中国对虾（Penaeus chinensis）幼体发育各阶段脂肪酸组成的研究↑（*）

通过对中国对虾幼体的五个发育阶段的脂肪酸组成的测定，分析比较了幼体脂肪中１１种主要脂肪酸的含量变化。在卵脂肪中占主要比例的脂肪酸为棕榈酸，棕榈油酸和ＥＰＡ，油酸；在仔虾脂肪中占主要比例的脂肪酸为棕榈酸，油酸，亚油酸，ＥＰＡ及ＤＨＡ。从卵到仔虾整个发育过程中，幼体脂肪中的豆蔻酸，棕榈酸，棕榈油酸的含量逐渐减少，而硬脂酸，亚油酸，亚麻酸和ＤＨＡ的含量逐渐增加。     

中国对虾卵巢发育过程中脂肪酸组成的分析及比较研究

通过分析中国对虾亲虾在卵巢发育的不同阶段的卵巢、肝胰脏和肌肉的脂肪酸组成来评估中国对虾在性腺成熟过程中对脂质的需要。从中国对虾亲虾不同组织的脂肪酸组成可见,棕榈酸(16:0)、棕榈油酸(16:1ω7)、油酸(18:1ω9)、二十碳五烯酸(20:5ω3,EPA)及二十二碳六烯酸(22:6ω3,DHA)占主要比例,这与其它海洋甲壳类的脂肪酸组成相类似。中国对虾亲虾的主要脂肪酸组成比例与日本对虾亲虾的主妥脂肪酸组成比例相近似。中国对虾亲虾在不同的卵巢成熟期同一器官中的主要脂肪酸组成比例没有明显的差别,而不同组织的主要脂肪酸组成中都含有大量的ω-3系列的高度不饱和脂肪酸。从成熟卵巢的脂肪酸组成中含有高比例的EPA、DHA含量可见,EPA、DHA在亲虾性腺发育过程中的必需性。     

ω—3及ω—6不饱和脂肪酸对中国对虾幼虾存活,蜕皮和生长的影响

用高纯度单一ω-3和ω-6系列脂肪酸、亚油酸、亚麻酸、花生四烯酸以及二十二碳六烯酸,分别以饵料1％的含量添加到含脂类4％棕榈酸和油酸的基础饵料中,组成四种试验饵料。对照饵料的脂类组成为5％的棕榈酸和油酸。对中国对虾幼虾进行32天的投喂试验,测定ω-3和ω-6系列不饱和脂肪酸对幼虾存活、蜕皮和生长的影响。结果表明,投喂不含ω-3和ω-6系列脂肪酸的对照饵料,幼虾生长几乎停止,存活率极低。添加1％的亚油酸或亚麻酸或花生四烯酸,效果较好;添加1％的二十二碳六烯酸,效果最佳。说明ω-3和ω-6系列不饱和脂肪酸对中国对虾幼虾的存活和正常生长是必需的。     

卤虫卵化学成分的分离和分析

本试验对幼虾、鱼苗的饵料卤虫卵进行了化学成分的分离和分析.卤虫卵含油量为7.1%,油中不皂化物含量为4.9%,主要为胆甾醇.脂肪酸中含有较大量的油酸、棕榈酸、棕榈油酸、花生四烯酸和EPA.卤虫卵含蛋白质为20.9%,还舍有多种氨基酸.     

锯缘青蟹幼体饵料的营养强化

用酵母、水球藻、鱼油强化和豆油强化四种不同方式培养轮虫，再分别投喂锯缘青蟹幼体，分析测定轮虫和体的生化组成，结果显示，（1）不同方式培养的轮虫之间以及摄食这些轮虫的锯缘青蟹幼体之间的蛋白质含量都没有显著差异；（2）轮虫的脂类含量和脂肪酸组成与培养方式密切相关，小球藻轮虫的脂类含量最高，20：5n-3(EPA)占总脂肪酸的比例也最高 ，为18.05%，鱼油轮虫则含有最多的22：6n-3(DHA)，占总脂肪酸3.16%，脂类含量仅次于小球藻轮虫；（3）锯缘青蟹幼体的脂类含量和脂肪酸组成受相应饵料营养成分的影响。另外，幼体培育实验也发现，饵料营养成分影响幼体的存活率，结果表明，提高轮虫的EPA和DHA含量，尤其晨DHA含量，将有利于锯缘青蟹幼体的存活和发育。     

大鳍鳠产卵前后肌肉脂肪酸组成变化的研究

采用毛细管气相色谱法,对产卵前后大鳍鳠肌肉中的脂肪酸组成进行了测定。结果表明,大鳍鳠肌肉中脂肪酸种类丰富,含有22种脂肪酸,油酸(C18:1n-9)所占比例最高,其次为软脂酸(C16:0)、棕榈酸(C16:1n-7)、亚油酸(C18:2n-6),所占比例分别为22.38%~37.57%、18.86%~23.95%、7.00%~11.52%、7.46%~9.97%。EPA和DHA在大鳍鳠肌肉中占有较高的比例,EPA占总脂肪酸的5.39%,DHA占5.44%。在野生大鳍鳠产卵前后的22种脂肪酸中有8种饱和脂肪酸(SFA),6种单不饱和脂肪酸(MUFA)和8种多饱和脂肪酸(PUFA),大鳍鳠肌肉中脂肪酸在产卵前后表现出差异。     

气质联用技术测定三角帆蚌肉中脂肪酸组成与含量

本研究采用气相色谱-质谱联用法分析测定三角帆蚌Hyriopsis cumingii肉中脂肪酸的化学组成及含量。利用石油醚作为溶剂对河蚌肉中脂肪酸进行提取,结合质谱数据库对脂肪酸甲酯化组成进行分析,用面积归一化法计算各种脂肪酸相对含量。结果表明:河蚌肉中主要含有棕榈酸、硬脂酸、油酸、亚油酸、花生一烯酸、二十烷五烯酸(EPA)、二十二烷六烯酸(DHA)等多种脂肪酸,其中不饱和脂肪酸含量超过70%。本研究可为河蚌肉产品开发提供科学依据。     

野生黄颡鱼雌鱼产卵前后肌肉脂肪酸的组成

采用毛细管气相色谱法,对贵州锦江河繁殖期产卵前后黄颡鱼肌肉中的脂肪酸组成进行了测定。结果显示：黄颡鱼产卵前后肌肉中脂肪酸种类都比较丰富,含有有22种脂肪酸。油酸（C18：1n-9）所占比例最高,其次是软脂酸（C16：0）、硬脂酸（C18：0）和棕榈酸（C16：In-7）,分别占总脂肪酸的40．31％-43．90％、22．94％-25．05％、6．05％-7．75％、6．26％-7．00%。廿碳五烯酸（C20：5n-3,EPA）和廿二碳六烯酸（C22：6n-3,DHA）之和占4．69％～5．38％,其中EPA约占总脂肪酸的1．4％,DHA占3．6％。同产卵前相比,软脂酸（C16：0）、硬脂酸（C18：0）、亚油酸（C18：2n-6）和花生四烯酸（C20：4n-6,ARA）所占比例下降较大,而C15：0、C22：0、亚麻酸（C18：3n-3）的比例显著升高。研究表明在黄颡鱼产卵后的饲料配制中,需要适当添加脂类物质,以恢复其在产卵后的体质。     

大黄鱼鱼种阶段脂肪酸组成研究

对人工培育的90-180日龄的大黄鱼鱼种,用GC/MS法分析比较了其肌肉和肝脏的脂肪酸组成,肌肉和肝脏分别检出脂肪酸25种和42种.试验结果表明,7-10月,肌肉中的脂肪不断积累,而肝脏中则保持相对恒定,且是肌肉的1.7～3倍;2种组织中均以C16∶0(棕榈酸)含量最高,其次为C18∶1(油酸);肝脏中脂肪酸以饱和脂肪酸(SFA)为主,SFA的平均含量是多不饱和脂肪酸(PUFA)的4倍,而肌肉中的SFA平均含量则与PUFA基本相当;花生四烯酸(AA)、二十碳五烯酸(EPA)、二十二碳六烯酸(DHA)及亚油酸(C18∶2)等n-3和n-6系列的PUFA在肌肉中含量更高;大黄鱼鱼种首先利用肌肉组织中以C16∶0为主的十八碳以下的SFA作为能量来源,而不轻易动用肝脏贮藏的能量.通过与幼鱼和成鱼比较可知,随着鱼体的成长,其脂肪酸种类不断丰富,组成也更趋合理.     

梅奇酵母C14菌株的生化组成分析

通过对梅奇酵母C14菌株的生化组成进行分析,发现梅奇酵母C14菌株具有水产动物饵料生物的营养价值。但是,该菌株缺乏多不饱和脂肪酸EPA和DHA,作为幼体饵料使用时,需要添加富含这两种多不饱和脂肪酸的藻类作为补充。     

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.     

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.     

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.     

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.     

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。     

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。     

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。     

Composition and diversity of fish and fish catches in closures and open-access fisheries of Kenya

Abstract  Catch composition, relative abundance and diversity of fish catches in open access and three old fisheries closures were compared and contrasted with previous ecological studies. There was less variation in catch community composition among the fishing grounds than the closures, suggesting that fishing has homogenised catch composition. The trap survey found that some parrotfish [ Leptoscarus vaigiensis (Quoy &Gaimard), Calotomus carolinus (Valenciennes) and Scarus ghobban Forsskål] were relatively more common and that some important predators of macro-invertebrates [ Balistapus undulatus (Mungo Park) and Cheilinus chlorourus (Bloch)] were less common in the fishing grounds than closures. Unexpectedly, and in contrast to visual census results, cumulative number of species in catch surveys was higher in open access than closures sites. This may result from fishers covering more area and habitat or a reduction in the catch of competitively subordinate and rare species by aggressive, early-caught fish that can dominate bait. Comparisons of ecological visual census surveys and fisheries-dependent methods indicated that small differences in catch composition can reflect larger ecological differences and that baiting methods can underestimate biodiversity. Ecological impacts of fishing and large-scale changes in marine ecosystems must be considerable given the many fisheries-dependent assessments report modest changes.     

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.