A method was developed for cryopreserving sperm of the sea urchin, Evechinus chloroticus. Sperm fertilisation ability, mitochondrial function and membrane integrity were assessed before and after cryopreservation. Highest post-thaw fertilisation ability was achieved with lower concentrations (2.5%-7.5%) of dimethyl sulphoxide (DMSO). In contrast, post-thaw mitochondrial function and membrane integrity were higher for sperm frozen in intermediate and high DMSO concentrations (5%-15%). Surprisingly, some sperm frozen in seawater only, without DMSO, were able to survive post-thawing, although the fertilisation ability (106 sperm/ml; ~50% fertilisation), mitochondrial function and membrane integrity of these sperm were notably lower than of sperm frozen with DMSO (106 sperm/ml; 2.5%-7.5% DMSO; >85% fertilisation) at the concentrations tested. Amongst sperm from individual males, fertilisation ability varied before and after cryopreservation for both males frozen with and without cryoprotectant. Specific differences among males also varied. Sperm mitochondrial function and membrane integrity was similar among males before cryopreservation but differed considerably after cryopreservation. Cryopreserved sperm were able to fertilise eggs and develop to pluteus stage larvae. This study has practical applications and will provide benefits such as reduced broodstock conditioning costs, control of parental input and opportunities for hybridisation studies.
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Document Type: Regular Paper
Publication date: 01 June 2004
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CryoLetters is a bimonthly international journal for low temperature sciences, including cryobiology, cryopreservation or vitrification of cells and tissues, chemical and physical aspects of freezing and drying, and studies involving ecology of cold environments, and cold adaptation
The journal publishes original research reports, authoritative reviews, technical developments and commissioned book reviews of studies of the effects produced by low temperatures on a wide variety of scientific and technical processes, or those involving low temperature techniques in the investigation of physical, chemical, biological and ecological problems.