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在温度分别为 2 6、30、32、34℃ ,湿度为 - 12KPa的条件下孵化中华鳖 (Trionyxsinensis)卵 ,孵化期分别 6 6 1、4 5 2、4 2 0和 39 4天将各温级中孵出幼体在实验室恒温 (2 9± 1℃ )饲养 ,测定其早期生长。结果表明 :孵化温度明显影响中华鳖幼体的早期生长 ,其中 2 6℃组生长最快 ,30、32℃组居中 ,34℃组生长最慢 相似文献
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利用变温促进罗非鱼生长的研究 总被引：8，自引：1，他引：8
在实验室内不同温度条件(恒温28℃、30℃和周期性变温28±4℃、30±4℃)下,分四组饲养罗非鱼,测定其增重、耗氧率、并推算能量同化率和组织生长效率(K_2)。结果表明,变温组均比相应恒温组生长迅速。其中以变温28±4℃组日增重最快,增重百分率最高,其次为变温30±4℃组,恒温28℃组日增重最慢,增重百分率最低。能量同化率和组织生长效率也以变温28±4℃组最高;30±4℃组能量同化率虽较高,但组织生长效率却最低。本文对变温促进罗非鱼生长的机理和其在生产实践中的意义进行了分析与探讨。 相似文献
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变温对刺参幼参生长、呼吸代谢及生化组成的影响 总被引：11，自引：0，他引：11
为研究刺参对温度周期性波动的响应,本实验测定了在12,15,18,21,24℃5个恒温处理组和15±2℃,18±2℃,21±2℃3个变温处理下刺参幼参的生长、呼吸代谢和生化组成。结果表明,在恒温条件下,随着温度的升高,刺参生长逐渐加快,在18℃生长最快,然后随温度增加,生长逐渐降低。在15~21℃恒温条件下,幼参呼吸代谢无显著差异。在不同恒温处理组中,幼参脂肪含量随体重增加而增加。与恒温对照组相比,变温对幼参生长有显著性影响(P<0.05)。与相应的恒温相比,平均温度低于最适温度的变温(15±2℃,18±2℃)可促进刺参的生长,而平均温度高于最适温度时的变温(21±2℃)会抑制刺参生长。变温使幼参耗氧率有增加的趋势,但未达到显著水平。变温造成刺参脂肪含量降低,可能与变温条件下呼吸代谢增加有关。 相似文献
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比较了中华鳖在昼夜周期变温,恒温条件下的日粮和对饲料的利用率。结果表明,中华鳖在昼夜周期变温条件下日摄食量增强。 相似文献
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在实验室内不同温度条件下，分４组饲养中华鳖，并测定其生长情况。结果表明，在适温范围内的昼夜周期变温，对中华鳖的生长具有促进作用。文中并利用昼夜周期变温促进中华鳖生长的实践意义进行了分析。 相似文献
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在适温范围内，昼夜周期变温有利促进中华鳖生长。但其昼夜周期变温幅度不宜太大，每24h内变幅以±3℃为宜。 相似文献
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变温对孔石莼生长和生化组成的影响 总被引：2，自引：0，他引：2
在光照培养箱中研究了变温(23±3)℃、(26±3)℃、(29±3)℃及相应的恒温对照23、26、29℃共6个温度处理对孔石莼生长、叶绿素含量、可溶性糖和蛋白质含量的影响。试验结果表明,与相应的恒温相比,变温对孔石莼的生长有促进作用,且随变温持续时间发生变化。(26±3)℃变温的促生长作用最强,其次为(23±3)℃、(29±3)℃。变温处理下孔石莼的叶绿素a、b含量降低,蛋白质含量减少。可溶性糖含量除在(26±3)℃变温处理下略有升高,其余变温处理下降低。变温虽然对孔石莼的生长有不同程度的促进作用,但不利于其叶绿素a、b合成及可溶性糖积累和蛋白质合成。这可能是藻类为适应环境因子变化而做出的积极生理调节。 相似文献
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鳖是一种冬眠动物 ,温度对其较为敏感。当温度下降到 1 5℃以下时进入冬眠 ,如果打破冬眠 ,给予最佳水温 3 0 .4℃ ,进行恒温养殖 ,能促使鳖进入最快的生长速度。当环境温度突变 ,温差过大时 ,会造成鳖应激发病死亡。笔者于 2 0 0 0年入冬时对美国佛罗里达鳖进行温差实验 ,实验组温差 1 0℃时将鳖从露天池移入温室 ,结果 2周内全部死亡 ,而对照组无温差投放到温室中全部正常 ,而且生长良好。鳖对水温变化的一般安全范围是 ,稚鳖±2℃ ,幼鳖± 3℃ ,成鳖± 4℃。在此范围内能自我调节。如果温差太大 ,鳖难以调节 ,将产生一系列应激反应 ,如内… 相似文献
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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
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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
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《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
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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
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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
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该研究选取具有多态性的6对微卫星引物对构建的2批合浦珠母贝(Pinctada fucata)完全双列杂交家系的遗传多样性进行了分析。6个微卫星标记在9个家系360个个体中共检测到32个等位基因,有效等位基因(Ne)为1.758 7~3.586 5,观测杂合度(Ho)为0.144 4~0.488 9,期望杂合度(He)为0.432 0~0.722 2,Shannon指数(I)为0.691 9~1.507 4。9个家系都有单态位点,平均Ho为0.129 2~0.466 7,平均He为0.155 0~0.439 6,平均I为0.248 5~0.712 2。有19个位点(占35.19%)极显著地偏离Hardy-Weinberg平衡。各家系之间的遗传距离为0.109 0~1.137 2,遗传相似性系数为0.320 7~0.896 8。家系L4B46与L4B48的遗传距离最大,与D3D313的遗传距离最小。UPGMA法聚类分析显示,9个家系分为3支,L4B48单独成一支,B4D426、B4D427与D4B445聚成一支,其余家系聚成一支。该研究结果为合浦珠母贝家系选择育种的亲本选择与交配设计提供了科学依据。 相似文献
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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
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Peter Howgate 《Journal Of Aquatic Food Product Technology》2013,22(5):516-532
It is well-established in fish technology that freshness should be measured primarily by sensory procedures, though considerable effort has been expended in looking for nonsensory alternatives. A variety of methods for sensory evaluation of freshness has been described and this historical review traces developments of these methods. Much of the source material derives from the research literature such as research journals and reports of research, and the use of sensory methods in commercial quality control has scarcely been documented. There is a brief discussion of possible future developments in sensory evaluation of freshness. 相似文献