The Effects of Brown Sugar as a Natural Cryoprotectant on Tor Soro (Valenciennes 1842) Spermatozoa Quality

Abstract

The endemic kancra fish (Tor soro, Valenciennes 1842) is one of Indonesia's endemic species whose population is dwindling as a result of environmental deterioration and overfishing. Cryopreservation is a method for preserving T. soro genetic resources and overcoming population decline. The success of cryopreservation in maintaining the spermatozoa quality depends on cryoprotectants. One of the obstacles in cryopreservation is reducing toxicity, which may be overcome with the inclusion of natural cryoprotectants. This researchinvestigated the effects of brown sugar as a natural cryoprotectant in combination with 10% methanol on T. soro spermatozoa quality after 48 hours post-cryopreservation. The sperm was collected by stripping and was then diluted. The concentrations of brown sugar used in this study were 5%, 10%, 15%, 20%, and 25%. Storage was carried out in the freezer at -10 °C for 48 hours. One-way ANOVA and followed by Tukey test showed that various concentrations (5-20%) of brown sugar in combination with 10% methanol had a significant (P < 0.05) effect on post-cryopreserved spermatozoa motility, abnormality, and fertilization rate. The 15% brown sugar showed the highest percentage of motility (81.85 ± 1.11%), the highest percentage of fertilization ability (89.75 ± 1.71%), and the lowest percentage of abnormality (14.50 ± 1.73%) on T. soro post-cryopreserved spermatozoa. The overall results showed that the 15% brown sugar in combination with 10% methanol is the optimum concentration to maintain the spermatozoa quality of T. soro 48 hours post-cryopreservation.