Liquid semen storage in elephants (Elephas maximus and Loxodonta africana): species differences and storage optimization.
Artificial insemination plays a key role in the genetic management of elephants in zoos. Because freshly extended semen is typically used for artificial insemination in elephants, it has become imperative to optimize conditions for liquid storage and semen transport. The objectives of this study were to examine the interactions between different extenders and storage temperatures on sperm total motility, progressive motility, and acrosomal integrity in Asian (Elephas maximus) and African (Loxodonta africana) elephants. Ejaculates were collected by rectal massage, diluted using a split-sample technique in 5 semen extenders: TL-Hepes (HEP), Modena (MOD), Biladyl (BIL), TEST refrigeration medium (TES), and INRA96 (INR), maintained at 35°C, 22°C, or 4°C. At 0, 4, 6, 12, and 24 hours, aliquots were removed and assessed for sperm total motility, progressive motility, and acrosomal integrity. After 24 hours of storage, African elephant spermatozoa exhibited greater longevity and higher values in sperm quality parameters compared with those of Asian elephants. In both species, semen storage at 35°C resulted in a sharp decline in all sperm quality parameters after 4 hours of storage, whereas storage at 22°C and 4°C facilitated sperm survival. In Asian elephants, MOD and HEP were most detrimental, whereas BIL, TES, and INR maintained motility up to 12 hours when spermatozoa were cooled to 22°Cor4°C. In African elephants, there were no differences among extenders. All media maintained good sperm quality parameters at 22°C or 4°C. However, although MOD, BIL, and INR were most effective at lower temperatures, HEP and TES maintained sperm motility at all storage temperatures. This study demonstrated sperm sensitivity to components of various semen extenders and storage temperatures and offers recommendations for semen extender choices for liquid semen storage for both Asian and African elephants.
Center for Species Survival, Smithsonian Conservation Biology Institute, National Zoological Park, PO Box 37012, MRC-5502, Washington, DC 20008, USA. kisow@si.edu
Wendy K
WK
Kiso
Janine L
JL
Brown
Frank
F
Siewerdt
Dennis L
DL
Schmitt
Deborah
D
Olson
Elizabeth G
EG
Crichton
Budhan S
BS
Pukazhenthi
D000818:Animals; D001947:Breeding; D003080:Cold Temperature; D004606:Elephants; D007315:Insemination, Artificial / Q000662:veterinary*; D008297:Male; D019188:Organ Preservation Solutions / Q000494:pharmacology; D055101:Semen Analysis; D012662:Semen Preservation / Q000379:methods / Q000662:veterinary*; D013045:Species Specificity; D013081:Sperm Motility / Q000187:drug effects; D013094:Spermatozoa / Q000187:drug effects*; D013696:Temperature
D019188:Organ Preservation Solutions