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 31 毫秒
1.
This study was conducted to determine suitable conditions fordisinfecting eggs of gilthead sea bream (Sparus aurata)with glutaraldehyde. Effects of the developmental stage (4–8 cells,morula, blastopore closure or heart beating), of the concentration (C = 200,300or 400 ppm) and of the duration of the glutaraldehyde treatment (T= 2 to 10 min) were investigated. Before the blastopore closurestage, egg manipulation and treatment induced mortality. After this stage, thetoxicity of the glutaraldehyde treatment was negligible if the value of theproduct C × T was less than 1000. Above this value, the percentage ofhatching and of normal larvae decreased and the percentage of imprisoned larvaeincreased. Toxic effects of glutaraldehyde varied according to the egg qualityat the time of the treatment. It was concluded that 200 ppmglutaraldehyde for 4 min, at the blastopore closure stage or attheheart beating stage, were acceptable conditions for disinfecting gilthead seabream eggs at 18 °C.  相似文献   

2.
Good knowledge of the spatial distribution of fish is critical to stock assessment and successful fisheries management. Depth is often the main gradient along which faunal changes occur when analyzing shelf and upper slope assemblages, and thus knowledge of the bathymetric distribution of fish species is of great importance. The depth distribution of 16 fish species (Chelidonichthys lucernus, Helicolenus dactylopterus, Hoplostethus mediterraneus, Lepidorhombus boscii, Lophius budegassa, Merlangius merlangus, Merluccius merluccius, Micromesistius poutassou, Mullus barbatus, Mullus surmuletus, Pagellus erythrinus, Peristedion cataphractum, Phycis blennoides, Serranus cabrilla, Trigla lyra, and Trisopterus minutus) of the Aegean and the Ionian Seas was evaluated by analyzing experimental bottom trawl data, using generalized additive modeling (GAM) techniques. A variety of bathymetric distribution patterns was observed. The main bathymetric zone of each species was defined based on the modeled relative density. Specifically, the lower and upper limits of the main bathymetric zone of each species were defined as the depths where the estimated relative density of the species becomes less than 1% of the maximum. This definition is proposed as a better and more informative alternative than reporting the minimum and maximum depths of encounter.  相似文献   

3.
The pseudo green water technology for sea bream(Sparus aurata) larval rearing was evaluated by analyzingresults of a 2-year study, performed in a pilot scale system. Thetechnology is characterized by the daily addition of phytoplankton in therearing tanks during the first month of rearing. Effects of egg origin,spawningseason and initial larval density on the larval rearing were investigated. Fishreared in pseudo green water systems for 60 days, presented highbiological performance in terms of survival (56 ± 16%), meanweight (62 ± 12 mg), total length (20 ± 1mm), conformity with wild standard (88 ± 9%), andfunctional swim bladder (93 ± 4%). The results present homogenitybetween the categories (origin of eggs, time of spawning, initial egg density)studied, proving the stability of the technology.  相似文献   

4.
Vasa基因编码DEAD-box家族成员中一种ATP依赖的RNA解旋酶,是决定生殖系发育的重要调控因子之一。采用同源克隆策略及SMART-RACE技术,克隆了海洋经济螠虫动物单环刺螠Vasa基因的全长cDNA,该序列长4 080 bp,开放阅读框2 322 bp,编码733个氨基酸,具有DEAD-box蛋白家族共有的全部9个保守域。整体原位杂交和半定量RT-PCR结果显示,Vasa基因在未受精卵、受精卵、2～8细胞的早期胚胎中均有明显的表达,显示其母源性提供的特点;从囊胚开始,表达量明显降低,在原肠胚表达信号主要集中在内中胚层细胞中;至担轮幼虫,表达信号进一步集中在消化道处;当发育至体节幼虫时,阳性细胞分布于消化道和体节的隔膜处,进入蠕虫状幼虫,信号仅在头部的腹刚毛附近以及后肠周围的细胞中表达。实验结果为探知刺螠动物生殖系的起源和分化以及低等型生殖腺的发生提供重要的数据。  相似文献   

5.
To further examine the concept of egg quality and the physiology of stored salmonid eggs, we investigated the effects of different oxygen tensions on the adenosine triphosphate (ATP) levels of unfertilized, activated, and fertilized chinook salmon (Oncorhynchus tshawytscha) eggs. The ATP levels of unfertilized chinook salmon eggs were 2.61±0.14 nmol ATP per egg (17.6±0.9 mol l–1 relative to cell water) and ranged from 1.98 to 3.63 nmol ATP per egg. The ATP content of unfertilized eggs maintained at 10 °C under 100% O2, 21% O2, and 100% N2 remained unaltered throughout a 120 h storage period. Storing eggs under identical conditions at 20 °C (in an effort to speed egg metabolism and ATP turnover) resulted in significant O2-independent decreases in ATP levels. However, ATP levels of unfertilized eggs exposed to 1 mmol l–1 potassium cyanide (a potent inhibitor of oxidative phosphorylation) at 10 °C were significantly decreased after 24 h and continued to decline throughout the 120 h maintenance period to about 30% of time=0 values. Maintenance with exogenous nutrients (5 mmol l–1 acetate plus 5 mmol l–1 pyruvate) over 120 h at 10 °C did not alter the ATP content of unfertilized eggs. Eggs activated by exposing them to 10 °C water for a few minutes showed a rapid decrease in ATP values, regardless of whether the eggs were fertilized or not. Following an initial 25% drop after fertilization, the ATP levels remained stable for the remainder (5 d) of the incubation period in eggs maintained in 10 °C water. Therefore, unfertilized chinook salmon egg ATP levels appear to be relatively stable and maintained by a low, cyanide-inhibitable metabolism. The stability of egg ATP levels may be one reason that salmonid eggs can be stored for several days while eggs from other fishes cannot.  相似文献   

6.
Metal pressure under farm conditions was examined on the gill and muscle tissues of farmed Sparus aurata and compared with their wild counterparts (Sparus aurata, Trachurus trachurus, Mullus barbatus). Al, Mn, Cd, Co, Cr, Cu, Ni, Pb and Zn accumulation amounts in gill tissue of farmed fish were 28.821, 37.620, 0.136, 0.300, 3.730, 2.441, 3.222, 2.474 and 127.494 mg/kg respectively. Among them, Cd, Cr, Cu and Pb concentrations in gill tissue of farmed fish were higher than that in wild fishes. Metal depositions in muscle tissue of farmed fish were far below that in the gill tissue. The accumulated Al (6.700 mg/kg) in the muscle tissue of farmed fish was higher than in wild ones. The results showed that metal accumulation levels (especially Cd, Cr, Cu and Pb) in the gill tissue of farmed fish indicate metal pressure under captive conditions. Furthermore, the calculated hazard index (HI) and total hazard index (THI) of the considered elements in the edible part of farmed fish were below the level considered safe, which elucidates that farmed fish do not pose any threat to the human consumer in terms of metal toxicity.  相似文献   

7.
Fisheries management in the Mediterranean is planned on the basis of fishing effort allocation, gear technical characteristics and minimum landing sizes (MLSs), the latter being a measure recently updated in the EU Mediterranean fisheries policy. Very few elements on the evaluation of the MLS in regard to the catch and landings of the small-scale fisheries in the Mediterranean exist and this is due to both the great heterogeneity of the sector and the lack of systematic monitoring. The catch length composition of five species (Merluccius merluccius, Diplodus annularis, Mullus barbatus, Sepia officinalis and Squilla mantis) from a yearly record of small-scale fishing operations in the Patraikos Gulf (w. Greece, e. Mediterranean) was associated with temporal (season), spatial (depth of fishing, substrate type) and fishery (métier) characteristics by means of general linear models. Smaller individuals appeared in the catch in autumn for all five species indicating this season as suitable if a seasonal fishery closure was established. When length was found to be significantly different between different métiers this was either due to smaller mesh sizes (M. barbatus) or due to gear type (M. merluccius). For all species except S. officinalis, depth significantly affected length of individuals in the catch providing in the case of M. merluccius a clear association of bigger individuals with deeper fishing grounds. Substrate types also affected the length for the species D. annularis, M. barbatus. In relation to MLSs, the sizes of Mullus surmuletus and Scomber japonicus were fully legal, M. merluccius, M. barbatus, Solea vulgaris, Trachurus mediterraneus, Pagellus erythrinus had higher than 80% of the catch over MLS, while D. annularis, Diplodus sargus, Sparus aurata and Pagellus acarne had high fractions of the total catch below MLS. The métiers where undersized individuals appear were identified. Further management implications of the findings are discussed taking into account the current management scheme and the discarding practices in the area.  相似文献   

8.
李媛媛  蔡生力  刘红 《水产学报》2012,36(11):1667-1674
卵黄磷蛋白作为卵黄蛋白的主要成分, 可为甲壳动物胚胎和早期幼体发育提供能量, 为研究其来源及合成规律, 实验应用SYBR GreenⅠ荧光定量PCR法检测了凡纳滨对虾和罗氏沼虾性腺不同发育时期卵巢和肝胰腺两种组织中卵黄蛋白原mRNA的表达水平。结果发现,凡纳滨对虾和罗氏沼虾的卵巢和肝胰腺中都有卵黄蛋白原mRNA的表达。随着卵巢的发育, 凡纳滨对虾卵巢中卵黄蛋白原mRNA的相对表达量在前5个阶段不断增加, 分别为1.1, 5.9, 10.4, 26.9, 85.0, 恢复期急剧减少, 为1.6。肝胰腺中的相对表达量也不断增加, 分别为1.3, 3.3, 7.1, 37.3, 51.6, 恢复期急剧减少, 为1.0。罗氏沼虾肝胰腺中卵黄蛋白原mRNA的相对表达量在前四个阶段不断增加, 分别为3.4, 12.6, 15.2, 38.9, 抱卵期急剧减少, 为2.9;而卵巢在整个发育过程中对卵黄蛋白原合成的贡献比较小, 分别为1.0, 1.3, 1.7, 4.8, 1.5。研究表明, 两种虾类的肝胰腺和卵巢均具合成卵黄蛋白的功能, 而且在不同的卵巢发育阶段呈现明显的规律性。  相似文献   

9.
牛雪莹  任志明  吴佳颖  母昌考  王春琳 《水产学报》2024,48(1):019609-019609
为了探究三疣梭子蟹受精卵的离体孵化技术及效果,本研究先后开展了受精卵块最适分离液种类及作用条件的筛选、分离液处理不同发育期受精卵离体孵化的差异、分离液处理对受精卵卵膜的结构影响,及分离液处理受精卵对孵化后幼体活力的影响实验。结果显示,木瓜蛋白酶是一种较为理想的分离液,在浓度为0.09 g/mL,分离时间30 min时,分离率可达到99%以上;经过分离液处理后的各期受精卵均能孵化出幼体,卵内溞状幼体期离体胚胎孵化率最高,为89.0%±3.3%,未经处理的对照组为70.0%±4.8%;卵裂期离体胚胎孵化率最低,为58.0%±3.9%,对照组为31.0%±2.3%,与对照组相比,处理组的孵化率明显提高。透射电镜结果显示,经过分离液处理的受精卵卵膜结构疏松,且厚度降低,符合处理组孵化率增加这一现象,干露、福尔马林溶液胁迫和行为学测试对不同处理组的幼体进行质量评价的结果显示,处理组和对照组幼体活力无显著差异。研究表明,实验所获得的分离液可以有效提高三疣梭子蟹受精卵的分离率和孵化率,且不影响幼体质量,可为三疣梭子蟹及其他甲壳动物受精卵的离体孵化提供参考。本研究可为三疣梭子蟹的苗种繁育提供新的技术手段,也将为基因编辑辅助育种等技术的实施奠定基础。  相似文献   

10.
European sea bass (Dicentrarchus labrax) and gilthead sea bream(Sparus aurata) are amongst the most important finfish speciescultured in the Mediterranean region. Production of these species isnowadays a well-controlled process, but knowledge of their nutritionalrequirements is still very limited. Nevertheless, a considerable amountof data has been accumulated in recent years, and the purpose of thispaper is to review the recent advances on the nutritional requirementsof sea bass and sea bream. The optimum protein to energy ratio of thediets of sea bass and sea bream seem to be higher than for salmonids,and there is some evidence that high dietary lipid levels have nobeneficial effects on fish performances. Although the essential aminoacid requirements were estimated by the ideal protein method, data basedon the dose-response method is only available for a few amino acids.Essential fatty acid requirements were estimated for sea bream juvenilesbut data is lacking for sea bass. Vitamin and mineral requirements ofthese species are practically unknown. Although the importance ofbroodstock nutrition on gonadal development, spawning and egg quality isrecognized, few studies were done to elucidate these aspects. The recentdevelopment of microparticulate diets for larvae will contribute to theaccurate evaluation of their nutritional requirements.  相似文献   

11.
Lysozyme was purified from the ovary of tilapia, Oreochromis mossambicus, with two steps, chitin coated-cellulose and Sephadex G-100, and its biological properties were investigated. Purified lysozyme had a molecular mass of 15kDa on SDS-PAGE under reducing condition. Analyses with antibody (a-EL) against the purified lysozyme revealed that serum and egg extract reacted with a-EL and the precipitin lines fused completely. The enzyme activities in serum and egg extract were inhibited by adding serially diluted a-EL. Therefore, egg extract and serum lysozyme was immunologically identical. Immunohistochemically, lysozyme was observed in the ooplasm of the oocytes laden with yolk but not in the follicle layers, egg envelope or immature oocytes (the peri-nucleolus stage). In addition, the enzyme activity in the large oocytes was higher than that in the small ones. These results suggest that lysozyme detected in the oocytes is derived from extra-ovarian tissue and transfers from the maternal circulation. Lysozyme activity in the serum of female tilapia increased with oocyte development, suggesting that the change in the enzyme level may be partially related to the reproductive events (especially vitellogenesis) of the female fish.  相似文献   

12.
Instrumental quality parameters related to freshness were evaluated for gilthead sea bream (Sparus aurata) after different storage periods on ice (2, 4, 7 and 11 days of storage) for one, four and eight days of pre-slaughter starvation. The study was carried out on 360 gilthead sea bream from five different groups reared on a commercial fish farm. Starvation period had a significant effect on fish texture: the force necessary to compress 4 mm of flesh after two days ice storage in 1 day starved fish (16.50 ± 0.59 Newtons) was less than that for four day (18.98 ± 0.63 Newtons) and eight day starved fish (20.43 ± 1.12 Newtons). Significant differences in flesh puncture and flesh compression were not detected, although these values did increase with increasing starvation period. A significant increase in pH and myofibrilar protein solubility was also detected for fish starved for one day.  相似文献   

13.
长江上游江津断面铜鱼鱼卵时空分布特征及影响因子分析   总被引：1，自引：0，他引：1  
为了解金沙江一期工程蓄水前后的长江上游铜鱼繁殖情况,2011—2014年每年5月5日—7月10日,在江津江段通过使用圆锥网捕捞鱼卵,定点进行早期资源调查。结果显示,在采集到的8 014粒鱼卵中铜鱼鱼卵数量最多,占总鱼卵数的14.76%。调查期间江津江段铜鱼卵苗年均年总径流量为22.45×107尾。2011年—2014年江津江段铜鱼鱼卵日均密度各年平均值分别为8.41、10.57、1.32和3.18个/1 000 m3,2013年和2014年铜鱼鱼卵日均密度显著低于2011年和2012年。对铜鱼鱼卵日均密度与水文环境因子进行相关性分析,发现鱼卵日均密度与透明度呈显著负相关,而2013年和2014年透明度显著高于2011年和2012年。根据鱼卵发育时期和流速推测江津白沙至羊石及榕山至兆雅两个江段为铜鱼的主要产卵区域,该区域铜鱼产卵量约占铜鱼产卵总量的56.96%。研究表明,金沙江一期工程蓄水对铜鱼产卵行为产生了影响,建议工程运行期间应根据长江上游铜鱼的产卵条件进行科学调度,并禁止在产卵江段进行捕捞。  相似文献   

14.
利用RACE-PCR技术,从牙鲆(Paralichthys olivaceus)的肝脏组织总RNA中克隆得到胰岛素样生长因子结合蛋白-1(insulin-like growth factor binding protein 1, IGFBP-1)基因的全长cDNA序列,该cDNA全长为1070 bp,开放阅读框为729 bp,编码242个氨基酸。通过系统进化树分析,牙鲆IGFBP-1与鱼类IGFBP-1基因聚为一支;通过同源性比对,牙鲆IGFBP-1基因的核苷酸序列与大菱鲆同源性最高,为95%,而其推导的氨基酸序列与其它鱼类如大菱鲆、五条鰤、黄金鲈、红点鲑、鲤鱼和斑马鱼的同源性分别为89%、89%、84%、79%、67%和67%。半定量RT-PCR分析表明,牙鲆IGFBP-1基因存在母源转录本,合子基因在孵化前的胚胎阶段及早期仔鱼中仅有较低水平的表达,在后期仔鱼中表达逐渐增高;牙鲆IGFBP-1基因在肝脏中表达量最高,在胃、脾、肠、性腺、肾、鳃、脑、心脏和肌肉中也有不同程度的表达。  相似文献   

15.
We propose a method of estimating natural mortality of marine pelagic fishes, especially for early-life stages, based on their fecundity. To estimate size-dependent fecundity, growth and mortality of Pacific anchovy (Engraulis japonicus), the most abundant fish species in coastal waters off the Korean peninsula, we undertook a synthesis of results from past studies and data. Assuming that the growth coefficient K varies with water temperature, we derived a modified von Bertalanffy growth equation covering all life stages based on otolith analysis of anchovies collected from southwestern coastal area of Korea in 1996. By revisting a past study on spawning and egg production of anchovies in the southern Korean coastal waters, we calculated a monthly-averaged fraction of mature females spawning per day to estimate that an average female anchovy spawns 36 times per year, and that the mean number of eggs produced by an average female is ca. 160 × 103 yr−1. Accepting the ‘bigger-is-better’ hypothesis, we derived a theoretical mortality curve that assumes instantaneous natural mortality as an inverse function of anchovy body length. Assuming equilibrium status of stock, estimated annual instantaneous mortality of anchovy between egg to age-1 stage was 11.3 yr−1 and estimated size-specific mortality was 1.24 d−1 mm in fork length. The derived theoretical mortality curve fit well the stage-specific mortalities, which were estimated independently based on ichthyoplankton surveys and anchovy samples collected by commercial nets, but underestimated the egg mortality (0.89 d−1 vs. 0.83 d−1).  相似文献   

16.
The spawning season and grounds of red sea bream in Hiuchi-nada, the central part of the Seto Inland Sea, were described using a new method based on monoclonal antibodies for identifying Pagrus major eggs, and the daily egg production (standardized by the incubation time and survival rate) was estimated. At the peak of spawning (May), the ranges of sea temperature, salinity, and chlorophyll a where red sea bream eggs occurred were 14.8–17.4°C, 32.0–33.0, 0.5–4.4 μg/L, respectively. The main spawning grounds of the red sea bream were confirmed as being the areas near the Geiyo Islands, Misaki Peninsula, Saijyo, Niihama. The spatial spread of red sea bream eggs increased with the egg developmental stage. The ranges of daily egg production in 2005 and 2006 were 0.3–19.3 and 0.2–6.7 × 109 eggs/day, respectively. In Hiuchi-nada, aquaculture farms are located close to the spawning grounds, and the potential spawning population from the aquaculture farms equaled or exceeded that of the estimated spawning population obtained by the egg production method. Red sea bream eggs in Hiuchi-nada might be produced by both wild and aquaculture-based spawning populations.  相似文献   

17.
The incorporation, and the capacity for desaturation and elongation in vivo, of intraperitoneally-injected,14C-labelled n-3 and n-6 C18 and C20 polyunsaturated fatty acids (PUFA) were investigated in juvenile golden grey mullet,Liza aurata. The results indicate that juvenile mullet have only limited ability to convert C18 polyunsaturated fatty acids to C20 and C22 highly unsaturated fatty acids (HUFA)in vivo. This suggests that juvenile golden grey mullet require the provision of preformed C20/22 HUFA, such as eicosapentaenoic and docosahexaenoic acids, in the diet. The impairment in the desaturase/elongase pathway was similar to that found in turbot,Scophthalmus maximus, and gilthead sea bream,Sparus aurata, being primarily at the level of Δ5-desaturase. The data from the largely herbivorous golden grey mullet juveniles are consistent with the hypothesis that marine fish in general, irrespective of dietary habits, have limited capacity for the desaturation and elongation of C18 PUFA. The defect in Δ5-desaturase activity combined with the consistent finding that arachidonic acid is selectively incorporated and retained in membrane phosphatidylinositol suggests that, like turbot and gilthead sea bream, golden grey mullet may also have a requirement for preformed arachidonic acid in the diet.  相似文献   

18.
The pharmacokinetics of ivermectin in the serum of cultured sea bream, Sparus aurata, after a single intraperitoneal injection of 100 μg kg−1 body weight was studied by the use of direct competitive ELISA. Pharmacokinetic analysis of the serum concentrations versus time points obtained was performed using non-comparmental analysis and a compartmental pharmacokinetic model approach. In the latter case a two-compartment open model with a lag time gave the best fitting. The maximum peak serum concentration was 308.4 ng ml−1 at 2 h post treatment. The AUC of ivermectin was 10700 ng h ml−1 and the elimination half-life 15.37 h, indicating a rapid uptake, high bioavailability and fast elimination of the drug by sea bream. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

19.
Two sets of experiments were carried out to evaluate the potential of eggs and endotrophic larvae of captive Paracentrotus lividus as alternative live prey for marine fish larvae first feeding. The first consisted in rearing sparids, Diplodus sargus and Sparus aurata, larvae until 15 days after hatching in a recirculation system. Compared with the commonly used live prey – rotifer Brachionus spp. – general lower values of survival and growth were obtained when fish larvae were fed with the alternative live prey. Among these, eggs showed to be the preferred feeding. Broodstock feed showed to play a fundamental role on prey quality and consequent fish larvae survival. In the second set of experiments, the 24‐h ingestions of the first feeding larvae in static water were determined for five currently cultured fish larvae species. Except for larger and more predatory Dicentrarchus labrax larvae, there was a trend for higher P. lividus egg ingestion, followed by pre‐plutei and prisms. Prey size, colour and movement affected food selection by fish larvae. It is concluded that, in spite of the alternative live prey being readily consumed by all tested fish larvae, they cannot however presently compete with rotifers in marine fish larvae first feeding.  相似文献   

20.
Body abnormalities constitute an important problem to fish aquaculture. Pigmentation, scale and skeleton abnormalities have been reported in different cultured fish species. Environmental and genetic factors or their interaction have been suggested to explain their origin. Gilthead seabream (Sparus aurata) is one of the most important European cultured species. Lordosis and lack of operculum are common abnormalities in this species, and can reach frequency of 80% or more of commercial batches. In spite of an important body of data suggesting environmental factors related with their origin, scarce and not conclusive genetic data have been reported to date. In our study, a large number of families originating from the usual production process of a commercial farm were used to estimate the heritabilities of both characters. Two independent experiments were carried out for each abnormality. Nine hundred and ninety four (5.6% lordotics; 157 full-sib families; 6.3 offspring/family) and 808 (7.9% lacking operculum; 83 families; 9.7 offspring/family) individuals were used for lordosis and lacking operculum heritability estimations, respectively. The results obtained adjusting an animal model indicated non significant heritabilities for both characters (0.021 (s.e. 0.019) and 0.032 (s.e. 0.023) for lordosis and lack of operculum, respectively). The corresponding values when a threshold model was used, though higher (0.152 and 0.203, respectively), evidenced large standard errors (0.119 and 0.146, respectively) suggesting h2 = 0 as the most confident hypothesis (P = 0.838 and 0.766, respectively). A non-parametric permutation test was also applied to evaluate if more related individuals had a higher phenotypic resemblance. The results obtained suggested only a slight familiar association (P < 0.05) when comparing individuals lacking operculum, but neither between lordotics nor between normal ones. These results suggest that most phenotypic variation observed for lordosis and lack of operculum in gilthead seabream is due to environmental factors.  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