The effects of osmolality and accidental urine
contamination on spermatozoa velocity and motility were studied, combined
with an examination of the biological characteristics of stripped and
testicular sperm. Analysis of Northern pike sperm showed higher ionic
concentrations of Na+ (123 ± 9 mM), Cl- (127 ± 7 mM),
and K+ (35 ± 5 mM) in the seminal fluid of testicular sperm (TS),
than in that of stripped sperm (SS): Na+ (116 ± 9 mM), Cl−
(116 ± 7 mM) and K+ (25 ± 4 mM). Highest osmolality of
seminal fluid was observed in TS with a value of 358 ± 77 mOsmol
kg−1 compared with 273 ± 21 mOsmol kg−1 for SS and 68 ±
36 mOsmol kg−1 for urine. A significantly higher spermatozoa
concentration was observed in TS (34 ± 5 × 109 ml−1)
than in SS (23 ± 4 × 109 ml−1). Spermatozoa
concentration per male and per kg body weight was 22 ± 17 ×
109 for TS and 18 ± 2 × 109 for SS, respectively.
Both TS and SS showed significantly higher spermatozoa velocities and
motilities after dilution in urine than after dillusion in distilled water
during the activity period. In conclusion, the results obtained from the
present study provide information on northern pike sperm physiology that be
used to improve sperm management efficiency for this species.