Spermatozoal capacitation of pink shrimp Farfantepenaeus paulensis

Abstract

The present study evaluated spermatozoal capacitation in Farfantepenaeus paulensis. This process has direct applications in aquaculture, and it consists of the ionic, biochemical and morphological changes during the period that the spermatophore is stored or adhered to the thelycum. These changes make the spermatozoa capable of fertilization. The morphological changes of spermatozoal capacitation have been previously investigated only in sicyoniids and open-thelycum penaeids. Thus, this study is the first morphological account of a closedthelycum penaeid. F. paulensis broodstock were captured offshore in southern Brazil, and spermatophores were collected from the terminal ampoule and from the thelycum of sexually mature females that had naturally copulated. The ultrastructure of the spermatozoal capacitation was investigated via transmission electron microscopy. Spermatozoa of F. paulensis show the following changes related to capacitation: (1) the chromatin became less condensed; (2) the acrosomal region became more electron-dense (3) the acrosomal cap became less concave; and (4) the subacrosomal region became much more electron-dense. These results demonstrate that the morphological changes in capacitated spermatozoa of F. paulensis are similar to those previously reported for open-thelycum penaeids, i.e., Litopenaeus species. Further studies on the capacitation process are required, especially to evaluate the interaction between biochemical and morphological changes. Such research could be useful for developing biotechnologies that will allow spermatozoal induction without storing the spermatophore in the thelycum and therefore allow in vitro larval production.

Three‐dimensional reconstruction of black tiger prawn (Penaeus monodon) spermatozoa using serial block‐face scanning electron microscopy

“…Our study showed the subacrosomal area of P. monodon spermatozoa in the spermatophore appeared less electron‐lucent and flocculent than the capacitated spermatozoa in the thelycum, as noted by Pongtippatee et al (). The subacrosomal change of P. monodon during capacitation also coincides with the similar observations of sperm capacitation in F. paulensis (Braga et al, ) and L. vannamei (Alfaro et al, ).…”

“…In addition, the electron density of the spike appeared to be lower in spermatophoral sperm of P. monodon, when it was compared to thelycal capacitated sperm (Pongtippatee et al, 2007). A similar pattern of morphological change has also been observed between noncapacitated and capacitated sperm in F. paulensis and L. occidentalis (Alfaro et al, 2007;Braga et al, 2014).…”

“…The cap‐like acrosomal vesicle covers almost half of the surface of the main sperm body in L. vannamei , L. stylirostris , L. occidentalis, F. chinensis , and P. kerathurus , but only about 1/3 in P. japonicus, F. paulensis , and P. monodon (Medina et al, ; Alfaro et al, ; Ge et al, ; Braga et al, ). The acrosomal vesicle was filled with flocculent components with a degree of electron‐density between that of the nuclear region and the electron‐dense spike; this region has also been reported to become more flocculent and electron‐lucent following capacitation (Alfaro et al, ; Pongtippatee et al, ; Braga et al, ).…”

“…A similar pattern of morphological change has also been observed between noncapacitated and capacitated sperm in F . paulensis and L. occidentalis (Alfaro et al, ; Braga et al, ).…”

Different aspects of reproduction strategies in crayfish: A review

“…The freshly ejaculated spermatophore is soft in decapods, but after mating it becomes hardened to protect the sperm mass (Malek and Bawab, 1971;Uma and Subramoniam, 1979). Post-mating spermatophore storage in crayfish and other decapods is accompanied by morphological and molecular changes that are necessary for the spermatozoon to develop fertilizing ability (Alfaro et al, 2003;Vanichviriyakit et al, 2004;Alfaro et al, 2007;López Greco and Lo Nostro, 2008;Aungsuchawan et al, 2011;Braga et al, 2014;Niksirat et al, 2014bNiksirat et al, , 2015b.…”