首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 796 毫秒
1.
Temperature stress on developing steelhead (Oncorhynchus mykiss) was evaluated using asymmetry of skeletal characters, fish condition factor, and metabolic fingerprints. Eggs from three female hatchery steelhead were fertilized by a single male. The eggs from each female were divided into two groups and incubated at either 8°C or 18°C. Mortality, growth, and condition factor were measured at stage 6 (32 cells), stage 20 (eyed), and stage 21 (caudal flexing). In addition, 1H-nuclear magnetic resonance (NMR) spectroscopy was used to establish metabolic fingerprints of developing eggs at the three stages. After hatching, all alevins were moved to tanks at 18°C and allowed to develop to 60 days post-emergence (DPE), at which point they were examined for structural asymmetry. Eggs incubated at 18°C experienced higher mortality, with all eggs from one hen dying at the higher temperature. Eggs incubated at the higher temperature that did survive hatched as larger larval fish than eggs incubated at the lower temperature. Fish incubated at the higher temperature exhibited greater structural asymmetry than fish incubated at the lower temperature. A principle components (PC) analysis of the metabolic fingerprints indicated that PC1 and PC2 accounted for 60% of the variance in the metabolites. Separation along PC1 corresponded to differences in developmental stage, and separation along PC2 corresponded to differences in hen. Eggs incubated at 18°C lagged behind eggs incubated at 8°C along PC1, indicating a potential problem with embryo staging. PC1 scores were highly correlated with the accumulated thermal units during development, indicating that scores along PC1 were a robust measure of developmental stage.  相似文献   

2.
The eggs of ornamental (koi) common carp Cyprinus carpi0 were stored at ambient temperature (～22–25 C) and at refrigerated temperatures (0–20 C) in extenders at different osmolalities. The treatments evaluated were dry (control), calcium‐free Hanks’balanced salt solution (C‐F HBSS), salt (NaCl), synthetic ovarian fluid (SOF), and Kurokura #2 (K2). In the first study, eggs were placed in extenders at osmolalities ranging from 130 to 450 mOsmol/kg and were fertilized after 2 h. The percentage of eyed embryos (our measure of fertilization capacity) was calculated 24 h later, and percent hatching was calculated at 60 h. Fertilization capacity of eggs suspended in C‐F HBSS (28%) or SOF (37%) was highest (P= 0.0001) at 250 mOsmol/kg, while eggs stored dry (control) had a fertilization capacity of 24%. Fertilization capacity of eggs suspended in NaCl (40%) or K2 (39%) was highest (P= 0.0001) at 200 mOsmol/kg. The percent of eyed embryos and percent hatch were found to be positively correlated (r= 0.9914). In the second study, eggs were stored in these extenders with the most effective osmolality from the previous study to evaluate percent eyed embryos and hatching over time. Samples of eggs were fertilized at every hour for 7 h. Eggs in the extenders C‐F HBSS and SOF yielded the highest (P= 0.0001) percent eyed embryos during 7 h. Percent hatch of these eggs was not significantly different (P= 0.1258) among treatments at each time interval. Eggs stored in the extenders SOF, C‐F HBSS, and NaCl had higher fertwzation capacity (P= 0.0271) at 7 h than did the dry control. Eggs were also stored at refigerated temperatures in these four extenders at the most effective osmolalities from the first study. A dry control (no extender) was also compared. The third study compared quality of eggs stored for 0, 2, 4, or 6 h in each of the extenders at 5 C or at ambient temperature (～22–25 C). Eggs suspended in C‐F HBSS had significantly higher fertilization capacity at ambient temperature over time than did eggs stored in NaCl, SOF, K2, or the dry control. Eggs suspended in C‐F HBSS and the dry control had significantly higher fertilization capacity at 5 C over time than did eggs stored in NaCl, SOF, or K2. Eggs held dry had higher hatch at ambient temperatures (P= 0.0001) and at 5 C (P = 0.0002) over time than did eggs stored in any extender. At 6 h, fertlllvltion capacity with eggs in C‐F HBSS or K2 was higher than with NaCl, SOF, or the dry control. The fourth study used C‐F HBSS (250 mOsmol/kg) as the extender to evaluate fertilizing and hatching ability during storage at temperatures 0, 5, 10, 15, 20, or 25 C. Eggs were fertilized after 0, 1, 3, 6, 9, or 12 h of storage. Eggs stored at 15 C had significantly higher fertilization capacity (P= 0.0001) than at any other temperature. Eggs stored at 15 C and 10 C had significantly higher hatch (P= 0.0001) than at any other temperature. Fertilization capacity at 12 h was significantly higher in eggs stored at 10 C (33%) or 15 C (29%) than at any other temperature. Storage of koi carp eggs in C‐F HBSS at remgerated temperatures extended fertilizing ability for as long as 12 h compared to storage in NaCl, SOF, K2, or the dry control.  相似文献   

3.
Groups of Atlantic salmon (Salmo salar) eggs were incubated at 12, 10 and 8° C. At 12° C mortality was high and fry averaged little more than half the weight of those hatched at 10 or 8° C. Development of alevins to the ‘swim-up’ stage was also abnormal at 12° C. The results suggest that 10° C is optimal for incubating Atlantic salmon eggs. For the period between hatching and swim-up, the most favourable temperature varies according to the temperature used during incubation. Mortality rate during the first 6 weeks of feeding was correlated with mortality during earlier development. Total numbers of day-degrees required by the eggs and fry to reach the eyed, hatching, and swim-up stages of development were significantly less at 12° C than at 10 or 8° C. However, total day-degrees required to reach an average weight of 0.5 or 0.6 g were almost the same regardless of temperature during hatching.  相似文献   

4.
The effects of temperature and salinity on the embryonation period and hatching success of eggs of Benedenia seriolae were investigated. Temperature strongly influenced embryonation period; eggs first hatched 5 days after laying at 28 degrees C and 16 days after laying at 14 degrees C. The relationship between temperature and embryonation period is described by quadratic regression equations for time to first and last hatching. Hatching success was >70% for B. seriolae eggs incubated at temperatures from 14 to 28 degrees C. However, no B. seriolae eggs embryonated and hatched at 30 degrees C and <2% of eggs hatched when incubated at 24 degrees C after transfer to 30 degrees C for 48 h. Embryonation period was similar for eggs incubated in sea water at 25, 30 and 35 per thousand salinity, but increased for eggs incubated at higher or lower salinities. When incubated at salinities ranging from 25 to 45 per thousand, more than 70% of B. seriolae eggs embryonated and hatched. Hatching success was lower at 20 and 50 per thousand salinity and few or no eggs hatched at 10 and 15 per thousand. Hatching of B. seriolae eggs can be prevented by desiccation for 3 min, by immersion in water at 50 degrees C for 30 s or by treatment with 25% ethanol for 3 min.  相似文献   

5.
NORIYUKI  HORIE  TOMOKO  UTOH  YOSHIAKI  YAMADA  AKIHIRO  OKAMURA  HUAN  ZHANG  NAOMI  MIKAWA  ATSUSHI  AKAZAWA  SATORU  TANAKA  HIDEO P  OKA 《Fisheries Science》2002,68(5):972-983
Development of embryos and larvae in the common Japanese conger Conger myriaster was observed after artificial fertilization. Eggs were obtained from females matured artificially by hormone injections and milt was obtained from males matured naturally. Fertilized eggs were kept in seawater at 12–14°C. The first cleavage occurred at 4 h, epiboly began at 24 h, the embryonic body was formed at 38 h and hatching occurred at 84 h after insemination. Newly hatched larvae were approximately 2.5 mm (total length) and similar to those of Anguilla japonica in terms of external features. The mouth and anus opened on the 7th day after hatching. Pigments began to appear at the tip of the tail on the 10th day. The total length of the larvae reached approximately 8 mm on the 11th day. Eye pigmentation began on the 14th day. One larva lived for 19 days without food.  相似文献   

6.
The elimination of egg stickiness is required for effective artificial reproduction of northern pike, but until now, available methods have required at least 40 min. Sodium hypochlorite was tested under laboratory conditions, and exposure to aqueous concentrations of 0.025–0.05% for 40 s effectively eliminated stickiness without adverse effects. Fertilization and hatching rates in laboratory trials were similar to those observed in eggs treated with traditional methods using clay or milk for 40 or 60 min, respectively, as well as those without treatment. Testing using conventional hatchery incubation techniques did not reveal differences in fertilization rates, while the number of hatched larva was significantly higher in eggs treated with sodium hypochlorite vs. clay. Eggs treated with sodium hypochlorite retained transparency, which facilitated monitoring of embryo development.  相似文献   

7.
ABSTRACT:   To protect chum salmon eggs from water mold infection during incubation, the eggs were treated daily with sodium hypochlorite solution (NaOCl) at 10 mg/L residual chlorine concentration for 15 min during their developmental period from fertilization to eyed stages. The number of infected eggs and number of eyed eggs were observed on day 23 of incubation. The percentage of infected eggs to total eggs was significantly lower with NaOCl treatment (1.8 : 33.4%) than in the control (11.3 : 59.3%, P  < 0.01). The percentage of eyed eggs to total eggs was significantly higher with NaOCl (85.9 : 98.6%) than in the control (66.1 : 97.5%, P  < 0.01). The antifungal activity of NaOCl resulted in improving egg survival. Accordingly, NaOCl is a useful antifungal agent against water mold infection on chum salmon eggs.  相似文献   

8.
This study was conducted to examine the effects of different forms and concentrations of ascorbic acid (vitamin C), and different enrichment times (24 and 48 h post ovulation) on egg, embryo and alevin ascorbate concentrations and survival of rainbow trout (enrichment was at the ova stage). In experiments 1 and 2, fertilized eggs were immersed in water containing ascorbate at 0 (control), 100, 1000 mg L?1 l ‐ascorbic acid (AA) and 2000 mg L?1 l ‐ascorbyl monophosphate (AP). In experiment 3, 0 (control), 500 and 1000 mg L?1 AA neutralized (N) with NaOH, 1000 mg L?1 AA non‐neutralized (NN), 1000 and 2000 mg L?1 AP immersions were used. The mean total ascorbic acid (TAA) and dehydroascorbic acid (DHA) concentrations were measured before fertilization, at 3 and 24 h after fertilization, at the eyed stage, and in hatched alevins. We observed significant differences in TAA concentration at different immersion levels at 3 and 24 h after fertilization. Survival decreased significantly depending on the level of vitamin C, pH of the solutions and immersion time. We suggest that when broodstock rainbow trout do not have enough vitamin C in their ovaries, immersion of eggs in 1000 mg L?1 of neutralized AA may be useful.  相似文献   

9.
Eggs of Pacific halibut were incubated under various environmental conditions. Optimum hatching occurred over a temperature range from 6 C to 8 C, whereas temperatures of 3, 10, and 11 C were lethal. Development time from fertilization to 50% hatching varied from 250 h (9 C) to 320 h (6.5 C). Salinity effects on hatching were not as critical as temperature, as long as eggs were floating during the incubation period. Light intensity between 5 and 15 lux did not affect hatching success, but high light intensity (15 lux) and red and blue light (5 lux) produced high levels of larval abnormality. Simulated transport of unfertilized eggs indicated that the eggs can be safely moved and that fertilization rate is acceptable during the first 12 h after collection.  相似文献   

10.
2008年10月,在福建宁德水产技术推广站进行了大黄鱼（Pseudosciaena crocea,♀）×黄姑鱼（Nibea alb-iflora,♂）杂交,观察了杂交子代胚胎发育。大黄鱼和黄姑鱼亲鱼平均体质量和体长分别为405 g、27.9 cm和390g、24.8cm,采用干法人工授精。受精卵浮性,为单油球端黄卵,卵径1060～1500μm,油球379.8μm左右。在水温25.8～26.2℃,盐度26的条件下,经18h55min半数受精卵破膜,胚胎发育分为卵裂期、囊胚期、原肠期、肌节出现期、心跳期、肌肉效应期、出膜前期和出膜期,初孵仔鱼全长2.75～2.98mm,受精率约为14.4%,孵化率约为31.9%,畸形率约为30%。共培育杂交初孵仔鱼5万尾。3日龄仔鱼开口摄食轮虫,7日龄开始摄食小型挠足类。  相似文献   

11.
2008年10月,在福建宁德水产技术推广站进行了大黄鱼（Pseudosciaena crocea,♀）×黄姑鱼（Nibea alb-iflora,♂）杂交,观察了杂交子代胚胎发育。大黄鱼和黄姑鱼亲鱼平均体质量和体长分别为405 g、27.9 cm和390g、24.8cm,采用干法人工授精。受精卵浮性,为单油球端黄卵,卵径1060～1500μm,油球379.8μm左右。在水温25.8～26.2℃,盐度26的条件下,经18h55min半数受精卵破膜,胚胎发育分为卵裂期、囊胚期、原肠期、肌节出现期、心跳期、肌肉效应期、出膜前期和出膜期,初孵仔鱼全长2.75～2.98mm,受精率约为14.4%,孵化率约为31.9%,畸形率约为30%。共培育杂交初孵仔鱼5万尾。3日龄仔鱼开口摄食轮虫,7日龄开始摄食小型挠足类。  相似文献   

12.
We report the effect of salinity and temperature on the viability of stored culture-based subitaneous eggs of the calanoid copepod Acartia tonsa for use of copepods in fish larvae culture. Quiescence induction was recorded at 17 and 25 °C, in salinities from 0 to 30. Quiescence was strongly induced at 0 salinity and partially at 5 in both temperatures. Eggs incubated at 0 salinity for up to 12 days at both temperatures showed a decline in the fraction able to be induced into quiescence by abrupt salinity changes. The hatching success of eggs that were able to enter quiescence stabilized after a 1-day incubation and remained ∼25% viable for 12 days in 17 °C. On the contrary, the 25 °C trial showed a gradual decline in viability until stabilizing ∼10% at day 7 and onwards. Longterm 17 °C incubation for 35 days showed that eggs remained quiescent with a viability of ∼14%. Hence, we recommend salinity storage of A. tonsa subitaneous eggs as a relevant shortterm technique, and a suitable alternative to the recently proposed cold storage of eggs when eggs are to be shipped from the copepod producer to a given fish larvae hatchery.  相似文献   

13.
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   

14.
About 70% of eggs of Cyprinus carpio reached the eyed stage in fertility tests with 1 ml of cryopreserved semen added to 1 g of eggs. When 1 ml of semen was added to 100 g of eggs, few eggs reached the eyed stage. In two fertility tests with sperm preserved for 342 days, using 5 g of eggs inseminated with 1 ml of semen, percentages of eyed eggs were 31.5 and 25.5, respectively. In a series of fertility tests, the chemical constituency of the medium in which fertilization was attempted influenced the fertility of cryopreserved sperm.  相似文献   

15.
Egg and larval quality of red snapper, Lutjanus campechanus from natural spawns of domesticated brooders and hormone-induced spawns of wild fish were compared. Eggs and larvae from natural spawns were found to be more viable in terms of fertilization, hatching and survival rate. Also, eggs from natural spawns were larger, and eggs and recently hatched larvae had larger oil-globule. These findings indicate that natural spawning of red snapper can be a sustainable and reliable source of good quality eggs.  相似文献   

16.
To standardize conditions during the final maturation and ovulation of ovarian follicles from Japanese eel, we have developed a culture system for the production of fertilizable eggs from post-vitellogenic ovarian follicles in vitro. Post-vitellogenic ovarian follicles were incubated in culture medium supplemented with 17α,20β-dihydroxy-4-pregnen-3-one (DHP) with or without bovine serum albumin (BSA) to assess the effects of protein concentration. Eggs that ovulated during incubation were fertilized, and the remaining follicles were incubated in prostaglandin F2α (PGF2α) for a further 3 or 6 h before fertilization. Male eels were injected repeatedly with human chorionic gonadotropin. The quality of eggs obtained under the different culture conditions was evaluated after artificial fertilization in terms of hatching success. Hatching rates tended to decrease with increasing concentrations of BSA in the incubation medium in a dose-dependent manner. The addition of PGF2α drastically increased the number of eggs that ovulated, but the rate of hatching was greatly decreased compared with eggs obtained earlier by DHP incubation alone. The larvae obtained from artificially fertilized eggs produced in vitro survived for 14 days without feeding. We conclude that in vitro culture systems thus have a great potential for the acquisition of good quality eggs under tightly controlled artificial conditions, culminating in the production of eel larvae.  相似文献   

17.
ABSTRACT:   To elucidate the utilization of the major yolk nutrient stocks in eggs and larvae of walleye pollock Theragra chalcogramma , the contents of free amino acids (FAA), the major yolk protein (180 kDa lipovitellin originated from vitellogenin B in ovulated eggs: oLv B), and lipids were measured. Most eggs hatched 18 days after fertilization at 5°C, and all larvae absorbed almost all their yolk mass by 28 days. The total FAA content showed no change during the first 6 days, and then decreased to 28% of the initial level by 18 days. The oLv B contents, measured by an enzyme-linked immunosorbent assay using a specific antiserum against oLv B, gradually decreased from 6 to 18 days, followed by a rapid decline. The content of phospholipids (PL) and triacylglycerols (TG) showed no marked change until hatching, and then decreased until disappearance of yolk sac. From these results, it is proposed that there are two main periods for nutrient utilization in embryos and larvae of walleye pollock. In the first period, FAA was mainly utilized until 18 days after fertilization. Active utilization of oLv B and lipids (PL and TG) instead of FAA occurred during the second period from 18 to 28 days.  相似文献   

18.
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   

19.
Optimal egg viability storage conditions for two commercial fairy shrimps, Branchinella thailandensis and Streptocephalus sirindhornae, were investigated. Eggs for each treatment were kept under eight different conditions at four different temperatures for 24 months. Every 2 months, representative eggs were hatched to evaluate hatching percentages. Low temperature and oxygen, darkness and dry conditions significantly influenced egg hatchability of both species. Undehydrated eggs hatchability in all conditions ranged from 0 to 10% in S. sirindhornae and 0 to 20% in B. thailandensis. Hatching percentages of B. thailandensis were higher than those of S. sirindhornae. Hatchability under all experimental regimes continuously decreased over time, except for dry eggs stored at ?18°C in dark‐anoxic conditions. Hatchability was markedly delayed in both species over time. We demonstrate that both species’ eggs can be stored at ?18°C at least for 24 months with high hatchability in B. thailandensis (80%) and S. sirindhornae (60%) under dry, dark, anoxic conditions.  相似文献   

20.
Diapause eggs of Centropages hamatus were used to investigate the effect of temperature and duration of incubation on egg hatching. Eggs were incubated for 10, 12, 14, 16, 20, 24, 28, 32, 36 and 40 h at 15°C and 14L–10D. After incubation for the designated period, eggs were transferred to 25°C and monitored periodically to determine egg hatching. Control eggs were incubated solely at 15°C and monitored for egg hatching. The greatest daily hatching success of eggs occurred within 1 or 2 days after transfer from 15°C to 25°C, while the controls required 3–4 days. The cumulative hatching success of eggs was significantly lower than the control, with the exception of eggs held for at least 36 h at 15°C before transfer to 25°C. These results indicate that overall time to hatching of diapause eggs of C. hamatus can be reduced by transferring the eggs to a higher temperature, for example, 25°C, following a minimum period of time (36 h) at reduced temperature, for example, 15°C. Exposure to 15°C for only 10 h does not appear to be sufficient to result in any subsequent hatching at higher temperature.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号