苜蓿、小麦、玉米经济效益比较   总被引：3，自引：0，他引：3  

刘会芳  南志标  唐增  王丽佳 《草业科学》2016,33(5):990-995

基于甘肃省5个样本县的调研数据,对农户苜蓿(Medicago sativa)、小麦(Triticum aestivum)和玉米(Zea mays)种植的投入和产出、要素产出弹性和要素边际产出进行测算并比较。结果表明,苜蓿在三者中投入最少,玉米产出最高,而苜蓿产出最低;现阶段小麦和玉米处于规模报酬递减阶段而苜蓿处于规模报酬递增阶段,苜蓿产业有很大的上升空间;小麦和玉米各要素边际产量基本趋近于零,苜蓿种子投入和肥料投入的边际产量均远大于零,增加苜蓿种子和肥料投入可实现苜蓿增产。  相似文献   

5种川西北沙化地草本植物生态适应策略的差异性     

李莹  曾晓琳  游明鸿  刘金平  蔡捡 《草业科学》2016,33(5):843-850

以5种川西北沙化草地自然留存植物沙生苔草(Carex praeclara)、赖草(Leymus secalinus)、紫花列当(Orobanche coerulescens)、藏茴香(Carum carvi)和地八角(Astragalus bhotanensis)为研究对象,通过测定5种草地植物的表观性状、构件含水量和生物量及其分配,分析5种植物的生长发育、资源分配对沙化生境的响应差异,探讨5种植物对沙化地生境的应对策略与适应机理。结果表明,1)5种植物的表观性状具有极显著差异(P0.01),沙生苔草通过冠幅,赖草通过根茎,地八角通过深根系,紫花列当和藏茴香通过扩大有性生殖来适应沙化生境。2)5种植物的含水量及其配比均存在极显著差异(P0.01),沙生苔草、赖草和地八角的水分优先分配到生殖枝,紫花列当优先分配到茎叶,藏茴香则采用相对均衡的水分分配方式。3)5种植物的生物量及其分配也存在极显著差异(P0.01),沙生苔草生物量优先分配到根茎,赖草优先分配到地上茎叶,紫花列当优先分配到生殖枝,地八角优先分配到根部,而藏茴香则相对均衡的分配生物量到各构件。5种沙生植物对资源权衡分配的方式不同,但均能通过表型可塑性、水分利用能力和生物量分配等应对策略来获取或分配有限的可利用资源,增加其对生境的适应性,得以在沙化草地中留存下来。  相似文献   

一种茶园小绿叶蝉抗药性快速检测方法的研究     

李良德  王定锋  李慧玲  张辉  曾明森  吴光远 《茶叶科学技术》2016,(1):48-53

茶小绿叶蝉具有虫体较小易隐蔽、行动活跃易逃脱、若虫脆弱易死亡等特点,导致室外捕虫工作量大、室内挑虫分装处理困难,是阻碍该虫抗药性研究进展缓慢的重要原因.通过采集叶蝉发生茶园嫩梢于室内水培、培育小绿叶蝉;通过调节改进的粉尘采样设备的不同采样流量收集叶蝉于带芽离心管;最后,通过联苯菊酯处理离心管内芽叶,测定管内小绿叶蝉的LC50值,校验方法的可行性.研究结果表明,田间虫口密度为1.538(头·梢-1)的茶园,室内水培7 d后可孵化出若虫至3.181(头·梢-1),收集室内叶蝉可减少室外采虫工作量.采用10 L·min-1的采虫流量,叶蝉收集速度快,且存活率为100%,改进的设备可简化挑虫难题.联苯菊酯对叶蝉的LC50为163.55 mg·L-1,毒力测定方法快速简便.  相似文献   

In vivo activity of cefquinome against Riemerella anatipestifer using the pericarditis model in the duck          下载免费PDF全文

Y. Qu  Y. Lu  M. Sun  Y. Zhang  J. Zhong  Z. Zeng 《Journal of veterinary pharmacology and therapeutics》2016,39(3):299-304

Cefquinome is a fourth‐generation cephalosporin with broad‐spectrum antibacterial activity, including activity against enteric gram‐negative bacilli such as Riemerella anatipestifer. The pericarditis model was used to examine the pharmacodynamic characteristics of cefquinome against R. anatipestifer. Serum levels of cefquinome following the administration of different doses were determined by LC‐MS/MS. Ducks with ca. 10⁶ CFU/mL at the initiation of therapy were treated with cefquinome at doses that ranged from 0.0156 to 2 mg/kg of body weight/day (in 3, 6, 12, or 24 divided doses) for 24 h. The percentage of a 24‐h dosing interval that the unbound serum cefquinome concentrations exceeded the MIC (fT > MIC) were the pharmacokinetic (PK)–pharmacodynamic (PD) parameter that best correlated with efficacy (R² 86.3% for R. anatipestifer, compared with 58.9% for the area under the concentration–time curve/MIC and 10.6% for peak/MIC). A sigmoid E_max model was used to estimate the magnitudes of the %fT > MIC associated with net bacterial stasis, a 1‐log₁₀ CFU reduction from baseline, and a 2‐log₁₀ CFU reduction from baseline; the corresponding values were (22.5 ± 1.3) %, (35.2 ± 4.5) %, and (42.4 ± 2.7) %. These data showed that treatment with cefquinome results in marked antibacterial effects in qvivo against R. anatipestifer and that the host's immunity may also play a key role in the anti‐infective therapy process.  相似文献   

Transport stress induces pig jejunum tissue oxidative damage and results in autophagy/mitophagy activation     

Yulong He  Zhan Sang  Yisha Zhuo  Xueyi Wang  Zeheng Guo  Lihua He  Cuiping Zeng  Hanchuan Dai 《Journal of animal physiology and animal nutrition》2019,103(5):1521-1529

Pig transportation is associated with intestinal oxidative stress and results in destruction of intestinal integrity. Autophagy has been contributed to maintain cell homeostasis under stresses. The purpose of this study was to evaluate the effects of transport stress on morphology, intestinal mucosal barrier and autophagy/mitophagy levels in pig jejunum. A total of 16 finishing pigs were randomly divided into two groups. The control group was directly transported to the slaughterhouse and rested for 24 hr. The experimental groups were transported for 5 hr and slaughtered immediately. The results showed that transportation induced obvious stress responses with morphological and histological damage in jejunum accompanying with an elevated level of malondialdehyde (MDA; p < .05), endotoxin (LPS; p < .05), lactic dehydrogenase (LDH; p < .05) and a decreased level of serum superoxide dismutase (SOD; p < .05). Also, hemeoxy genase 1 (HO‐1; p < .01) as well as tight junction protein (claudin‐1 [p < .001], occludin [p < .05] and zonula occludens 1 [ZO‐1; p < 0.05]) levels were attenuated in jejunum tissue, and NADPH oxidase 1 (NOX1; p < .01) mRNA expression was up‐regulated. Further research indicated that transport stress could induce autophagy through increasing microtubule‐associated protein light chain 3 (LC3; p < .05) and autophagy‐related gene 5 (ATG5; p < .01) levels and suppressing p62 expression. Additionally, transport stress increased the protein levels of PTEN‐induced putative kinase 1 (PINK1; p < .05) and Parkin (p < .05) which was associated with mitophagy. In conclusions, transport stress could induce the destruction of intestinal integrity and involve in the intestinal mucosal barrier oxidative damage, and also contribute to activation of autophagy/mitophagy.  相似文献   

Distribution and quantitative analysis of CIDEa and CIDEc in broiler chickens: accounting for differential fat deposition between strains     

J. Z. Huang  L. M. Huang  Q. J. Zeng  E. F. Huang  H. P. Liang  Q. Wei 《British poultry science》2018,59(2):173-179

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Preparation,characterization, and pharmacokinetics in swine of a florfenicol enteric formulation prepared using hot‐melt extrusion technology          下载免费PDF全文

Y. Xu  X. Wen  X. Feng  Z. Liang  X. Ye  H. Nie  X. Liao  J. Li  Y. Zeng  S. Tang  J. He 《Journal of veterinary pharmacology and therapeutics》2018,41(4):572-580

The objective of this work was to manufacture an enteric formulation of florfenicol (FF) using hot‐melt extrusion (HME) technology and to evaluate its in vitro dissolution and in vivo pharmacokinetics. For the HME process, hypromellose acetate succinate LG (HPMCAS‐LG) was the enteric polymer mixed with FF, and the two components were extruded with a standard screw configuration at a speed of 50 rpm. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), powder X‐ray diffraction (PXRD), and Fourier transform infrared spectroscopy (FT‐IR) were performed to characterize the HME extrudate. The release percentage of the enteric formulation in the acidic stage was <10% of the loaded FF, whereas that in the phosphate buffer stage was >80%. Pharmacokinetic evaluations in swine revealed that the enteric formulation had a longer t_1/2λ and MRT than commercially available FF powder (FULAIKA^®), indicating that the novel formulation exhibited enteric and sustained release properties. Compared with the commercial product, the relative bioavailability of the enteric formulation reached up to 117.2%. This study suggests that this formulation may have potential for future commercialization.  相似文献   

青藏高原东部乡土植物对高寒沙化草地土壤性质的影响   总被引：1，自引：0，他引：1  

张潇喜  曾凯  蔡义民  马赛男  宋洋  刘琳  陈冬明  周春梅  孙飞达  陈有军 《草业科学》2018,35(4):749-759

以青藏高原东部高寒沙化草地为研究对象,通过比较分析狭叶红景天(Rhodiola rosea)、硬秆仲彬草(Kengyilia rigidula)、垂穗披碱草(Elymus nutans)和高山红柳(Salix cupularis)4种乡土植物对沙化草地的土壤理化性质、土壤酶活性及微生物生物量的影响,旨在为高寒草地沙化地生态植被的重建与恢复选择适宜的治理植物提供理论依据。结果显示:1)种植4种植物治理恢复5年后,土壤含水量均有显著升高(P0.05),土壤容重和土壤pH有不同程度的下降,垂穗披碱草处理下土壤含水量最高,与对照相较增加了357.70%;2)植被恢复显著提高了土壤中与碳氮磷循环相关的各种酶的活性(P0.05),其中狭叶红景天样地中的土壤纤维素酶、过氧化物酶、蔗糖酶、蛋白酶和磷酸酶活性最高,分别为对照的3.19、1.98、3.22、1.87和4.59倍。3)种植4种植物治理恢复5年后,不同土壤微生物生物量碳(MBC)、微生物生物量氮(MBN)均有显著提高(P0.05),狭叶红景天的MBC、MBN和微生物生物量碳氮比(MBC/MBN)均为最高,分别为对照的4.39、3.46和1.27倍;4)种植狭叶红景天和高山红柳样地,土壤酶活性与土壤理化性质及微生物生物量呈极显著(P0.01)和显著(P0.05)相关,种植垂穗披碱草样地,土壤酶活性与土壤理化性质及微生物生物量相关性较差。研究表明,4种植物种植5年后,狭叶红景天对高寒沙化草地的土壤特性改善更明显。  相似文献   

镉胁迫对茶园绿肥槐叶决明“茶肥1号”的生长及吸收积累的影响     

向芬  李维  刘红艳  周凌云  丁玎  曾振 《草业科学》2018,35(7):1679-1684

以槐叶决明(Cassia sophera)"茶肥1号"为材料,采用盆栽法研究了不同浓度(0、5、10、20、40、80、120、160mg·kg~(-1))镉(Cd)胁迫对"茶肥1号"生长及Cd吸收积累特性的影响。结果表明:土壤中添加0~160mg·kg~(-1) Cd,随Cd胁迫浓度的增加,各器官生长量受到明显抑制。"茶肥1号"各器官Cd含量与Cd胁迫浓度、土壤有效态Cd含量均呈显著正相关关系(P0.05),各器官Cd积累量顺序为根茎叶。土壤中Cd元素大部分被根固定,向地上部运输的比例较低,说明"茶肥1号"植株根部最易受到Cd毒害。随着Cd浓度的增加,"茶肥1号"的种子Cd累积量增加缓慢。本研究在较高的Cd胁迫浓度条件下,"茶肥1号"在较短的时期内对Cd具有明显的富集作用,其根、茎、叶中浓度分别为113.85、20.15、7.00mg·kg~(-1)。因此,"茶肥1号"可作为土壤修复类的植物,在污染地区种植,对环境保护与田地污染治理有重要的意义。  相似文献   

Lactobacillus plantarum BS22 promotes gut microbial homeostasis in broiler chickens exposed to aflatoxin B1          下载免费PDF全文

Y. Zeng  D. Zeng  Y. Zhang  X. Q. Ni  J. Wang  P. Jian  Y. Zhou  Y. Li  Z. Q. Yin  K. C. Pan  B. Jing 《Journal of animal physiology and animal nutrition》2018,102(1):e449-e459

Probiotics promote the health of the host by maintaining intestinal microbial homeostasis. This study aimed to investigate the benefits of Lactobacillus plantarum BS22 (LP) in the gastrointestinal tract (GIT) microbial homeostasis of broiler chickens exposed to aflatoxin B₁ using the PCR‐DGGE, viable count and real‐time PCR. The toxin adsorption experiment demonstrated that treatment R5 (1.0 × 10⁸ CFU/g LP) exhibited good absorptive effect in adsorbing the aflatoxin B₁ (AFB₁) in vitro. DGGE showed that the composition and structure of gut microbiota were more similar in the mucosa than in the content of all the samples. In addition, higher diversity of the microbiota was observed in the caecum and glandular stomach than in other segments. Lactobacillus, Enterococcus and Enterobacteriaceae were more abundant in the ileum than in the other segments. Enterobacteriaceae in groups I (basal diet) and II (basal diet+50 μg/kg AFB₁) showed a significant difference in group III (basal diet + 50 μg/kg AFB₁ + 1 × 10⁸ CFU/g LP) in the crop content and duodenum mucosa (p < .05). This investigation indicates that the L. plantarum BS22 promotes GIT microbial homeostasis in broiler chickens exposed to AFB₁, particularly for the intestine mucosa microbiota. Thus, L. plantarum BS22 is a possible candidate for degrading AFB_1.  相似文献