共查询到20条相似文献，搜索用时 172 毫秒
1.
2.
3.
温度和盐度对日本黄姑鱼胚胎发育的影响 总被引：2，自引：0，他引：2
为了确定日本黄姑鱼（Nibea japonica）胚胎孵化的最适水温和盐度,采用不同水温和盐度对日本黄姑鱼受精卵进行了孵化试验。结果显示,在盐度为30的条件下,日本黄姑鱼受精卵在14～28℃范围内均能正常孵化,最适孵化水温为18～20℃。孵化时数与温度呈幂函数相关,孵化时间随温度升高而缩短。盐度试验表明,在水温为18℃的条件下,日本黄姑鱼受精卵在盐度25—32的海水中呈悬浮或者半悬浮状态,在盐度14～45范围内均能孵化,适宜孵化盐度为26～32。盐度对初孵仔鱼全长有显著影响,盐度较低组仔鱼全长显著大于高盐度组（P〈0．05）。 相似文献
4.
研究了不同盐度对克氏原螯虾受精卵孵化的影响.水温25 ℃条件下,盐度0～8时克氏原螯虾的受精卵均可孵出幼体.但以盐度0～4时孵化率较高,每个亲体平均孵出的幼体数量较多,高出此盐度范围时孵化率明显降低,且随着盐度升高,孵化时间延长.试验表明,0～4的盐度为克氏原螯虾孵化的适宜盐度,孵化率较高,孵化时间较短. 相似文献
5.
6.
7.
欧洲丁鱥人工繁殖的亲鱼以3～4龄较好，个体要求雌鱼到达400g，雄鱼到达250g以上；催产时间（鹰潭地区）为4月下旬-5月中上旬为好；适宜水温为18～30℃，最适水温为25～28℃，32℃以上时产卵率、受精率和孵化率都较低；催产激素可选择混合激素，剂量为50μg/kg LHRH—A2和5mg／kg DOM合剂；催产方法以两针注射法为好，针距为8～10h；效应时间（水温25℃时）为11—16h；产卵既可自然产卵也可人工授精，孵化一般在网箱中充氧孵化即可，有条件的地方可以实行脱粘后在环道或孵化漕中进行孵化。三年的最高产卵率87％、受精率91％、孵化率93％。 相似文献
8.
水温、pH值和光照对斑马鱼受精卵孵化率的影响 总被引：1，自引：0，他引：1
分别通过单因素实验和正交实验探究水温、pH值和光照对斑马鱼受精卵孵化率的影响。依次进行的单因素实验显示,水温28℃,pH值7.5,光照强度100 lx,光周期10L∶14D时孵化率最高。正交实验结果表明上述因素对斑马鱼受精卵孵化率的影响为:水温pH=光照强度光照周期,理论最佳孵化条件为水温28℃,pH值8.0,光照强度100l x,光周期12L∶12D。在孵化过程中,受精卵孵化时间随着孵化温度的提高而缩短,且在发育过程中存在不同步现象。 相似文献
9.
2010年2～5月进行了金鳟自繁试验,获得金鳟受精卵9.55万粒.在同一孵化室内培育至发眼卵,分别置于室内和室外不同的环境条件下继续孵化,结果显示:受精卵在孵化室内(水温6.1℃)经40～42 d的孵化,全部发眼,发眼率96.8%,发眼积温达244～256℃·d.发眼卵在孵化室内的积温达到336～342℃·d时开始破膜,孵化率91.2%;在凉棚下积温达到315～322℃·d时开始破膜,孵化率89.1%.试验证明:在金鳟发眼卵孵化时适当提高水温可缩短孵化期,昼夜温差对金鳟发眼卵孵化率的影响不大. 相似文献
10.
11.
The variation of virulence of Renibacterium salmoninarum , the causative agent of bacterial kidney disease (BKD) in salmonid fish, was studied by infecting rainbow trout, Oncorhynchus mykiss (Walbaum), with two isolates (strains 325 and 932) from diseased Atlantic salmon, Salmo salar L., and one isolate (strain 4366) from an apparently healthy Atlantic salmon. Coho salmon, Oncorhynchus kisutch (Walbaum), were injected with the strain 932 to estimate difference in fish species resistance. Fish were removed by random sampling for other study purposes, a study design possible with analysis of lifetime distributions incorporating both sampling-, death- and survival-times. At the end of the experiment, the rainbow trout infected with strains 325, 932 and 4366 had a survival probability of 33%, 51% and 72%, respectively. The coho salmon infected with strain 932 had a 26% survival probability. The strain differences were significant according to the log-rank test, and the risk ratio between the strains ranged from 1·8 to 5·4. The strain from the apparently healthy fish was least virulent. The survival of the fish species was different over time. Rainbow trout were more likely to die early in the time course, but high numbers of coho died later, resulting in an overall risk of mortality of 1·4 in favour of rainbow trout. Differences in virulence may reflect changed selective pressure on R. salmoninarum when introduced from feral stocks into the environment of fish farms. 相似文献
12.
水硬度对七彩神仙鱼幼鱼发育的影响 总被引：4，自引：0，他引：4
采用不同硬度的水对七彩神仙鱼幼鱼进行饲养。6周龄幼鱼在硬度为7.94°dH±0.30°dH时饲养84d后,比在硬度为14.71°dH±0.23°dH水中的幼鱼个体大,生长速度快。表明较高硬度的水有利于七彩神仙鱼幼鱼的生长发育。 相似文献
13.
牙鲆刺激隐核虫病的防治 总被引：1，自引：0，他引：1
2005年七、八月份,乐亭、滦南一带多家工厂化牙鲆养殖场发生刺激隐核虫病,此种病虫害发病急、传染快、死亡率高。发生过该病的养殖场牙鲆死亡率一般都在50％～80％之间,这种病害给牙鲆养殖业带来很大损失。 相似文献
14.
《水生生物资源》2003,16(5):461-465
Anti-proteinase activity was demonstrated in the seminal plasma of cyprinid fish species (bream, chub, ide, dace, asp, goldfish, roach, common carp) using electrophoretic techniques combined with a detection method based on inhibition of bovine trypsin. We found species-specific protease inhibitors in the seminal plasma of cyprinids. At least three bands of protease inhibitors with different migration rates could be identified by native PAGE. Higher variability was characterized for bands with slower migration rates. Visualization of inhibitors after SDS-PAGE under non-reducing conditions allowed estimation of their molecular weights. Apparent molecular weights were within the range of 51–59 and 47–54 kDa for the bands with slower and moderate migration rates, respectively. The molecular weight of fast migration bands for roach and common carp were estimated to 23 and 30 kDa, respectively. Inhibitors of common carp seminal plasma differed in their affinity toward serine proteases. Three inhibitors in common carp seminal plasma could be visualized using cod and bovine trypsin, but only two inhibitors (of high molecular weight) were recognized with chymotrypsin. There were differences in anti-proteinase activity and seminal plasma protein concentration in relation to the origin of common carp seminal plasma (breeding lines) and time of milt collection (spawning vs. post-spawning season). 相似文献
15.
七种甲壳类水产品脂肪酸组成的分析研究 总被引：5，自引：0，他引：5
水产动物食品中富含ω—3型多稀酸,其中尤其是C_(20:5)(EPA)和C_(22:6)(DHA)对人体有特殊保健功能。本文对七种常见的甲壳类水产品进行脂肪酸组成分析,它们是中国对虾、日本沼虾、安氏白虾、克氏原螫虾、葛氏长臂虾、中华绒螯蟹和三寺疣梭子蟹。测定主要采用黄志斌、李淡秋(1990)的“快速制备脂肪酸甲酯用于气相色谱分析”一文所提供的方法。结果显示,被测样品中不饱和脂肪酸含量高于饱和脂肪酸,而不饱和脂肪酸中多烯酸含量高达60%,且以长碳链(C_(20)、C_(22))ω—3型为特征,表明甲壳类水产品体脂中EPA和DHA含量甚高,超过淡水鱼的一倍,但略逊于海水鱼。值得注意的是,甲壳类水产品中EPA的含量高于DHA的含量,这与鱼类中的情况正好相反。 相似文献
16.
17.
猪的胎盘属于弥散型胎盘,这种胎盘的结构特点和饲养管理的不当,常常导致母猪胎衣不下发生,给生猪的生产繁殖带来极大损失。本文针对母猪胎衣不下发生病因、综合防治进行详细阐述,旨在对预防和治疗胎衣不下能有所帮助。 相似文献
18.
19.
鳟鱼发眼卵和旨种运输是养鳟生产的重要环节。发眼卵多在冬季和早春运输,苗种多在晚春和夏季运输。苗种运输大多以鱼篓充氧进行短距离汽车运输,长途运输冷水性鱼苗种的实例很少。本文总结了金鳟和虹鳟苗种长途运输方法,以期与养鳟业界共同交流提高。一、包装材料和方法内包装材料是苗种运输专用塑料袋,规格54×104cm,外包装是泡沫塑料箱,规格63.5×45.5×30．5cm,纸箱规格64×46×32．5cm。塑料袋采取双层式,内装苗种和水共12.5kg,其中苗种0.5-1．3kg,100－2000尾。起运前苗种停食1－2天。运鱼用水水温调至6℃,鱼、水入袋后袋内… 相似文献
20.
该研究通过肉眼观察、镜检,进行干露、饥饿、盐度突降、福尔马林等抗性试验,并采用病毒检测等方法,以期建立评估斑节对虾（Penaeus monodon）虾苗活力和质量标准。结果表明,斑节对虾健康虾苗具有趋光性、集群性,体表光洁,肌肉透亮,肠胃食物充盈等特性。测试虾苗干露时间以15min为宜,健康虾苗干露后能立即恢复活力,而病弱虾苗多出现死亡、昏迷现象;虾苗的成活率随饥饿时间的延长而降低,随福尔马林浓度升高和时间延长而降低,随盐度突降幅度增加而降低。健康虾苗能忍受100～200μL·L^-1福尔马林溶液30min,成活率近100％;在盐度20～30下虾苗的成活情况较好,而其在淡水中仅能存活1h。对虾苗进行病毒检测,可以避免养殖中因虾苗携带病毒而可能导致的病毒性疾病的暴发。 相似文献