Motility of sea urchin Paracentrotus lividus spermatozoa in the post-activation phase

Abstract

The characterization of sperm motility patterns, particularly post‐activation changes, is the first step in setting up species‐specific protocols involving gamete management and embryo production, for both aquaculture and laboratory research purposes. This study is aimed at the characterization of the sperm motility pattern of the purple sea urchin Paracentrotus lividus. Semen samples were individually diluted in artificial sea water for sperm motility activation. They were then incubated at 18°C for up to 24 hr. Motility was evaluated on dilution, and 1 hr, 3 hr and 24 hr after activation, by computerized analyser. The semen fertilization capacity was also evaluated. Under our experimental conditions (dilution 1:1,000 in artificial sea water plus 0.05% BSA, 18°C, in the dark), P. lividus semen remained viable for up to 24 hr, as the total motile sperm and the fertilization percentages did not change significantly during the incubation time. In contrast, the mean curvilinear velocity and the subpopulation of rapid sperm (those having a curvilinear velocity > 100 µm/s) slightly but significantly decreased after 3 hr, thereafter remaining unchanged for up to 24 hr after activation. In conclusion, our results show that diluted P. lividus semen can be used for a longer period than that of most fish species, with no need for motility inhibition procedures, supporting its wider use in laboratory research. In addition, the development of artificial fertilization protocols for aquaculture production is simplified by long‐lasting sperm motility.

Optimizing cryopreservation of sea cucumber (Apostichopus japonicus) sperm using a programmable freezer and computer-assisted sperm analysis

“…Because the sperm concentration of fresh semen was nearly double that of frozen semen (Table 2), the fresh sperm control group may have contained too much sperm, resulting in poor water quality and affecting embryo growth. This may explain the suboptimal fertilization and hatchability results in the fresh sperm treatment group (Adams et al, 2004;Fabbrocini and D'adamo, 2017). In future studies, we will optimize the sperm-egg ratio for fresh sperm and frozen sperm and determine how to prolong and maintain the quality of sea cucumber eggs.…”

Quality assessment of cryopreserved black-lip pearl oyster Pinctada margaritifera spermatozoa

“…Linhart et al (2005) (Figueroa et al 2016), 97 µm s -1 to 134 µm s -1 in Prochilodus lineatus (Viveiros and Leal 2016;Viveiros et al 2017), 57 µm s -1 in rainbow trout Oncorhynchus mykiss (Suquet et al 2012b) and µm s -1 in Siberian sturgeon Acipenser baerii spermatozoa (Sarosiek et al 2014). VSL of sea urchin spermatozoa was shown to be 170-240 µm sec -1 in Hemicentrotus pulcherrimus (Hiramoto and Baba 1978) and 150-200 µm sec -1 in Paracentrotus lividus (Fabbrocini and D'Adamo 2017). The factors contributing to the relatively low velocity observed for black-lip pearl oyster in our study may be twofold: firstly, the activation of oyster sperm motility and its duration is associated with internal concentration of cAMP (Demoy-Schneider et al 2014) under internal pH control (Boulais et al 2018).…”

Ocean Acidification, but Not Environmental Contaminants, Affects Fertilization Success and Sperm Motility in the Sea Urchin Paracentrotus lividus

“…In particular, compared to sperm activated at pH 8.1, in those exposed to acidification, a 6% reduction in the speed (equal to 20 µm/s) and 9% in the number of motile sperm were observed. The 0-5 time interval is important considering that in other species, under laboratory conditions, the majority of fertilization episodes happen within this time range [91], and despite optimal conditions, fertilization ability in P. lividus is maintained for longer [92]. In another marine invertebrate, the madrepora Acropora digitifera, Nakamura, and Morita [40] found that the percentage of motile spermatozoa decreased by 36.5% when comparing preindustrial levels of pCO 2 (300 ppm = pH 8.1) with those expected for the end of this century (1000 ppm = pH 7.7).…”