共轭亚油酸对免疫应激仔猪生长抑制的缓解作用

试验选用 72头 (2 8± 2 )d断奶的仔猪 ,采用 2× 2因子试验设计 ,研究共轭亚油酸 (CLA)是否有缓解仔猪免疫应激的作用。结果显示 ,添加CLA缓解了因注射脂多糖 (LPS)引起的日增重降低 (P <0 .0 5 ) ,并改善了试验全期的饲料转化效率 (P <0 .0 5 )。两次LPS刺激后 ,CLA抑制 (P <0 .0 5 )了由LPS诱导的血浆白细胞介素 6 (IL 6 )、肿瘤坏死因子 α(TNF α)和α 乙酰糖蛋白 (AGP)浓度的上升。在第 14d和 2 1d ,LPS刺激提高 (P <0 .0 5 )了血浆IL 1β和皮质醇含量 ,而CLA则降低了IL 1β和皮质醇含量。本试验证明 ,CLA能缓解免疫应激引起的仔猪生长抑制 ,其防止免疫应激诱导的生长抑制作用可能与CLA抑制炎性细胞因子的分泌有关     

近100年喀斯特槽谷区洼地沉积速率与流域产沙强度

首次尝试通过沉积物定年反演喀斯特洼地流域单元近100年尺度的侵蚀产沙历史,这有助于认识人类活动对喀斯特石漠化演化过程的影响。以喀斯特槽谷区典型洼地—常家洼洼地为研究对象,应用137Cs、210Pbex定年法分析了近100年的流域产沙强度特征。结果表明:(1)洼地平均沉积速率为1.00cm/a(1917—1963年)和0.25 cm/a(1963—2017年),流域的平均产沙模数为609t/(km^2·a)(1917—1963年)和152t/(km^2·a)(1963—2017年);(2)1917—1963年期间流域产沙强度远高于1963年以后,这与该地区民国至新中国建国初期强烈的人类活动有密切关系,尤其是上世纪50年代末大规模伐木;(3)1963年以来产沙强度明显减小,这是由于此前发生过较强侵蚀导致土壤变少,局部基岩出露,加之此间植被恢复、人类扰动强度降低和水土保持工程实施;(4)常家洼流域产沙强度高于西南其他喀斯特地区,与流域岩性和人为扰动有关。喀斯特石漠化并非仅是近50年人类活动的结果,也与近100年乃至更长时间尺度的人类活动有关。     

不同冬小麦品种气冠温差与抗旱节水性的关系研究

为给小麦抗旱性快速鉴定中气冠温差(CTD)的应用提供依据,采用20个冬小麦品种,设置水、旱两种处理,研究了冬小麦不同抗旱节水性品种的气冠温差CTD的信号表达差异及其最佳测定时期(生育期、单日时间)和影响因素,探讨品种鉴定筛选的量化评判指标.结果表明,在小麦扬花期的13:30～14:00时利用红外测温仪和精密温度计测定CTD,能够较好地鉴别出不同品种对水分反应的生理特性差异.不同小麦品种间的CTD差异很大,但不同水旱处理的CTD变化趋势基本一致.小麦扬花期(4月30日前后)CTD出现最高值,单日测定时间在13:30～14:00时出现最高值,且品种间差异较大.旱作处理下CTD平均值为7.09℃,变化范围为5.6～8.5℃;灌水处理CTD平均值8.81℃,变化范围为7.8～10.3℃;CTD与产量、抗旱指数及水分利用效率均呈极显著正相关,因此CTD既可作为旱作条件下抗旱品种的选择指标,也可作为灌溉条件下高效节水品种的选择指标.CTD≥7.92℃的品种抗旱性好,CTD≥9.55的品种水分利用效率高.     

喀斯特峰丛洼地坡面土壤水分空间变异研究

以线形取样方式测定了喀斯特峰丛洼地坡面表层(0～5、5～10、10～15 cm)的土壤水分,采用经典统计结合地统计学方法分析了其空间分布特征及变异结构。结果表明：在坡面特定土地利用结构下(上坡到下坡分布有自然坡地、退耕地和耕地),表层土壤水分沿上坡向下具有不断减小的变化趋势,坡面纵向和横向土壤水分均呈中等变异,横向上由于特殊的土壤分布和地形地貌特征使得变异程度较纵向强烈,土地利用和坡度因子是造成坡面土壤水分分布和变异的重要因素;半方差分析显示,坡面表层土壤水分具有明显的块金效应和较大的基台值,呈中等或较强的空间相关性,土壤水分总体上具有较好的变异结构和空间连续性,因此可以应用地统计学方法在该地区开展土壤水分空间变异研究。     

兔出血症病毒形态学的研究

用氯仿抽提、PEG沉淀、Scpharosc 4B柱层析、超离及蔗糖密度梯度离心等方法纯化了兔出血症病毒。电镜下观察到兔出血症病毒粒子为无囊膜,大小为32～34nm。外观呈现独特的结构。正二十面体对称,髓蕊直径15～17nm,衣壳厚8～9nm。由内、外衣壳组成。外衣壳上按T=3排列着32个壳粒,壳粒呈中空的管状,长5～6nm,直径约4～5nm。中心孔径约2nm。有一环状呈不连续的内衣壳,厚2～3nm,内环上不连续每段约4nm,与壳粒相连。在5、3和2次轴对称时,病毒表面有大的、3个以上特征性的表面凹陷(Surfacc dcpression),这种表面凹陷呈一定的分布。呈五次轴对称时,病毒表周有10个向外管状突起。病毒表周不规则,表面含丰富的突起和大、小的凹陷(dcpression and small indentation)是兔出血症病毒形态学特点之一,其大小和形态,在动物病毒中比较类似于嵌杯样病毒。     

大豆光合日变化的不同类型及其影响因素

用同一品种在不同生育期,不同季节、不同天气以及不同生长条件下研究了大豆的光合日变化。大豆的光合日变化随气候条件,生长环境以及大豆的生育期不同而变化,不遵循一种固定不变的模式,概括起来有单峰型、双峰型、波动型和平缓型四种不同类型。大豆在春、夏、秋三季均能产生午休,土壤水分亏缺使午休加重,在结荚期以前条件适宜的情况下,大豆不易产生午休,此后随着生育期的进展,大豆午休加重,鼓粒期大豆的午休最为严重。     

Flood effect on CH4 emission from the alas in Central Yakutia,East Siberia

During four years (2006–2009), methane (CH₄) emission was measured at different biomes (dry, wet grasslands, lake and lake vegetation) of mature thermokarst depression located at the most typical thermokarst terrain on the east bank of the Lena River, Central Yakutia, Russia (62°08′N, 130°30′E). To estimate total CH₄ emission from the whole thermokarst depression ecosystem, CH₄ emissions via plant bodies and ebullition were measured in addition to diffusive CH₄ flux measurement. The lake area increased twice from 20.4 ha in 2006 to 43.3 ha in 2007 and then did not change significantly in 2008 and 2009 (46.5 and 44.4 ha, respectively). Ebullition was considered to be a minor source for CH₄ emission from the lake in the studied thermokarst depression. CH₄ emissions from the lake water surface and via the plant body of lake vegetation (hygrophyte and hydrophyte vegetation) were the main sources of CH₄ and these increased by flooding both CH₄ emission rate and area. Using spatial changes of these biomes, the annual emission of CH₄ was calculated taking into account different sources of CH₄. Total CH₄ emission from the studied alas (63.7 ha) was 5.7, 5.2, 20.1 and 50.1 Mg carbon (C) in 2006–2009, respectively, and its difference during this period reached about 10 times. An extreme increase in CH₄ emission from the lake occurred in the second year of continuous flooding (2008), which might have been caused by the decomposition of flooded organic C. So, the lake water ecosystem is the main source of CH₄ in thermokarst depression controlled by the duration of flooding. Under future global climate change, thermokarst depressions in Central Yakutia have potential for lake expansion, causing significant increase in CH₄ emission in the studied region.     

Diversity of the Icelandic goat breed assessed using population data

Abstract

The Icelandic goat breed is a closed population consisting of around 700 animals kept in 45 herds. Several population bottlenecks are known to have occurred and the population has at least twice declined below 100 animals. Here the genetic diversity of the breed was estimated using pedigree information, D-loop sequencing and microsatellite markers. The annual rate of inbreeding was estimated as 3% and the effective population size as 5.1 animals. The effective population size based on molecular markers was estimated in the range of 4.1–8.8 individuals and mtDNA D-loop sequencing identified only three haplotypes. The results presented here show the population to be highly inbred, fragmented and the level of genetic variation among the lowest found in livestock. The results will be an important input into conservation planning for the Icelandic goat.     

从气机升降出入论癫痫

癫痫是一种发作性神经功能异常的慢性脑部疾病。本文从气机升降出入角度论癫痫,认为癫痫患者大多数具有“脏气不平”的先天因素或病理体质,其气机升降出入异常（气郁）是导致癫痫发病的关键。临床应重视肝脾同调、升降相宜,从郁、风、痰论治每获良效。本文还以“玄病”、“络病”理论为补充,论治癫痫持续状态及难治性癫痫,其实质是气机升降出入理论在人体超微结构的延伸与拓展,但相关研究仍需进一步完善发展。     

Influence of a marine algae supplementation on the oxidative status of plasma in dairy cows during the periparturient period

This study was part of a larger study that addressed the effects of marine algae (ALG) supplementation in the ration of high yielding periparturient dairy cows. The objectives were to induce milk fat depression (MFD) in early lactation by feeding docosahexaenoic acid (DHA) from ALG and to determine the effects on milk production, milk components and metabolic status early post partum. This study focuses on the oxidative status in the plasma during the ALG supplementation. Plasma samples were collected from 16 Holstein Friesian cows at the day of parturition and at −1, 2, 4 and 6 weeks relative to calving with half of the cows receiving the ALG supplement (44 g DHA/d) from 3 weeks pre partum on. The following parameters were measured in plasma: ferric reducing ability of plasma (FRAP), α-tocopherol level, glutathione peroxidase activity (GSH-Px) and thiobarbituric acid reactive substances (TBARS) concentration. There was a significant effect of time for FRAP and α-tocopherol indicating changes in the plasma oxidative status around parturition. The ALG supplementation was successful in creating a milk fat depression (MFD) but could not improve the energy balance. Feeding of ALG significantly increased lipid peroxidation as measured by TBARS, probably through their high content of n-3 polyunsaturated fatty acids.