The reproduction of fish either in nature or controlled condition in aquaculture is a biological event that can be strongly related to the reproductive success. In addition, study of sperm physiology and control of sperm quality can be taken into account as an issue to obtain successful production in aquaculture systems. It is often admitted that sperm quality as one of the limiting factors of the fertilization success is affected by different factors, so some researches have paid attention to sperm quality. Motility is regarded as one of the most reliable parameters for predicting sperm quality, and to evaluate the sperm fertilizing potential, observation of decrease in sperm motility performance under in vivo or in vitro circumstances has been commonly used. These studies were conducted based on the hypothesis that aims to assess sperm motility characteristics and some physiological changes of spermatozoa (such as antioxidant enzymes activity and lipid composition) in out range of spawning temperature of each species. The investigation of the fish spermatozoa motility function and enzymatic response in relation to different in vitro temperatures was carried out using activation of spermatozoa from taxonomically distant fish species (common carp, rainbow trout and sterlet) at 4, 14, and 24° C. Special attention was taken to the sperm motility parameters (motility rate, duration and velocity), activity of catalase (CAT) and superoxide dismutase (SOD), and thiobarbituric acid-reactive substance (TBARS) content as marker of lipid peroxidation. As results of this study, duration of motility in three aforementioned species were shown to be longest at 4° C compared to 14 and 24° C. In rainbow trout and carp, velocity was significantly increased at 14 °C after 10 and 30 s of spermatozoa activation respectively. While, at 60 s post-activation, the velocity of spermatozoa in sterlet was highest at 24° C. Activity of CAT was in the highest level at 4° C in rainbow trout and sterlet, while no difference was observed in carp spermatozoa. As second aim of the present study, lipid composition was analyzed in motile or immotile carp spermatozoa at different in vitro temperatures (4, 14 and 24° C). The lower proportions of some fatty acids, 18:3 (n-3) and 22:6 (n-3) in motile spermatozoa were detected at 24° C. With respect to importance of phospholipids as source of energy in fish spermatozoa movement, the total phospholipid content was lesser in motile than in immotile spermatozoa at 24° C. At 24° C also, phosphatidylcholine and phosphatidylserine proportions were lesser in motile than immotile spermatozoa. On the basis of these data, lipid composition of carp motile spermatozoa is affected by temperature, with decrease in proportion of some lipid compositions at higher temperature, elevation of sperm curvilinear velocity and decreased duration of the period over which motility is sustained. The third study was designed to investigate role of different factors that might control the activation of spermatozoa motility, using physiological functions of osmolality, calcium (Ca2+) ion and particularly temperature in burbot. Spermatozoa motility was tested at temperatures of 4 and 30° C in following media: seminal fluid (SF), isotonic media (plus Ca2+ and without it) and hypotonic media (plus Ca2+ and without it). With regard to activation of burbot spermatozoa motility in seminal fluid at high temperature (30° C), it seems that no risk of semen handling will occur during hatchery routine practice. The results suggest that initiation of spermatozoa motility in burbot is mediated by the simultaneous involvement of Ca2+ and temperature. Thus, it might be concluded that burbot spermatozoa is more sensitive to high temperature for initiation of motility relative to other freshwater fish species.
| Identifer | oai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:386588 |
| Date | January 2018 |
| Creators | DADRAS ASYABAR, Hadiseh |
| Source Sets | Czech ETDs |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/doctoralThesis |
| Rights | info:eu-repo/semantics/restrictedAccess |
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