Sperm motility of kancra fish (Tor soro, Valenciennes 1842) after frozen: The effect of soybean milk as a natural cryoprotectant

Sperm cryopreservation is a way of managing and maintaining kancra fish (Tor soro) resources that increasingly threatened because of over-exploitation. The optimization of sperm cryopreservation is carried out using a natural cryoprotectant with lower toxicity than a chemical cryoprotectant. The purpose of this study was to analyze the effect of soybean milk as a natural cryoprotectant on sperm motility percentage of kancra fish after 48 hours preservation. The sperm was collected through stripping and was diluted into the soluble liquid of fish ringer + methanol 10% + soybean milk. Importantly, the concentration of soybean used were 0%, 5%, 10%, 15%, 20%, and 25%. The sample was equilibrated at the temperature of 5 °C for 10 minutes, frozen at the-10 °C for 48 hours and thawed at 40 °C for 1 minute. The motility percentage was analyzed using ANOVA and Tukey test. The result showed soybean milk had effects (p < 0.05) on the post-cryopreservation sperm motility. Additionally, 5% of soybean milk showed the highest sperm motility (84.37 ± 1.54%).