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1.
Using the cryopreservation method of Lahnsteiner, Berger, Weismann & Patzner (1995, Aquaculture Research 26 , 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.  相似文献   

2.
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.  相似文献   

3.
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).  相似文献   

4.
基于线粒体COI基因序列的亚东鲑DNA条形码研究   总被引：7，自引：0，他引：7  
以亚东鲑为研究对象,测定分析了线粒体COI基因638bp碱基序列,探讨了该基因作为DNA条形码在鲑科三种鱼类(亚东鲑、大西洋鲑和红点鲑)鉴定方面的可行性和有效性。亚东鲑33个个体共享1种单倍型。利用Kimura-2模型分析得到亚东鲑与大西洋鲑遗传距离最小,为0.079;大西洋鲑与红点鲑遗传距离最大,为0.141;亚东鲑与红点鲑遗传距离为0.120。基于COI基因片段序列构建的NJ显示,亚东鲑和大西洋鲑首先聚到一起,然后再与红点鲑相聚。结果表明COI基因片段作为三种鱼类DNA条形码进行分类鉴定具有一定可行性。  相似文献   

5.
The effects of extender composition and freezing rate on motility and fertility of frozen‐thawed Arctic char, Salvelinus alpinus, spermatozoa were investigated. Three freezing rates, two semen diluents and three cryoprotectants were tested. Semen frozen in 0.3 mol L?1 glucose diluent with 10% methanol as a cryoprotectant or in a diluent described by Lahnsteiner with 10%N,N‐dimethylacetamide (DMA) resulted in the highest sperm motility. Fertility was the highest for semen frozen in a glucose–methanol extender but was not significantly different than that for semen frozen in Lahnsteiner's diluent with 10% DMA. Dimethyl sulphoxide (DMSO) at 10% was a relatively ineffective cryoprotectant with either semen diluent. Semen frozen at 6 cm above the surface of liquid nitrogen resulted in a higher post‐thaw sperm motility and fertility than semen frozen at 5 cm. The addition of 7% fresh egg yolk to glucose diluent containing methanol or DMSO did not improve the fertility of frozen‐thawed spermatozoa. However, the addition of 7% fresh egg yolk to glucose–DMA extender significantly improved the fertilization percentages of frozen‐thawed spermatozoa. In conclusion, dilution of semen 1:3 in 0.3 mol L?1 glucose with 10% methanol and freezing 6 cm above the surface of liquid nitrogen (freezing rate of 40±8°C min?1, mean±SD from ?5 to ?55°C) is a promising protocol for cryopreservation of Arctic char semen.  相似文献   

6.
Abstract – Otoliths preserve a continuous record of the life cycle from the natal through the adult stage. For that reason, the morphological and chemical characteristics of otoliths of two nonnative Salmonids, brown trout (Salmo trutta) and brook charr (Salvelinus fontinalis) from populations on the Kerguelen Islands were compared. Several approaches were used to study the relationships between otolith morphometry, crystal morph and chemical elemental composition. These salmonids sampled in Kerguelen are well differentiated in terms of species through their otolith shape. The results indicate that ecotypes and river populations can be reasonably well differentiated on the basis of otolith shape. The crystallisation study has revealed the presence of a particular form: the vaterite, present at a high rate: 45% of S. fontinalis and 18% from Salmo trutta fario. Moreover, vaterite and aragonite otoliths presented differences in chemical composition.  相似文献   

7.
The effects of extender composition, cryoprotectant concentration and freezing and thawing on the fertilization efficiency of cryopreserved spermatozoa of Puntius gonionotus were evaluated. Computer‐aided motility analysis of semen was conducted to check the suitability of spermatozoa for cryopreservation after mixing with different extenders and cryoprotective agents (CPAs). Extender‐4 with an osmolality 260 mOsmol kg−1and pH 7.6 was used for the cryopreservation study. Among the CPAs, dimethyl sulphoxide (DMSO) was least toxic and more than 60% fertilization was achieved when used at 1.4 M at 0 °C for 10 and 30 min, whereas the toxicity of all CPAs to spermatozoa was evident when tested at 30 °C. Semen frozen at −16 °C min−1 with 1.4 M DMSO showed 70% fertilization, which was significantly higher (P<0.05) than other freezing rates. Samples thawed at 35 °C water showed a fertilization rate comparable with that of fresh semen. Computer‐assisted semen analysis of fresh and frozen semen after thawing showed variations in different types of motility in spermatozoa and in their class. There was no significant difference in motility before or after cryopreservation; however, significant differences could be observed in the average path velocity (VAP), straight line velocity (VSL) and curve linear velocity (VCL). Semen of silver barb could be cryopreserved with extender‐4 by addition of 1.4 M DMSO to a final cryopreservation medium (MED 2) cooled at a rate of −16 °C min−1, stored in liquid nitrogen (−196 °C) and utilized after thawing at 35±2 °C.  相似文献   

8.
Despite long‐standing interest in foraging modes as an important element of animal space use, few studies document and compare individual foraging mode differences among species and ecological conditions in the wild. We observed and compared foraging modes of 61 wild Arctic charr, Salvelinus alpinus, 42 brown trout, Salmo trutta, and 50 Atlantic salmon, Salmo salar, in their first growing season over a range of habitats in 10 Icelandic streams. We found that although stream salmonids typically sit‐and‐wait to ambush prey from short distances, Arctic charr were more mobile during prey search and prior to prey attack than Atlantic salmon, whereas brown trout were intermediate. In all three species, individuals that were mobile during search were more likely to be moving when initiating attacks on prey, although the strength and the slope of this relationship differed among species. Arctic charr also differed from salmon and trout as more mobile individuals travelled longer distances during prey pursuits. Finally, coupled with published data from the literature, salmonid foraging mobility (both during search and prior to attack) clearly decreased from still water habitats (e.g., brook charr), to slow‐running waters (e.g., Arctic charr) to fast‐running waters (e.g., Atlantic salmon). Hence, our study suggests that foraging mode of young salmonids can vary distinctly among related species and furthers our understanding of the behavioural mechanisms shaping the geographical distribution of wild salmonids.  相似文献   

9.
The aim of this study was to develop a simple cryopreservation protocol for silver barb, Barbodes gonionotus, semen using a dry shipper. Freezing rates within the upper and lower chambers of dry shipper were recorded for 14 days post liquid nitrogen loading (dpl). To regulate freezing rates, straws (250 and 500 µl) wrapped with various insulators (polystyrene foam box, oxygen tube, silicone tube and electric wire) were frozen within the upper chamber. Straws containing semen diluted with Calcium‐free Hank's Balanced Salt Solution (Ca‐F HBSS) and 10% dimethyl sulphoxide were cryopreserved with or without insulators. Appropriate protocols were selected based on sperm quality during a 45‐day cryostorage. The upper chamber had potential as a freezing chamber within 9 dpl due to no significant (p > 0.05) change in freezing rates. High percentages of sperm motility and viability (p < 0.05) were observed when 250 µl straws with silicone tube (T4) frozen for 5 min, non‐insulated 500 µl straws (T9) and 500 µl straws with polystyrene foam box (T12) frozen for 1–5 min, having freezing rates of 43.1 ± 1.3, 71.3 ± 1.4 and 14.7 ± 0.4°C/min respectively. Dry shipper can be used as a freezing tool to cryopreserve silver barb semen.  相似文献   

10.
Cryopreservation of Arctic charr Salvelinus alpinus (L.) semen was investigated using three diluents, three cryoprotectants [10% dimethyl sulphoxide (DMSO), 10% dimethylacetamide (DMA) or 20% glycerol] and three sizes of straw. The three diluents and three cryoprotectants were combined, resulting in nine extenders. One part semen was added to three parts extender, and motility was evaluated to assess the toxicity of six of the extenders. Semen in nine extenders was frozen in 0.5‐mL straws using liquid nitrogen vapour. Semen extended in 0.3 m glucose and each of the cryoprotectants was also frozen in 0.5‐mL, 1.7‐mL (flat) or 2.5‐mL straws. The freezing rate in each size of straw was measured. Fertility trials were conducted to determine the post‐thaw viability of the frozen semen. The motility of activated spermatozoa was higher in the DMA and DMSO extenders than in the glycerol extender. For the trial using 0.5‐mL straws, post‐thaw fertility results were higher for all extenders containing DMSO, or 0.3 m glucose and DMA, than for all other combinations of diluent and cryoprotectant. For the straw size comparison, the highest fertility was obtained for the 1.7‐mL straw using either DMSO or DMA and for the 2.5‐mL straw using DMSO. For all cryopreservation trials, fertility was low for extenders containing glycerol.  相似文献   

11.
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.  相似文献   

12.
Abstract. Vibriosis is a significant problem in rainbow trout, Salmo gairdneri Richardson, culture in fresh water in north-eastern Italy. Furunculosis is the main cause of disease in brown trout, Salmo trutta L., and brook trout, Salvelinus fontinalis (Mitchill). Spontaneous outbreaks over the period 1975–1978 are described together with relevant husbandry and environmental parameters associated with them. Biological, chemical and physiological characteristics of 40 bacterial strains isolated from outbreaks are described.  相似文献   

13.
Spring activation of the gill Na+---K+-ATPase, osmotic variations after direct exposure to sea-water of high salinity (35.5‰), survival, and growth were studied in three salmonid species reared in France (Salmo trutta, Salmo gairdneri, Salvelinus fontinalis) and in the hybrid tiger trout (♀ S. trutta × ♂ S. fontinalis).The brown trout (S. trutta) studied showed physiological characteristics of smoltification: increase of the gill enzyme activity in fresh-water, rapid control of the osmotic lack of balance after sea-water contact, good growth and survival in summer.Rainbow trout presented characteristics of sedentary species: low values of the gill Na+---K+-ATPase in fresh-water, and greater and more durable osmotic variations. In spite of a certain degree of euryhalinity in spring and winter, this species suffered significant losses in sea-water during summer.Brook trout appeared as a very stenohaline species unable to survive in sea-water of high salinity; the hybrid presented intermediate characteristics between the two parents.The level of activity of the gill Na+---K+-ATPase in fresh-water, as well as its evolution after sea-water contact appears as a good indicator of the adaptability of the species to a very hyperosmotic environment, and reveals different strategies for regulating the hydromineral balance, which are discussed.

Résumé

L'activation printanière du système Na+---K+-ATPasique des microsomes de la branchie chez trois espèces de salmonidés existant en France (Salmo trutta, Salmo gairdneri, Salvelinus fontinalis) et de l'hybride tigre (Salmo trutta ♀ × Salvelinus fontinalis ♂), les modifications osmotiques après transfert en mer de salinitéélevée (35,5‰) et les performances de survie et croissance ont étéétudiées.La truite fario testée se comporte comme une espèce à smoltification: élévation de l'activité branchiale en eau douce, rapide contrôle du déséquilibre osmotique après transfert en mer, bonnes survie et croissance. La truite arc-en-ciel domestique répond comme une espèce sédentaire, avec des valeurs ATPasiques faibles en eau douce, un déséquilibre ionique relativement important à court terme, et plus long à disparaître. En dépit d'un niveau d'euryhalinitéà certaines époques, les mortalités observées sont élevées en été. L'omble de fontaine présente un très faible niveau d'euryhalinité et n'a pas survécu en mer dans les conditions de l'expérience, l'hybride se comporte de façon intermédiaire par rapport aux deux parents.Le niveau d'ATPase en eau douce ainsi que l'augmentation d'activité après transfert paraissent un bon indicateur des facultés d'adaptation de l'animal à un milieu très hypertonique et révèlent des stratégies différentes de régulation de la balance hydrominérale selon les groupes d'espèces envisagés. Tous ces faits sont discutés.  相似文献   

14.
To identify the pathogens causing saprolegniosis among farmed fish in Nova Scotia, 172 infected tissues and 23 water samples were collected from six species of teleosts: Atlantic salmon (Salmo salar), brown trout (Salmo trutta), Arctic charr (Salvelinus alpinus), brook trout (Salvelinus fontinalis), striped bass (Morone saxatilis) and rainbow trout (Oncorhynchus mykiss) at nine facilities over a 600 km range. Following laboratory culture, 132 isolates were recovered. Six species of oomycetes were identified from analysis of the internal transcribed spacer (ITS) sequence of the nrDNA: Saprolegnia parasitica, Saprolegnia ferax, Saprolegnia diclina, Saprolegnia aenigmatica, Saprolegnia torulosa, Saprolegnia sp. and Pythiopsis cymosa. Further phylogenetic analyses of the ITS and cytochrome c oxidase subunit 1 (Cox1) regions revealed four strains of Saprolegnia parasitica (named here as S1, S2, S3 and S4), of which S1 and S2 were common (37% and 42% of the isolates), and two strains of S. ferax. Among S. parasitica, S2 and S3 are more closely related to each other than to S1 based on the phylogenetic analyses and predicted RNA secondary structure of the ITS region. Sexual structures with a similar morphology were formed by S1 and S3 in vitro, but were not formed by S2.  相似文献   

15.
A series of experiments to study the preservation of rainbow trout semen in the liquid and frozen state was carried out.For the preservation of liquid semen both undiluted and diluted semen was stored in total darkness at 20° or 4°C under a number of different gasses (air, O2, O2 + N2 (1:1), N2, CO2, N2 + H2 + CO2 (8:1:1)). The best results were obtained when storing semen in an undiluted state at 4°C under O2 (hatching rate after 15 days was 80.6%, controls were 98.2%). Good results were also obtained under air (after 9 days 94.7% vs 94.9% for the controls). Anaerobic conditions, dilution or an increase in temperature all rendered less favourable results.For the purpose of cryopreservation a diluent was developed on the basis of the composition of rainbow trout seminal plasma. The semen was mixed with the diluent immediately before freezing at a ratio of 1:1 or 1:3. The pellet-technique (Nagase, 1964) was found to be more convenient and successful than freezing in straws. The pellets were thawed in a 1% NaHCO3-solution. The hatching results after storage periods of 1–4 months were very variable (2.6–80.3%).  相似文献   

16.
In this study, post‐mortem myofibril proteins change in myosin heavy chain (MHC) mass using sodium dodecyl sulphate‐polyacrylamide gel electrophoresis (SDS‐PAGE), texture properties such as hardness, stickiness, cohesiveness, elasticity, chewiness, gumminess and stress relaxation test parameters (Fmax, Fmin and Fmax‐Fmin) were determined and compared on the days 0, 3, 6 and 9 in three different trout species (Oncorhynchus mykiss, Salmo trutta fario and Salvelinus fontinalis). In terms of texture properties, post‐mortem hardness, cohesiveness, elasticity, chewiness and gumminess were decreased day by day, whereas stickiness, Fmax, Fmin and Fmax‐Fmin were significantly increased (p < .05). According to SDS‐PAGE results, a decreased value on MHC was determined (p < .05). Texture properties and SDS‐PAGE results were found different among groups (p < .05). Correlation between chewiness, gumminess, MHC and hardness; between chewiness and gumminess; between Fmin, Fmax‐Fmin and Fmax; between Fmin and Fmax‐Fmin were significant. As a result of the study, S. fontinalis exhibited least deterioration in comparison with other species and it was determined that SDS‐PAGE results and texture properties support each other.  相似文献   

17.
Application of good sanitation practice in cryopreservation process is the key issue to improve the quality of cryopreserved fish sperm. This study implemented standard sanitation protocol with minimal contamination and evaluated the source of bacterial contamination associated with laboratory equipment and related materials across a series of cryopreservation process of silver barb (Barbodes gonionotus) semen. The use of 16s rRNA sequencing and traditional biochemical methods were performed for bacterial identification. Animal origin (anal fin, culture water and semen contaminated with faeces and urine) and non‐animal origin (liquid nitrogen from liquid nitrogen dewar, outer surface of straw, air circulation in cryopreservation laboratory and latex gloves used during cryopreservation procedure) were determined for bacterial contamination. Aeromonas punctata subsp. caviae was the most abundant species in anal fin, latex groves and semen contaminated with faeces and urine. Bacillus safensis and Bacillus sp. were found as frequently recovered species from liquid nitrogen dewar. Aeromonas hydrophila subsp. hydrophila and Pseudomonas fluorescens, fish pathogenic bacteria, were isolated from all animal origin samples. This was the first report indicating that standard sanitation and hygiene methodologies are recommended for sperm cryopreservation of B. gonionotus to prevent bacterial contamination.  相似文献   

18.
The commercial‐scale production of fish by use of artificial (induced) spawning would require reliable, large‐volume sources of sperm. Cryopreservation can be used to preserve and store sperm within commercial and research germplasm repositories, but is limited in its application to aquaculture. Straw volume and cooling chamber size restrict the quantity of sperm that can be frozen, and straws must be filled by hand. In contrast, the dairy industry has refined methods for freezing of bull sperm, including automation of straw filling and the use of large cooling chambers. These methods could be used for commercial‐scale cryopreservation of fish sperm, although application would require testing. To supply sperm in large volumes, bags originally developed for swine semen could be cooled using dairy protocols and used as a container for fish sperm. The current study documented the use of commercial‐scale dairy cryopreservation techniques for the production of hybrids of channel catfish Ictalurus punctatus (female) by blue catfish Ictalurus furcarus. Four cryoprotectants (methanol, dimethyl sulfoxide, dimethyl acetamide, and glycerol) were initially evaluated for use with blue catfish sperm. During May 2000 and March to April 2001, suspensions of blue catfish sperm were cryopreserved with 10% methanol in 0.5‐mL French straws and in commercial swine semen bags (Cochette* bags, IMV International. Minneapolis, Minnesota, USA). Cryopreservation took place at a dairy breeding cooperative, using technology employed for bull semen. Sperm motility before freezing was 26 ± 18% during Year 1 (2000) and 62 ± 30% during 2001. Sperm were thawed at 40 C and used to fertilize the eggs of channel catfish (yielding hybrids). Motility after thawing for sperm frozen in 0.5‐mL straws was 11 ± 10% during 2000 and 50 ± 24% during 2001. Motility after thawing was 41 ± 17% for sperm frozen in swine semen bags in 5‐mL aliquots and 43 ± 10% for sperm frozen in 10‐mL aliquots. Neurulation of eggs fertilized with thawed sperm from straws was 83 ± 13% during 2000 and 54 ± 27% during 2001. Neurulation was 57 ± 24% using sperm frozen in swine semen bags in 5‐mL aliquots and 55 ± 10% using sperm frozen in 10‐mL aliquots. There was no correlation between sperm motility before freezing (in 0.5‐mL straws) and after thawing during 2000 (r= 0.52) or during 2001 (r= 0.49). In addition, there was no correlation between initial motility and neurulation of channel catfish eggs fertilized using thawed sperm during 2000 (r= 0.14) or during 2001 (r= 0.29). Sperm of blue catfish can thus be cryopreserved at a commercial scale using dairy protocols and can be made available for the production of hybrid catfish when viable eggs are available.  相似文献   

19.
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.  相似文献   

20.
The present study investigated the influence of ovarian fluid (OV) on the gamete physiology in the brown trout (Salmo trutta f. fario). In comparison to water OV prolongs the duration of sperm motility for >'5 min and the fertilizability of eggs for >'10 min independent from the quality of the egg batch from which the OV derived. These stabilizing effects are related to the inorganic composition of OV as similar results are obtained in buffered artificial saline solution (AFS). OV compensates also for sub-optimal environmental conditions as demonstrated in fertilization experiments with mixtures of OV and buffer solutions of different pH. At a dilution ratio of OV: water of 1:1 the stabilizing effect on gametes is significantly decreased and at a dilution ratio of 1:8 it is completely lost. Due to the described effects significantly higher fertilization rates are obtained in OV than in water. In OV the fertilization rates are also higher than in AFS but only at low sperm to egg ratios or when semen with low motility rates and swimming velocities is used. This is considered to be due to a semen dependent egg activation which is partly suppressed by a OV protein with a molecular weight between 20 and 62 kdaltons. The phenomen is discussed in detail.  相似文献   

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