NaCl胁迫对羽衣甘蓝生理生化指标的影响

试验采用水培种植的方法研究不同NaCl浓度对羽衣甘蓝幼苗光合色素含量、可溶性蛋白质含量、过氧化氢酶(CAT)活性以及过氧化物酶(POD)活性的影响。结果表明:随着NaCl浓度的增加,叶绿素含量总体呈下降趋势;可溶性蛋白质含量、CAT和POD活性随着NaCl浓度的增加先上升后下降;在NaCl浓度为600mmol/L时可溶性蛋白质含量、CAT活性达到最高值,而POD活性则是在NaCl浓度为800mmol/L时达到最高。     

Dietary fiber in a low-protein diet during gestation affects nitrogen excretion in primiparous gilts,with possible influences from the gut microbiota

We investigated the effects of dietary fiber (DF) supplementation in normal or low crude protein (CP) diets on reproductive performance and nitrogen (N) utilization in primiparous gilts. In total, 77 Landrace × Yorkshire pregnant gilts were randomly allocated to four dietary treatments in a 2 × 2 factorial design. The groups comprised 1) equal intake of normal CP (12.82% and 0.61% total lysine), 2) low CP (LP) (10.53% and 0.61% total lysine), and 3) with or 4) without DF supplementation (cellulose, inulin, and pectin in a 34:10:1 ratio). A low-protein diet during gestation significantly reduced daily weight gain from days 91 to 110 of pregnancy (−162.5 g/d, P = 0.004). From N balance trials conducted at days 35 to 38, 65 to 68, and 95 to 98 of pregnancy, DF addition increased fecal N excretion at days 65 to 68 (+24.1%) and 95 to 98 (+13.8%) of pregnancy (P < 0.05) but reduced urinary N excretion (P < 0.05), resulting in greater N retention at each gestational stage. DF increased fecal microbial protein levels and excretion during gestation. An LP diet also reduced urinary N excretion at different gestational stages. An in vitro fermentation trial on culture media with nonprotein N urea and ammonium bicarbonate (NH₄HCO₃) as the only N sources revealed that microbiota derived from feces of gestating gilts fed the high DF diet exhibited a greater capacity to convert nonprotein N to microbial protein. Microbial fecal diversity, as measured by 16S rRNA sequencing, revealed significant changes from DF but not CP diets. Gilts fed an LP diet had a higher number of stillbirths (+0.83 per litter, P = 0.046) and a lower piglet birth weight (1.52 vs. 1.37 kg, P = 0.006), regardless of DF levels. Collectively, DF supplementation to gestation diets shifted N excretion from urine to feces in the form of microbial protein, suggesting that the microbiota had a putative role in controlling N utilization from DF. Additionally, a low-protein diet during gestation negatively affected the litter performance of gilts.     

补播羊草和黄花苜蓿对退化草甸植物群落特征的影响

呼伦贝尔草原区是我国北方重要的生态屏障,近年来不合理的利用方式导致该地区退化草地面积不断扩大,为了探究牧草补播时间及补播比例对呼伦贝尔退化草甸草原植物群落特征的影响,为该地区退化草地修复提供依据。本研究以羊草（Leymus chinensis（Trin.） Tzvel.）和黄花苜蓿（Medicago falcata L.）为试验材料,采用双因素随机区组试验设计,通过测定幼苗数、高度、生物量等群落指标,并综合评价补播效果,结果表明：夏播羊草和黄花苜蓿幼苗数量显著高于春播和秋播（P<0.05）,夏播和秋播植物群落总生物量呈增加趋势,春播则呈减少趋势;补播措施提高了退化草地植物群落Shannon-Weiner指数、Simpson指数和Pielou指数,豆科和禾本科植物重要值呈增加趋势,其他科植物呈下降趋势。呼伦贝尔地区夏季补播羊草和黄花苜蓿以1∶3补播效果较好,而春播由于恢复时间短,需进一步观察。     

目录

为了表达牛环形泰勒虫（Theileria annulata）截短HSP70基因编码蛋白并研究该蛋白的结构与功能特性,本研究扩增牛环形泰勒虫HSP70目的基因并构建重组质粒pMD18-T-HSP70,选取其他种的同源HSP70蛋白序列构建系统进化树;利用生物信息学方法分析HSP70基因编码蛋白的氨基酸组成、基本理化性质、亲疏水性、跨膜区结构、信号肽、可能的磷酸化位点、亚细胞定位及蛋白的二级结构和三级结构;对重组蛋白HSP70进行蛋白互作网络分析;构建原核表达载体pET28a-HSP70,筛选诱导表达条件,镍柱纯化重组蛋白及检测反应原性。结果显示,牛环形泰勒虫HSP70蛋白序列与小泰勒虫的序列同源性较高,蛋白分子质量为42 ku,理论等电点（pI）为5.61,属于酸性亲水性蛋白,无跨膜区及信号肽;蛋白功能预测结果显示,HSP70包含32个可能的磷酸化位点,亚细胞定位分析显示该蛋白主要分布于细胞质。蛋白质二级结构中α-螺旋、β-转角、无规则卷曲、延伸链分别占39.18%、8.51%、30.41%和21.91%。蛋白互作网络构建结果显示,与HSP70相互作用的蛋白主要为HSP90家族成员,另外还有伴侣蛋白GrpE同系物,预示着HSP70可能在细胞内与HSP90形成复合体发挥作用。本试验成功构建原核表达载体,获得了大小约为48 ku的融合蛋白,以0.6 mmol/L IPTG于37 ℃诱导5 h,蛋白表达较好;点状印迹及Western blotting结果表明,表达产物可被自然感染的牛环形泰勒虫阳性血清识别,具有良好的反应原性。本试验结果为进一步探讨牛环形泰勒虫HSP70功能机制提供了理论依据。     

The effects of maxillary nerve block,ethmoidal nerve block and their combination on cardiopulmonary responses to nasal stimulation in anesthetized Beagle dogs

ObjectiveTo describe an approach for ethmoidal nerve block (E_BLOCK) and to compare the effects of a maxillary nerve block (M_BLOCK), E_BLOCK and their combination (M-E_BLOCK) on heart rate (HR), systolic (SAP), mean (MAP), diastolic (DAP) arterial pressures and respiratory rate (f_R) during nasal stimulation in dogs.Study designProspective, blinded, randomized, crossover placebo-controlled study.AnimalsBeagle dogs (five cadavers, nine live dogs), with a median (interquartile range) weight of 10.5 (10.3–11.0) kg.MethodsThe accuracy of iohexol injections (each 1 mL) at the maxillary and ethmoidal foramina in cadavers was evaluated using computed tomography. Then, anesthetized dogs were administered four bilateral treatments separated by 1 week, saline or 2% lidocaine 1 mL per injection: injections of saline at the maxillary and ethmoidal foramina (Control), injections of lidocaine at the maxillary foramina and saline at the ethmoidal foramina (M_BLOCK), injections of saline at the maxillary foramina and lidocaine at the ethmoidal foramina (E_BLOCK) and injections of lidocaine at all foramina (M-E_BLOCK). The ventral nasal meatus was bilaterally stimulated using cotton swabs, and HR, SAP, MAP, DAP and f_R were continuously recorded. Values for each variable were compared before and after stimulation using Wilcoxon signed-rank test. Changes in variables among treatments were analyzed using Mann–Whitney U and Kruskal–Wallis tests (p ≤ 0.05).ResultsComputed tomography revealed iohexol distribution around the openings of the target foramina in all cadavers. In living dogs, HR, SAP, MAP, DAP and f_R significantly increased after stimulation within each treatment (p < 0.03). Physiologic responses were significantly attenuated, but not absent, in the M-E_BLOCK [HR (p = 0.019), SAP, MAP, DAP and f_R (all p ≤ 0.001)] compared with those in the Control.Conclusions and clinical relevanceConcurrent injections of lidocaine at the maxillary and ethmoidal foramina attenuated HR, arterial pressure and f_R responses to nasal stimulation in Beagle dogs.     

两种无抗制剂对育肥猪生长性能及肠道健康的影响

本试验通过在生长育肥猪饲粮中添加两种不同的无抗制剂,探究其对育肥猪生长及肠道健康的影响。选取体重为（85.95±3.48） kg的LDY三元杂交猪60头,分为对照组、试验1、2组,每组5个重复,每个重复4头猪（阉公猪和母猪各半）。对照组饲喂基础饲粮,试验1组在基础饲粮中添加0.5%的红曲合生元酵母硒锗复合制剂,试验2组在基础饲粮中添加0.5%的复方中药提取物。结果表明：①3组间生长性能各项指标均差异不显著（P>0.05）。②与对照组相比,试验1组空肠的绒毛高度（VH）、绒毛高度/隐窝深度（V/C）以及回肠的绒毛高度均显著增加（P<0.05）,试验2组空肠和回肠的绒毛高度均显著增加（P<0.05）;试验1组空肠和回肠的绒毛高度显著高于试验2组（P<0.05）。③与对照组相比,试验1和2组盲肠菌群香浓指数均显著升高（P<0.05）、辛普森指数均显著降低（P<0.05）;试验1组的香浓指数显著高于试验2组（P<0.05）。④在门水平上,与对照组相比,试验1组盲肠菌群变形菌门和放线菌门丰度均显著升高（P<0.05）,厚壁菌门丰度显著降低（P<0.05）;试验2组厚壁菌门和变形菌门丰度显著升高（P<0.05）,拟杆菌门丰度显著降低（P<0.05）;试验1组放线菌门丰度显著高于试验2组（P<0.05）,厚壁菌门丰度显著低于试验2组（P<0.05）。在属水平上,与对照组相比,试验1组链球菌属丰度显著升高（P<0.05）,苏黎世杆菌属、uncultured_bacterium_f_Muribaculaceae和乳杆菌属丰度显著降低（P<0.05）;试验2组瘤胃菌属和链球菌属丰度显著升高（P<0.05）,苏黎世杆菌属、梭菌属_13、乳杆菌属丰度显著降低（P<0.05）;试验1组梭菌属_13和链球菌属丰度显著高于试验2组（P<0.05）,试验1组uncultured_bacterium_f_Muribaculaceae、瘤胃菌属显著低于试验2组（P<0.05）。⑤试验1组Occludin、Zo-1、Claudin-1表达量显著高于对照组（P<0.05）,Occludin、Claudin-1表达量显著高于试验2组（P<0.05）。以上结果表明,红曲合生元酵母硒锗复合制剂和复方中药提取物对育肥猪肠道健康均有改善作用,但红曲合生元酵母硒锗复合制剂组饲喂效果优于复方中药提取物组。     

“1237”P氏生物安全立体非洲猪瘟防控体系

在目前非洲猪瘟疫苗毒株、变异毒株、野毒株并存背景下,只做好外部生物安全已不足以达到防控非洲猪瘟的目的。因疫苗毒株隐蔽性强、检测难度大,不知道通过引种是否会将疫苗毒株带到猪场。因此,未来猪场生物安全不能只关注场外生物安全,更重要的是要运用“以猪为本”的“1237”P氏生物安全立体非洲猪瘟防控体系,即在做好“控五流”等外部生物安全的同时,更要关注饮水安全、注重猪的自身健康度、提高猪的非特异性免疫力,才能实现“与非共存,与蓝共舞”。所谓“立体防控”是指全方位的防控,而不是仅仅针对猪场大门的传统生物安全防控。     

蛋鸡不同阶段营养调控

蛋鸡养殖期间不同生长发育阶段的营养需求有所差异,为更好地满足不同阶段蛋鸡的生长需求,应对饲料配方做出动态化调整,加强营养调控技术的研究。通过对饲料配方进行科学调整,能保证营养供给更加充足,更加均衡满足蛋鸡生长需求,保证蛋鸡健康生长,减少饲料成本,提高饲料利用效率。该文主要论述蛋鸡在不同生长阶段的营养调控技术,并提出完善蛋鸡营养调控技术的措施。     

对我国加入WTO后农田水利建设的思考

为提高我国产业在加入WTO后接受挑战的能力，在研究农业“绿箱政策”和国外有关农田水利建设方面措施的基础上，提出加大提入力度，加强科学研究和推广等后对加入WTO的措施。     

覆膜防沙治沙方法

沙漠、沙尘暴和沙化问题已经成为威胁人类生存的头号敌人，如何根治沙漠、沙尘暴和沙化是摆在人类面前的十分紧迫的任务。覆膜防沙治沙方法的研究和提出，成功地解决了人类面临的重大防沙治沙难题。为人类征服自然，征服沙漠树立了信心。介绍了覆膜防沙治沙的技术方式、方法、原理和覆膜栽培技术，供防沙治沙工程参考和推广。