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  • Articles: DFG German National Licenses  (33)
  • Electronic Resource  (33)
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  • Articles: DFG German National Licenses  (33)
Material
  • Electronic Resource  (33)
Years
  • 1
    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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  • 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
    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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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Aquaculture research 29 (1998), S. 0 
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The cryopreservation of semen from the Northern pike, Esox lucius L., was investigated with a method that was originally developed for the Salmonidae. Because the amounts of semen obtained by stripping were insufficient, the suitability of testicular sperm was tested for cryopreservation. Frozen-thawed testicular sperm had fertilization rates similar to frozen-thawed semen obtained by stripping (74.2-84.7%), and at sperm to egg ratios of S= 4.5 × 105 spermatozoa per egg, the post-thaw fertilization rates were also similar to fresh, untreated semen controls. Out of all the fertilization solutions investigated, a 100-mm NaCl, 10-mm Tris (pH 9) solution resulted in the highest post-thaw fertilization rates. To facilitate the fertilization of large egg batches, 1.2-mL straws were used for cryopreservation with a similar efficiency to 0.5-mL straws.
    Type of Medium: Electronic Resource
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  • 4
    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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  • 5
    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.
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  • 6
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The present study describes a uniform method for cryopreservation of semen of Salmonidae (Oncorhynchus mykiss (Walbaum), Salmo trutta f. fario L., Salmo trutta f. lacustris L., Coregonus sp.). It presents a new type of extender and experiments demonstrating that warming of frozen/thawed semen to 20°C prior to fertilization significantly increases the fertilization rate. Freezing is performed in straws in the vapour of liquid nitrogen and for insemination a diluent technique is used. The consistency of the method was tested by repeating the experiments with different batches of semen and eggs. The following fertilization rates (% of control) were obtained: Oncorhynchus mykiss: 89.6 ± 16.0% (mean ± standard deviation, n= 25, n of control = 20, sperm/egg ratio of 1.6 ± 0.2 × 106 spermatozoa/ egg). Salmo trutta f. fario: 93.8 ± 6.4% (n= 12,9.9 ± 1.2 × 106spermatozoa/egg), Coregonus sp.: 92.8 ± 2.4% (n= 6, 0.5 × 106 spermatozoa/egg), Salmo trutta f. lacustris: 85.0 ± 8.4% (n= 12, 4.8 ± 1.4 × 106 spermatozoa/egg).
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Aquaculture research 27 (1996), S. 0 
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Using the cryopreservation method of Lahnsteiner, Berger, Weismann & Patzner (1995, Aquaculture Research26, 801-807) the influence of allowable variations of methodical parameters (storage of semen before cryopreservation, dilution ratios in the extender, equilibration in the extender, cooling rates, storage of deep-frozen semen in liquid nitrogen, storage of frozen/thawed semen, minimal sperm/egg ratio) was investigated under the aspect of routine utilization.Under optimized experimental conditions, fertilization rates were 90-100% of controls in Oncorhynchus mykiss (Walbaum), Salmo trutta L. f. lacustrisSalmo truttaL.f. fario and Salvelinus fontinalis (Mitchill). The following results were obtained: 1. Storage of untreated semen for more than 1 h before cryopreservation decreased the postthaw fertility. 2. Equilibration of semen up to 20 min in the extender did not affect the postthaw fertility. 3. Optimal dilution ratio of semen in the extender was threefold in Oncorhynchus mykiss and Salvelinus fontinalis. Lower dilution ratios decreased the postthaw fertility, higher dilution ratios did not affect the postthaw fertility. In Salmo trutta f. lacustris and Salmo trutta f. fario, which have a higher sperm density, optimal dilution ratio of semen in the extender was fivefold to sevenfold. 4. In Oncorhynchus mykiss, as in Salmo trutta f lacustris and Salmo trutta f. fario, the optimal freezing height was at 1.5 cm above the level of liquid nitrogen (-110 ± 2oC); in Salvelinus fontinalis it was 2.5 cm above the level of liquid nitrogen (-92 ± 2oC). Changes in the freezing height of 0.5 cm (about 10oC) resulted in a significant decrease of postthaw fertility. 5. Storage of deep-frozen semen for up to 370 days in liquid nitrogen had no influence on its postthaw fertilization rate. 6. Storage of frozen/thawed semen for 30 s before insemination significantly decreased its postthaw fertility. 7. Reliable minimal sperm:egg ratio to obtain fertilization rates of 90-100% of control was 3-5 X 105 spermatozoa egg-1.
    Type of Medium: Electronic Resource
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  • 8
    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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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Aquaculture research 28 (1997), S. 0 
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: For salmonid semen, the cryoprotective action of 10% methanol was compared with a 5% dimethyl sulphoxide (DMSO), 1% glycerol mixture, until now one of the most effective cryoprotectants. In Oncorhynchus mykiss (Walbaum), Salmo trutta L. f. fario, Salmo trutta L. f. lacustris and Salvelinus alpinus (L.), semen cryopreserved with both cryoprotectants yielded post-thaw fertilization rates of 90-100% of control with untreated semen at sperm-to-egg ratios of 1.8 × 106-2.4 × 106 spermatozoa per egg. However, at sperm-to-egg ratios of 0.9 × 106-1.2 × 106 spermatozoa per egg, semen cryopreserved with methanol had significantly higher fertilization rates than semen frozen with the DMSO/glycerol mixture. In other studies we obtained similar data for Coregonus sp., Salvelinus fontinalis (Mitchill), Thymallus thymallus (L.) and Hucho hucho (L.), proving that methanol is the most effective and generally applicable cryoprotectant for semen of the studied salmonid species.To facilitate the insemination of large egg batches we investigated the suitability of 1.2 ml and 5 ml straws for deep freezing of semen of Oncorhynchus mykiss, Salmo trutta f. fario, Salmo trutta f. lacustris and Salvelinus alpinus. With 1.2 ml straws the fertilization rates were similar to 0.5 ml straws when using lower freezing and higher thawing temperatures. The 5 ml straws resulted in a fertilization success of only about 40% of fresh semen control.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 0044-8486
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
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