沙生针茅种子萌发特性及其影响因素

利用控制试验研究了不同温度蒸馏水水分、盐分胁迫等生态因子对沙生针茅种子萌发的影响,探索了沙生针茅种子对各种生态因子的适应性。结果表明:(1)蒸馏水浸泡种子,以60℃温水浸泡、自然降温至常温12h最好;(2)低温处理与未经低温处理的种子发芽率差异不显著(P0.05),说明沙生针茅种子不存在生理后熟因素影响;(3)随着PEG-6000浓度的增加,沙生针茅种子的发芽率、发芽势、发芽指数呈下降趋势,种子发芽率的PEG-6000浓度的临界值和极限值分别为15.9%和26.3%;(4)沙生针茅种子的发芽率、发芽势、发芽指数随着盐分浓度的增加呈下降趋势,其中Na2CO3处理下的沙生针茅种子萌发率下降幅度明显大于NaCl,表明沙生针茅种子对相同质量浓度的Na2CO3的耐受能力显著低于对NaCl的耐受能力。     

The effect of relaxing massage on heart rate and heart rate variability in purebred Arabian racehorses

The objective of this study was to assess the effect of relaxing massage on the heart rate (HR) and heart rate variability (HRV) in young racehorses during their first racing season. In the study, 72 Purebred Arabian racehorses were included. The study was implemented during the full race season. The horses from control and experimental groups were included in regular race training 6 days a week. The horses from the experimental group were additionally subject to the relaxing massage 3 days a week during the whole study. HR and HRV were assumed as indicators of the emotional state of the horses. The measurements were taken six times, every 4‐5 weeks. The HRV parameters were measured at rest, during grooming and saddling the horse and during warm‐up walking under a rider. The changes of the parameters throughout the season suggest that the relaxing massage may be effectively used to make the racehorses more relaxed and calm. Moreover, the horses from the experimental group had better race performance records.     

夏、冬两季猪源葡萄球菌耐药情况比较

本研究旨在比较夏、冬两季某规模化养猪场猪源葡萄球菌的耐药情况。分别在夏、冬两季对猪场同一猪采集其直肠肛拭子样和鼻腔鼻拭子样,采用微量肉汤稀释法对分离出的葡萄球菌进行临床9种常用抗菌药物的药敏试验。结果显示,夏季鼻腔分离的葡萄球菌对阿米卡星、氟苯尼考、氧氟沙星、苯唑西林和克林霉素5种抗菌药物的耐药率均高于冬季分离的鼻腔菌。夏季直肠分离的葡萄球菌对阿莫西林/克拉维酸、苯唑西林、庆大霉素、氧氟沙星、四环素、克林霉素和利福平7种抗菌药物的耐药率低于冬季分离的直肠菌。且夏、冬两季鼻腔分离的葡萄球菌多药耐药种数在0~9耐均有分布,夏、冬两季直肠分离的葡萄球菌多药耐药种数在1~9均耐有分布。冬季鼻腔分离的葡萄球菌6耐的多药百分率显著高于夏季分离菌的多药百分率（P＜0.05）,冬季直肠分离的葡萄球菌8耐的多药百分率显著高于夏季分离菌的多药百分率（P＜0.05）。结果表明,夏、冬两季猪不同部位分离的葡萄球菌对大多数被检抗菌药物的耐药率情况不同,其耐药率与养殖场季节性用药呈现相关性。     

放牧率和放牧时期对绵羊排粪量、采食量和干物质消化率关系的影响

实验研究表明，绵羊在同一放牧时期，随着放牧率的增大，鲜粪量有所减少，粪中干物质含量有所增大，但只有处理1．33羊／hm2·138天与6．67羊／hm2·138天问存在显著性差异。在同一放牧率条件下，不同放牧时期相比，以8月份粪中干物质含量最低；在各种处理之间，放牧绵羊全天干粪量均无显著性的差异。在同一放牧时期，随着放牧率的增大日采食量显著减少，而同一放牧率不同放牧时期的日采食量保持相对稳定。粪便的干重与干物质采食量的关系很小，与干物质消化率呈负相关。放牧绵羊白天排粪量为晚上的2倍，但粪中干物质含量几乎没有差异，同时，不同放牧率和不同放牧时期对粪便的颜色和形状等均有较明显的影响。     

青藏高原金露梅灌丛与矮嵩草草甸枯枝落叶的分解作用

研究青藏高原金露梅灌丛和矮嵩草草甸两种植被类型枯枝落叶分解作用强度及其随着埋放时间延长的变化规律.结果表明,两种植被的枯枝落叶在埋放的前3个月均显示出明显的分解效果.其总分解率分别达到20.31%和30.4%,随后分解率逐渐降低,埋放后个月的总分解率仅为前3个月的37.60%和39.33%.矮嵩草草甸枯枝落叶的分解率显著高于金露梅灌丛.土壤温度、微生物数量和枯枝落叶本身的化学成分是影响分解率的主要因素.与其相比,动物粪便的分解率很低.     

The Effect of Levothyroxine Treatment on Resting Energy Expenditure of Hypothyroid Dogs

Thirty adult, client-owned dogs were diagnosed with hypothyroidism based on history, physical examination findings, hematologic and biochemical abnormalities, thyrotropin (TSH) response testing, endogenous canine thyrotropin (cTSH) concentration, or both, and total serum thryoxine concentration. All dogs received levothyroxine (L-thyroxine) at an initial dose of 22 μg/kg PO sid in either a tablet (13 dogs) or chewable form (17 dogs). Energy expenditure of each dog during apparent rest was estimated with an open-flow indirect calorimetry system by determining the rates of carbon dioxide production and oxygen consumption. Energy expenditure of apparent rest (EE) was lower in untreated hypothyroid dogs compared with reference values for EE. After treatment with L-thyroxine, EE of the hypothyroid dogs was significantly ( P < .05) higher than pretreatment values.     

6种热带亚热带豆科牧草抗寒性及营养品质比较

为了筛选华南地区适宜的优质冬季青饲料草种,本研究比较了旋扭山绿豆(Desmodium intortum)、大叶山蚂蟥(Desmodium laxiflorum)、异果山绿豆(Desmodium heterocarpum)、显脉山绿豆(Desmodium reticulatum)、糙毛假地豆(Desmodium heterocarpum var.strigosum)和柱花草(Stylosanthes guianensis)6种热带亚热带豆科牧草在广州越冬期的抗寒性及营养品质。结果表明,除柱花草外,其它5种豆科牧草均能保持青绿越冬,其中旋扭山绿豆和大叶山蚂蟥的叶绿素含量均显著高于其它牧草(P0.05)。旋扭山绿豆的净光合速率最高(P0.05),其次是大叶山蚂蟥(P0.05),因此这两种牧草具有相对较强的抗寒性;与其它牧草相比,旋扭山绿豆在冬季能保持较高的粗蛋白含量(15.99%~20.26%)(P0.05)以及较低的洗涤纤维(NDF 27.92%~30.89%、ADF 23.96%~27.06%)和缩合单宁含量(6.05~11.95mg·g~(-1))(P0.05),因而具有较高的营养价值。因此,旋扭山绿豆可以作为华南地区冬季豆科青饲料的潜在优选草种。     

华北驼绒藜雨季移栽成活率研究

本文是不同季节移栽华北驼绒藜(Ceratoides arborescens)系列研究之一。干旱区春季生态建植有补水之苦,雨季移栽表明,不需坐水或补水,成活率可高达60%,浸根可提高成活率至90%;说明雨季移栽是可行的。移栽植株数日内叶片含水量和叶绿素含量急剧下降、脯氨酸含量骤然升高,含量恢复过程则较缓慢,说明移栽使植株突然损伤,但终能恢复至正常生理状态。     

几种中草药饲料添加剂对黄鳝免疫功能和生长性能的影响

将300尾13～17g的健康黄鳝(Monopterus albus)随机分为1个对照组和4个试验组,每组3个重复,试验组分别饲喂添加有茯苓、五加皮、黄芪以及这3种中药的混合物的饲料。经30d饲养后,结果表明,茯苓、黄芪及五加皮可使黄鳝血液白细胞的吞噬活性、血清的溶菌酶活性和超氧化物歧化酶(SOD)活性显著提高(P<0.05);同时,五加皮、黄芪、茯苓及这3种中药的混合物均对黄鳝增重有显著促进作用(P<0.05),其中五加皮对黄鳝的增重最为明显。     

活性氧(ROS)对小鼠早期胚胎胚细胞分裂的影响

在体外CZB培养的不同时期添加过氧化氢(2.1μmol/L),发育至囊胚阶段,制作胚胎标本,观察其囊胚发育率、胚细胞数和分裂相数。结果显示:0~12 h组和0~72 h组的胚胎发育率显著低于其他几组(P<0.05),对照组、12~24 h组、24~36 h组、36~48 h组之间均差异不显著(P>0.05);各组之间的胚细胞数和分裂指数均无显著差异。说明胚胎在体外培养时,2细胞期胚胎对外源性H2O2最敏感,也最容易发生发育阻滞。但是经H2O2处理之后,度过2细胞期发育阻滞的胚胎能在以后的发育中发生补偿性生长,其胚细胞数和分裂指数都和体外正常发育的胚胎没有差异。