Effects of glycine and alanine on short-term storage and cryopreservation of striped bass (Morone saxatilis) spermatozoa

Three experiments were designed to examine the effects of the amino acids glycine and alanine on short-term storage and cryopreservation of striped bass spermatozoa. In the first experiment, the effect of glycine on post-equilibration,motility was evaluated. In the presence of 2.5 or 5.0% Me2SO, glycine treatments (25, 50, and 75 mM) yielded higher (P < 0,05),post-equilibration:motility at all equilibration times examined compared to the control. There was no difference (P > 0.05) among these three glycine treatments. In the second experiment, glycine,and alanine at concentrations of 25, 50, 75, or 100 mM were evaluated for post-thaw motility in the-presence of 2.5 or 5% Me2SO, When compared to the control, both the glycine and alanine treatments showed positive effects on post-thaw motility at all concentrations tested. The highest (P < 0.05) post-thaw motility was achieved with 50 mM glycine or 75 mM alanine using 5%,Me SO. No interaction (P > 0.05) between Me2SO and glycine or alanine was observed, indicating that the effect of glycine or alanine was independent of the concentrations of Me3SO. In the third experiment, glycine was evaluated for sperm motility, after short-term refrigerated storage and after cryopreservation of the same refrigerated semen. Sperm motility decreased after 24 h of refrigerated storage in 50 mM glycine treatment and the control, when compared to fresh sperm motility. However, 50 mM glycine treatment yielded higher(P < 0.01) sprm motility after both 24 and 48 h of storage as well as higher (P < 0.01) post-thaw motility when compared to the control. An average 30 +/- 2.9% and 16 +/- 2.4% post-thaw motility was achieved with the 50 mM glycine treatment after 24 and 48 h of refrigerated semen, respectively. (C) 2002 Elsevier Science (USA) All rights reserved.