Effects of nucleotides on growth performance,immune response,disease resistance and intestinal morphology in shrimp <Emphasis Type="Italic">Litopenaeus vannamei</Emphasis> fed with a low fish meal diet     

Jingping Guo  Benyue Guo  Hanle Zhang  Wei Xu  Wenbing Zhang  Kangsen Mai 《Aquaculture International》2016,24(4):1007-1023

Nucleotides (NT) are widely used as an immunostimulant in aquaculture. A 10-week feeding trial was conducted to evaluate the effects of dietary NT on the growth performance, immune response, disease resistance and intestinal morphology of the Pacific white shrimp Litopenaeus vannamei (initial mean body weight: 0.39 ± 0.00 g). Five isolipidic (about 7 % crude lipid) and isonitrogenous (about 39 % crude protein) practical diets were supplemented with graded levels of NT (0, 60, 90, 120 and 1200 mg kg^?1), respectively. These diets were named as N1, N2, N3, N4 and N5. Each diet was randomly fed to six tanks of shrimps, and each tank contained 40 shrimps. The shrimps were fed four times daily (07:00, 11:00, 16:00 and 21:00 h). The results showed that there were no significant differences in survival, final weight, specific growth rate, feed intake, feed conversion ratio and whole-body compositions among all the treatments (P > 0.05). Shrimps fed the control diet had the significantly lowest activities of superoxide dismutase, total nitric oxide synthase and lysozyme (P < 0.05). However, those parameters increased when dietary NT increased from 60 to 120 mg kg^?1 and decreased as inclusion level increased to 1200 mg kg^?1 (P < 0.05). The cumulative mortality of the shrimps challenged with Vibrio parahaemolyticus was significantly higher in the treatments without dietary NT supplementation than those in treatments with dietary NT (≥90 mg kg^?1) (P < 0.05). The jejunum wall thickness in shrimps fed the control diet was significantly lower than that in the treatments of N2, N3 and N4 (P < 0.05). For the villus height, the highest value (49.29 µm) was found in N3. In summary, the present study showed that 90 mg kg^?1 of dietary NT is the optimum dietary level for good gut health, immune response and disease resistance of Pacific white shrimp fed a diet with 18 % fish meal.  相似文献   

高效液相色谱法测定黄皮果实中的有机酸     

朱敏  何书强  罗石荣  麦贤家  陈业渊 《中国农学通报》2016,32(34):187-192

为深入了解黄皮果实中有机酸,采用水浴超声提取果实中的有机酸、高效液相色谱法测定的方法,对12份黄皮种质果实中有机酸的组分及含量进行研究。结果表明:在色谱柱Venusil XBP C18(T)(4.6 mm×250 mm,5μm)、流动相为0.01 mol/L(NH4)2HPO4(H3PO4调p H至2.7)、流速1 m L/min、柱温27℃、检测波长210 nm的条件下,黄皮果实中柠檬酸、草酸、乳酸、苹果酸、抗坏血酸、酒石酸得到良好分离,且测定精确灵敏、回收率高、重复性好,标准曲线相关系数为0.9975~0.9996,相对标准偏差为1.02%~1.84%,回收率为95.60%~101.78%。黄皮果实中有机酸以柠檬酸、草酸和苹果酸为主,乳酸在少部分种质中有测出,不同种质果实中柠檬酸、草酸、苹果酸含量分别为0.780~8.090、0.773~4.205、0.478~3.212 mg/(g·FW),分别占总酸的22%~65%、16%~40%、11%~20%。  相似文献   

Impact of Bacillus amyloliquefaciens S13‐3 on control of bacterial wilt and powdery mildew in tomato          下载免费PDF全文

Shoko Yamamoto  Soma Shiraishi  Yumi Kawagoe  Mai Mochizuki  Shunji Suzuki 《Pest management science》2015,71(5):722-727

  相似文献   

低温胁迫下西瓜同源二倍体和三倍体甲基化及基因表达的差异分析     

杨炳艳  霍秀爱  刘云婷  段会军 《园艺学报》2014,41(11):2313-2322

为了揭示西瓜二倍体及三倍体在低温胁迫下的耐冷性分子机制,以西瓜二倍体自交系‘83166’（‘京欣1号’品种的母本）及其同源三倍体为材料,利用MSAP及cDNA-AFLP技术研究低温处理前后基因表达的差异,并对差异带进行克隆、测序和比对。28对MSAP引物扩增得到2 356个位点,其中二倍体经低温处理后总甲基化率下降8.5%,三倍体下降10.4%。将13条差异带与西瓜基因组数据库比对,有7条带确定是西瓜基因组序列。26对cDNA-AFLP引物组合扩增出1 267条带,其中二倍体上调表达占48.2%,下调表达占51.8%;三倍体上调表达占51.3%,下调表达占48.7%。21条差异带在NCBI中找到了同源序列基因,包括假定蛋白（38.1%）、能量与代谢（38.1%）、信号转导（9.5%）、物质运输（9.5%）以及DNA修饰（4.8%）,另有9条无同源序列。低温胁迫后,三倍体去甲基化率与上调表达量均大于二倍体,而且三倍体诱导出更多的差异基因参与了能量代谢调控、信号转导、物质运输等过程,说明在抵御低温胁迫中三倍体比二倍体有更强的耐冷性。  相似文献   

转基因水稻恢复系及其F1代Bt蛋白的时空表达分析   总被引：1，自引：0，他引：1  

汪秀峰  叶芬  李莉  陆徐忠  倪大虎  王德正  麦霄黎  王淑云  杨剑波 《分子植物育种》2014,(6)

本研究以抗虫水稻恢复系9311(Bt)及其杂交种F1(Bt)为研究材料,以非转基因的9311为阴性对照,利用ELISA方法研究9311(Bt)及F1(Bt)各生育时期可溶性总蛋白和Bt蛋白的时空变化规律,为转Bt基因抗虫水稻的安全监管提供科学依据。结果表明：外源基因的导入没有引起水稻组织中可溶性总蛋白含量的明显变化;9311(Bt)的Bt蛋白表达量在整个生长周期的各个部位均高于相应的F1(Bt)植株;同一植株不同组织器官中Bt蛋白表达量为：叶片跃胚乳跃颖壳及茎秆跃根;同一植株不同发育期叶片Bt蛋白的测定结果整体表现为：营养生长阶段跃生殖生长阶段跃成熟衰老阶段。研究结果为转Bt基因抗虫水稻适宜检测时期的选择提供了一定的参考。  相似文献   

叶面肥对无土栽培樱桃番茄性状的影响及产量与植株性状的数学模型研究     

冀春花林升强  黄露茹史欧阳庄令  麦全法 《中国农学通报》2014,30(4):175-178

为了探索樱桃番茄无土栽培在海南热带地区种植效果及植株产量效应,本研究通过增施不同量叶面肥,设计3种处理、3次重复随机试验,并对试验最佳效果的植株产量、株高和茎粗建立相关数学模型。结果表明,增施叶面肥较传统施肥有明显增产效果,平均增产2250 kg/hm²,增产20.2%。而樱桃番茄株高与产量、茎粗与产量具有显著相关性,其模型分别为Y_单株产量=(47.92060X_{株高-24.95763)² (P= 0.0114＜0.05)和Y单株产量=(61.885X茎粗-46.97988)² (P=0.0372＜0.05),符合植株生长趋势变化。因此,在海南开展樱桃番茄无土栽培是可行的,且可以通过调控来调节植株生长情况从而提高产量,增加经济效益。  相似文献}   

冻土环境下泄漏油污的微生物修复   总被引：5，自引：0，他引：5  

YANG Si-Zhong  JIN Hui-Jun  WEI Zhi  HE Rui-Xi  JI Yan-Jun  LI Xiu-Mei  YU Shao-Peng 《土壤圈》2009,19(3):371-381

Oil spills have become a serious problem in cold environments with the ever-increasing resource exploitation, transportation, storage, and accidental leakage of oil. Several techniques, including physical, chemical, and biological methods, are used to recover spilled oil from the environment. Bioremediation is a promising option for remediation since it is effective and economic in removing oil with less undue environmental damages. However, it is a relatively slow process in cold regions and the degree of success depends on a number of factors, including the properties and fate of oil spilled in cold environments, and the major microbial and environmental limitations of bioremediation. The microbial factors include bioavailability of hydrocarbons, mass transfer through the cell membrane, and metabolic limitations. As for the environmental limitations in the cold regions, the emphasis is on soil temperatures, freeze-thaw processes, oxygen and nutrients availability, toxicity, and electron acceptors. There have been several cases of success in the polar regions, particularly in the Arctic and sub-Arctic regions. However, the challenges and constraints for bioremediation in cold environments remain large.  相似文献   

不同蛋能比对凡纳滨对虾幼虾生长、饲料转化、血清指标和体组成的影响     

Y.Hu B. Tan K. Mai Q.Ai S.Zheng K. Cheng 《饲料与畜牧》2009,(4):52-55

导读：虾料配制时首先考虑的因子。 前言 凡纳滨对虾原产于美洲中南部的太平洋沿岸,我国于1988年引进,由于该虾生长快、适应性强、食性广、价格高、抗病力强等优点,迅速成为主要养殖品种。当前,饲料成本占总养殖成本的50～60％,而蛋白水平又是影响生长性能和饲料成本的主要因素。那么怎样才能降低饲料成本呢？通过优化蛋白能量和非蛋白能量在饲料中的比例,可以达到这一目的。如果蛋白相对于能量过量,那么,  相似文献   

3个新引进脐橙品种在桂林花芽分化的解剖学观察   总被引：1，自引：0，他引：1  

区善汉  李雁群  麦适秋  洪棋斌  梅正敏  黄荣韶  莫健生  王明召 《分子植物育种》2009,7(4):767-771

本研究以Hutton脐橙、Navelate脐橙和石棉脐橙为试材,研究了它们的花芽分化特性.结果表明,Hutton脐橙、Navelate脐橙和石棉脐橙花芽分化顺序一致,均分为6个时期,包括末分化期、花芽分化始期、萼片原基、花瓣原基、雄蕊原基、雌蕊原基分化,花芽形态分化从11月开始至次年3月完成,历时5～6个月;不同品种花芽分化各阶段所持续的时间略有不同.石棉脐橙花芽分化进程总体上早于Hutton脐橙和Navelate脐橙,其次是Hutton脐橙,最迟是Navelate脐橙.同时,初步证明气温的降低也是脐橙花芽分化的必需条件.  相似文献   

云南轿子雪山自然保护区生态环境及有效管理评价     

陈哲  郭辉军  龙春林 《林业调查规划》2009,34(2):64-68

利用德尔菲法（Delphi）进行专家咨询,选取多样性、自然性、稀有性、代表性、生态脆弱性、面积适宜性和人类威胁共7项指标对云南轿子雪山自然保护区进行生态环境状况评价,通过指标等级化处理,结合实地调查得出保护区生态环境综合指数为74．82,评价结果,保护区生态环境质量较好;选取管理条件、管理措施、科研基础、管理成效等13项指标对保护区进行有效管理评价,通过专家咨询和实际调查,得出该保护区有效管理综合指数为55．53,评价结果,保护区有效管理水平一般．针对评价结果,分析影响保护区生态环境质量和有效管理成效的关键因素及保护区目前所面临的主要问题,提出了相应的对策和建议．  相似文献