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1.
日本沼虾体表寄生物对胚胎附着的影响   总被引:3,自引:0,他引:3  
用扫描电镜技术研究了体表寄生物对日本沼虾(Macrobrachium nipponense)受精卵(胚胎)附着的影响,发现在流产个体1-4对腹肢原肢与内肢的表面密布钟虫类原生动物,这些寄生原生动物影响粘液腺的分泌活动,使其不能正常分泌粘液,受精卵的被膜、卵柄及卵索均不能正常形成,卵与卵之间的摩擦力加大,胚胎供氧困难,最终导致死胎和流产,体表寄生物是造成养殖日本沼虾胚胎提早脱落的重要原因之一。  相似文献   

2.
锯缘青蟹卵膜变化与卵子附着研究   总被引:13,自引:1,他引:12  
康现江 《水产学报》2000,24(6):500-504
利用光镜和电镜观察了锯缘青蟹成熟卵及其受精后卵膜变化和卵子附着特征。锯缘青蟹成熟卵子卵膜有三层即外层、内层和质膜。卵子产出后,无论受精与否,外层和内层卵黄膜形成壳膜,与卵子附着有关。刚产出的卵子卵膜具有溶胶性和延展性,卵子与刚毛表面之间或卵子之间接触便粘在一起,由于刚毛摆动和卵子的重力作用,形成卵柄或卵索。卵子受精后,发生皮层反应形成受精膜。由壳膜和受精膜构成的孵化膜为初级卵膜,保护胚胎发育,直至  相似文献   

3.
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   

4.
This study was conducted to determine whether water source and water treatment affected flame angelfish (Centropyge loriculus) reproduction. Flame angelfish broodstock were maintained and monitored for reproductive performance (fecundity, egg fertilization rates and egg viability) in either untreated well‐water (WW), sterilized ocean water (OW) or WW treated by intensive recirculation treatment (biological filtration, protein skimming, UV sterilization and mechanical filtration) (RAS). Results of this experiment indicated that although pairs maintained in WW initially exhibited good spawning performance, fecundity, egg fertilization rates and egg viability declined after 25 weeks. Treatment of WW by recirculation did not significantly improve flame angelfish reproductive performance with only moderately improved fecundity compared with pairs in the WW treatment. In contrast, pairs held in sterilized OW exhibited significantly greater fecundity, egg fertilization rates and egg viability from week 25 onwards than pairs in either the WW or RAS treatments. However, in the process of developing OW biosecurity protocols, we found that sterilization of OW using chlorine at levels >25 mg L?1 (30 min) negatively affected flame angelfish egg fertilization rates indicating that alternative methods of water sterilization may be warranted.  相似文献   

5.
Egg strings of salmon lice, Lepeophtheirus salmonis (Krøyer 1837), collected from farmed and wild Atlantic salmon had similar length and number of eggs string?1. Egg production was investigated at water temperatures from 7.1 °C to 12.2 °C. A regression model indicated that at low temperatures egg strings were longer and had more eggs. Mean length of single eggs was significantly smaller and the percentage of non‐viable eggs in the strings was higher at 7.1 °C than at 12.2 °C. Adult females survived for up to 191 days at 7.2 °C, and during this period 11 pairs of egg strings were produced.  相似文献   

6.
皱纹盘鲍卵的形态与超显微结构↑(*)   总被引:14,自引:0,他引:14       下载免费PDF全文
本文用扫描电镜和透射电镜观察了皱纹盘鲍成熟未受精卵和受精卵的形态及超显微结构。皱纹盘鲍的成熟卵无卵极标志,卵质中含有线粒体、内质网和高尔基复合体等细胞器,未发现中心粒。皮层中有皮质小泡,受精后发生皮层反应。在鲍的受精卵中,线粒体、高尔基复合体和内质网的数量明显减少。在鲍的成熟卵和受精卵中,均观察到光滑内质网合成脂滴以及脂滴形成卵黄粒的现象  相似文献   

7.
The size and specific gravity of eggs of marine pelagic fish partly determine their dispersal and survival. Using an original dataset of anchovy and sardine eggs, sampled in spring over the last decade in the Bay of Biscay, we provide a parameterization of these properties on ambient water temperature and salinity. We used the density gradient column for measurement of egg specific gravity. The column was also filled with homogeneous water for sinking velocity experiments. For anchovy, these experiments confirm that the effect of egg permeability through the chorion could be neglected when modelling sinking, while it has to be considered for sardine, its perivitelline space representing 78.6% (±6.2%) of the total egg volume, as opposed to 5–10% for most teleosts species. We estimated a coefficient of permeability of the chorion of 0.0038 mm s?1. However, permeability should not affect the measurement of sardine egg specific gravity in a gradient column, provided a minimum duration before reading is respected for equilibrium to be reached. In relation to their environment, we found that the egg specific gravity is largely determined by sea surface salinity for both species, whereas egg size is weakly but significantly impacted by temperature, for sardine only. On average, the estimated difference in specific gravity between egg and surface water is ?0.92 σT for anchovy and ?1.06 σT for sardine. The detailed parameterization of the relationship between eggs and water properties should prove useful, in particular to modellers dealing with the dispersal of fish early life stages.  相似文献   

8.
Pseudocapillaria tomentosa is a common pathogen of zebrafish (Danio rerio) in research facilities. We developed a method to collect and concentrate the nematode eggs using a modified sugar centrifugation method and documented their normal development. Embryonating stages with blastomere formation followed by elongation of the embryo prior to larva formation cumulated in developed larvae inside the eggs and hatching after 5–10 day. We then evaluated the efficacy of heat and chlorine to kill them based on a larva development assay. Eggs were exposed to 40, 50, 60 °C for 30 min and 1 h. Chlorine treatment was performed at 100, 250, 500, 1000, 3000 and 6000 ppm for 10 min. Samples exposed to 40 °C for 30 min or 1 h showed incidences of larvated eggs similar to controls. In contrast, no larvation occurred with eggs exposed to either 50 or 60 °C for 30 min or 1 h. Remarkably, in repeated assays, samples exposed to low doses of chlorine (100, 250, 500 and 1000 ppm for 10 min) showed significantly higher incidence of larvation than controls. Eggs treated with 3000 ppm for 10 min did not develop larvae, and no eggs were found after 6000 ppm treatment.  相似文献   

9.
To investigate egg storage capacity of the copepod Acartia bilobata for aquaculture interest, we tested hatching success rate (HSR) of inclusive eggs (mixture of all egg types) after 4°C storage. The HSR peaked after 14 days storage when incubating at 28°C for 48 hr (85.8 ± 1.6%) and 72 hr (87.6 ± 0.9%), then gradually declined until 1 year (48 hr: 7 ± 0.6%; 72 hr: 19.4 ± 3.9%). Reallocation of fatty acid profile suggests that docosahexaenoic acid (DHA) is correlated with the HSR of A. bilobata eggs. Additionally, we investigated the HSR of diapausing eggs (unhatched eggs after 72 hr incubation of the inclusive eggs) after 4°C storage. Their HSR peaked after 14 days storage (48 hr:75.3 ± 3.5%; 72 hr:78.2 ± 2.1%), then gradually declined until 60 days (48 hr HSR:42.1 ± 2.3%; 72 hr HSR:53.0 ± 3.2%). Overall, we illustrated the hatchability of diapausing and quiescent eggs of A. bilobata after 4°C storage. The cold storage capacities were low (<60% HSR after 60 days), and it could be limited by the egg DHA content. Our findings provide implications for future studies aiming to improve cold storage techniques of tropical copepod eggs for aquaculture applications.  相似文献   

10.
舒在习 《畜禽业》2001,1(9):64-65
对禽蛋在贮藏期间的品质变化进行了分析,对各种贮藏保鲜技术的应用进行了探讨。  相似文献   

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