Effect of L-Tryptophan on Sperm Quality of Tigris Scraper (Capoeta umbla) (Pisces: Cyprinidae) after Cryopreservation

BACKGROUND: The aromatic amino acid L-tryptophan is a versatile molecule and needed for the biosynthesis of proteins. Due to metabolic functions, it has been widely used in research and clinical trials. OBJECTIVE: The present study aimed to test the usefulness of L-tryptophan as an extender of Tigris scraper (Capoeta umbla) sperm during cryopreservation. MATERIALS AND METHODS: Semen samples were diluted with a ratio of 1:3 (sperm: extender) and base extenders were supplemented with L-tryptophan (0 mM, 0.5 mM, 1 mM, 2 mM and 4 mM). Sperm motility and duration of post-thawed samples were assessed after the cryopreservation process. RESULTS: Our results revealed that motility rate and duration of sperm increased when the cryomedia was supplemented with L-tryptophan. On the other hand, an increase in the concentration of L-tryptophan in the extender caused a significant decrease (p<0.05) in the motility rate of Tigris scraper (C. umbla) sperm. The ideal results were obtained at 1 mM L-tryptophan; however, no motile sperm were shown in any samples when a concentration of 2 mM was used. CONCLUSION: The current study shows the importance of conducting further studies related to long-term storage and reproduction management.