Sperm physiology and quality in two marine teleosts: Anguilla anguilla & Takifugu niphobles
The conservation status of the species studied in this thesis (European eel and pufferfish) is currently frail, thus the main goal of this research was to develop, improve and apply several techniques and protocols with the aim of increasing the knowledge about their sperm biology, improving their r...
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| Other Authors: | , |
| Format: | Doctoral or Postdoctoral Thesis |
| Language: | English |
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Universitat Politècnica de València
2013
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| Online Access: | http://hdl.handle.net/10251/34625 https://doi.org/10.4995/Thesis/10251/34625 |
| Summary: | The conservation status of the species studied in this thesis (European eel and pufferfish) is currently frail, thus the main goal of this research was to develop, improve and apply several techniques and protocols with the aim of increasing the knowledge about their sperm biology, improving their reproductive performance and even helping future breeding in captivity. The reproductive performance of the males is often assessed through the sperm motion parameters analysed by the CASA system, so first we focused on how to standardize this technique in terms of procedural and biological settings. In this respect, we laid the foundations for applying a standard method to assess sperm quality in fish, making it possible for sperm studies to be compared both intra- and inter-laboratories using the proper CASA settings. Secondly, with the aim of improving the reproductive performance of European eel males, 3 thermal regimes (two of them variable: T10 and T15; and one of them constant: T20) and 3 hormonal treatments (hCG, hCGrec and PSMG) were assessed based on different sperm quality parameters. In the case of the thermal regimes, our results demonstrated that the onset and progression of spermiation are strongly influenced by water temperature, with treatment T20 showing the best results in all the sperm quality parameters. In the case of hormonal treatments, hCGrec produced the best results in all the sperm quality parameters, becoming an economically profitable/viable treatment and an effective alternative to the standard hCG treatment often used to induce spermiation in eel species. A preliminary physiological study regarding the changes to the main ions involved in the fish sperm activation process was carried out. Our results showed that intracellular concentrations of Ca2+ and K+ increased upon eel sperm activation, while pH gradually decreased over time, thus it is likely that all of them play an important role in the initiation of sperm motility in the European eel, as with other marine and freshwater ... |
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