Cellular damage in spermatozoa from wild-capturedSolea senegalensisas detected by two different assays: comet analysis and Annexin V-Fluorescein staining

Improved sperm analysis in Senegalese sole (Solea senegalensis) males could provide some clues to reproduction constraints that have been restricting the introduction of this species in the aquaculture market. More accurate methodologies such as sperm membrane and DNA stability surveying might help overcome this problem. In this study spermatozoon cells were analysed in thirteen individual samples using single-cell gel electrophoresis to assess DNA fragmentation, and the Annexin V-FITC assay to assess cell apoptosis. Both techniques revealed significant individual differences. Sperm samples showed 10–50% DNA fragmentation (DNAt). All the males presented apoptotic spermatozoa ranging from 1.4% to 20%. Annexin V proved to be an appropriate tool in differentiating between subpopulations of necrotic, apoptotic and viable cells in this species. The comet assay revealed that some individuals had a high percentage of cells with high DNA fragmentation. The Annexin V assay also revealed a high percentage of necrotic cells in some individuals. These two factors, despite not being correlated, could explain the low sperm quality of Senegalese sole males in captivity.