ultramicroscopic analyses, are essential for understanding species-specific sperm morphology and addressing potential reproductive issues that may impact conservation efforts. In this study, two adult male rusa deer were sedated using a dart containing ketamine (2 mg/kg) and xylazine (1 mg/kg). Semen was collected by electroejaculation, and a 60 μL aliquot of each sample was fixed in modified Karnovsky solution. The samples were sent for evaluation by scanning electron microscopy and transmission electron microscopy to observe the cell surface and internal structures. Head length and width, midpiece length, and tail length were measured at 8.68, 5.55, 13.89, and 36.69 µm, respectively. The internal structures observed included the mitochondrial sheath, outer dense fibers, axoneme, nucleus, acrosome, and plasma membrane. These findings demonstrate that the spermatozoa of the rusa deer share structural similarities with those of other mammals, such as pigs, humans, and guinea pigs, while also exhibiting specific morphometric characteristics that may contribute to the development of effective conservation and assisted reproduction strategies. These results not only underscore the importance of preserving this species but also provide a foundation for future research aimed at optimizing reproductive techniques and maintaining genetic diversity in cervids.