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1.
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).  相似文献   

2.
采用扫描电子显微镜和普通光学显微镜观察方法,结合全光谱扫描分析方法,对栉孔扇贝和虾夷扇贝的精子及卵子的受精生物学特性进行了详细的观察,包括精卵产出后形态学变化、卵水的特性、精子顶体反应、卵子皮层反应以及精子分级分离组分对卵子的作用5个方面.结果表明,这两种扇贝精卵生物学特性没有本质的区别,扇贝精子排入海水中10min以内,外形没有太大的变化,但30min以后约有1/4的精子出现头部膨大变成圆球形的现象,受精能力明显下降;扇贝卵子产入海水中1h以内受精能力没有变化,但2h以后,约1/3的卵子出现卵裂现象,未见极体的排放,且卵裂多停止在2细胞期,少数达到4细胞期,基本属于均等卵裂,并失去受精能力;滴入卵水中的精子极易发生自溶解体,未解体的精子发生凝集,10min之后卵水中基本检测不到完整的精子,卵水和钙离子载体A23187均能诱导精子发生顶体反应;精子分级分离组分分别为精浆、精子头部和精子尾部,这三部分除了少数精子头部能够附着在卵子表面外,其他都不具备激活卵子的作用.对扇贝精子和卵子的生物学特性的研究将为解释不同种扇贝的精卵相互识别并受精的现象提供基础资料.  相似文献   

3.
The use of saline solutions was tested to determine their efficacy as replacements for ovarian fluid as sperm activators and to eliminate variability encountered with the use of Ovarian fluid. We tested fertilization rate of semen from eight males on Atlantic salmon Salmo salar eggs after five sperm-activating solutions and a non-activating saline were substituted for ovarian fluid. We used solutions shown acceptable for use with other salmonid species. The six solutions tested were a non sperm-activating phosphate-buffered saline (PBS, 7.2 g/L NaCl, 1.48 g/L Na2HPO4, 0.43 g/L K H2PO4), a Tris buffer (6.99 g/L NaCl, 3.63 g/L Tris and 2.42 g/L glycine), a Borax buffer (12.2 g boric acid/L in solution 1, 76 g disodium tetraborate/L combined 100:118, then 1 L combined with 3.7 L water and 18 g NaCl), and three solutions of 9.25 g/L (125 mM) NaCl buffered to pH 6.0, 7.5, and 8.9. The latter five solutions activated sperm immediately on contact, while PBS required additional water to activate sperm. The PBS solution was the least effective (mean percent eyed eggs 37.6%) for egg fertilization. The mean percent eyed eggs for the other five saline solutions (range 78% to 86%) were not significantly different. Sperm from one male provided significantly lower egg fertilization (39.6%) when compared with the other seven males (67.2–87.4% egg fertilization). Percent egg fertilization was not related to number of live sperm cells per egg. Our results show that osmotically-balanced sperm-activation solutions, even those with a pH range from 6.0 to 8.9 provide adequate media for fertilization of Atlantic salmon eggs. Fertilization in a deactivation saline and water reactivation of sperm resulted in low egg fertilization.  相似文献   

4.
星突江鲽胚胎发育的研究   总被引：2，自引：2，他引：0       下载免费PDF全文
对人工干法授精、微量充气孵化条件下星突江鲽的胚胎发育进行了研究。星突江鲽受精卵为分离的球形浮性卵,无油球、卵膜薄、光滑且透明,具弹性。吸水前卵径为0．66～0．70mm,吸水后为0．91～1．06mm。根据胚胎发育的外部形态及典型特征将星突江鲽胚胎发育过程划分为卵裂期、囊胚期、原肠期、神经胚期、胚孔关闭、眼泡和肌节形成、尾芽形成、晶体出现、听囊出现、出膜前期和出膜期11个连续的典型时期。在11±0．5℃水温下,受精卵经过101h仔鱼脱膜孵出。初孵仔鱼全长2．3～2．5mm,卵黄囊长径1．075～1．25mm,短径0．60～0．675mm。  相似文献   

5.
对施氏鲟Acipenser schrenckii♀×西伯利亚鲟A.baeri♂进行人工繁殖,观察杂交子代的胚胎发育过程。结果表明,在水温15~22℃时,杂交鲟胚胎发育历时141~151 h,所需总积温为2 608.5~2 793.5℃·h。施氏鲟成熟卵为多黄卵,卵裂呈特殊的辐射裂,受精后胚盘隆起不明显。根据对施氏鲟♀×西伯利亚鲟♂杂交子代胚胎发育外部形态及典型特征的观察,将胚胎发育分为受精卵、卵裂期、囊胚期、原肠胚期、大小卵黄栓塞期、神经胚期、眼囊形成期、心脏形成博动期和孵出期9个时期。  相似文献   

6.
Egg quality, those characteristics of the egg that determine its capacity to survive, is a significant problem for many species of fish currently being farmed. Little is known about the determinants of egg quality and there is little agreement regarding reliable methods for its assessment. To be of practical benefit, assessments should be simple to perform and should be carried out as early in development as is possible. Fertilization rates are often used as measures of quality. For the Atlantic halibut Hippoglossus hippoglossus, fertilization rate and assessments of cell symmetry at early cleavage stages provide reasonable indicators of quality. Regardless of assessment method, it is strongly recommended that performance data from all batches of each broodfish be examined when surveying the overall quality of a stock. The misleading effects of pooling such information are demonstrated for a rainbow trout Oncorhynchus mykiss broodstock. Although a large number of factors have been implicated as possible determinants of egg quality, only 1) bacterial colonization of the eggs, 2) nutritional status of the broodfish and, 3) overripening, the process of aging that occurs when eggs are retained within the broodfish after ovulation, have been clearly shown to affect egg quality. The effect of overripening on fish egg quality is discussed in detail. Species-specific differences in the time scale of overripening are pointed out and related to spawning strategy and water temperature. Rainbow trout eggs and those of other salmonids should be fertilized within approximately one week of ovulation. Overripening proceeds much more rapidly in warm water species, e.g., tilapia eggs must be fertilized within an hour or so of ovulation. Egg viability also decreases rapidly for batch spawning species. Fertilization data are presented for Atlantic halibut demonstrating that egg quality decreases 4–6 h after ovulation. The rate of overripening was comparable for eggs held in vitro in ovarian fluid to those retained within the ovarian lumen. These halibut data, combined with information from other marine and freshwater fish, indicate that overripening is a significant determinant of egg quality for many if not all fish.  相似文献   

7.
Egg quality in Arctic char, Salvelinus alpinus, kept indoors at 7 °C during spawning season was morphologically classified. Four egg categories based on lipid droplet distributions and egg diameter were characterized. Eggs with homogenous lipid vesicle distributions and a uniform size were classified as Good. Eggs with some yolk lipid droplets coalesced toward one pole but were homogeneous in size were classified as Fair. Eggs with lipid vesicles that were usually coalesced at one or two poles with were classified as Poor. The fourth egg category was Heterogeneous, in which lipid vesicle distribution and egg size were inhomogeneous. This distribution pattern of the lipid vesicle had a strong relationship with the percentage of fertilized and eyed eggs. Percentages of fertilized and eyed eggs in Good and Fair eggs were 85.5 and 83.4; 30.2 and 28.2, respectively. With Poor and Heterogeneous eggs, the percentages of fertilized and eyed eggs were zero. Egg diameter and absolute weight was increased in Poor eggs than in other egg categories. Relative weight increase during hardening after 30, 45 and 60 min were higher in Good and Fair eggs than in Poor and Heterogeneous eggs. Ovarian fluid collected from egg batches with low rates of fertilized and eyed eggs (Heterogeneous and Poor) had a lower pH and higher protein and aspartate amino-transferase enzyme than ovarian fluid from eggs batches classified as Good or Fair, while the ovarian fluid osmolality did not significantly differ. ATP contents of Poor and Heterogeneous eggs were lower than for Good and Fair eggs. In Heterogeneous eggs, both ATP and acid phosphatase contents were very variable.  相似文献   

8.
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   

9.
This study was conducted to determine the effects of dietary highly unsaturated fatty acids (HUFA) on flame angelfish (Centropyge loriculus) reproduction, and egg and larval quality. In the experiment, formulated diets containing 1.8, 2.9 or 3.6% n‐3 HUFA were fed to flame angelfish broodstock (n = 4) for 5 months. Mean fecundity (daily egg production), egg fertilization rates and embryo viability were used as indicators of egg quality. In addition, mean egg diameter, oil globule diameter, per cent hatch, larval size at hatch, per cent survival to yolk exhaustion and larval size at yolk exhaustion were recorded for each treatment. Flame angelfish fed the diet containing 3.6% n‐3 HUFA exhibited significantly increased fecundity, fertilization rates and embryo viability than fish that were fed the other two formulated diets. Egg diameter, egg oil globule diameter, larval size at hatch, larval survival to yolk exhaustion and larval size at yolk exhaustion from the 3.6% n‐3 HUFA broodstock treatment group were not significantly different from those derived from the Control broodstock treatment. These data revealed that flame angelfish egg quality could respond rapidly (within weeks) to maternal dietary changes. Results from this study further support that dietary HUFA composition can significantly affect broodstock reproductive performance as well as subsequent performance of eggs and larvae.  相似文献   

10.
Variable quality and yield (percentage development from eggs) D-veligers of the scallop, Pecten fumatus Reeve, prompted assessment of fertilization and incubation protocols. Various sperm to egg ratios were tested on eggs suspended in sea water at different densities. Ratios of 1000:1 led to the highest D-veliger yield when eggs were incubated in suspension at one per millilitre. With increasing egg densities, the addition of 1000 sperm per egg led to increasing average numbers of sperm visible at the periphery of each egg, indicating that fewer sperm were necessary for fertilization at higher egg densities. The time period and temperature over which released gametes were stored before fertilization were also found to significantly affect D-veliger yield. Decreasing gamete storage temperature from 26 to 14oC increased D-veliger yield, as did a reduction in the gamete storage period from 6 to 1 h. The incubation of embryos at densities in the 5-50 ml-1 range did not affect D-veliger yield. A significant increase in total bacterial counts in the culture water occurred with increasing embryo stocking densities. However, presumptive Vibrionaceae counts did not increase significantly with increasing embryo stocking densities. In a comparison of the viability of self- and cross-fertilized embryos and larvae, fewer self-fertilized embryos developed to D-veliger stage; however, percentage survival, although highly variable, did not differ significantly in subsequent larval rearing. Cross-fertilized larvae had attained a significantly larger size by day 7.  相似文献   

11.
With the aim of improving artificial fertilization (AF) in turbot, Scophthalmus maximus (L.), a series of fertilization experiments was carried out under dry conditions and different wet conditions (eggs/sea water: 2V/V and V/V). Another series of fertilization experiments was carried out with different quantities of sperm pool to determine the optimal ratio of spermatozoa to eggs for each AF method. Sperm pool from two males and eggs from spawns with a viability rate of > 70% were used. The sperm pool’s density (0.4–5.18 × 109 sperm mL–1) and motility (1–5) had been assessed previously. Significantly different fertilization rates were found when comparing 2V/V and V/V wet conditions. Significantly higher fertilization rates were found in dry fertilization when the sperm–egg ratio was > 9000 spermatozoa per egg and, under wet condition V/V, at 3000–4000 spermatozoa per egg.  相似文献   

12.
The cytological process of induced gynogenetic development and subsequent chromosome duplication by a cold shock treatment was observed in Japanese flounder Paralichthys olivaceus (Temminck et Schlegel). Mature eggs were at the metaphase of the second meiosis when inseminated with ultraviolet (UV)-irradiated sperm of red sea bream Pagrus major . After the beginning of cold shock treatment, the previously visible spindle became invisible, probably due to the side effect caused by cold shock treatment. The chromosomes at the centre of the metaphase plate were condensed. This condition continued during the duration of the cold shock treatment and several minutes after it. The release of the second polar body was blocked and it developed into a female-like pronucleus. Then, it fused with the female pronucleus to generate a diploid zygotic nucleus, and the egg exhibited the first mitosis. Consequently, the haploid female chromosome set of the egg was doubled by the inhibition of the second polar body release. There was a significant delay in developmental time in the gynogenetic eggs when compared with that in the normal eggs. From the time of insemination to early cleavage, the UV-irradiated heterospecific sperm nucleus remained condensed.  相似文献   

13.
Cryoprotectant is the crucial factor in the cryopreservation process. In general, there are two types of cryoprotectant, permeating and non‐permeating cryoprotectants. Dimethyl sulfoxide (DMSO) and egg yolk are common permeating and non‐permeating cryoprotectants respectively. Hence, the objective of the present study was to determine the best proportion of DMSO and egg yolk for the cryopreservation of Rasbora tawarensis sperm. A completely randomized experimental design was used in this study which involves two types of cryoprotectant and their combination at different concentrations, namely 5% DMSO, 5% egg yolk, 5% DMSO + 5% egg yolk and 2.5% DMSO + 2.5% egg yolk. Every treatment was conducted in three replicates. Combination of 5% DMSO + 5% egg yolk gave the best results cryoprotectant treatment had significant effects on sperm motility, fertilization and hatching rate of the R. tawarensis eggs (p < .05). It is concluded that the best proportion of cryoprotectants for sperm cryopreservation in this species is 5% DMSO + 5% egg yolk.  相似文献   

14.
Folate mobilization from the yolk compartment during larval development was studied by analysing the folate concentration in whole body, embryo and yolk in a single batch of Atlantic halibut, Hippoglossus hippoglossus L., eggs and larvae that showed successful fertilization and development. There was a net loss of approx. 50% of folate from yolk during endogenous feeding. Further, only 23% of the decrease in yolk folate was retained in the larval body. The data suggest a need for folate for metabolic and growth purposes during embryogenesis of approximately 2 μg g?1 weight gain. Relative to these data and published folate requirement for cold‐water species, batches of egg from 16 Atlantic halibut brood fish contained variable and, for some batches, critically low levels of folate. This may constitute a potential problem for larval development until start feeding.  相似文献   

15.
Twenty egg batches spawned naturally from 17 different females over two spawning seasons were used to evaluate the egg quality of cobia Rachycentron canadum. A reduction in egg size was observed towards the end of the spawning season for both years. The proportion of floating eggs demonstrated a positive linear relationship with both yolk‐sac larval survival (r2=0.91, P<0.05) and batch larval production (r2=0.80, P<0.01). Viable egg batches (i.e. fertilization success >50%) were of higher batch fecundity, had larger eggs and a higher proportion of floating eggs than non‐viable batches (i.e. 0% fertilization success). Also, biochemical analyses revealed that these viable eggs had significantly higher protein and amino acid contents. A multiple regression model based on the proportion of floating eggs, batch fecundity and fertilization success provided the most accurate predictions of batch larval production (r2=0.95, P<0.001). Similarly, using the egg content of arginine/glycine and methionine significantly increased the correlation coefficient in the multiple regression model predicting larval deformity (r2=0.92, P=0.002). This study reveals that accurate determination of egg quality in cobia can be improved using a combination of several variables rather than a single variable.  相似文献   

16.
In this study, the embryonic development of the eggs in the Mastacembelus mastacembelus (Bank & Solender, 1794) was examined. At the same time, possibilities of artificial breeding through artificial insemination were investigated. Artificial insemination was achieved by mixing the eggs of the mature female and sperm of the mature male samples caught with gill nets (22 × 22) in Ataturk Dam Lake in Turkey. To this end, first in a Petri dish (100 × 20), the testes were cut into small pieces with a lancet and the mixture of sperm–testes‐tissue was obtained. The fertilization rate of the eggs was found to be 80%. The diameter of the eggs ranged from 2.015to 1.147 mm. The perivitelline space formed 0.5 h after insemination. The first cleavage occurred at the animal pool 4 h after insemination. The oil droplets had fused to a single droplet 19 h after insemination. The blastoderm became an embryonic shield 30 h after insemination. The blastoderm covered almost half the egg 40 h after insemination and embryonic body was formed. The blastoderm covered almost the whole egg 50 h after insemination. Some somites were discernible 59 h after insemination. The embryonic body reached two‐third of the circumference of the egg 70 h after insemination. The tail bud began to separate from the yolk 77 h after insemination. A newly hatched larva was observed at 85 h after insemination.  相似文献   

17.
中国对虾精子入卵过程的观察   总被引：2，自引：1，他引：2  
利用光镜和电镜对中国对虾精子入卵过程进行了观察。结果表明，精子的核物质籍胞吐作用穿过卵黄膜到达卵膜，其余部分则留在卵黄膜外。只有在卵子激活前到达卵膜的精子才能参与受精作用，其余的精子将被卵子激活所形成的胶质层推离卵子。中国对虾精子激活过程，没有发现顶体丝的形成。精子的入卵开始于卵子的皮层反应后期，此时精卵的接触逐渐密切，首先接触部位的卵膜稍有突起，然后开始下陷，同时这一部位的卵膜变得粗糙不平，随后卵膜解体，精子由此进入卵子。中国对虾精子的入卵位置是随机的，有多精入卵的现象。  相似文献   

18.
This study was designed to determine the effect of ovarian fluid pH of stripped unfertilized channel catfish, Ictalurus punctatus, eggs on fertilization and hatch rate of channel catfish ♀ x blue catfish, Ictalurus furcatus♂, hybrid catfish eggs. A significant correlation was established between ovarian fluid pH of stripped channel catfish eggs and hybrid embryo hatch rate (R2 = 0.75, P = 0.01), suggesting ovarian fluid pH of stripped catfish eggs prior to fertilization can be predictive of the hatching success of hybrid catfish embryos. These data were used to categorize pH of stripped eggs: pH <7.0 as “low pH eggs,” pH 7.0–7.4 as “medium pH eggs,” or pH >7.4 as “high pH eggs” quality eggs. The range in percent hatch rate for these pH categories was <15%, 15–30%, and >30%, respectively. Higher calcium concentrations during incubation do not appear to improve hatching success of “low pH eggs.” The predictive model presented herein describes a quick method for evaluating stripped catfish eggs for hybrid fry production in catfish hatcheries.  相似文献   

19.
Egg content originating from ruptured ova progressively reduced the success of fertilization in coho salmon (Oncorhynchus kisutch) eggs. The salmon egg differs in ionic composition from the ovarian fluid in exhibiting higher K+ and Mg2+ and lower Na+ concentrations. Normal ovarian fluid induced spermatozoan motility whereas ovarian fluid contaminated with egg content progressively lost the ability to induce motility. Loss of motility was related to decreasing Na+K+ ratios in the ovarian fluid, indicating that reduced fertility may be caused by inactivation of sperm cells in the insemination medium. Removal of contaminated ovarian fluid by rinsing ova in isotonic media induced spermatozoan motility and restored fertility completely. The use of an isotonic NaHCO3 solution for rinsing of ova is suggested as a routine procedure for artificial insemination in salmonids where the presence of broken eggs is suspected.  相似文献   

20.
Banded morwong (Cheilodactylus spectabilis) are of interest for marine finfish aquaculture in temperate southern Australia. To improve their ovulatory response, adult females were implanted during the autumn spawning season with slow‐release pellets containing 0–400 μg luteinizing‐hormone‐releasing hormone analogue (LHRHa)/kg body weight within 24 h of capture from the wild. Compared to the sham control group, animals treated with LHRHa produced significantly more eggs on each day after implantation for the following 7 d (91 ± 39 and 290 ± 38 mL) and a higher proportion ovulated (8/12 and 27/27). Of fish treated with LHRHa, 93% ovulated 2 d after implantation and 79% ovulated three times at 2‐d intervals, whereas control animals showed no cyclicity of ovulation and few ovulated more than once. Egg production was highest at the first ovulation after LHRHa treatment and declined at subsequent ovulations. In a second experiment investigating the range 100–400 μg LHRHa, there was no effect of dose rate on ovulation parameters, which additionally examined implantation either immediately after capture or after a 5‐d delay. Compared to immediate implantation, a delay resulted in a lower proportion of animals that could be stripped after implantation (100 and 50%, respectively) and the volume of eggs was lower (135 ± 15 and 107 ± 10 mL). The egg quality was poor following delayed implantation, resulting in no fertilization after artificial insemination compared with immediate implantation in which fertilization and hatch rates were higher for eggs collected on Day 2 after implantation (79 ± 8% and 58 ± 9%) than on Day 4 (23 ± 7% and 15 ± 6%). Thus, it is important to implant animals as soon as possible after capture to ensure optimum egg quality. Good‐quality eggs were buoyant and spherical and had a diameter of 1050 ± 25 μm with a single pigmented oil droplet of 190 ± 9 μm. When a separate large batch of eggs collected 2 d after implantation with 100 μg LHRHa was inseminated and cultured at 18 C, larvae hatched after 63 ± 2 h at a standard length of 2.6 ± 0.4 mm. Newly hatched larvae were buoyant and transparent with only a few melanophores, eyes were nonpigmented and jaws were nonfunctional. By the fourth day, jaws were functional and eyes were fully pigmented. Utilization of the endogenous yolk and oil was completed by Day 6, and swimming commenced with exogenous feeding. Larvae, initially fed lipid‐enriched rotifers followed by Artemia, reached 8.9 ± 0.7 mm length on Day 55, after which they metamorphosed to the postlarval paperfish stage of development, 22 ± 0.9 mm on Day 100, and 43 ± 1.0 mm at 6 mo of age. The results show that treatment of wild‐caught females with slow‐release pellets containing LHRHa is effective for the production of eggs for hatchery rearing.  相似文献   

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