翘嘴红鲌肝脏G6Pase催化亚基的克隆以及摄食和饲料中碳水化合物对其表达的影响

本文采用RT-PCR和RACE法分离、克隆了翘嘴红鲌G6Pase催化亚基基因全长cDNA,共1900 bp [不含poly(A)], 包括49 bp 5'非翻译区,1068 bp阅读框以及含Poly(A)信号AATAAA的778 bp 3'非翻译区[不包括Poly(A)].阅读框共编码355个氨基酸,分子量为39.89 ku.序列比对分析表明翘嘴红鲌G6Pase与斑马鱼G6Pase的相似性高达95%,与鼠、狗、人G6Pase的相似性为63%,和光滑爪蟾、金头鲷、河豚等G6Pase的相似性分别为69%、55%、76%,并具有G6Pase特有的3个保守基序.为了研究摄食以及饲料中碳水化合物对G6Pase的影响,使用实时定量RT-PCR分别测定了饲喂等能但不含碳水化合物和含23.98%碳水化合物的饲料的翘嘴红鲌肝脏G6Pase基因的表达水平,在使用上述饲料饲喂8周后,禁食48 h, 然后测定禁食和摄食后3、6、12、24 h G6Pase mRNA的表达量,结果显示摄食后12 h,两组G6Pase的表达明显增加,说明摄食影响G6Pase基因的表达,禁食和摄食后3～12 h,含糖组G6Pase基因的表达量为无糖组的2～4倍,这表明碳水化合物可以诱导G6Pase mRNA的表达.     

翘嘴红肝脏G6Pase催化亚基的克隆以及摄食和饲料中碳水化合物对其表达的影响

采用RT-PCR和RACE法分离、克隆了翘嘴红G6Pase催化亚基基因全长cDNA，共1900 bp ［不含poly(A)］, 包括49 bp 5′非翻译区，1068 bp阅读框以及含Poly(A)信号AATAAA的778 bp 3′非翻译区［不包括Poly(A)］。阅读框共编码355个氨基酸，分子量为39.89 ku。序列比对分析表明翘嘴红G6Pase与斑马鱼G6Pase的相似性高达95%，与鼠、狗、人G6Pase的相似性为63%，和光滑爪蟾、金头鲷、河豚等G6Pase的相似性分别为69%、55%、76%，并具有G6Pase特有的3个保守基序。为了研究摄食以及饲料中碳水化合物对G6Pase的影响，使用实时定量RT-PCR分别测定了饲喂等能但不含碳水化合物和含23.98%碳水化合物的饲料的翘嘴红肝脏G6Pase基因的表达水平，在使用上述饲料饲喂8周后，禁食48 h, 然后测定禁食和摄食后3、6、12、24 h G6Pase mRNA的表达量，结果显示摄食后12 h，两组G6Pase的表达明显增加，说明摄食影响G6Pase基因的表达，禁食和摄食后3～12 h，含糖组G6Pase基因的表达量为无糖组的2～4倍，这表明碳水化合物可以诱导G6Pase mRNA的表达。图5参21 关键词：快速扩增cDNA末端；葡萄糖6磷酸酶；碳水化合物；翘嘴红；实时定量PCR E-mail:gexp@ffrc.cn     

兴凯湖四种野生鲌消化酶活性比较研究

本文分析兴凯湖定点同日随机采集的翘嘴鲌Culter alburnus、蒙古鲌C.mongolicus、兴凯鲌C.dabryi和红鳍原鲌Cultrichthys erythropterus肝胰脏和肠道消化酶的活性,比较2龄鱼和≥3龄鱼两实验组样本的特点和差异。结果表明:四种鲌肠道蛋白酶和淀粉酶活性显著高于肝胰脏;蒙古鲌肝胰脏脂肪酶活性高于肠道,其他三种鲌类肠道脂肪酶活性高于肝胰脏(P0.05)。2龄和≥3龄鱼蒙古鲌肝胰脏蛋白酶活性最高,翘嘴鲌和兴凯鲌分别次之(P0.05);2龄鱼兴凯鲌、蒙古鲌、翘嘴鲌肠道蛋白酶活性较高,≥3龄鱼蒙古鲌和红鳍原鲌显著高于兴凯鲌、翘嘴鲌(P0.05)。2龄组和≥3龄鱼翘嘴鲌肠道脂肪酶活性和肝胰脏、肠道淀粉酶活性均较高,≥3龄蒙古鲌和兴凯鲌肝胰脏脂肪酶活性显著高于翘嘴鲌和红鳍原鲌(P0.05)。本研究结果对科学保护与利用相关鱼类有参考价值。     

碳水化合物、脂肪对翘嘴红鲌PEPCK基因表达的影响

使用实时定量RT-PCR测定了摄食无糖(脂肪9.13%，蛋白63.38%)、高糖(糖23.93%，脂肪9.94%，蛋白40.53%)、低脂(中糖)（脂肪9.92%，糖14.45%，蛋白50.14%）、高脂(脂肪19.93%，糖14.98%，蛋白40.88%)饲料的翘嘴红鲌在摄食后0、3、6、12、24 h PEPCK的表达水平。结果显示，饲料中糖含量一致的情况下，高脂组和低脂组翘嘴红鲌PEPCK的表达差异不显著；脂肪水平一致时，高糖(23.93%)和中糖(14.45%)饲料组翘嘴红鲌PEPCK的表达，除了在0、3 h时高糖组显著高外，6、12、24 h没显著差异，但12、24 h高糖组PEPCK相对较低，分别是中糖组的75%和65%；无糖组PEPCK的表达量除了在12 h和其他各组一致(均较低)外，在其他时间均明显高，特别是摄食后24 h其表达量为其他组同期的2.5～4.7倍。由此可见，当饲料中至少含14.45%糖但又低于23.93%时，饲料中的营养成分对PEPCK的表达没显著影响，而无糖饲料PEPCK的表达明显较高，和无糖饲料会引起较强的糖异生作用一致。表2参17     

不同温度对翘嘴红鲌幼鱼脂肪酶活性的影响

研究了不同温度条件下翘嘴红鲌(Erythroculter ilishaeformis)前肠、中肠、后肠和肝胰脏中脂肪酶活性的变化规律.结果显示,在设定的温度范围内,翘嘴红鲌消化道各段中脂肪酶的活性均随着温度的升高呈现先升后降的变化趋势;翘嘴红鲌肠道和肝胰脏中脂肪酶的最适温度均为40℃,而肠道中前肠、中肠、后肠中脂肪酶的最适温度分别为44℃、40℃和36℃;翘嘴红鲌脂肪酶活性存在器官特异性,在最适温度下,脂肪酶的活性为肝胰脏＞肠道,在肠道各段则有中肠≈前肠＞后肠,除中肠与前肠脂肪酶活性差异不显著外(P＞0.05),其余各部位之间差异显著(P＜0.05).研究表明,翘嘴红鲌幼鱼肝胰脏对饲料脂肪的消化起重要作用.     

翘嘴鳊及其亲本肌肉营养成分分析

为研究新型杂交鱼翘嘴鳊(二倍体鲂鲌F1♀×团头鲂♂)的肌肉营养价值,实验运用生化方法测定和分析了翘嘴鳊、翘嘴红鲌、团头鲂、二倍体鲂鲌F1(团头鲂♀×翘嘴红鲌♂)的肌肉营养成分,包括这些样品的水分、脂肪、蛋白质和灰分含量,以及脂肪酸组成和氨基酸组成。结果表明,翘嘴鳊与其原始亲本相比具有较高的蛋白质和较低的碳水化合物含量;脂肪酸分析发现翘嘴鳊的不饱和脂肪酸,尤其是油酸、DHA等含量显著高于其原始父母本和其他有关鱼类(P0.05);翘嘴鳊肌肉中具有较高呈味氨基酸比例,该比例高于其父母本的相应比例。研究表明,翘嘴鳊是一种营养价值高、口感好的优质鱼类。     

太湖鲌鱼数量变化规律及生态效应分析

通过2003~2005年的食性分析和渔获物组成调查,研究了太湖翘嘴红鲌、蒙古红鲌数量变化的规律及在鱼类群落演替过程的作用。食性分析表明:太湖翘嘴红鲌、蒙古红鲌主要摄食鲚鱼,其次是小型鱼类和虾。其中鲚鱼在翘嘴红鲌、蒙古红鲌消化道的出现率分别为95.24%、59.26%;在翘嘴红鲌食物中的重量组成比例为59.2%±11.4%。渔获量统计表明:1952~1958年鲌鱼平均年产量为406.4±102.5 t、占渔获总量的6.28%±0.85%;1987年达到历史最高产量1 090.8 t、占渔获总量7.65%;1993年后鲌鱼资源在快速减少,由1993年的922.3 t、占6.55%下降到近年的100~160 t、仅占渔获总量的0.4%~0.8%。2004年调查表明,在74 667kg渔获物中,翘嘴红鲌、蒙古红鲌仅占0.0038%。分析历年渔获量变化趋势发现,随着鲌鱼数量的不断减少,鲚鱼和小型其它鱼类均呈相反的快速增加趋势,而银鱼则有大体一致的持续下降趋势。简单相关和偏相关分析发现,鲌鱼-鲚鱼、鲌鱼-小型鱼类渔获量的负相关关系达到显著水平;鲌鱼-银鱼渔获量的正相关关系达到显著水平。研究认为:太湖翘嘴红鲌、蒙古红鲌对鲚鱼和小型鱼类有很强的抑制作用,对银鱼可能有间接促进作用;人为过度捕捞使翘嘴红鲌、蒙古红鲌数量不断减少,从而导致鱼类群落向鲚鱼为绝对优势种、小型鱼类不断增加的方向变化。鲚鱼和小型鱼类主要摄食浮游动物,其快速增加抑制了浮游动物、有利于浮游植物生长,这是太湖蓝藻频繁暴发的生物学因素之一。     

饲料中脂肪含量对翘嘴红鲌幼鱼消化酶活性的影响

本文旨在研究不同饲料脂肪含量翘嘴红鲌消化酶的影响.以鱼粉和豆粕作为蛋白源,以鱼油为脂肪源.鱼油的添加水平分别为2%、4%、6%、8%、10%,设计出饲料脂肪含量分别为2.07%、4.28%、7.14%、9.26%、11.17%、15.32%的6种等蛋白(40%左右)、等能(16.21KJ/g左右)的饲料.对19.36±2.17g/尾的试验翘嘴红鲌进行60d的养殖,结果表明:饲料脂肪含量在7.14%时,试验翘嘴红鲌胃蛋白酶和肝胰蛋白酶活性均达最大,分别为1216.41U和1599.94U;此时,淀粉酶活性达到最大,胃、肠、肝胰淀粉酶活性分别为85.75U、115.29U和92.87U;肠、肝胰脂肪酶活性也达到最大,分别为752.13U和199.71U当饲料脂肪含量在9.26%时,试验鱼肠蛋白酶和胃脂肪酶活性达到最大,分别为1934.09U和391.29U.本试验中饲料脂肪含量为7.14%～9.26%时,能显著提高翘嘴红鲌消化酶活性,促进对饲料的消化利用率.     

运输时间和MS-222浓度对翘嘴鲌皮质醇、乳酸及氧气袋内水质的影响

釆用MS-222浓度为0(C0组)、5 mg/L(C1组)、10 mg/L(C2组)、15 mg/L(C3组)、20 mg/L(C4组),运输时间为0、2、4、6、8、10 h,运输密度为33 g/L,采用5×6双因素实验,氧气袋运输翘嘴鲌(Culter alburnus)稚鱼,研究了运输时间和MS-222浓度对翘嘴鲌全鱼皮质醇、乳酸含量及氧气袋内水质的影响。结果显示:翘嘴鲌全鱼皮质醇、乳酸水平随运输时间呈现先升高后降低的趋势,随麻醉剂浓度的增加而显著降低;C1-C4组的DO、p H随运输时间呈现先降低后升高的趋势,C0组则随运输时间的增加显著降低,各组的DO和p H随MS-222浓度的增加而显著增加;C1-C4组的氨氮(TAN)和游离CO_2浓度随运输时间呈现先升高后降低的趋势,而C0组则随运输时间的增加显著升高,各组的TAN和游离CO_2浓度随MS-222浓度的增加而显著降低。时间和浓度的交互作用都显著。运输时间T6 h时,MS-222刺激翘嘴鲌,不利于运输,运输时间T6 h时,MS-222能显著降低其应激水平及代谢强度,其中C4组皮质醇、乳酸含量最低,C3、C4组水质条件最好,其适宜的麻醉剂浓度为15~20 mg/L。     

翘嘴鲌鱼种饲料中脂肪适宜水平的初步研究

以鱼粉和酪蛋白为蛋白源,以鱼油和豆油的混合物(1︰1)为脂肪源,配制7种等氮不同脂肪水平(1.82%dm~15.02%dm)的试验饲料,饲养平均体重为2.85±0.15g的7组翘嘴鲌隔冬鱼种30d。试验结果表明,翘嘴鲌鱼种饲料中脂肪水平对鱼体生长、饲料系数和蛋白质校效率均有显著的影响(p<0.05)。饲料中适宜的脂肪水平为6.48%~8.78%。     

Achieving sustainable aquaculture: Historical and current perspectives and future needs and challenges

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.     

Fish assemblage associations and thresholds with existing and projected oil and gas development

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.     

Gar biology and culture: status and prospects

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.     

Esophagoscopy and gastroscopy in dogs and cats. Technics and indications

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.     

加快城乡统筹，推进我国农垦体制创新与经济发展的研究与思考

“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。     

添加植酸酶日粮不同磷水平和钙磷比对生长肥育猪血液生化指标和骨骼性能的影响

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。     

温度与盐度对老年低额蚤和蚤状蚤生长及生殖的影响_

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...     

奶牛酮病发病机理研究进展

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。     

川渝地区鸡皮刺螨的流行与综合防治

鸡皮刺螨是鸡的一种体外寄生的节肢动物,流行十分广泛,对养殖业发展有严重影响。为了解鸡皮刺螨的发病情况,对川渝两地的126个鸡场进行流行病学调查,感染率高达71%。同时,介绍了鸡皮刺螨的生活史、危害及防治措施,是防制鸡皮刺螨不可多得的资料。     

Shrimp and fish pond soils: processes and management

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.