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1.
In this study, the effects of spermiation time are investigated on milt quality of Russian sturgeon over the course of the spawning season. The milt samples were collected from three broodstock batches at three time points including: the beginning, middle and at the end of the spawning season. According to the results, the milt quality parameters including pH, sperm density, spermatocrit, duration of sperm motility and percentage of sperm motility were significantly low in the beginning and end of season than middle of season. The values of milt quality parameters in the middle of season were as follows: (motility percentage: 69.6 ± 3.5, motility duration: 460.3 ± 37.2 s, sperm density: 8.7 ± 0.4 × 109, milt volume: 86.3 ± 8.1 and milt pH: 8.3 ± 0.15). Significant positive correlations were also found between milt pH and sperm motility as well as between sperm density and spermatocrit. In conclusion, our study showed that the middle of season is the best time for collection of milt with appropriate quality in Russian sturgeon. Selection of milt with good quality is necessary aim to cryopreservation of spermatozoa in endangered fish species including Russian sturgeon.  相似文献   

2.
This study was carried out to evaluate milt quality in male Caspian brown trout (Salmo trutta caspius) over the course of the winter spawning season. Milt samples were collected biweekly during December and January. Chemical composition of seminal fluid, sperm production (milt volume, sperm density, spermatocrit,) and sperm motility characteristics (percentage and duration of motility) were measured. Milt volume, sperm density, osmolality, seminal minerals (Ca2+, Mg2+, K+, Na+, Cl?), and total protein gradually decreased over the spawning season. Glucose and triglyceride content of milt did not show significant changes over the spawning season. Milt pH and the percentage and duration of motility were comparatively stable, declining only at the end of the season. Significant positive correlations were found between sperm density and seminal minerals, total protein and spermatocrit; percentage of motile spermatozoa and seminal minerals, total protein; and duration of motility and K+, Cl?, total protein, and pH. Results show that season has a significant influence on milt quality in male Caspian brown trout, with the best milt being available at the beginning of spawning season.  相似文献   

3.
To determine the effect of gonadotropin releasing hormone‐analogue (GnRHa) treatment on the milt quality of endangered Caspian brown trout, Salmo trutta caspius, the sperm motility (percentage and duration of motility), sperm production (sperm density, spermatocrit and milt volume) and milt pH were measured for GnRHa‐treated (the treatment group) and untreated groups (the control group) during the spawning season. For untreated brooders, the values of the motility per cent, sperm density and spermatocrit decreased continuously during the spawning season while the milt volume, duration of motility and milt pH showed only a significant decrease at the end of the season. For GnRHa‐treated males, these parameters increased 14 days after GnRHa treatment (first milt collection) and then decreased continuously towards the end of the season. In addition, the values of milt and sperm density yielded per treated male were higher than that in the untreated group, although these were not statistically different. In any case, the total sum of yielded milt from the treatment group over the spawning season was higher than that in the untreated group. In this experiment, significant positive correlations were found between milt parameters as follows: sperm motility vs. milt pH; sperm density vs. spermatocrit; milt volume vs. spermatocrit; and milt volume vs. sperm density. The results show that the treatment of Caspian brown trout by GnRHa can improve the milt quality in terms of sperm motility and sperm production during a spawning season.  相似文献   

4.
This study investigated the effects of broodstock age (2‐ and 3‐yr‐old), and sperm collection time at the beginning, middle, and end of a natural spawning period, on the ability of sperm to tolerate cryopreservation in farmed greenlip abalone, Haliotis laevigata. The quality of sperm was assessed by motility, fertilization rate, plasma membrane integrity, mitochondrial membrane potential (MMP), and acrosome integrity (AI). The sperm collected at the middle of a natural spawning period had significantly higher quality than those collected at the beginning and the end of the spawning period in terms of plasma membrane integrity, MMP, and AI of fresh and post‐thaw sperm, post‐thaw sperm motility, and fertilization rate. No significant difference was found between 2‐ and 3‐yr‐old animals in most quality parameters evaluated. The results suggested that sperm collected during the middle of the spawning season should be used for cryopreservation. The efficiency of genetic improvement programs can be further enhanced by using sperm collected from 2‐yr‐old abalone which has a similar ability to tolerate cryopreservation as 3‐yr‐old counterparts.  相似文献   

5.
Sexually mature males (BW?=?1600?±?150 g and TL?=?235?±?30 mm) of northern pike (Esox lucius L.) were randomly selected from a pond to record changes in their sperm quality parameters (spermatozoa morphology, sperm volume, density, and motility parameters) during the spawning season. The morphological and motility parameters changed significantly during the reproductive season with following trends. Only, head width was not changed during the spawning season. The longest spermatozoa and its flagellar length were found at the middle of spawning period (TL?=?38.24?±?0.37 μm and 35.14?±?0.26 μm) and shortest at the beginning of spawning period (TL?=?34.81?±?0.29 μm and 32.53?±?0.18 μm). Other morphological characters were always the lowest at the beginning of spawning period. Sperm volume was changed from 0.33?±?0.3 ml in February, 0.43?±?0.2 ml in March to 0.24?±?0.1 ml in April, and density from 16.2?±?0.2?×?109 spermatozoa ml?1 in February, 19.4?±?0.2?×?109 spermatozoa ml?1 in March to 4.8?±?0.2?×?109 spermatozoa ml?1 in April. Same sperm velocity was observed in all spawning terms at 10 and 20 s after activation. Higher velocity was found at 30 and 40 s after activation in sperm collected at the middle and the end of spawning period. Significantly, higher percentage of motile sperm was observed at 20, 30, and 40 s after activation in sperm sampled at the end of spawning period. This study supports the hypothesis that longer spermatozoa swim faster.  相似文献   

6.
舟山渔场银鲳人工授精及孵化   总被引：10，自引：0，他引：10  
2005-2008年,在舟山海域银鲳(Pampus argenteus)繁殖季节(4-5月),随流刺网或张网捕鱼船出海,捕捞性腺成熟的银鲳,进行人工授精和孵化.人工授精试验采用干法、湿法和半干法,比较受精率和孵化率.通过4年连续测量银鲳成熟卵的卵径、油球径等形态指标,对卵子成熟度进行判别,在水温16.0～18.5 ℃、盐度28.0±0.5的条件下进行孵化.结果表明,以干法受精后间隔3～5 min水洗和半干法受精的方法受精率最高,受精率达18.50%～33.50%,最高达40%;孵化率达到43.83%～51.00%,最高达66%.银鲳成熟卵子的卵径为(1.368±0.082)mm,油球径为(0.550±0.031)mm,油球1个.对影响海捕银鲳亲体受精率和孵化率的环境条件也进行了讨论.  相似文献   

7.
Haddock, Melanogrammus aeglefinus, is a serial spawning, marine gadid characterized by low survivorship during the early life history stages. The potential for predicting future survival to hatching based on cleavage patterns of early embryos (8–32 blastomere stages) was investigated in order to improve efficiency of early rearing practices. In 2001, data from 36 egg batches (>95% fertilization) suggested that hatching success was inversely related to the percentage of embryos with abnormal cleavage. Mean percentage of normal cleavage did not differ throughout the spawning season but variability was much higher for embryos from early and late batches than those collected during the middle of the spawning season. In 2002, abnormalities in blastomere cleavage for 12 egg batches were further categorized as (1) asymmetric blastomere arrangement, (2) inequality of blastomere size, (3) poor adhesion between blastomeres and (4) poor definition of blastomere margins. Results suggested that all four abnormalities were co-occurring, which prevented negative effects on hatching success from being attributed to a single abnormality. Incubation of embryos with only one type of cleavage abnormality suggested that low adhesion between blastomeres significantly reduced embryo viability, while asymmetry in blastomere arrangement did not. However, because cleavage abnormalities tended to co-occur, hierarchical multiple regression revealed that asymmetry could be used to accurately predict hatching success, even if reduction in embryo viability was due to abnormalities other than asymmetry. Analysis of additional cleavage abnormalities suggested that complete separation between blastomeres was indicative of a very poor egg batch and resulted in little or no hatching, while cellular outcrops had no negative effect on hatching success. Information from detailed studies such as these could be used to predict hatching success of individual egg batches, allowing time and resources to be allocated more efficiently in hatcheries.  相似文献   

8.
The biology of cod reproduction is well described in the scientific literature. However, sperm biology and spermatozoa management are poorly studied in this species. Because of its recent farming expansion, a better knowledge of cod gametes is becoming especially useful. This work aimed at establishing tools to study sperm biology in cod, and also investigated the existence of changes in cod sperm quality during the spawning period. We showed that sperm concentration could be assessed using spectrophotometry at 260 nm. Sperm motility significantly decreased after a 168‐h storage at 4 °C. A 1:9 dilution of sperm in a non‐activating medium (1/3 seawater and 2/3 freshwater, osmotic pressure: 360 mOsm kg?1) improved sperm storage. Sperm concentration, sperm velocity and storage capacity at 4 °C peaked during the medium period of the spawning season and then decreased to values close to those observed at the beginning of the reproductive period. The measured values of osmotic pressure, pH, protein, Na+, Cl? and Ca2+ concentrations of the seminal fluid were modified along the spawning period. Cell damage was noted at the end of the spawning period: local blebs were observed on the flagellum but also loops at its distal part. On the other hand, spermatocrit did not vary with the sampling date. In conclusion, cod sperm quality is modified during the spawning period, the highest‐quality samples being collected during the medium part of this season.  相似文献   

9.
In broodstocks of Atlantic halibut, Hippoglossus hippoglossus, male and female gamete production often becomes unsynchronised towards the end of the spawning season—milt becomes very viscous and difficult to express while the females are still producing batches of good quality eggs. Gonadotrophin-releasing hormone agonist (GnRHa) has been shown to stimulate spermiation in a number of fish species. Therefore, we conducted two experiments where male halibut were implanted intramuscularly with pellets containing GnRHa. The effect of the pellets was tested at three periods: before, at the height of and at the end of spermiation. In the middle period, GnRHa was tested at two doses (5 and 25 μg/kg bodyweight). Measurements were made of milt hydration, sperm motility and fertilisation rate. Implanted males began spermiation at least 4 weeks before control males. Both doses of GnRHa increased the fluidity of the milt. This effect lasted for at least 20 days in the low dose group and for 40 days in the high dose group. When applied at the end of the season, GnRHa reversed the normal trend for the milt to become more viscous. GnRHa treatments did not affect fertilisation rates obtained with the sperm. However, towards the end of the spawning season, sperm motility was enhanced in males treated with the high dose of GnRHa (25 μg/kg) compared to controls. As described previously, plasma concentrations of the gonadal steroids, 5β-pregnane-3β,17,20β-triol 20-sulphate and 17,20-dihydroxy-4-pregnen-3-one, were significantly enhanced by GnRHa treatment. Concentrations of testosterone on the other hand decreased when spermiating males were treated with GnRHa. Our data suggest that 17,20β-dihydroxy-4-pregnen-3-one or its metabolites are involved in milt hydration, possibly through affecting ion transport.  相似文献   

10.
Cultured red porgy Pagrus pagrus (L.) males (n=6) were sampled every 2 weeks for milt, in order to monitor changes in sperm quality parameters during a whole spawning period. On 11 January 2001, 60% of the fish were spermiating, increasing to 100% in mid‐February and dropping to 30% by mid‐April. Sperm density showed a slight increasing trend, with mean values ranging between 8.6 and 23.7×109 spermatozoa mL?1. Sperm motility percentage exhibited a significant improvement during the spawning season (analysis of variance (anova ) P=0.0001). The duration of forward motility for the major part of the monitoring period ranged between 2 and 4 min. Red porgy spermatozoa maintained their viability for many days after whole storage of milt at 4°C. During the monitoring period there were significant changes in the mean duration of sperm survival after cold storage, ranging from 5 to 12 days. The total volume of expressible milt was maximal on 28 March, increasing from a mean value of 1.7 mL to 5.3 mL kg?1. Milt production of captive‐reared red porgy does not appear to be limiting, when compared with the volume of expressible milt produced by other cultured marine fishes.  相似文献   

11.
Multiple spawnings are special reproductive tactics that many fish evolved to obtain different types of direct and/or indirect spawning benefits. This has led to two pertinent questions: (a) what types of benefit does a commercially important fish provide during multiple induced spawnings annually? and (b) is there any trade‐off between traits during these spawnings? To address these questions, the present study was carried out with two separate experiments during two spawning events of an Indian major carp (Catla catla) to assess: (a) male's spawning performances and (b) female's spawning performances. The male's spawning data revealed that they produced significantly higher amount of milt and hatchlings during the first spawning, while they significantly reduced hatchling deformation rate, enhanced offspring survival rate and enlarged offspring body size during the second spawning. The female's spawning information unveiled no significant differences in total egg weight, hatching rate and hatchling deformation rate between the first and second spawning. However, females had significantly higher offspring survival rate during the first spawning and enhanced offspring body size during the second spawning. Interestingly, the analysis of trait associations revealed that males allocated energy with a trade‐off between milt weight and offspring survival rate, whereas females showed a trade‐off between hatching rate and offspring survival rate. Thus, the study provides some important information for carp breeders and associated stakeholders to know which spawning season is preferable for the higher production of eggs, milt and good quality larvae.  相似文献   

12.
The present study investigated the effects of sequential collection of milt, time of post-mortem storage and anesthesia on rainbow trout (Oncorhynchus mykiss) sperm motility parameters (using computer-assisted sperm analysis – CASA) as well as seminal plasma osmolality and sperm concentration. The post-mortem storage and time of anesthesia altered motility characteristics of rainbow trout sperm to different extents. The moderate impact of time of anesthesia was manifested in a shortened duration of sperm motility after 10 min exposure of fish to anesthetic. The prolonged post-mortem storage (≥40–60 min), in addition to lowering sperm motility duration, also significantly influenced sperm motility parameters, such as sperm velocities, percentage of motile sperm and sperm trajectory parameters. These results clearly demonstrate that when milt from sacrificed fish is used for sperm motility studies, the time of post-mortem storage significantly alters sperm motility characteristics. Since sperm motility rate and swimming velocity could predict fertilizing ability, detrimental effects of prolonged post-mortem storage may lead to reduced fertilization success. Sperm concentration and seminal plasma osmolality were lower in the first fractions and increased with successive collections of milt. It suggests the presence of urine contamination of the first milt fractions which were collected by stripping. Therefore, testing of sperm concentration and/or seminal plasma osmolality should be mandatory while handling stored milt.  相似文献   

13.
Collection of fish milt by stripping risks the danger of milt contamination by urine. This may seriously influence milt characteristics and quality, including usefulness for cryopreservation. Urine contamination of milt may be avoided by using a catheter for sperm collection. The objectives of this study were to provide basic characteristics of milt collected with a catheter, to test the usefulness of this milt for cryopreservation, and to correlate characteristics of fresh and cryopreserved semen with sperm fertility rates. Milt from 25 rainbow trout Oncorhynchus mykiss (Walbaum) males were used. All samples were cryopreserved using the pellet method within 1 h of collection, using 0.6 m sucrose and 10% dimethyl sulphoxide (DMSO) as an extender. Catheterization resulted in semen of very good motility (> 90% motile spermatozoa) and high fertilization rates after cryopreservation (mean fertilization rate 81.8 ± 13.3% of control, at a sperm/egg ratio of 2.4 ± 0.3 × 106). Osmolality of seminal plasma and concentrations of sodium, potassium and magnesium ions had low variability, which suggests that they are important for creating a stable environment for sperm storage in the sperm duct. Higher variability of certain seminal plasma characteristics, such as protein concentration and antiproteinase activity, suggests that these characteristics are related to individual semen features of particular males. A strong correlation of seminal plasma zinc concentration with protein concentration may reflect an importance of zinc in semen biology. Cryopreservation caused a significant release of protein and acid phosphatase from spermatozoa. Our results did not reveal any single characteristic of semen collected by catheter that could be used as a powerful predictor of cryopreservation success, presumably because all samples were of high quality.  相似文献   

14.
Black sea bass Centropristis striata L. are protogynous hermaphrodites that develop and spawn as females before changing sex to male. Since all fish eventually become males, determining the relationship between sperm production, sperm quality and seasonal changes in plasma levels of testosterone (T) and 11‐ketotestosterone (11‐KT) could be useful for identifying appropriate males to maintain as broodstock. Milt and blood samples were collected three times during an 8‐week spawning season. Milt volume (3.5±0.76 mL kg?1), sperm density (3.2 × 108± 0.31 cells mL?1), sperm production [11 × 108±3.4 cells kg?1 body weight (BW)] and sperm motility (80±0.6%) were at their highest during the first sampling interval and coincided with the highest 11‐KT levels (1.0± 0.11 ng mL?1). All of the sperm indices decreased to their lowest levels during the final 3 weeks of the study. Sperm viability was highly correlated (adjusted R2=0.84) with sperm motility. Sperm cryopreserved in modified Mounib's extender (MME) had the highest post‐thaw motility compared with two other extenders. Post‐thaw motility of sperm cryopreserved in MME was not different from fresh after 90 days of storage. There was no difference in fertilization rates between fresh (69±2.4%) and post‐thaw (67±4.1%) sperm samples taken from the same male or among males. These results demonstrate that the quality of black sea bass spermatozoa is higher earlier in the spawning season and that acceptable post‐thaw fertilization rates can be obtained from cryopreserved sperm.  相似文献   

15.
Cultivated Atlantic cod (Gadus morhua) entering their first year of gamete maturation were fed diets with different levels of arachidonic acid (ARA) and eicosapentaenoic acid (EPA) for 6.5 months prior to commencement of spawning. Gravid females were stripped three times: at the beginning, peak and end of spawning. Lipid composition and egg and larval quality of 34 family crosses were investigated. Results indicated that ARA uptake into eggs from broodstock diet was highly efficient achieving proportions of ARA up to 84% higher in eggs than in the diet. EPA was 42–76% higher, and DHA was 155–173% higher in eggs than in diets. Cod fed the diet with the lowest EPA/ARA ratio had the greatest egg production. Eggs from fish on a diet with high ARA level had significantly higher fertilization and hatching success than those fed low levels of ARA. This diet produced on average 71 viable eggs g?1 female compared with 32.5 and 4 eggs in diet B and C, respectively. Furthermore, larval survival until 8 days posthatch was higher in diets with lower ARA levels. The combined results showed that ARA dietary supplementation and low EPA/ARA ratio yielded a greater number of viable larvae kg?1 female.  相似文献   

16.
Milt from individual males of northern pike, Esox lucius L., was separately cryopreserved. Concentration of spermatozoa in fresh milt and spermatozoa motility before freezing and after thawing was evaluated. Activity of aspartate aminotransferase (AspAT, E.C. 2.6.1.1.) and acid phosphatase (AcP, E.C. 3.1.2.2.) in fresh and thawed sperm were determined. In comparison with the control group, egg fertilization with cryopreserved milt varied from 6.6% to 96.0%, depending on the donor male. Fertilization success with cryopreserved pooled milt was 71.8%. Freezing and thawing procedure caused loss of proteins from injured spermatozoa, resulting in significantly lower enzymatic activity in spermatozoa. Intensity of enzyme leakage in thawed milt correlated negatively with fertilization success. Concentration of spermatozoa could be a possible accessory quality indication, useful when selecting sperm samples appropriate for cryopreservation.  相似文献   

17.
The spermiation of tench males was stimulated with Supergestran containing mammalian LHRHa lecireline at the following doses: 5, 10, 20 and 40 g kg−1 b.w.; then with carp pituitary suspension (CPS) at a dose of 2 mg kg−1 b.w. and with a control of saline physiological solution. The following days, meaning 24, 48 and 72 h after injection, sperm was collected to evaluate volume and the number of sperm per male per kg body weight (B.W.) The percentage of motile sperm and velocity of spermatozoa were measured 48 h after hormonal injection, and 72 h after hormonal injection the sperm was evaluated for fertilization and hatching ability. All 42 males in experimental groups were diploid. Live weight did not differ significantly among experimental groups. The strongest stimulation of spermiation was achieved with LHRHa in dosage of 20 and 40 g kg−1 b.w. and CPS compared to males of the control group and lower dosage of LHRHa. Analysis of variance showed no significant influence of the treatment on the velocity and percentage of motile spermatozoa. The effect of different treatment on the fertilization capacity (the number of spermatozoa per egg was equilibrated) was significant. Significantly the highest quality of sperm collected 72 h after injection expressed by percentage of fertilization and hatching (62–65% fertilization and 61–64% hatching rates, respectively) was found for LHRHa in dosage of 20 and 40 g kg−1 b.w. Significantly the lowest parameters of fertilization and hatching were found for the control group, on the 12% level.  相似文献   

18.
Australian bass, Macquaria novemacideata (Steindachner),mature but do not spawn in fresh or brackish water ponds. Ovulation and spawning of captive (n = 158)and wild Australian bass (n = 123) was induced in the normal breeding season by single injections of human chorionic gonadotropin (hCG). Doses of 100-4000IU kg-“ hCG induced ovulation and the optimum dosage was 500 IU kg” hCG. The breeding season was from mid-May to late August for wild fish,and extended into September for captive fish. There was a tendency for mean fertilization and hatching success to decline over the breeding season. Greater fertilization and hatching success was obtained from fish which spawned naturally than from stripped fish. Fish spawned after 34,2 ± 0.4 h (mean ± SE, n = 74). Ovulating fish that failed to spawn were stripped after 40.2 ± 0.3 h (n = 76). The timing of stripping and fertilization was an important factor determining hatching success. There was no apparent difference in latency periods or the number of eggs spawned between captive and wild fish. However, the mean number of eggs obtained from naturally spawned fish was higher than for stripped fish. The techniques described in this paper will assist the largescale production of Australian bass by increasing the quality and quantity of larvae from hCG-induced spawnings.  相似文献   

19.
The aim of this study was to evaluate the sperm quality of Brazilian flounder Paralichthys orbignyanus throughout its reproductive season. Sperm was collected at the beginning, middle and end of the breeding period. Spermatozoa density was maximum at the beginning (12.7 ± 0.92 × 109 cells mL?1) and at the end (11.8 ± 0.39 × 109 cells mL?1) of the breeding season (P<0.05). Sperm production and the percentage of spermatozoa moving fast forward increased significantly towards the end of the breeding season (P<0.05). The mean duration of progressive motility of spermatozoa was around 10 min. No difference was observed during the reproductive season in the percentage of motile cells, pH, osmolality and K+, Cl? and Mg2+ concentrations in seminal plasma. The concentration of Na+ increased throughout the breeding season, reaching 174.62 ± 12.68 mmol L?1 at the end (P<0.05). There was a decline in the concentration of Ca2+ (12.31 ± 3.08 mmol L?1) in the middle of the breeding season, which coincided with the shortest motility duration of spermatozoa. The information reported in this study should help to improve management and optimize the development of protocols for short‐term storage and cryopreservation of Brazilian flounder semen.  相似文献   

20.
Three cryoprotectants (dimethyl sulphoxide, propylene glycol and glycerol) and two diluents (sucrose based and saline based) were mixed (9 parts diluent–1 part cryoprotectant) factorially to produce six extenders that were tested to develop an effective sperm cryopreservation protocol for winter flounder Pseudopleuronectes americanus (Walbaum). Sperm were diluted 1:3 with each extender and frozen by flotation on liquid nitrogen before being submerged and stored for 30 days. Sperm left unfrozen in each extender for 20 min showed no toxic effects on motility. Extenders containing propylene glycol (PG) as cryoprotectant yielded higher post‐thaw sperm motilities than those containing dimethyl sulphoxide (DMSO) or glycerol. The sucrose‐based diluent performed better than the saline‐based diluent when DMSO was used as cryoprotectant, but there were no differences in post‐thaw motility between diluents for the other cryoprotectants. Activating sperm with ovarian fluid and sea water instead of sea water alone had no effect on post‐thaw motility. In fertilization trials, no differences were observed between any of the extenders and fresh milt when milt, eggs and sea water were left in contact for 1 h. When sperm were forced to compete for eggs by reducing contact time to 20 s, fertilization results followed those of sperm motility rates. Percentage hatch and morphology of larvae at hatching did not differ for eggs fertilized by cryopreserved and fresh sperm. This study represents the first reported successful attempt at cryopreserving winter flounder sperm and should improve gamete and broodstock management protocols for this species.  相似文献   

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