Reproduction Abstracts

Few studies have evaluated sperm function and intracellular calcium levels when storage of semen for a long period of time. We have assessed sperm viability, morphology, motility and intracellular calcium levels in fish semen after a prolonged storage period. Semen samples from Atlantic salmon were preserved at 4 °C for 25 days and then evaluated for viability. The motile sperm was determined using the Image J-CASA program. To measure the calcium content, the sperm were loaded with a calcium fluorescent probe and evaluated by confocal microscopy and microfluorimetry. Reduced sperm viability was observed after 10 days of storage. Motility remained high for the first 3 days. A decrease in the calcium content of more than 50% was observed after 20 days of storage. When sperm were activated, calcium levels increased over 200% of relative fluorescence units (RFU); this increase was lost when the samples were stored for extended periods and only partially manifested in a zero calcium solution. Our results suggest that in vitro storage of Atlantic salmon sperm at 4 °C for a period of 3 days preserves viability and motility at levels similar to those of fresh sperm and also maintains intracellular calcium stores, which are critical for sperm function.