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  • Articles: DFG German National Licenses  (10)
  • 2000-2004  (10)
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  • Articles: DFG German National Licenses  (10)
Material
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Aquaculture research 35 (2004), S. 0 
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The present study investigated motility, acrosome reaction, fertility and cryobiological parameters of the semen of the sterlet, Acipenser ruthenus L. Sperm motility persisted for about 4 min in water, and the main swimming type was the linear motion. Motility was prolonged at osmolalities of 12.5 mosmol kg−1 and in the presence of magnesium ions, while calcium had no effect. Also a pH in the range of 7.0–9.0 had no effect on ` motility. At osmolalities of 25–50 mosmol kg−1 the sperm motility was partly inhibited, at osmolalities of 100 mosmol kg−1, completely and irreversibly. In 50 mosmol kg−1 solutions with 2.5–5 mM L−1 KCl the motility inhibition was total, but reversible. The acrosome reaction was not induced by one of the described solutions, but the percentage of spermatozoa with reacted acrosomes was low (〈20%) and highly variable in all experiments. The optimal extender base for cryopreservation was a solution consisting of 50 mM L−1 NaCl, 5 mM L−1 KCl, 10 mM L−1 Tris (pH 8.5). From the tested cryoprotectants only dimethylsulphoxide (DMSO) and methanol provided sufficient cryoprotection. After freezing and thawing, the motility rates and swimming velocities were higher with DMSO than with methanol. However, the fertility was very significantly reduced with DMSO (10.3±0.5%) while with methanol fertilization rates in a similar range (32.7±4.4%) as with fresh semen (33.90±0.8%) could be obtained. Optimal freezing conditions for sterlet semen were in the vapour of liquid nitrogen 3–5 cm (−95°C to −85°C) above its surface, the optimal thawing conditions at 25°C for 30 s. The acrosome reaction was not induced by these cryopreservation protocols.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Aquaculture research 31 (2000), S. 0 
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Aquaculture research 31 (2000), S. 0 
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The present paper summarizes the data on a semen cryopreservation method for the Salmonidae (Oncorhynchus mykiss, Salmo trutta f. lacustris, Salvelinus fontinalis, Salvelinus alpinus, Salmo trutta f. fario, Hucho hucho, Coregonus lavaretus, Thymallus thymallus) and for the Northern pike (Esox lucius) published during recent years. It describes (1) methods used for the determination of sperm viability; (2) the protective efficiency of substances specifically for protection of internal and external parts of cells and the process of extender development; (3) the freezing, thawing and fertilization conditions; and (4) the tolerable deviations from the freezing protocol for more easy application. Finally, biomarkers are reported that predict the suitability of semen for cryopreservation and the quality of frozen–thawed semen.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Aquaculture research 35 (2004), S. 0 
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Semen of the African catfish, Clarias gariepinus (Burchell, 1822), was investigated with respect to its cellular composition, sperm cell density, maturation grade, motility and fertility. Storage conditions were tested, whereby sperm viability was assessed by measurement of the motility after activation and by fertility tests. Testicular semen differed in its composition, i.e. the sperm density and numbers of spermatids, according to the maturity grade of the testis. Two semen types could be distinguished: semen type I was characterized by high sperm densities and low numbers of spermatids and semen type II had lower sperm densities and higher numbers of spermatids. Two semen types did not differ in motility and fertility (when adjusted for differences in sperm density). During storage, the sperm viability was influenced by the sodium concentration of the storage medium, temperature, membrane stabilizers as bovine serum albumen (BSA) or hen egg yolk, antibiotics and oxygen. Semen viability was maintained best when it was diluted at a ratio of 1:5 in storage solution (150 mmol L−1 NaCl, 2.5 mmol L−1 KCl, 1 mmol L−1 CaCl2, 1 mmol L−1 MgSO4, 20 mmol L−1 Tris (pH 8.5) and 0.5% BSA or 0.5% hen egg yolk) and stored at 4 °C. Oxygen gassing and addition of antibiotics (1 mg mL−1 gentamycine sulphate) to the storage solution affected the two semen types in different ways. Antibiotics had no effect on type I semen, but had a positive effect on type II semen. Oxygen gassing had a positive effect on type I semen but a negative effect on type II semen.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK; Malden, USA : Blackwell Science Ltd
    Journal of fish biology 65 (2004), S. 0 
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Using four different sperm types from brown trout Salmo trutta fario(Salmonidae), chub Leuciscus cephalus(Cyprinidae), burbot Lota lota(Gadidae) and African catfish Clarias gariepinus(Clariidae) the effect of inorganic (cadmium, copper, mercury, lead, zinc and nitrite) and organic (cyclohexane and 2,4-dichlorophenol) environmental pollutants on sperm motility was investigated. Spermatozoa were activated in double distilled water containing the different test substances and the motility was compared to controls of similar pH. From the investigated motility variables the sperm motility rate and swimming velocity reacted most to the environmental pollutants whereby the changes depended on the species and on the test substance. African catfish spermatozoa were the most resistant, chub and burbot spermatozoa showed medium resistance and brown trout spermatozoa were the most sensitive to the pollutants. With exception of 2,4-dichlorophenol and zinc the effective concentrations of the tested pollutants exceeded the recommendation for surface waters 100–10·000-fold and were in a range lethal for the fish themselves. Therefore, it was concluded that fish sperm motility is not a suitable marker for risk assessment of environmental pollutants.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 61 (2002), S. 0 
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Androgenetic development of salmonid embryos was induced in recipient oocytes from the same or other species (intra- or interspecies androgenesis). Parameters for induced androgenesis were investigated in brown trout Salmo trutta and brook trout Salvelinus fontinalis. Reciprocal androgenetic and control crosses were conducted among fishes from three genera: Oncorhynchus (rainbow trout, O. mykiss), Salmo (brown trout) and Salvelinus (brook trout), and within two genera: Salmo (brown trout and Atlantic salmon, S. salar) and Salvelinus (brook trout and Arctic charr, S. alpinus). Live hatched androgenetic progenies were obtained in all intraspecies variants, where oocytes and sperm originated from the same species. Interspecies androgenesis resulted in no viable larvae, despite the fact that most hybrid controls and intraspecies androgenetic individuals were viable. When recipient oocytes originated from other genera (interspecific intergeneric androgenesis), embryonic development ceased in early developmental stages, except for haploid controls of brook trout produced in eggs of brown trout. Survival of embryos to the eyed-egg stage was relatively high in the intrageneric androgenesis experiment. Nevertheless, none of these embryos survived to hatching. Some of the presumed Atlantic salmon individuals developing in brown trout eggs contained maternal DNA, questioning the accuracy of enucleation using irradiation. The inability to induce interspecific androgenesis among the examined salmonid species may have been the result of substantial kariotypical and developmental differences between spermatozoal donors and oocyte recipients, causing an incompatibility between maternal cytoplasmic regulatory factors and the paternal nuclear genome.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 60 (2002), S. 0 
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The spermatozoon of the African catfish Clarias gariepinus is a simple organized aquasperm although it reveals very unique characteristics: the cytoplasmic channel is lacking, the mitochondria form a complex structure and the arrangement of the centriolar complex is species specific. Semen has high initial motility rates (c. 70–90%) and swimming velocities (c. 120–140 μm s−1), the main swimming type is linear. Motility duration in water is 30 s and is prolonged only to 40 s in NaCl solutions or more complex bu ered motility activating saline solutions. A pH between 7.0 and 9.0 has no e ect on the sperm motility parameters. Motility is completely and reversibly suppressed in electrolyte and non-electrolyte solutions with an osmolality of 200 mosmol kg−1. During immotile storage the sperm viability is influenced by the osmolality and the potassium levels of the storage medium, by the temperature and by the dilution. At optimal conditions (bu ered sperm motility inhibiting saline solution: 150 mmol l−1 NaCl, 2.5 mmol l−1 KCl, 1 mmol l−1 CaCl2, 1 mmol l−1 MgSO4, 20 mmol l−1 Tris solution, pH 8.5; dilution rate 1: 5; storage temperature, 4°C) sperm viability persists for 〉7 days. High viscosity of the pure seminal vesicle secretion completely inhibits the sperm motility. When the seminal vesicle secretion is diluted in water the viscosity decreases and the motility suppressing e ect is neutralized. When semen is mixed with seminal vesicle secretion the sperm viability decreases to zero within 10 min.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of fish biology 62 (2003), S. 0 
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The gametes of the cardinal fish Apogon imberbis had the following characteristic: the semen contained both biflagellate ( c. 20% in the investigated samples) and monoflagellate ( c. 80%) spermatozoa. The spermatozoa were acrosomless, had an ovoid head, and a cylindrical midpiece. The midpiece contained a high number of mitochondria (seven–10). The distal centriole was fastened to the nucleus via electron-dense material. The proximal centriole was completely reduced. The eggs were spherical, had a smooth surface and one micropyle consisting of the micropylar channel, the vestibulum and a ring-like convulsion bordering the vestibulum. The zona radiata was formed out of four layers which could be distinguished by their fine structural and histochemical features. It was only c. 1·5 µm thick and therefore much thinner than in other marine teleosts. The internal organization of the eggs (homogenous protein yolk containing cortical granules and lipid droplets) as well as the qualitative and quantitative biochemical composition of proteins, lipids and carbohydrates was similar to that of the pelagic eggs of other marine species.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Berlin Germany : Blackwell Science Ltd.
    Journal of applied ichthyology 18 (2002), S. 0 
    ISSN: 1439-0426
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The relative weight of fish eggs increases during water hardening; this increase is significantly correlated with egg viability in rainbow trout when determined after 120 min, providing an assay test for egg quality control. In the present paper, additional investigations on egg water uptake at different time intervals during the hardening process were performed to correlate these with egg viability and to improve the sensitivity of the assay while also reducing the handling time. Eggs of high quality had a significantly higher rate of water uptake than low quality eggs, with the highest rate occurring during the first 30 min of hardening. Bivariate correlation coefficients and regression models revealed that in addition to egg weight increase after 120 min of water hardening, the increases in weight after 30 min and 60 min were also significantly related to egg viability (P 〈 0.001). In contrast, the initial weight increase after 15 min of hardening revealed a lower correlation (P 〈 0.006) with egg viability. These results indicate the initial velocity of water uptake is not a valid criterion, but that the total amount of water imbibed during hardening provides the most reliable information on egg quality. The present study confirms the previously reported sensitivity of the assay, and also shows that a shorter incubation time of 30 min is adequate for reliable results. The shorter handling time is an improvement for testing large numbers of egg batches.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Fish physiology and biochemistry 23 (2000), S. 107-118 
    ISSN: 1573-5168
    Keywords: egg ; Oncorhynchus mykiss ; ovarian fluid ; overripening ; rainbow trout
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In rainbow trout (Oncorhynchus mykiss) freshly ovulated eggs and over-ripened eggs which had been retained in the coelomic cavity for 7, 14 and 21 days were investigated in aspects of morphology, physiology and biochemistry. Egg viability was significantly reduced from 85.9±16.4% in freshly ovulated eggs to 25.1±21.9% in over-ripened eggs which had been retained in the coelomic cavity for 21 days. Further during over-ripening in the ovarian fluid the pH significantly decreased, while the levels of proteins, of esterified and non esterified fatty acids and the activities of aspartate aminotransferase and acid phosphatase significantly increased. Also egg parameters changed: the wet weight of the unhardened eggs increased, the weight increase during hardening and the levels of esterified and of non esterified fatty acids significantly decreased. In freshly ovulated eggs the yolk consisted of a homogenous mass and the perivitelline space was small, but in over-ripened eggs the yolk was non homogenous with numerous vesicular inclusions and the perivitelline space was enlarged. When freshly ovulated eggs were incubated in water the cortical reaction was detectable within 5 min, in over-ripened eggs hardly no extrusion of cortical vesicles was visible and the width of the perivitelline space was very irregular. For the investigated freshly ovulated and over-ripened samples the egg viability significantly correlated with ovarian fluid parameters (pH, protein, non esterified fatty acids, esterified fatty acids, aspartate aminotransferase, acid phosphatase) and egg parameters (weight increase during hardening, weight of the hardened eggs).
    Type of Medium: Electronic Resource
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