Changes in sperm metabolome during carp sperm short-term storage in different media: In search of sperm quality and storage capability markers

Although short-term hypothermic storage of sperm is already widely used in artificial fish reproduction and is considered very useful for resolving multiple problems related to logistics and broodstock maintenance, this approach continues to be explored and developed. In the present study, targeted and global metabolome LC/MS analyses of common carp sperm during refrigerated storage in undiluted and diluted (in a buffer: NaCl 55 mmol/L, KCl 40 mmol/L, CaCl2 1 mmol/L, MgSO4 0.5 mmol/L, sucrose 87.5 mmol/L, Tris 10 mmol/L, pH 8, with or without 5% methanol) conditions were used to find potential metabolic markers of fish sperm quality and storage capability evaluated by sperm motility parameters. Sperm motility percentage started to decline from the 6th day of the storage, followed by a significant drop in ATP content in all studied groups, ADP content in undiluted sperm, and creatine phosphate content in sperm diluted by the methanol-containing buffer. Correlation analysis of whole metabolome and sperm motility data allowed us to suggest several potential markers belonging to different chemical classes (mainly nucleotides and their components). Considering motility preservation and changes in the content of proposed markers of sperm quality/storage ability, sperm storage in the methanol-containing buffer is more promising for further application. At the same time, further searches for reliable markers and their validation remain necessary.