Nuestro último artículo, aceptado en Theriogenology

Sperm motility parameters and spermatozoa morphometric characterization in marine species: a study of swimmer and sessile species

V. Gallego, L. Pérez, J.F. Asturiano and M. Yoshida

Abstract

The biodiversity of marine ecosystems is diverse and a high number of species coexist side by side. However, despite the fact that most of these species share a common fertilization strategy, a high variability in terms of the size, shape and motion of spermatozoa can be found. In this study, we have analysed both the sperm motion parameters and the spermatozoa morphometric features of two swimmer (pufferfish and European eel) and two sessile (sea urchin and ascidian) marine species.

The most important difference in the sperm motion parameters was registered in the swimming-time period. The sperm of the sessile species displayed notably higher values than those of the swimmer species. In addition, the sperm motilities and velocities of the swimmer species decreased sharply from the moment the sperm was activated, whereas the sessile species were able to maintain their initial values for a long time. These results are linked directly to the species-specific lifestyles. While sessile organisms, who demonstrate limited or no movement, need to have sperm with a capacity to swim for long distances in order to find the oocytes, swimmer organisms can move towards the female and release gametes near it, and therefore the spermatozoa does not need to  be able to swim for such a long time period.

On the other hand, sperm morphology is related to sperm motion parameters and in this study an in depth morphometric analysis by CASA software of ascidian, sea urchin and pufferfish spermatozoa has been carried out for the first time. A huge variability in shapes, sizes, and structures were found using electron microscopy in the studied species.