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Updated: Jul 16, 2026
Fish Sperm Assessment Using Software and Cooling Devices
Published on: July 28, 2018
Flow cytometry and ultrastructure of cryopreserved red seabream (Pagrus major) sperm
1Center of Biotechnology R&D, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China.
Abstract:
The objectives were to assess motility, fertilizing capacity, structural integrity, and mitochondrial function in fresh versus frozen-thawed (15% DMSO was used as a cryoprotectant) sperm from red seabream (Pagrus major). Mean (+/-S.D.) rates of motility, fertilization and hatching of frozen-thawed sperm were 81.0+/-5.4, 92.8+/-1.9, and 91.8+/-5.2%, respectively; for fresh sperm, they were 87.5+/-7.7, 95.8+/-2.4, and 93.8+/-4.2%. Although motility was lower in frozen-thawed versus fresh sperm (P<0.05), there was no effect (P>0.05) of cryopreservation on fertilization or hatching. Based on scanning and transmission electron microscopy, 77.8+/-5.6% of fresh sperm had normal morphology, whereas for frozen-thawed sperm, 63.0+/-7.2% had normal morphology, 20.6+/-3.1% were slightly damaged (e.g. swelling or rupture of head, mid-piece and tail region as well as mitochondria), and 16.4+/-4.2% were severely damaged. Sperm were stained with propidium iodide and Rhodamine 123 to assess plasma membrane integrity and mitochondrial function, respectively, and examined with flow cytometry. For fresh sperm, 83.9% had an intact membrane and functional mitochondria, whereas for frozen-thawed sperm, 74.8% had an intact membrane and functional mitochondria, 12.7% had a damaged membrane, 9.9% had nonfunctional mitochondria, and 2.6% had both a damaged membrane and nonfunctional mitochondria. In conclusion, ultrastructure and flow cytometry were valuable for assessment of frozen-thawed sperm quality; cryopreservation damaged the sperm but fertilizing ability was not significantly decreased.
Insights
Cryopreservation of red seabream sperm using 15% DMSO reduced motility and structural integrity but maintained fertilizing capacity. Ultrastructure and flow cytometry effectively assessed sperm quality after cryopreservation.
Area of Science:
- Aquaculture and Reproductive Biology
- Fish Gamete Cryopreservation
- Sperm Quality Assessment
Background:
- Effective cryopreservation of fish sperm is crucial for aquaculture and genetic resource management.
- Red seabream (Pagrus major) sperm quality parameters require detailed evaluation post-cryopreservation.
Purpose of the Study:
- To compare motility, fertilizing capacity, structural integrity, and mitochondrial function of fresh versus cryopreserved red seabream sperm.
- To evaluate the efficacy of ultrastructural analysis and flow cytometry in assessing cryopreserved sperm quality.
Main Methods:
- Sperm samples were cryopreserved using 15% DMSO and compared to fresh samples.
- Motility, fertilization, and hatching rates were assessed.
- Scanning and transmission electron microscopy were used for morphological evaluation.
- Flow cytometry with propidium iodide and Rhodamine 123 staining assessed membrane integrity and mitochondrial function.
Main Results:
- Cryopreserved sperm showed reduced motility (81.0%) compared to fresh sperm (87.5%).
- Fertilization (92.8%) and hatching (91.8%) rates were not significantly affected by cryopreservation.
- Electron microscopy revealed decreased normal morphology in cryopreserved sperm (63.0%) versus fresh sperm (77.8%).
- Flow cytometry indicated lower membrane integrity (74.8%) and mitochondrial function (74.8%) in cryopreserved sperm.
Conclusions:
- Cryopreservation using 15% DMSO impacts red seabream sperm ultrastructure and function but preserves fertilizing ability.
- Ultrastructure and flow cytometry are valuable tools for assessing the quality of cryopreserved fish sperm.
- Cryopreservation protocols can be optimized to minimize damage while maintaining reproductive potential.
