Motility activation and short-term storage of silver carp, Hypopthalmichthys molitrix, sperm

Abstract

Sperm activation and short-term storage have important implications in breeding programs. Although silver carp, Hypophthalmicthys molitrix, is an important aquaculture species in South Asia, information on sperm biology and storage is limited. The study aims to test the efficacy of NaCl solutions for activation and short-term storage of silver carp sperm. We found that the motility of silver carp sperm lasted for 45 sec after activation in distilled water. Sperm motility was higher within the first 10 sec of sperm activation, but sperm movement decreased with increasing activation time. When sperm was suspended a graded dilution of NaCl solutions (17 mM to 188 mM), sperm was immobilized at 154mM NaCl (287 mOsmol kg–1). The efficacy of sperm immobilizing solutions was validated during short-term storage at 4°C. A total of 7.1 ± 3.1% sperm was motile in 154 mM NaCl after 5 days of storage. Sperm motility lasted up to 2 days when sperm diluted in 103, 120, 171 and 188 mM NaCl solutions. The osmotic balance between seminal plasma and NaCl solution prepared at 154 mM prevented sperm activation and provided a suitable media for short-term storage. A 154 mM NaCl solution can be used for sperm collection and short-term storage of silver carp sperm.