Assessment of motility,acrosomal integrity,and viability of giant panda (Ailuropoda melanoleuca) sperm following short‐term storage at 4°C

Short‐term cool storage of semen affords many of the same benefits as cryopreservation, without the extensive cryoinjury to sperm associated with freezing. Semen storage for artificial insemination (AI) is an integral part of giant panda captive breeding programs. AI functions to generate offspring from males that have never bred, are underrepresented, or are unable to breed with genetically desirable females due to geographic separation. In the present study, semen was collected by electroejaculation from six giant pandas and extended in four media (TEST with 0% or 5% glycerol, or SFS with 0% or 5% glycerol). Subsequently, initial motility (MOT), speed of progression (SOP), percent live (% L), and percent normal acrosome (% NAR) values were recorded. These parameters were assessed again at 4, 8, 24, and 48 hr of incubation at 4°C in each medium. Motility scores (MS) were calculated as MOT×SOP². The MS of each sample was also recorded after the addition of 20 mM caffeine. Results were expressed as a percent of the initial value (% I). Although all three parameters decreased over time, the MS decreased at a faster rate than either the % L or the % NAR. There were significant differences between individual pandas for each measured parameter, while only % IMS was significantly affected by medium (P=.0006). The addition of caffeine increased % IMS at all time periods and reduced the differences between media to nonsignificant levels. The addition of glycerol was not beneficial for short‐term semen storage. These data indicate that storage of giant panda semen at 4°C for up to 48 hr maintains sperm viability at a level sufficient for use in an AI program. Zoo Biol 22:529–544, 2003. © 2003 Wiley‐Liss, Inc.