Use of supplemental amino acids on the success of reducing dietary protein levels for Jian carp (Cyprinus carpio var. Jian)

A feeding trial was conducted to investigate the effects of essential amino acids (EAA) supplementation on the success of dietary protein reduction for Jian carp (Cyprinus carpio var. Jian). Five diets were formulated including a positive control (Diet 1, 378.4 g/kg protein), a negative control (Diet 5, 289.8 g/kg protein) and three test diets (Diet 2‐Diet 4, 340.4–299.0 g/kg protein supplemented with EAA). No significant decline of growth performance in fish fed decreased dietary protein with EAA supplementation, which were significantly higher than the negative control. The apparent digestibility coefficients (ADC) of protein and most EAAs were not significantly affected by the dietary treatments. Dietary treatments did not affect whole‐body composition, but influenced protein and EAAs retentions. Total ammonia nitrogen (TAN) excretion decreased with the decreasing dietary protein, and the highest plasma ammonia content was observed in fish fed Diet 5. Plasma glucose concentration increased with the decreasing dietary protein reduction, while other plasma parameters were not affected by dietary treatments. These results indicated that low‐protein diets (299.0 g/kg) supplemented with EAA can maintain protein, EAA digestibility and retention in Jian carp, and also has benefit in the reduction of TAN excretion.     

乌苏里拟Chang人工繁育技术及开发利用——乌苏里拟Chang仔幼鱼食性与生长的初步研究

对乌苏里拟Chang仔幼鱼的食性与生长进行了初步研究,在18-22℃水温下分别以水蚯蚓、鱼肉糜和人工配合饲料投喂进行对比试验,结果发现其仔幼鱼具有较广泛的食性,且不同饲料投喂后各试验组的生长没有呈现出显差异。     

黑龙江省湖泊水域成熟白鲢卵巢周期变化的研究

本文对黑龙江省湖泊、水库等水域成熟白鲢卵巢进行了解剖学、组织学观察。对卵巢的色泽和不同时相卵细胞的组织演变和数量的关系作了叙述。着重讨论了在高寒地区白鲢卵巢发育的特点：即第4时相退化卵的滤泡细胞膜不论在秋、冬两季或在春季均呈扁平，没有吞噬卵黄的现象。退化卵一直延迟到翌年5月中旬才开始吸收，于此同时，正是第3时相卵细胞迅速发育阶段，退化卵的吸收和新一代卵细胞的成长两者几乎是在同一时间进行的。所以卵巢成熟系数在周期变化中，它的波动幅度不大。     

对虾池混养缢蛏高产技术

缢蛏肉味鲜美,营养丰富,是我国沿海群众喜爱的海味佳品.养殖缢蛏具有生产周期短,易管理,成本低,效益高,投资少,见效快等特点.在对虾塘里混养缢蛏,可充分利用水体,不但可以增加贝类的产量;还可避免因残饵腐败引起的水质恶化,减少虾病发生;贝类的排泄物又能促进浮游生物和底栖硅藻的繁殖,为对虾提供天然饵料,有利于对虾生长,形成良性循环,达到虾贝双丰收的目的.     

Expression and functional characterization of glutamine synthetase from giant freshwater prawn (Macrobrachium rosenbergii) under osmotic stress

The freshwater prawn, Macrobrachium rosenbergii naturally lives in the freshwater, though it migrates to the brackish water environment during spawning that claimed to be resistant on a broad range of saline fluxes. However, little is known about the osmoregulatory patterns and the effect of an enzyme glutamine synthetase (GS) in M. rosenbergii under stress. Here, we described the identification and functional characterization of GS from M. rosenbergii (Mr‐GS) at molecular and protein levels. The identified Mr‐GS was comprised of 361 amino acids that phylogenetically shared the highest identity with other crustaceans and predicted to contain Gln‐synt_C and Gln‐synt_N domains at the respective terminal regions. Tissue distribution analysis in M. rosenbergii revealed that the Mr‐GS was highly expressed in muscle, and commonly existed in other examined tissues in the following order gills > heart > stomach > brain > haemolymph. Whereas, the mRNA of Mr‐GS was significantly up‐regulated in the muscle and gill tissues following challenges with either hyper (0 → 13‰), or hypo (13 → 0‰) osmotic stress at 3, 6 and 12 hr. Furthermore, the level of Glutamine concentration was positively correlated with the GS mRNA and protein expression patterns in hyper‐osmotic stress, whereas in hypo‐osmotic stress a slight decrease in the gills and maintained a level in the muscle tissues at 3, 6 and 12 hr post‐treatments. Our findings suggest that Mr‐GS potentially exhibited the osmoregulation responses in the gill and muscle tissues of M. rosenbergii throughout the time of osmotic stress, which will benefit for future study on osmoregulation.     

黄河三角洲暗管排水土工布外包滤料的试验研究

黄河三角洲地区多为近代黄河泥沙淤积形成的粉细砂土,其质地均一、结构松散,在农田排水明沟建设中边坡不稳定的问题突出。近年来该地区大力开展了暗管排水系统建设,但当地砂滤料来源不足,因此,迫切需要筛选出适合当地土壤特点的土工布外包滤料。该文在对研究区土壤特性分析的基础上,利用自制水力渗透仪,通过理论计算和渗透试验观测,研究了所选择土工布的反滤、透水以及防淤堵性能。结果发现,在满足测试条件的2种型号土工布中,Typar 3201G能够满足防淤堵与透水要求,但是有一定的淤堵风险;另一型号土工布(Typar SF20)则能较好的满足研究区暗管排水外包滤料的反滤、透水与防淤堵要求。研究结果表明,满足研究区特殊土壤类型的土工布外包滤料厚度不宜过大,土工布的开孔直径应符合选择标准。研究成果可为黄河三角洲地区暗管排水土工布外包滤料的选择提供技术支撑。     

新疆哈密地区嗜盐菌的特征

从新疆哈密地区的土壤样品中分离出5株嗜盐菌,它们均能在10%—30%NaCl中生长,最适NaCl浓度为15%—18%。生长pH范围为6—11。在0—80mM Mg~(++)时生长良好。在蒸馏水中不破裂。在固体培养基上为球状,在液体培养基中为杆状,细胞大小为0.5—1×2—4um。在牛奶——盐——琼脂培养基上菌落圆形,表面光滑。颜色有橙红,橙黄和浅橙黄,直径1—1.5mm。5株菌均为革兰氏阴性好氧菌。最适生长温度为37℃。接触酶,氧化酶,硝酸盐还原试验均为阳性,不能发酵糖类。其中4株菌对红霉素敏感。根据《伯杰系统细菌学手册》第三卷,它们属于嗜盐菌科的微生物,但与该科各属的特征明显不同。     

马尾松低效防护林多层经营技术研究

用系统整体的观点。结合乔木层郁闭度（Ｘｌ）、灌木层盖度（Ｘ２）、草本层盖度 （Ｘ３）、枯落物层盖度（Ｘ４）与林地土壤侵蚀模数建立的回归模型分析，提出了多 层经营的概念，即“同步经营林分的乔木层。灌木层、草本届和枯落物层，根 据各层目标功能确定经营措施，获取生态经济的整体效益。使林分在高效高产 水平上持续协调发展”。并通过分析马尾松低效防护林系统群落各层次的目标 功能，确立了多层经营的指导思想，据此分层阐述经营技术。     

联苯肼酯43%悬浮剂防治温室蔬菜叶螨田间药效试验示范

近几年来,随着温室水肥一体化技术的应用,温室内高温低湿的环境使得叶螨危害越来越重,给温室蔬菜生产带来很大的损失。在无公害蔬菜生产中,我们选用了低毒、对螨的各个阶段均有效的新型杀螨剂—联苯肼酯43%悬浮剂做试验示范。试验示范结果显示:联苯肼酯43%悬浮剂稀释3 000倍液在温室蔬菜—黄瓜、辣椒上使用效果显著。施药期间注意观察蔬菜叶螨发生危害动态,在叶螨发生始期进行防治,可有效控制叶螨蔓延危害。     

吉林省黄牛“猝死症”的病因学研究

１９９４年以来，对吉林省黄牛“猝死症”的病因进行了多方面的研究，包括细菌学检验、病毒学检验、人工感染试验、毒物检验、牛毛硒元素分析及病尸病理形态学观察。结果表明，Ａ型魏氏梭菌是主要病原菌，其他细菌有协同作用；牛冠状病毒或粘膜病病毒感染、缺硒等为本病的诱因