Standardizing CASA analysis to accurately assess sea urchin Paracentrotus lividus sperm motility

Gacem, Sabrina ; Paredes, Estefanía ; Campos, Sara ; Sevilla, Francisco ; Soler, Carles ; Yániz, Jesús (Universidad de Zaragoza) ; Valverde, Anthony ; Silvestre, Miguel A.

Resumen: Although computer-assisted sperm analysis (CASA) system is widely applied for evaluating sperm motility in numerous vertebrate species, its application to sea urchin sperm remains comparatively underexplored, with limited data available on this invertebrate model. This study aimed to standardize the frame rate, type of counting chambers, extender, and dilution rate to use CASA system to evaluate sea urchin sperm motility. Semen samples were collected and diluted in artificial sea water alone (ASW) or supplemented with 0.3 % serum bovine albumin (ASW-BSA). The diluted semen was filled in 4 chamber types: drop displacement, Spermtrack® (SK) and R2D10 (R2); and capillary, Kubus® (KU); and SpermLide® (SL). Three dilutions ranging from low to high were studied. Sperm motility was evaluated using a commercial CASA system (AI Station v1.2; Sperm Analysis Technologies S.L., Buñol, Spain) that employs artificial intelligence for sperm recognition. Spermatozoa were immotile in drop displacement chambers when diluted in ASW; however total motility (TMOT) and progressivity (PMOT) did not differ significantly across chamber types when semen was diluted in ASW-BSA, independently of filling chamber type. KU chamber showed significantly higher velocity parameters compared to SL chamber when semen was diluted in ASW. However, these differences disappeared when in ASW-BSA medium, and straight line velocity (VSL) was even significantly higher in SL chamber. As dilution increased (i.e., lower cell concentration), sperm velocity increased, and linearity decreased. The optimal frame rate for accurate measurement of curvilinear velocity (VCL) was 510 fps, whereas lower frame rates (< 360 fps) were sufficient for evaluating VSL and average path velocity (VAP). In conclusion, to optimally assess sea urchin sperm motility using CASA requires a frame rate of 510 fps, dilution in ASW-BSA to concentrations below 75 × 106 sperm/mL and using capillary-filling chambers.

Idioma: Inglés

DOI: 10.1016/j.aquaculture.2025.743197

Año: 2026

Publicado en: AQUACULTURE 612 (2026), 743197 [9 pp.]
ISSN: 0044-8486

Tipo y forma: Artículo (Versión definitiva)

Área (Departamento): Área Producción Animal (Dpto. Produc.Animal Cienc.Ali.)