Ejaculate Traits and Sperm Cryopreservation in the Endangered Baird's Tapir (Tapirus bairdii)

Abstract

There is little information on the reproductive biology of the male Baird's tapir (Tapirus bairdii). In this study, we characterized the ejaculate traits and evaluated the efficacy of 2 cryodiluents on sperm cryosurvival. Ejaculates were assessed for volume, pH, sperm motility, forward progression, osmolality, sperm concentration, sperm morphology, and acrosomal integrity. For cryopreservation, ejaculates with .50% total sperm motility were washed, and sperm pellets were resuspended in either Botu-Crio (CryoVital, Grandau, Germany) or INRA 96 containing 2% egg yolk and 2.5% each of methyl-and dimethylformamide (INRA 96), and they were cryopreserved over liquid nitrogen vapor. Thawed samples were incubated in vitro (25uC) and evaluated for percent total sperm motility, forward progression, and acrosomal integrity at hourly intervals for 4 hours. Spermic ejaculates were obtained from all males, and the mean seminal volume, sperm concentration per milliliter, percent sperm motility, progressive status, and percent morphologically normal cells were 20.4 6 4.3 mL, 101.2 6 24.0 6 10 6 /mL, 46.1% 6 5.0%, 2.9 6 0.1, and 6.9% 6 1.4%, respectively. There was a positive significant correlation between percent normal sperm and animal age (r 5 0.66; P , .004). Cryopreservation in either Botu-Crio or INRA 96 resulted in a decline (P , .05) in percent sperm motility and acrosomal integrity. Sperm forward progression remained unaffected immediately after thawing in INRA 96 but continued to decline over time. These results characterize, for the first time, the ejaculate traits of the tapir; demonstrate that tapir spermatozoa can be cryopreserved in diluents containing amides alone or in combination with glycerol; and provide fundamental information critical for development of assisted reproductive technologies for the Baird's tapir.

A review of the reproductive biology and breeding management of tapirs

“…Tapirs are tractable for many types of evaluations; however, there are no reports of semen collection using an artificial vagina or a dummy mount on unanesthetized individuals. Rather, ejaculates have been collected using electroejaculation (Table 1; Pukazhenthi et al 2011;Tipkantha et al 2011). Tapir ejaculates are milky-white to yellow in color and the volume ranges from 10 mL (Malayan) to 20 mL (Baird's).…”

Cryoprotectants & Cryopreservation of Equine Semen: A Review of Industry Cryoprotectants and the Effects of Cryopreservation on Equine Semen Membranes

“…A recent set of studies looked the activity of proteins, apoptosis and ROS, the proteins involved in the activation of apoptosis and the inductor protein involved in the activation of the mitochondrial pathway of apoptosis-have been found in fresh, frozen and thawed equine spermatozoa [54,55]. Together these studies support the idea that ejaculated spermatozoa can trigger activation the nuclear matrix potentially leading to cleavage of the entire sperm DNA into small fragments [56].…”

Tapiridae

“…After PZP use for 3 years, discontinuation will allow the female to regain fertility within 1 to 4 years, otherwise the continuation of PZP use every other year will render the female infertile in 5 to 7 years (Kimberly Frank, personal communication 47 however, the oldest tapir to give birth was a lowland tapir at 28 years of age. Spermatozoa collection (via electroejaculation) and cryopreservation in the Baird' s tapir has been demonstrated, 62 but not successful artificial insemination of tapirs. Spermatozoa collection (via electroejaculation) and cryopreservation in the Baird' s tapir has been demonstrated, 62 but not successful artificial insemination of tapirs.…”