共查询到20条相似文献,搜索用时 46 毫秒
1.
2.
试验选用小型浮游动物、鱼浆、蛋黄和鳗鱼配合饲料等4种饵料作为黑莓鲈仔鱼的开口饵料,经20 d培育,结果显示,在不同饵料条件下,黑莓鲈仔鱼的开口摄食率、生长速度和成活率存在显著差异(P0.05)。小型浮游动物组开口摄食率最高,为94.44%,生长速度较快,平均日增全长为0.43 mm,最终存活率为56.03%;鱼浆、蛋黄和鳗鱼饲料组的生长速度和成活率均较低,平均日增全长分别为0.22、0.14、0.11mm,成活率分别为15.24%、12.80%、8.05%。4种开口饵料中,小型浮游动物是黑莓鲈仔鱼的适宜开口饵料。Logistic生长模型能较好地拟合不同开口饵料黑莓鲈仔鱼的生长曲线(R2≥0.96)。 相似文献
3.
分别采用浮游动物、蛋黄、水丝蚓、鳗鱼饲料对黑斑原鮡(Glyptosternum maculatum)仔鱼进行投喂,探讨这4种开口饵料对其成活率及生长的影响。试验开始时,黑斑原鮡仔鱼全长为(10.60±0.34)mm,体重为(0.025±0.003)g,试验周期共计21 d。结果显示:鳗鱼饲料组和浮游动物组成活率最高,仔鱼的平均全长体重增长率也均高于其他两组。水丝蚓组存活率上明显低于其他组,且生长速度也最低。结果表明,4种开口饵料效果比较,推荐浮游动物和鳗鱼饲料作为黑斑原鮡仔鱼最适宜的开口饵料。 相似文献
4.
长薄鳅开口饵料的研究 总被引:1,自引:0,他引:1
为寻找合适的长薄鳅仔鱼开口饵料,分别以卤虫、枝角类、蛋黄、卤虫+蛋黄、枝角类+蛋黄、卤虫+光合细菌、枝角类+光合细菌等7种不同的饵料对刚脱膜4d的仔鱼进行了饲喂试验.结果表明:(1)不同饵料对长薄鳅仔鱼的生长具有显著影响(P<0.05),其中,枝角类+光合细菌组生长最快,绝对增重率和特定增重率分别为4.63±0.075 mg/d和19.02±0.404 %/d;蛋黄组生长最慢,绝对增重率和特定增重率与其他各组差异显著(P<0.05).(2)第1周投喂卤虫+光合细菌组合的饵料,仔鱼的成活率最高,为96%;蛋黄组的最终成活率最低,只有34%,且该组仔鱼个体发育较为缓慢,与其他各组差异显著(P<0.05).根据试验结果,建议在水泥池育苗的条件下,对刚脱膜4d的长薄鳅仔鱼,第1周投喂卤虫+光合细菌,后期投喂枝角类+光合细菌,以提高仔鱼的成活率和成长率. 相似文献
5.
6.
利用小型浮游生物、蛋黄、蛋黄加小型浮游生物、丰年虫作为开口饵料,分别在玻璃缸培育神仙鱼改良种三色神仙仔鱼,进行生长效果对比试验。从成活率、生长速度及个体生长差异三方面来看,认为用丰年虫投喂效果最理想,蛋黄加小型浮游生物次之,单纯投喂小型浮游生物或蛋黄较差。 相似文献
7.
三种饵料培育珍珠马甲仔鱼的对比试验 总被引:1,自引:0,他引:1
利用轮虫、草履虫或蛋黄作为开口饵料 ,分别在玻璃缸培育珍珠马甲仔鱼 ,进行生长效果对比试验 ,从成活率、生长速度及个体生长差异三方面来看 ,认为用轮虫投喂效果最理想。 相似文献
8.
9.
10.
不同温度、饵料对宽体金线蛭仔蛭生长和存活的影响 总被引:1,自引:0,他引:1
本文研究了不同温度和饵料对宽体金线蛭仔蛭生长和存活的影响。结果表明:宽体金线蛭( Whitmania pigra)仔蛭在不同温度条件下的生长速度和存活率存在显著差异( P /0.05)。在水温为27℃条件下,仔蛭生长速度最快、存活率最高;而33℃下的仔蛭存活率最低、生长最慢。投喂不同的饵料,仔蛭的生长速度和存活率也有显著的差异( P /0.05);投喂轮虫和圆田螺组的仔蛭生长速度最快、存活率最高;投喂蛋黄组的仔蛭存活率最低、生长速度最慢。 相似文献
11.
D. C. Dauwalter 《Fisheries Management and Ecology》2013,20(4):289-301
Energy development threatens fish and wildlife resources worldwide. This study used constrained ordinations to show fish assemblage structure associated with oil and gas well densities in the Colorado River Basin, Wyoming, but well densities explained only 6.4% of assemblage structure when compared to other factors. Threshold Indicator Taxonomic ANalysis showed significant negative threshold responses by some species to small levels of development (<0.15 wells km?2), whereas positive thresholds were less distinct. Some native and imperilled species could be disproportionately affected if future oil and gas development proceeds in a manner that will impact aquatic resources. Although existing development has not substantially influenced regional fish assemblage structure, it appears to affect a subset of species. Understanding assemblage‐level responses to development can help land managers determine appropriate development levels, prioritise areas for monitoring associated with future development and identify where land protection measures may be needed to offset potential risks. 相似文献
12.
Claude E. Boyd Louis R. D'Abramo Brent D. Glencross David C. Huyben Lorenzo M. Juarez George S. Lockwood Aaron A. McNevin Albert G. J. Tacon Fabrice Teletchea Joseph R. Tomasso Jr Craig S. Tucker Wagner C. Valenti 《Journal of the World Aquaculture Society》2020,51(3):578-633
Important operational changes that have gradually been assimilated and new approaches that are developing as part of the movement toward sustainable intensive aquaculture production systems are presented via historical, current, and future perspectives. Improved environmental and economic sustainability based on increased efficiency of production continues to be realized. As a result, aquaculture continues to reduce its carbon footprint through reduced greenhouse gas emissions. Reduced use of freshwater and land resources per unit of production, improved feed management practices as well as increased knowledge of nutrient requirements, effective feed ingredients and additives, domestication of species, and new farming practices are now being applied or evaluated. Successful expansion into culture of marine species, both off and on shore, offers the potential of substantial increases in sustainable intensive aquaculture production combined with integrative efforts to increase efficiency will principally contribute to satisfying the increasing global demand for protein and food security needs. 相似文献
13.
Roberto Mendoza Alfaro Carlos Aguilera González & Allyse M Ferrara 《Aquaculture Research》2008,39(7):748-763
Many lepisosteid populations in North America have declined and many are now threatened as a consequence of habitat loss and alteration and commercial and sport overfishing. Over the last two decades, morphological, histological and molecular studies allowed distinguishing between different phases of development and the nutritional condition of larvae. Ontogeny of the digestive enzymes of gar larvae indicated the possibility to feed them artificial feeds since early developmental stages. An in vitro digestibility system to test different feed ingredients has been used. Important characteristics of artificial diets were identified through different feeding experiments. Endocrinological studies showed the feasibility of altering larval development and the digestive capacity of larvae. Cloning of gar growth hormone opened new avenues to enhance growth in the gars. Plasmatic vitellogenin was isolated and purified, to develop a competitive enzyme‐linked immunosorbent assay, which allowed the straightforward separation of males from females to establish appropriate proportions for reproduction and also was used to evaluate hormonal protocols to induce gonad recrudescence and spawning. This review analyzes the biology, ecology and physiology of different gar species as a basis for their domestication, mass production of larvae for repopulation experiments and for the culture of commercial‐size gar. 相似文献
14.
A report is presented of esophagoscopy and gastroscopy in cats and dogs using flexible endoscopes. Following consideration of the basic equipment, an account is given of patient preparation and anesthesia, topography, investigation technique and normal findings. Diagnostic potential, indications and risks involved are discussed. 相似文献
15.
“十一五”以来,我国农垦加快体制机制改革、结构调整和经济增长方式的转变的步伐,参与市场竞争,努力提升企业和产品竞争力,经济社会事业发展较快,对国家的贡献提升,职工收入、生活质量明显提高和改善,示范引领作用不断增强。本文针对农垦体制机制创新进展滞缓,战略定位与发展方向不明,经济增长方式转变和结构调整缺乏资本、人才、技术的支撑,没有处理好改革、发展、稳定、民生的关系,投资匮乏,发展后劲不足,人才短缺和劳动力素质低下的现状,提出在未来农垦体制机制创新中要特别关注改革方向、目标设定与评估,改革要在现行法律法规的框架内运作,改革时机的选择,处理好改革发展稳定与民生的关系,调整好内部利益分配关系,自觉融入区域经济,与地方协同发展等问题。为了促进农垦的发展,建议国家加大对农垦体制机制创新、现代农业建设、国有农场土地资源的保护、社会保障体系的完善等财政和政策的支持力度。 相似文献
16.
奶牛酮病发病机理研究进展 总被引:2,自引:0,他引:2
结合国内外目前研究状况较为详细的综述了奶牛酮病的病因与发病机理,并分析了奶牛酮病发生的生化机制。旨在对临床实践中很好的认识诊断和群体监控奶牛酮病提供较为系统的理论依据,保证奶牛群的高产和稳产,从而创造良好的经济效益。 相似文献
17.
本试验利用饲养试验方法,研究玉米-豆粕型日粮中添加植酸酶时不同磷水平和钙磷比对生长肥育猪血清指标和骨骼性能的影响。试验选用162头20kg左右的杜长大三元杂交猪进行2×3(磷水平×钙磷比)因子饲养试验,试验分2个阶段进行,前期为生长期体重在20-60kg,后期为肥育期体重为为60-100kg。结果表明:添加植酸酶日粮磷水平对血清磷含量和碱性磷酸酶的活性影响显著(P<0.05);钙磷比对血清钙和血清磷含量的影响显著(P<0.05);添加植酸酶日粮磷水平和钙磷比对生长肥育猪骨骼性能的影响不显著(P>0.05)。在添加植酸酶条件下,降低日粮磷水平不影响猪的正常生长发育。 相似文献
18.
温度与盐度对老年低额蚤和蚤状蚤生长及生殖的影响王丹丽,李明云,杨天勇,胡章(宁波大学,315010)关键词老年低额 ,蚤状 ,温度,盐度,生长,生殖EFFECTSOFTEMPERATUREANDSALINITYONGROWTHANDREPRODUCT... 相似文献
19.
20.
Shrimp and fish pond soils: processes and management 总被引:7,自引:0,他引:7
The pond bottom soil and the accumulated sediments are integral parts of ponds. Concentrations of nutrients, organic matter and microorganism density in the pond bottom are several orders of magnitude greater than in the water. The accumulation of organic sediments may limit pond intensification. The intensive organic matter degradation at the pond bottom and high sediment oxygen demand exceeds the oxygen renewal rate. This leads to the development of anoxic conditions in the sediments and at the sediment–water interface. A series of anaerobic processes, affected by the redox potential of the system, are taking place. A large number of potentially toxic materials are generated. Among those are organic acids, reduced organic sulfur compounds, reduced manganese and sulfides.
Shrimp, as animals that normally live on or near the bottom, are exposed to conditions on the pond bottom. Exposure to toxic materials endanger the well being of the cultured shrimp. Reduced feeding, slower growth, mortality and possibly higher sensitivity to disease are reported.
The rational use of aerators to minimize the area of sludge accumulation, construction of ponds to trap sludge, stirring sediments, chemical poising of the redox system and environmentally accepted treatment and reuse of drained sediments are means to control the conditions at the pond bottom. 相似文献