Effect of short-term storage on sperm quality and microbiome dynamics in blue catfish, Ictalurus furcatus

Supplying high-quality sperm from blue catfish, Ictalurus furcatus is a requirement for channel catfish, I. punctatus ♀ × blue catfish ♂ hybrid production. Storing sperm at low temperatures (4 °C) is a simple and inexpensive method to facilitate hatchery production. Our study objective was to determine the effect of short-term storage on sperm quality and microbiome dynamics in blue catfish. Mature males (n = 8) were selected, testes dissected, milt extracted and stored at 4 °C. Sperm swimming kinematics [motility, curvilinear velocity (VCL), average path velocity (VAP), straight-line velocity (VSL)], viability, and lipid peroxidation were quantified in conjunction with microbial community composition at 0, 24, 48, and 72 h post-storage. Sperm kinematics and viability declined during short-term storage, while malondialdehyde (MDA), an indicator of lipid peroxidation, significantly increased within the first 24 h. Time-specific microbiome changes were observed in sperm during short-term storage. Amplicon sequence variant (ASV) richness was significantly decreased at 72 h. Evenness and Shannon index of bacterial communities significantly decreased at 24 h and remained unchanged from 48 to 72 h. The ASVs belonging to potentially harmful bacterial species, Pseudomonas fluorescens and Aeromonas hydrophila, showed significantly higher abundances following 48 and 72 h. Our results demonstrate changes in sperm quality and microbial communities during short-term storage. These findings can be used to improve sperm storage techniques for hybrid catfish hatchery facilities.