Chemical and thermal effects on the viability and motility of spermatozoa from the turtle epididymis

The viability and motility of spermatozoa harvested from the epididymides o f turtles were estimated to elucidate properties that might enable them to be stored over long periods of time. Spermatozoa from the painted turtle, C hrysemys picta, were analysed and compared with spermatozoa from two other turtles, Trachemys scripta and Sternotherus odoratus using the Cellsoft ana lysis system for videotaped images. Spermatozoa from C. picta and T. script a, suspended in F-10 medium, showed low motility (3-6% motile) and motion v elocities, whereas the motility of spermatozoa from S. odoratus was higher (40% motile). Spermatozoa from C. picta and S, odoratus, but not T. scripta , had higher motilities and motion velocities when incubated at 2 degrees C before analyses. C. picta spermatozoa were unresponsive to calcium concent rations ranging from 10(-8) to 10(-1) mol l(-1), potassium concentrations r anging from 0.1 to 10 mmol l(-1), and to pH values in the range 5.9-8.4. Sp ermatozoa from C. picta were sensitive to hypoosmotic media, and showed red uced motility at 25% of normal osmolarity and no motility at 10% of normal osmolarity. Distorted cells and missing flagellae were noted at 50% of norm al osmolarity. C. picta spermatozoa were viable up to 40 days after harvest when incubated at 4 degrees C; during this time, both motility and motion velocity were increased in response to 0.5 mmol 3-isobutyl-1-methylxanthine l(-1). Spermatozoa from turtles have osmotic properties and resistance to changing chemical environments similar to spermatozoa from other vertebrate s that have internal fertilization, and appear to be stable over long perio ds of time compared with spermatozoa from other vertebrate species.