EFFECT OF INDIVIDUAL MALE VARIABILITY ON CRYOPRESERVATION OF NORTHERNPIKE, ESOX-LUCIUS L, SPERM

Milt from individual males of northern pike, Esox lucius L., was separ ately cryopreserved. Concentration of spermatozoa in fresh milt and sp ermatozoa motility before freezing and after thawing was evaluated. Ac tivity of aspartate aminotransferase (AspAT, E.C. 2.6.1.1.) and acid p hosphatase (AcP, E.C. 3.1.2.2.) in fresh and thawed sperm were determi ned. In comparison with the control group, egg fertilization with cryo preserved milt varied from 6.6% to 96.0%, depending on the donor male, Fertilization success with cryopreserved pooled milt was 71.8%. Freez ing and thawing procedure caused loss of proteins from injured spermat ozoa, resulting in significantly lower enzymatic activity in spermatoz oa, Intensity of enzyme leakage in thawed milt correlated negatively w ith fertilization success, Concentration of spermatozoa could be a pos sible accessory quality indication, useful when selecting sperm sample s appropriate for cryopreservation.