Analysis of motility parameters from paddlefish and shovelnose sturgeon spermatozoa

Ninety to 100% of paddlefish Polyodon spathula were motile just after transfer into distilled water, with a velocity of 175 mu m s(-1), a flagellar beat frequency of 50 Hz and motility lasting 406 min. Similarly. 80-95% of shovelnose sturgeon Scaphirhynchus platorynchus spermatozoa were motile immediately when diluted in distilled water, with a velocity of 200 mu m s(-1), a flagellar beat frequency of 48 Hz and a period of motility of 2-3 min. In both species, after sperm dilution in a swimming solution composed of 20 mM Tris-HCl (pH 8.2) and 20 mM NaCl a majority of the samples showed 100% motility of spermatozoa with flagella beat-frequency of 50 Hz within the 5 s following activation and a higher velocity than in distilled water. In such a swimming medium, the time of motility was prolonged up to 9 min for paddlefish and 5 min for sturgeon and a lower proportion of sperm cells had damage such as blebs of the flagellar membrane or curling of the flagellar tip, compared with those in distilled water. The shape of the flagellar waves changed during the motility phase, mostly through a restriction at the part of the flagellum most proximal to the head. A rotational movement of whole cells was observed for spermatozoa of both species. There were significant differences in velocity of spermatozoa between swimming media and distilled water and between paddlefish and shovelnose sturgeon. (C) 2000 The Fisheries Society of the British Isles.