Relationships between reproductive characteristics in male Vimba vimba L. and the effects of osmolality on sperm motility

In Vimba vimba, GSI, sperm volume, and spermatozoa concentration range from 3 4-7 4 %, 0 1-1 1 ml, and 13.3-34 8 x 10(9) spz ml(-1), respectively. Gonad mass (r = 0 90) and sperm volume (r = 0.35) significantly correlated with weight of males Significant correlation was also found between gonad mass and length of males (r = 0 85) Sperm motility (r = 0.99) and velocity (r = 098) significantly decreased after activation in Tris-HCl 20 mM, pH 8 5 Osmolality of the seminal plasma was 273 2 mOsmol kg(-1) Sperm motility and velocity were significantly affected by the osmolality of the activation medium (P < 0 01) Hyper-osmolality compared to seminal plasma osmolality totally suppressed the sperm activation. At 15 s post-activation, the sperm motility significantly decreased at 240 mOsmol kg(-1) in KCl or NaCl media The highest sperm motility and velocity (at 60 s post-activation) were observed at 200 mOsmol kg(-1) in NaCl, KCl, or sucrose media In all treatments, the tip of the flagellum of spermatozoa became curled into a loop shape after activation of sperm in distilled water containing 20 mM Tris-HCl, pH 8 5 that shortened the flagellum. (C) 2010 Elsevier Inc. All rights reserved