Cryopreservation of sea cucumber Apostichopus japonicus (Selenka) sperm |
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| Authors: | Ming Yu Shao Zhi Feng Zhang Li Yu Jing Jie Hu Kyoung Ho Kang |
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| Institution: | Laboratory of Marine Genetics and Breeding, Ocean University of China, Qingdao, China; Department of Aquaculture, Chonnam National University, Yeosu, South Korea |
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| Abstract: | A simple and convenient method for the cryopreservation of sea cucumber Apostichopus japonicus (Selenka) sperm was tested in the present study. The highest motility (76.7±2.9%) of post‐thawing sperm was obtained in 15% dimethyl sulphoxide (DMSO) with a 1:9 dilution (semen volume to DMSO volume) when 0.5 mL semen–DMSO mixture was frozen at 6 cm above liquid N2 in a closed styrofoam box. After thawing, sperm cryopreserved in glycerol almost lost motility entirely. Although there was no significant difference in percentage of motile sperm between 15% and 20% DMSO, the duration of sperm motility of 15% DMSO group was longer than that of 20% DMSO group. The motility of post‐thawing sperm enhanced when the dilution ratio of semen increased from 1:1 to 1:9. Morphological changes such as the loss of mitochondria, swollen plasma membrane and broken or rolled‐up tails were observed in post‐thawing sperm using an eosin–nigrosin staining. The fertility of cryopreserved sperm was significantly lower than that of unfrozen sperm. The 10‐fold increase in sperm to egg ratio resulted in double fertility for cryopreserved sperm, and about 70% fertility relative to the control. |
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| Keywords: | sea cucumber Apostichopus japonicus (Selenka) sperm cryopreservation motility fertility |
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