Standardization of European eel (Anguilla anguilla) sperm motility evaluation by CASA software
V. Gallego, P.C.F. Carneiro, I. Mazzeo, M.C. Vílchez, D.S. Peñaranda, C. Soler, L. Pérez and J.F. Asturiano
Abstract
The development of powerful computerized-assisted sperm analysis software (CASA) has made kinetic studies of spermatozoa possible. This system has been used and validated for several species, but some technical questions have emerged regarding fish sample evaluations (i.e., frame rates, sperm dilution, chamber models, time of analysis, magnification lens, etc). In the present study, we have evaluated the effects of different procedural and biological settings with the aim to measure sperm quality parameters on the European eel correctly.
The use of different chambers did not affect the sperm motility parameters. However, regarding lens magnification, 10x was the most accurate lens, showing the least variation in the acquired data. Similarly, the frame rate setting resulted in a dramatic effect in some sperm kinetic parameters, primarily in terms of curvilinear velocity, we therefore recommend using the camera's high frame rate setting available. Finally, the reduction in sperm motility over post-activation times suggests that sperm analysis should be performed within the first 60 s after activation of the European eel sperm. In conclusion, some protocol variables of sperm analysis by CASA software can affect the measurement of eel sperm quality parameters, and should be considered before directly comparing results obtained by different laboratories. Moreover, as marine fish species show relatively similar features to sperm kinetic parameters, these results could be considered in the evaluation of the motility of sperm from other fish species.
