甘肃高山细毛羊细管鲜精低温保存效果研究

为了研究甘肃高山细毛羊种公羊细管精液低温保存的效果.用葡萄糖、柠檬酸钠、鲜奶和卵黄为主要成分配制了3种稀释液,10倍稀释精液,并在4℃保存,分别在12h,24 h,36h,48 h,60h和72 h观测精子活力和人工授精受胎率.结果显示,配方Ⅲ稀释精液后,细管封装,4℃保存,72 h后精子活力可达0.49,与配方Ⅰ和Ⅱ差异显著,而且配方Ⅲ稀释精液后,在远距离输精后受胎率可达78.3％.以柠檬酸钠和葡萄糖为基础,添加卵黄和TCM199,在4℃下,能有效保护甘肃高山细毛羊精液,延长精子寿命,且在3d内可以满足远距离人工授精要求,有效利用种公羊价值.     

黄鳝皮肤黏液抗菌肽的分离纯化及其部分特性研究

以黄鳝皮肤黏液为材料,通过Sephadex G-50凝胶层析和DEAE Sepharose Fast Flow离子交换层析,分离纯化了具有抗菌和镇痛活性的多肽MAS-Ⅳ-4,用Tricine-SDS-PAGE测得其分子量为10.4 kD,用显微熔点仪测得其熔点为208～211℃.用抑菌圈法测定其抑菌活性,结果表明,MAS-Ⅳ-4对嗜水气单胞菌、金黄色葡萄球菌、枯草芽孢杆菌有较强的抑菌效果.此外,每只注射0.75 ml以上的MAS-Ⅳ-4样品液能显著提高小白鼠的痛阈值.MAS-Ⅳ-4还具有微弱的溶血活性和丝氨酸蛋白酶抑制活性.     

锰、铜、锌、铁添加水平对产蛋鸡生产性能和养分表观利用率的影响

设计锰、铜、锌、铁不同添加水平的A,B,C,D和E 5组日粮(A组为不添加4种微量元素的基础日粮;B组添加锰14 mg/kg;C组添加锰34 mg/kg;D组添加锰54 mg/kg、铜2 mg/kg、锌13 mg/kg;E组添加锰10mg/kg、铜2 mg/kg、锌17.5 mg/kg、铁22.5 mg/kg)分别饲喂5组275日龄罗曼褐壳蛋鸡,每组6个重复,每重复15只,试验期60 d,研究锰、铜、锌、铁不同添加水平对产蛋鸡生产性能和养分表观利用率的影响。结果表明,不添加4种微量元素的基础日粮(A组)的产蛋性能和养分利用率较高;锰是影响鸡产蛋率、产蛋量和其他元素吸收率的主要因素,添加锰使生产性能和养分利用率降低,锰添加量为34 mg/kg时产蛋率和能量表观利用率显著降低(P<0.01),日粮中锰和表观可利用锰的推荐含量应分别低于46和14 mg/kg;基础日粮中添加铜、锌和铁不影响蛋鸡生产性能和能量、粗蛋白质、钙和磷的表观利用率(P>0.05)。说明基础日粮中锰和铁已能满足或超过蛋鸡营养需要,添加锰对生产不利,而基础日粮中铜和锌相对缺乏。     

三峡水库小江流域消落区土壤重金属时空分布与来源分析

2010年3-9月对小江流域消落区5个断面的土壤重金属含量进行监测.结果表明,2010年小江流域消落区土壤Cu、Zn、Pb、Cr、Fe和Mn均值分别为28.90、72.73、23.58、20.70、35.58×103和517.14 mg/kg.土壤综合污染指数为0.99,污染等级处于警戒级.小江消落区土壤重金属含量沿程分布以高阳站点较低,黄石站点较高,且大部分重金属含量随高程升高总体呈现升高的趋势.时间分布上以3月和7月各重金属均值含量较高.与2009年相比,2010年消落区土壤重金属Fe、Mn和Zn含量有所降低,Cu和Pb含量有所增高.利用相关性分析和因子分析对5种重金属的相关性和来源进行解析,结果表明Fe、Mn与其他重金属相关性显著(P＜0.05或P＜0.01),而Cu和Pb也显著相关(P＜0.01),Cr与Fe、Mn之外的重金属的相关性都较弱,初步推断Fe、Mn和Zn属于“自然因子”类别元素,Cu和Pb属于“污染因子”类别元素.     

Is the decline of birds and amphibians in a steppe lake of northern Patagonia a consequence of limnological changes following fish introduction?

• 1. Laguna Blanca, in Laguna Blanca National Park, is a lake in Patagonia which has been designated as a Ramsar site since 1971 because of bird diversity and abundance and importance for nesting, particularly for the black neck swan, Cygnus melanocoryphus. It is also valued for its populations of endemic amphibians, Atelognathus patagonicus and Atelognathus praebasalticus.
• 2. Avian and amphibian populations have decreased dramatically in recent years. Percichthys colhuapiensis, Percichthys trucha (Pisces, Percichthyidae), Salmo trutta and Oncorhynchus mykiss (Pisces, Salmonidae) were introduced into Laguna Blanca in 1965. Since 1986, no Atelognathus frogs have been found. The abundance of swans and coots, which are strongly associated with macrophytes for nesting and feeding, has diminished drastically, whereas piscivorous birds have increased.
• 3. The fishless condition of some neighbouring small lakes with abundant pond weeds, aquatic birds and endemic amphibians, was assessed in order to compare the physical and chemical characteristics and the quantitative composition of the benthos among lakes. Fish presence at Laguna Blanca and its absence at El Burro, Antiñir and Jabón lakes, were confirmed. Compared with previous results, it seems that the abundance of Amphipoda (Hyalella), Copepoda and Cladocera at Laguna Blanca has decreased, while Acari has increased and Notostraca has disappeared. Water transparency has diminished in Laguna Blanca and now is lower than that of fishless lakes.
• 4. P. colhuapiensis were captured only in Laguna Blanca, with the highest captures in the littoral zone. The population shows rapid individual growth in the early years and an absence of fish older than 6 years. The preponderance of benthos and the presence of macrophytes in the gut contents of adult P. colhuapiensis appear to indicate that they are important consumers of these resources.
• 5. This paper concludes that fish introduction in Laguna Blanca led to a complex trophic cascade effect (fish predation on tadpoles, fish competition for avian food, bottom disturbance, zooplankton reduction) producing deleterious effects on the amphibian and bird populations.

Copyright © 2006 John Wiley & Sons, Ltd.     

Tail Muscle Free Amino Acid Concentration of Pacific White Shrimp,Litopenaeus vannamei,Fed Diets Containing Protein‐bound versus Crystalline Amino Acids

Tail muscle tissue free amino acids (FAA) concentration is reported for subadult (4.3 g) Litopenaeus vannamei fed diets containing only protein‐bound amino acids, crystalline lysine as a supplement to protein‐bound lysine, and only crystalline amino acids (CAA). FAA were determined in shrimp at 0.00, 0.25, 0.5, 1, 2, 4, and 8 h postfeeding. Highest total tissue concentrations of essential amino acids and individual amino acids were typically observed 4 h postfeeding for shrimp fed intact and crystalline lysine‐supplemented feeds. Those shrimp offered diets containing only CAA showed no tissue maxima. Similar uptake patterns for lysine shown by shrimp fed the intact and crystalline lysine‐supplemented diet indicate the potential use of small amounts of crystalline lysine in shrimp feeds.     

马来眼子菜和POM稳定同位素对污染物的指示作用

为了探究大型植物马来眼子菜（Potamogeton malaianus）和颗粒有机物质（Particulate organic matter,POM）对湖泊主要污染来源的指示作用,在贡湖湾选取14个样点,采集马来眼子菜和POM样品,分析其碳、氮稳定同位素的变化。结果显示,马来眼子菜和POM有相似的δ15N值趋势,都是随着离入湖口距离越远,其δ15N值逐渐增加,马来眼子菜的δ15N值为10.8‰～14.1‰,POM的δ15N值为6.69‰～14.1‰;而马来眼子菜的δ13C值随着离入湖口距离越远有下降趋势,变化范围为-17.6‰ ~ -14.5‰;POM的δ13C值则有增加趋势,变化范围为-26.9‰ ~ -24.6‰。马来眼子菜较高的δ15N值指示了人类生活污水来源的氮,表明贡湖湾的主要污染源为生活污水。相关分析表明,水中总溶解磷（TDP）与马来眼子菜的δ15N值有明显的负相关关系,水中的总氮（TN）与POM的δ15N、δ13C值则呈很好的正相关关系。而POM的N占比和底泥的δ15N值分别与POM的δ15N值有明显的正相关性。研究表明,马来眼子菜和POM的δ15N、δ13C值能够指示太湖贡湖湾的主要污染来源。     

列当杂草及其防除措施展望

根寄生杂草列当Orobanche spp.每株可产生大量细小的种子,易于传播,且在出苗前已经对寄主作物造成危害,使列当的防除成为一个世界性难题。本文详述了列当的生活史、为害现状以及防除措施,并突出了生物防除的生态效益与经济效益。基于＂诱捕＂作物及＂捕获＂作物诱导列当种子＂自杀发芽＂理论的防除机制,本文提出了新型可持续生态防除思想,为列当科杂草防除提供参考。     

优化施肥对上海产区温州蜜柑生长的影响

研究不同优化施肥模式对温州蜜柑产量、品质及树体生长的影响,为实现温州蜜柑高产优质提供技术指导。以温州蜜柑田间试验为基础,设置4个处理:FM处理(农户习惯施肥)、OF处理(FM+有机肥)、OPT处理(氮、磷、钾优化+有机肥)、COF处理(OPT+钙、镁)。3种优化施肥模式均可促进温州蜜柑的生长,施用有机肥短期效果不明显,优化氮、磷、钾并施用有机肥可以显著地促进树体后期的生长。优化氮、磷、钾并施用有机肥的基础上再补充钙、镁元素效果最佳,相较于农户习惯施肥,显著提高了春梢各生长指标;叶片SPAD值和矿质养分含量均显著提高;果实横径、果实纵径、单果重、挂果数和产量分别显著提高了9.69%、8.66%、6.68%、4.74%、11.76%;果实还原糖、维生素C、可溶性固形物、固酸比和可食率分别显著提高了55.67%、21.45%、8.21%、27.12%、2.48%。综合优化养分管理可以平衡树体养分,激发树体产量潜力并提高品质。     

论我国旅游投诉解决机制及其完善——以非诉讼纠纷解决方式为视角

随着我国旅游业规模的不断扩大,旅游体系也日趋完善。在推进旅游产业快速发展的进程中,各种类型的旅游纠纷也随之迅速增加。在目前我国多元化纠纷解决机制日趋完善的背景下,旅游投诉解决机制对于确保旅游业和谐稳步推进有着特殊的功能优势。但鉴于旅游投诉解决机制的固有局限性,需要从明确旅游投诉处理结果的效力、增设旅游投诉解决机制为司法救济的前置程序等方面予以完善。