烟酸对未去势湘中公牛生长性能、肉品质和血清生化指标的影响

本研究旨在研究烟酸对未去势湘中公牛生长性能、肉品质和血清生化指标的影响。选择1.5岁左右体重[(385.08±15.20)kg]匀称的未去势湘中黑公牛21头,随机分成3组,每组7头,各组分别在基础饲粮中添加0、800、1 200 mg/kg烟酸。预试期14 d,正试期120 d。结果表明:烟酸对公牛的平均日增重、日均采食量、饲料转化率、背膘厚、眼肌面积均没有显著影响(P0.05)。烟酸对背最长肌的p H、肉色亮度和红度值、剪切力、滴水损失以及水分、粗脂肪和粗蛋白质含量均没有显著影响(P0.05)。1 200 mg/kg烟酸显著降低血清总胆固醇和高密度脂蛋白胆固醇(HDL-C)含量(P0.05),800 mg/kg烟酸显著降低血清HDL-C含量(P0.05),烟酸对低密度脂蛋白胆固醇含量没有显著影响(P0.05)。1 200 mg/kg烟酸可以提高血清非酯化脂肪酸(P0.05)和葡萄糖含量(P=0.06),降低血清尿素氮含量(P=0.07)。综上,本研究并没有观察到烟酸对未去势湘中公牛生长性能和肉品质等指标有影响,但对血脂指标有一定调节作用,推测可能是未去势公牛的雄性激素的作用覆盖了烟酸的作用。     

粪肠球菌替代抗生素对断奶仔猪生长性能、腹泻率、血液生化指标和免疫器官的影响

本试验在断奶仔猪饲粮中添加不同水平的粪肠球菌,研究其替代抗生素对断奶仔猪生长性能、腹泻指数和腹泻率、血液生化指标以及免疫器官的影响。选取120头(28±2)日龄平均体重为(7.60±0.81)kg的"杜×长×大"断奶仔猪,随机分为5组,每组6个重复(公母各占1/2),每个重复4头,每个重复为1圈。对照组饲喂基础饲粮,抗生素组在基础饲粮中添加100mg/kg硫酸黏菌素和400 mg/kg杆菌肽锌,3个粪肠球菌组分别在基础饲粮中添加40、200和1 000 mg/kg粪肠球菌,试验期31 d。试验结果显示:1)在1~14 d,饲粮中添加抗生素和粪肠球菌对断奶仔猪的平均日采食量(ADFI)、平均日增重(ADG)以及料重比(F/G)无显著影响(P0.05)。在15~31 d,与对照组和抗生素组相比,200和1 000 mg/kg组可极显著提高ADFI和ADG(P0.01)。在1~31 d,与对照组相比,200和1 000 mg/kg组的ADFI均极显著提高(P0.01),而ADG分别显著和极显著增加(P0.05和P0.01);与抗生素组相比,1 000 mg/kg组可极显著提高ADFI(P0.01),而200和1 000 mg/kg组的ADG分别显著和极显著增加(P0.05和P0.01)。2)在1~14 d,与对照组相比,40 mg/kg组的腹泻指数和腹泻率显著降低(P0.05)。在15~31 d和1~31 d,与对照组和抗生素组相比,40和1 000 mg/kg组均可在一定程度上降低腹泻率(P0.05)。3)与对照组相比,粪肠球菌可以显著提高血液中总蛋白含量(P0.05),其中200和1 000 mg/kg组达到极显著水平(P0.01),且这2组分别可以显著和极显著提高球蛋白含量(P0.05和P0.01)。与抗生素组相比,200和1 000 mg/kg组可以显著提高总蛋白含量(P0.05)。与对照组相比,抗生素组和1 000 mg/kg组的白球比显著降低(P0.05),另外,抗生素组血液中谷丙转氨酶和谷草转氨酶活性显著降低(P0.05),200 mg/kg组的谷丙转氨酶活性显著降低(P0.05)。4)与对照组相比,1 000 mg/kg组的肝脏重量和脾脏指数有一定程度的提高(P0.05),与抗生素组相比,200和1 000 mg/kg组可显著提高肝脏重量(P0.05)。结果表明,饲粮中添加粪肠球菌可改善断奶仔猪的生长性能(饲喂15~31 d),降低腹泻率,提高仔猪免疫力,其中添加量为1 000 mg/kg时效果最好。     

Pharmacokinetics of cefquinome in tilapia (Oreochromis niloticus) after a single intramuscular or intraperitoneal administration

The pharmacokinetics of cefquinome was studied in plasma after a single dose (10 mg/kg) of intramuscular (i.m.) or intraperitoneal (i.p.) administration to tilapia (Oreochromis niloticus) in freshwater at 30 °C. Ten fish per sampling point were examined after treatment. The data were fitted to two‐compartment open models following both routes of administration. The estimates of total body clearance (CL/F), volume of distribution (Vd/F), and absorption half‐life (T_1/2ka) were 0.049 and 0.037 L/h/kg, 0.41 and 0.33 L/kg, and 0.028 and 0.035 h following i.m. and i.p. administration, respectively. After i.m. injection, the elimination half‐life (T_1?2β) was calculated to be 5.81 h, the maximum plasma concentration (C_max) to be 49.40 μg/mL, the time to peak plasma cefquinome concentration (T_max) to be 0.14 h, and the area under the plasma concentration–time curve (AUC) to be 204.6 μg h/mL. Following i.p. administration, the corresponding estimates were 6.05 h, 44.39 μg/mL, 0.17 h and 267.8 μg h/mL. The minimum inhibitory concentrations of cefquinome, determined for 30 strains of Streptococcus agalactiae isolated from diseased tilapia, ranged from 0.015 to 0.12 μg/mL. Results from these studies support that 10 mg cefquinome/kg body weight daily could be expected to control tilapia bacterial pathogens inhibited in vitro by a minimal inhibitory concentration value of ≤2 μg/mL.     

桑叶和桑枝综合利用概况

近年来,桑叶和桑枝的综合利用研究取得较大进展。桑树资源的开发利用,具有广泛的生态、经济和社会效益,对促进传统蚕桑产业的转型升级具有重要意义。桑叶富含多种保健和营养成分,桑叶茶和桑叶饲料开发已初具规模;桑枝资源丰富,成本低廉,桑枝食用菌栽培、桑枝地板、桑枝造纸以及桑枝制药原料已初见成效。     

基于火强度的西山国家森林公园主要可燃物类型划分

通过外业调查和室内测定,获得西山国家森林公园主要可燃物的相关参数,输入BehavePlus模型,得到潜在火行为参数,以火强度大小为主要指标划分主要可燃物类型,结果表明:在坡度分别为25°和35°情形下,高强度火的林分为地盘松林、麻栎林和云南油杉林,中强度火的林分是华山松林和滇青冈林,低强度火的林分只有旱冬瓜林。研究结果可合理划分火险等级,实施科学的火管理。     

酒糟厌氧消化产甲烷特性与微生物菌群结构分析

酒糟是酿酒生产过程中的副产物,以酒糟为研究对象,分别考察不同底物总固体（Total solid, TS）质量分数（0.5%、1%、1.5%、2%）、接种比（接种污泥与酒糟的挥发性固体质量比）（0.25、0.5、0.75、1、1.5）和温度（25、37、50℃）条件下酒糟的厌氧消化产甲烷特性。结果表明,随着TS浓度的增加,产甲烷量逐渐增加, 2%TS条件下可获得最大的累计产沼气量（532.8mL/g）和产甲烷量（294.7mL/g）。接种比是影响厌氧消化系统的重要因素,随着接种比的增大,系统累计产沼气和产甲烷量呈先增加后减少的趋势,在接种比为0.25和0.5的条件下,系统发生崩溃,并未产甲烷,当接种比为1时,获得最大的累计产沼气和甲烷量。当TS质量分数为2%、接种比为1.5、发酵温度为50℃的条件下,获得最大的累计产沼气量为559.4mL/g,相较37℃条件下提高了10.2%,而获得的累计产甲烷量为284.0mL/g,相较37℃并未显著提升（P>0.05）。利用修正的Gompertz模型进行产气动力学分析后,发现TS质量分数越高、接种比越大、温度越高,产甲烷迟滞期越短。同时对不同温度反应体系中的微生物群落进行了分析,发现Bacteroidetes和 Firmicutes为优势菌门,随着温度的升高,产甲烷菌逐渐由氢营养型代替乙酸营养型。因此, TS浓度、接种比和温度是厌氧发酵重要因素,初步确定2%TS、接种比为1的中温酒糟厌氧发酵产甲烷性能相对较好。     

A highly specific enzyme-linked immunosorbent assay for the detection of Cry1Ac insecticidal crystal protein in transgenic WideStrike cotton

A highly selective enzyme-linked immunosorbent assay (ELISA) has been developed for the quantitative detection of the Cry1Ac protein expressed in transgenic cotton. Two Cry1Ac-specific monoclonal antibodies (MAb), Kbt and 158E6, were developed and selected to form a sandwich format ELISA. The MAb Kbt was used as a capture antibody, and 158E6 was conjugated with horseradish peroxidase and served as a detection antibody. The assay was optimized and validated with different cotton matrices. Tissues were extracted with phosphate-buffered saline containing 0.05% Tween 20 and 1% polyvinylpyrrolidone. The extract was then treated with trypsin to truncate full-length Cry1Ac into the core toxin for quantitation. The resulting assay has good accuracy and precision with a validated limit of quantitation ranging from 0.1 to 0.375 mug/g dry weight of cotton tissues. This assay is highly specific for Cry1Ac protein and has no cross-reactivity with the nontarget proteins tested such as Cry1Ab and Cry1F.     

Flumorph Is a Novel Fungicide That Disrupts Microfilament Organization in Phytophthora melonis

ABSTRACT The mechanism of the effects of flumorph (a novel fungicide) was investigated by analyzing alterations of hyphal morphology, cell wall deposition patterns, F-actin organization, and other organelles in Phytophthora melonis. Calcofluor white staining suggested that flumorph did not inhibit the synthesis of cell wall materials, but disturbed the polar deposition of newly synthesized cell wall materials during cystospore germination and hyphal growth. After exposure to flumorph, zoospores were able to switch into cystospores accompanied with the formation of a cell wall, whereas cystospores failed to induce the isotropic-polar switch and did not produce germ tubes but continued the isotropic growth phase. In flumorph-treated hyphae, the most characteristic change was the development of periodic swelling ("beaded" morphology) and the disruption of tip growth. Newly synthesized cell wall materials were deposited uniformly throughout the diffuse expanded region of hyphae, in contrast to their normal polarized patterns of deposition. These alterations were the result of F-actin disruption, identified with the fluorescein isothiocynate (FITC)-phalloidin staining. The disruption of F-actin also was accompanied by disorganized organelles: each swelling of subapical hyphae was associated with a nucleus. Vesicles did not undergo polarized secretion to the apical hyphae, but diffused around nuclei for the subapical growth; thus, the cell wall was thickened with periodic expansion along the hyphae. Upon removing flumorph, normal tip growth and organized F-actin were observed again. These data, as well as data published earlier, suggest that flumorph may be involved in the impairment of cell polar growth through directly or indirectly disrupting the organization of F-actin. The primary site of action by flumorph in the disruption of the F-actin organization is under investigation.     

金线草药材薄层鉴别及含量测定

采用薄层色谱法（TLC）,以甲苯∶乙酸乙酯∶甲酸（10∶3∶1.5）为展开剂,展开,晾干,喷3%三氯化铝-乙醇溶液,晾干,置紫外灯（360 nm）下检视。采用高效液相色谱法,以色谱柱Eclipse XDB-C18柱（250 mm×4.6 mm,5μm）,10μL进样,乙腈-0.1%的磷酸水溶液为流动相,梯度洗脱,流速1.0 mL/min,柱温30℃,检测波长360 nm,建立金线草（Antenoron filiforme）药材薄层鉴别方法以及含量测定。结果表明,对金线草药材进行薄层鉴别,斑点清洗,分离度好,能有效鉴别出金线草。同时,在30 min内完成对3种黄酮成分的分析,各成分间均达到基线分离,芦丁、槲皮素、山奈酚的线性范围分别为2.12～100.80μg/mL(r=0.999 4)、25.50～758.86μg/mL(r=0.999 8)、2.62～250.48μg/mL(r=0.999 5),平均加样回收率（n=6）分别为98.42%、101.21%、97.92%。     

杂交稻对产量和氮素利用率影响的荟萃分析

【目的】与常规稻相比,杂交稻具有更高的产量潜力。但是,对杂交稻和常规稻在氮素利用率上的差异尚存争议。本研究采用Meta分析以明确杂交稻对产量和氮素利用率的影响。【方法】以常规稻为对照,杂交稻为处理,筛选出56篇文献,建立了包含367对观测值的数据库。利用Meta分析方法,针对不同杂交稻类型、氮肥施用量及施用次数、土壤全氮、土壤碳氮比和土壤质地,探究了杂交稻对产量和氮素利用率的影响。【结果】与常规稻相比,杂交稻显著提高了产量（+11%）和生物量（+14%）,而对收获指数无显著性影响。在各氮肥施用水平下,与常规稻相比,杂交稻均显著提高了产量;然而,随着氮肥施用量的增加,杂交稻的增产优势显著降低。另外,与常规稻相比,杂交稻显著提高了氮素吸收（+8.1%）、氮素生理利用率（+2.9%）和氮素回收率（+3.6个单位）。【结论】与常规稻相比,杂交稻能够提高产量和氮素利用率。本研究为评估杂交稻的推广应用对我国水稻产量和氮素利用率的影响提供了数据支撑。