Long-term variation in brown trout, Salmo trutta L., stocking success in a large lake: interplay between availability of suitable prey and size at release

Abstract –  Factors affecting long-term variation in brown trout, Salmo trutta L., stocking success were examined in a large lake, Lake Oulujärvi, in central Finland. Brown trout were stocked in spring (late May to early June) in 1974–1991 and in summer (late June to early July) in 1992–2001. The biomass of the vendace, Coregonus albula (L.), population (prey) at release time had the largest positive effect on stocking success within both periods: biomass of adult vendace in spring and both 0+ and adult vendace in summer. Increasing the size of stocked fish had a positive effect if the vendace available at release were only adults. The increasing trend of predator-catch-per-unit-effort (CPUE) [combined CPUE of northern pike Esox lucius L., burbot Lota lota (L.), and pike-perch Stizostedion lucioperca (L.)] through the study period and its negative effect on trout stocking success suggested an increasing effect of predation within the entire time series.     

不同播期和不同肥力条件下向日葵干物质形成和物质分配对杂交种产量的影响

不同的播期明显影响向日葵籽实产量及病害发生的程度。通过调整播期，可防止或减轻叶部斑病和菌核病的发生，在向日葵生产上起着很大作用。向日葵不同品种干物质积累规律符合Logistic生长曲线，可用方程y=k/(1 ae^-bx）模拟。向日葵植株的器官平衡依次为：除空壳外，茎秆（28.5%)、籽实（24.5%)、叶片（22.5%)、葵盘（17.3%)、叶柄（4.9%)。土壤肥力对向日葵的器官平衡有较大影响。经济系数不高是向日葵的一个特点。栽培条件不同，经济系数差异较大。在一般情况下，春播条件下经济系数较高，夏播条件下经济系数较低。     

薄层扫描法测定人工诱生牛黄中主要成分的含量

应用岛津CS-910型薄层扫描仪测定了5份人工诱生牛黄和3份天然牛黄中胆酸(CA)、去氧胆酸(DCA)和胆红素(BR)的含量。CA和DCA用荧光扫描,λ_(ex)470nm和λ_(em)550nm;BR用可见光扫描,λ_S402nm和λ_R650nm。测定结果表明,前者中CA和DCA的含量高于后者;BR的含量则前者低于后者。     

Feline Ubiquitin Fusion Protein Genes

Using cDNA from a CRFK cell line as a template, PCR amplification was performed with the Ub1S and poly(dT) primers to isolate feline ubiquitin genes. Sequencing of the 495 bp PCR fragment revealed that the putative amino acids induced by this fragment gave a fusion protein consisting of a ubiquitin polypeptide (76 amino acids) and an extension protein of ribosomal proteins L40 (52 amino acids). The putative amino acid sequence of ubiquitin was identical to those of humans, rats and pigs.The recombinant glutathione S-transferase (GST)–feline ubiquitin fusion proteins were produced in Escherichia coli and purified. The fusion proteins had a molecular weight of about 42 kDa and were detected by immunoblot assay with rabbit anti-ubiquitin antiserum.The mRNAs from heat-shocked and non-heat-shocked cells were subjected to RT-PCR (Ub1S and poly(dT) primers) analysis. The molecular weights of the ubiquitinated proteins in heat-shocked CFRK cells were between 18 kDa and 24 kDa by immunoblot assay.These results suggested that there were more ubiquinated proteins in the heat-shocked CRFK cells than in the pre-heat-shocked cells.     

用台盼兰—姬姆萨染色检测家畜精子顶导反应的研究

本文探讨了用台盼兰—姬姆萨染色检测家畜精子顶体反应的可行性。用肝素或钙离子载体诱发精子顶体反应。根据染色结果将精子分为四类:a)核后帽部不着色或淡青色,顶体不着色或部分紫红色(有顶体反应活精子);b)核后帽部暗青色.顶体部不着色或部分暗红色(有顶体反应死精子);c)核后帽部不着色或淡青色,顶体部紫红色(无顶体反应活精子);d)核后帽部暗青色,顶体部暗紫红色(无顶体反应死精子)。有顶体反应活精子百分率与仓鼠卵穿透率呈强正相关。从而证明台盼兰—姬姆萨染色是检测家畜精子顶体反应的有效手段,并能预测获能处理后精子的受精能力。     

三分域模型在研究单胃动物内源氨基酸排泄中的应用

本文在分析三分域链状系统模型及单胃动物内源氨基酸排泄特点的基础上 ,讨论了如何将三分域链状模型用于单胃动物内源氨基酸排泄模式的确定。研究分三步进行 :1.测定动物血液体积 ;2.静脉连续灌注同位素标记的氨基酸并使之于体内达到平衡 ;3.检测消化道中同位素标记氨基酸的排泄率。文章指出 ,若能对所有必需氨基酸的内源排泄率均进行测定 ,则可得出内源氨基酸排泄模式 ,因而在实际测定饲料或日粮真可消化氨基酸含量时 ,只需测定某种氨基酸的内源排泄量即可知其它氨基酸的内源排泄状况     

牛磺酸在猫营养中的应用

主要综述近年猫的牛磺酸营养,从研究方法来看衡量牛磺酸利用的方法与指标已较完善,对牛磺酸的代谢有了深入的了解,并进一步关注猫肠道菌群影响牛磺酸代谢的机理的研究;初步揭示大豆蛋白和脂肪等营养物质降低牛磺酸利用率的原因;在猫粮加工方面指出不良热处理导致的猫粮中牛磺酸利用率降低的机制,并分析了一些不适合配制猫粮的原料如米糠、大豆蛋白对牛磺酸代谢的影响;以及在猫粮中直接添加晶体牛磺酸的重要性。从文中可以看到,作为必需氨基酸的牛磺酸对于猫的生长繁殖来说十分重要。     

RT-PCR及RFLP分析技术对鸡传染性支气管炎病毒的诊断和S1基因分型的研究

本研究使用分别扩增整个S1糖蛋白基因 (引物A)和S1糖蛋白基因N_端高变区Ⅰ (引物B)的 2对引物对 3个IBV标准株M41、Connecticut、Arkansas及 5个地方分离株 (C60 ,D41A ,D41B ,A112 1,A1171)进行RT_PCR扩增。用引物A时 ,有 5个IBV毒株扩增到目的片段 (172 0bp) ;用引物B时 ,所有 8个IBV毒株均得到与预计大小相符的目的产物 (2 2 8bp)。对 172 0bp的PCR产物用限制性内切酶HaeⅢ进行酶切 ,结果得出 3个不同的RFLP图谱 ,其中M41、Connecticut、D41B具有相同的HaeⅢ酶切图谱。Arkansas和D41A则分别具有互不相同的图谱 ;对 2 2 8bp的PCR产物进行DdeⅠ、RsaⅠ限制性内切酶消化 ,根据它们的RFLP图谱 ,8个IBV毒株可分为 5个基因型。综合 2对引物的PCR产物的RFLP分析结果 ,8个IBV毒株可分为 7个基因型 ,分型的结果与传统的血清学方法吻合。本研究建立的方法和技术具有快速、简单、特异、灵敏等优点 ,为现场流行毒株的定型(基因型 /血清型 )及其S1基因变异的跟踪研究以及更有效防制传染性支气管炎奠定了基础。     

Effect of ruminal dosing of mechanical stimulating brush on rumination time, ruminal passage rate and rumen fermentation status in Holstein steers fed a concentrate diet

This experiment was conducted to determine the effect of ruminal dosing of a mechanical stimulating brush on rumination time, ruminal passage rate and rumen fermentation status in steers fed a concentrate diet at maintenance level. Animals were dosed three Rumen Faibu (RF) per head through the rumen fistulae (RF treatment) and not dosed (control) in a change‐over design. The organic cell wall content of the concentrate diet was 12.7% of dry matter. Daily time spent on rumination was very short in both treatments with 24 min in RF treatment and 15 min in control. The turnover rate of ruminal fluid in RF treatment was higher than that in control. There were no differences in ruminal pH and total volatile fatty acid concentration between RF treatment and control. Acetic and butyric acid concentrations were not different between the treatments. Propionic acid concentration tended to be higher in the animals on RF treatment than in control animals. The RF dosing in Holstein steers fed a low fiber diet did not affect the rumination time, but increased rumen digesta passage rate and ruminal propionic acid production.     

含铅的多元氢阴极电催化性能的研究

用电沉积法制备Ｍｏ－Ｗ－Ｎｉ－Ｐｂ－Ｃａ多元活性阴极，研究了在０．５ｍｏｌ／Ｌ Ｈ２ＳＯ４中的析氢反应，结果表明，多元阴极具有较高的电催化活性，其析氢过电位比软钢阴极降低３０５ｍＶ，ｉ０提高三个数量级，且有较好的稳定性，并用光电子能谱研究了表面组成和结构。证实表面有：Ｎｉ，ＮｉＯ，ＭｏＯ２，ＭｏＯ＾２－４，ＷＯ３，ＰｂＯ２，ＰｂＯ，Ｃａ＾＋＋等物质。