安普霉素对仔猪养分代谢率及氮沉积的影响     

姚浪群  罗海祥  佟建明  萨仁娜  霍启光 《畜禽业》2006,(15):14-16

20头28日龄大长北三元杂交断奶仔公猪随机分为4组,分别饲养于不同环境温度(28℃、15℃)下的代谢笼内,饲喂含有不同剂量安普霉素(0、90、150mg/kg)的日粮,试验期为2周,后7d进行全收粪代谢试验,观测安普霉素对仔猪物质表观代谢率及氮沉积的影响。研究结果表明,在低温环境下日粮中添加安普霉素可抵御寒冷应激,改善仔猪日粮干物质和蛋白质的表观代谢率,增加机体氮的沉积,其中150mg/kg安普霉素可显著提高仔猪日增重70.5%(P<0.05)、改善饲料转化率32.7%(P<0.05),并能提高采食量、降低发病死亡率。在低温环境下,应适当加大抗生素的添加剂量。  相似文献   

中间偃麦草、长穗偃麦草及其杂交种抗旱性评价     

马小廷  米福贵  王毅  伏兵哲  撒多文 《草业科学》2010,27(12):92-95

测定了杂交种植物组织相对含水量、脯氨酸、叶绿素、可溶蛋白、丙二醛生理指标,利用主成分分析、隶属函数综合评价偃麦草属不同材料[中间偃麦草（Elytrigia intermedia）、长穗偃麦草（E.elongata）及其杂交种]的抗旱性。结果表明,5个单项生理指标可综合为3个相互独立的综合指标;正交杂种（E.intermedia×E.elongata）的抗旱综合值为 0.529,反交杂种（E.elongata×E.intermedia）为0.702,而其2个亲本中间偃麦草和长穗偃麦草仅为0.308和0.191,杂交种材料的抗旱能力远高于2个亲本,其中反交杂种的抗旱性最强。  相似文献   

胡杨PeSOS1对拟南芥盐诱导H₂O₂信号途径的调控     

王美娟  王洋  申泽丹 《西北农林科技大学学报(自然科学版)》2015,43(2):79-91,98

【目的】研究胡杨质膜Na+/H+逆向转运蛋白(SOS1)通过H2O2信号途径对盐胁迫的感知和适应作用。【方法】克隆胡杨质膜SOS1基因(PeSOS1),并将其转化到拟南芥中,比较野生型和转PeSOS1基因拟南芥在100mmol/L NaCl胁迫下的萌发率,根长,干质量,K+、Na+和Ca2+含量,活体植株根尖离子流(K+、Na+和H+)的流动情况,H2O2的产生和抗氧化酶活性的变化以及抑制剂对根尖离子流的影响,分析100mmol/L NaCl胁迫下异源表达PeSOS1基因拟南芥与野生型拟南芥耐盐性的差异。【结果】在NaCl胁迫下,转PeSOS1基因拟南芥株系的萌发率、根长和干质量明显高于野生型拟南芥;转PeSOS1基因拟南芥K+和Ca2+含量也高于野生型拟南芥,而Na+含量较野生型拟南芥低。100mmol/L NaCl处理后,转PeSOS1基因拟南芥中K+和Na+的平衡(K+/Na+值)与NaCl胁迫前相比下降幅度较小。转PeSOS1基因植株在NaCl胁迫下能更快地产生H2O2,并使抗氧化酶保持较高的活性。SOS1抑制剂阿米洛利(Amiloride)对NaCl胁迫下野生型和转基因拟南芥根尖离子流的变化有明显影响,用质膜NADPH氧化酶抑制剂DPI(抑制H2O2的产生)处理后,转PeSOS1基因拟南芥根尖K+内流减弱,Na+外流和H+内流增强,植株维持K+和Na+平衡的能力减弱。【结论】在拟南芥中异源表达PeSOS1基因可促进H2O2快速产生,维持了SOS1mRNA的稳定性,调控了K+和Na+平衡,并激活了抗氧化防御系统,因而显著提高了其耐盐性。  相似文献   

Photofragment helicity caused by matter-wave interference from multiple dissociative states     

TP Rakitzis  SA Kandel  AJ Alexander  ZH Kim  RN Zare 《Science (New York, N.Y.)》1998,281(5381):1346-1349

Isolated diatomic molecules of iodine monochloride (ICl) were photodissociated by a beam of linearly polarized light, and the resulting ground-state Cl atom photofragments were detected by a method that is sensitive to the handedness (helicity) of the electronic angular momentum. It was found that this helicity oscillates between "topspin" and "backspin" as a function of the wavelength of the dissociating light. The helicity originates solely from the (de Broglie) matter-wave interference of multiple dissociating pathways of the electronic excited states of ICl. These measurements can be related to the identity and to the detailed shapes of the dissociating pathways, thus demonstrating that it is possible to probe repulsive states by spectroscopic means.  相似文献   

"罗望子+木豆"乔灌复合模式林水土保持功能的叠加效应初探     

拜得珍  纪中华  沙毓沧  赵艳萍  潘志贤 《西南农业学报》2006,19(4):611-615

以降水等级为主要影响因子,研究了罗望子(Tamarindus indica) 木豆(Cajanus cajan)乔灌复合模式林对降雨的截留、贮存所产生的水保效应。结果表明:罗望子人工林冠层和复合木豆人工灌木林林冠层年截留降雨量分别为97.99和145.4 mm,分别占全年降雨量水的17.48%和25.86%;罗望子人工林的树干茎流率占大气降水的2.37%;复合模式林枯枝落叶的蓄积量为7.08 t/hm2,对降水的平均截留率为12.47%,其最大持水量相当于1.8 mm的降水;模式林表层土壤(0~40 cm)滞留水分能力相当于2.7mm降雨,贮存土壤水分能力可达1553.2 t/hm2,产生径流的最小降雨量为35.4 mm,其侵蚀模数和径流模数比对照减少98.52%和93.21%,体现出了良好的水土保持和水源涵养效应。  相似文献   

甘露寡糖对断奶仔猪肠道菌群的影响   总被引：5，自引：0，他引：5  

萨立富  边连全  潘树德 《畜禽业》2005,(11):54-55

选取28日龄断奶的三元[杜×(大×长)]杂交仔猪96头,平均体重为(7.46±0.38)kg,按体重和性别随机分为4个处理组,每个处理组3个重复,每个重复8头仔猪,公母各半。第一个处理组为空白组,第二、三、四个处理组在相同的基础日粮中分别添加0.1%、0.2%和0.4%的甘露寡糖,研究甘露寡糖对断奶仔猪肠道菌群的影响。结果表明:(1)各实验组肠道大肠杆菌的浓度极显著低于对照组;(2)第三组和第四组其结肠、盲肠和直肠中双歧杆菌增殖显著。第二组中只有结肠中双歧杆菌显著高于对照组,但盲肠和直肠中双歧杆菌增殖不明显;(3)各个处理组肠道中乳酸杆菌的浓度与对照组相比差异不显著。  相似文献   

秸秆降解菌系的筛选及其对酸碱度的响应     

张云  萨如拉  包桂荣  萨茹拉其其格  邰继承  李响 《中国农学通报》2022,38(28):21-27

为给冷凉地区秸秆还田提供菌株资源,以常年处于低温环境的土壤与富含纤维素的腐烂物为菌源,以富集、继代培养方法筛选秸秆降解菌系和生产中主推的秸秆腐熟剂为试材,在15℃和20℃,pH 4.5、5.5、6.5、7.5、8.5、9.5条件下发酵秸秆,每隔24 h测定发酵液OD₆₀₀值,发酵15天测定滤纸酶、纤维素酶活性和秸秆降解率,探讨其对玉米秸秆的降解效果。结果表明,继代培养5~6代菌系分解纤维素的速度加快;15℃ 2种试材不同pH发酵液OD₆₀₀值第6天达到峰值,最高峰值均在pH 7.5;20℃ 2种试材不同pH发酵液OD₆₀₀值第7天达到峰值,秸秆降解菌系8号最高峰值为pH 8.5,秸秆腐熟剂最高峰值为pH 5.5。15℃ pH 8.5秸秆降解菌系8号滤纸酶活性显著高于秸秆腐熟剂;pH 7.5秸秆降解菌系8号纤维素酶活性显著高于秸秆腐熟剂;而秸秆腐熟剂纤维素酶活性在20℃ pH 4.5时高于秸秆降解菌系8号。15℃和20℃条件下,秸秆降解菌系8号pH 7.5秸秆降解率高,而秸秆腐熟剂为pH 4.5和pH 5.5秸秆降解率高;相同发酵条件下,秸秆降解菌系8号秸秆降解率显著高于秸秆腐熟剂。秸秆降解菌系8号降解秸秆适宜条件为中低温中性偏碱性,而秸秆腐熟剂为中温偏酸性。  相似文献   

Thermal antinociceptive pharmacodynamics of 0.1 mg kg⁻¹ hydromorphone administered intramuscularly in cats and effect of concurrent butorphanol administration     

BDX  Lascelles †  SA Robertson‡  PM Taylor§  J Hauptman¶ 《Veterinary anaesthesia and analgesia》2003,30(2):107-108

Hydromorphone (HY) has not been objectively assessed as an analgesic in cats. It has been suggested that butorphanol (B) can have a synergistic action with pure μ‐agonists. The aim of this study was to assess the antinociceptive activity of a single dose of HY, and to examine the effect of concurrent B administration on the thermal threshold (TT). Thermal thresholds were measured following IM administration of HY, B, a combination of B and HY (HY‐B), or saline (S). Six cats (four spayed females, two castrated males, 4.75–6.8 kg) were used. Each cat received HY (0.1 mg kg^?1), B (0.4 mg kg^?1), HY (0.1 mg kg^?1), and B (0.4 mg kg^?1) (HY‐B), or S (0.05 mL kg^?1) in a randomized, blinded, cross‐over study design. Each cat received each treatment, with at least 12 days interval between the treatments. All injections were IM randomized to left or right quadriceps using a 24 SWG needle. Twenty‐four hours prior to each study, the thorax of each of the cats was shaved. On the day of the study, TT was measured using a thorax‐mounted thermal threshold‐testing device specifically developed for cats. Skin temperature was recorded before each test and then the heater was activated. When the cat responded by flinching, turning, or jumping, the stimulus was terminated and the threshold temperature was recorded. Three baseline thresholds were recorded over 1 hour before IM injection of test drug. Thermal threshold cut‐off was 55.5 °C. TT was measured at 5 and 15 minutes, every 15 to 360 minutes, every 30 minutes to 8 hours, every hour to 12 hours, and at 24 hours post‐injection. Threshold data were analyzed using an anova with a repeat factor of time. Behavioral adverse effects (dysphoria) were associated with B administration, but not with HY or HY‐B administration (these produced calm euphoria). The control group was stable over time (p = 0.22) (mean threshold 40.15 °C). Overall, there was no period effect, no significant effect of administering B, but a significant effect (raised TT) of administering HY or HY‐B. If the mean value of one of the experimental groups differed from the control group (40.075 °C) by more than 2.355 °C (>42.425 °C), that mean was significantly different from control at p < 0.05 (Bonferroni's t‐tests). This occurred between 15 and 165 minutes for B, from 15 to 345 minutes for HY, and between 15 and 540 minutes for HY‐B. In this model, HY provided up to 5.75 hours of antinociception at 0.1 mg kg^?1, and concurrent administration of butorphanol (0.4 mg kg^?1) decreased the intensity of antinociception over the first 2 hours, but extended the duration of significant antinociception to about 9 hours.  相似文献   

Experimental Leptospira borgpetersenii serovar hardjo infection of pregnant cattle     

CR SMITH  MR McGOWAN  CS McCLINTOCK  BG CORNEY  PJ KETTERER  L. SMYTHE  W. WARD 《Australian veterinary journal》1997,75(11):822-826

Objective To observe the effect upon the foetus of experimental infection of pregnant cattle with Leptospira borg-petersenii serovar hardjo .
Design A disease transmission study using pregnant cattle.
Procedure Fourteen heifers serologically negative to L hardjo were artificially inseminated and later challenged with a north-Queensland isolate of L hardjo by conjunctival inoculation. The heifers were serologically monitored and their urine examined for the presence of leptospires using culture and fluorescent-antibody tests at appropriate intervals. Elective caesarean sections were performed on pregnant heifers at 6.5 weeks after the challenge. Foetuses were examined using serological, histopathological, microbiological and fluorescent-antibody tests.
Results Ten of the heifers became pregnant, but three subsequently aborted before challenge. After challenge, all 14 heifers seroconverted and L hardjo was isolated from the urine of 6 of the 7 pregnant heifers. No evidence of foetal L hardjo infection was detected. Two of the foetuses had histopatho-logical lesions consistent with Neospora s p infection.
Conclusion It is likely that the isolate of L hardjo used in this study does not normally infect the foetus. Neospora s p may be a more significant cause of bovine reproductive wastage.  相似文献   

A prospective clinical trial on the effects of inhaled albuterol on the Pao₂ of hypoxaemic anaesthetized horses     

SA Robertson  J Bailey  L Pablo  S Cantwell  WL Davies 《Veterinary anaesthesia and analgesia》2002,29(2):94-95

  相似文献