Common helminth infections of donkeys and their control in temperate regions

Roundworms and flatworms that affect donkeys can cause disease. All common helminth parasites that affect horses also infect donkeys, so animals that co‐graze can act as a source of infection for either species. Of the gastrointestinal nematodes, those belonging to the cyathostomin (small strongyle) group are the most problematic in UK donkeys. Most grazing animals are exposed to these parasites and some animals will be infected all of their lives. Control is threatened by anthelmintic resistance: resistance to all 3 available anthelmintic classes has now been recorded in UK donkeys. The lungworm, Dictyocaulus arnfieldi, is also problematical, particularly when donkeys co‐graze with horses. Mature horses are not permissive hosts to the full life cycle of this parasite, but develop clinical signs on infection. In contrast, donkeys are permissive hosts without displaying overt clinical signs and act as a source of infection to co‐grazing horses. Donkeys are also susceptible to the fluke, Fasciola hepatica. This flatworm can be transmitted, via snails and the environment, from ruminants. As with cyathostomins, anthelmintic resistance is increasing in fluke populations in the UK. A number of the anthelmintic products available for horses do not have a licence for use in donkeys, and this complicates the design of parasite control programmes. As no new equine anthelmintic classes appear to be near market, it is important that the efficacy of currently effective drugs is maintained. It is important that strategies are used that attempt to preserve anthelmintic efficacy. These strategies should be based on the concept that the proportion of worms in a population not exposed to anthelmintic at each treatment act as a source of ‘refugia’. The latter is an important factor in the rate at which resistance develops. Thus, it is imperative that parasite control programmes take into account the need to balance therapy to control helminth‐associated disease with the requirement to preserve anthelmintic effectiveness.     

硒对镉中毒鸡免疫功能的保护效应

饲料中添加45ppm镉的鸡,在整个实验期间(120d),ANAE+淋巴细胞百分率、B淋巴细胞EAC花环形成百分率、血清γ-球蛋白含量及血清IgG含量均降低。镉对鸡细胞免疫和体液免疫的抑制程度与接触镉的时间长短有关。饲料中添加镉的同时,分别添加5ppm、10ppm、15ppm硒,在实验第60～90d期间能(?)抗镉的免疫毒性,基本维持鸡的正常免疫功能,其中以加10ppm硒的保护效应为佳。     

杂交野猪适宜日粮磷水平与钙磷比例的研究

选用纯种野公猪与杜洛克母猪的杂交后代含50%野猪血缘的42日龄杂交野猪36头,随机分成9组,试验为双因子3水平(3×3)析因安排分组,完全随机区组设计,每个因子3个水平,共9个处理。结果显示,不同磷水平与钙磷比例对各处理组的平均日耗料量、平均日增重、料重比差异均不显著(P>0.05)。不同钙磷比例水平下对血清钙的影响差异极显著(P<0.01),日粮磷和钙磷比例互作效应对血清钙影响差异极显著(P<0.01)。不同日粮钙磷比例对血清磷水平差异显著(P<0.05),日粮磷和钙磷比例互作效应对血清磷影响显著(P<0.05);0.4%的日粮磷水平与0.6%的磷水平对血清AKP活性影响差异极显著(P<0.01)。     

Type 2 diabetes mellitus with pancreatic β cell dysfunction in 3 horses confirmed with minimal model analysis

Reasons for performing study: Type 2 diabetes mellitus (T2DM) is diagnosed rarely in equine practice although it may be under‐recognised. A greater awareness of the condition and therapeutic considerations would be to the benefit of such cases presenting in practice. More investigation into the pharmacological management of these cases is needed. Objectives: Three cases of diabetes mellitus were investigated using a specific test for insulin sensitivity and pancreatic β cell function in order to define accurately and characterise the existence of T2DM in all 3 subjects. Methods: The insulin‐modified frequently sampled i.v. glucose tolerance test was performed in each case and the data so obtained were subject to minimal model analysis of insulin‐glucose dynamics. Cases were then monitored following treatment using a combination of dietary modification, metformin, glibenclamide and pergolide. Results: Marked insulin resistance was identified in each case and, furthermore, severe pancreatic β cell dysfunction was present therefore classifying each case as end stage T2DM. Treatment was nevertheless associated with restoration of normoglycaemia in all cases. Conclusions: T2DM in horses may be more common than generally considered. In some cases individuals may respond to therapy aimed at restoring insulin sensitivity and pancreatic function. Drugs used in other species for the treatment of T2DM have not yet been adequately tested in horses. Potential relevance: T2DM should be considered as an important differential diagnosis in mature to elderly horses and ponies suffering from weight loss, polydipsia and polyuria. Clinicians should be encouraged to offer treatment and management advice when such cases are encountered.     

镉对柠条种子萌发及幼苗生长的影响

为探讨重金属镉(Cd)对柠条种子萌发的毒物刺激效应,采用培养皿滤纸萌发法,研究了不同Cd2+浓度(0,2,5,10,15,50mg/L)对柠条种子萌发、幼苗生长和酶活性的影响。结果表明:在5mg/L的Cd2+浓度下柠条种子的发芽率、胚芽和胚根的长度达最大,分别比对照提高3.8%,13.4%和11.2%,根和芽的POD活性分别比对照增加19.2%、1.8%,CAT活性比对照增加6.3%、10.4%;Cd2+浓度为50mg/L时,柠条种子的发芽势、发芽指数、活力指数分别比对照显著降低46.9%,26.1%和27.8%;高浓度Cd2+(10,15和50mg/L)对柠条种子萌发及酶活性表现为抑制作用,低浓度Cd2+(2、5mg/L)表现为促进作用。镉对柠条种子萌发具有"低促高抑"的毒物刺激效应,5mg/L的Cd2+浓度为柠条种子萌发刺激效应的临界浓度。     

吸血节肢动物体内细菌研究进展

吸血节肢动物体内广泛存在着多种细菌,这些细菌对其具有重要生理功能和生态意义,同时对其所携带病原有一定的影响.根据吸血节肢动物体内细菌研究所取得的一些新进展,从体内细菌常见种类、与宿主相互作用、对病原体影响和研究方法等方面对吸血节肢动物体内细菌研究现状进行概述.     

20份无芒雀麦种质材料苗期抗旱性综合评价及光合特性分析

在温室条件下,采用反复干旱法,对引进的20份无芒雀麦(Bromus inermis Leyss.)种质材料,以存活率、株高、绿叶数、地上生物量、地下生物量和根冠比6个指标的抗旱系数值,采用聚类分析法、标准差系数赋予权重法进行综合评价。结果表明:20份无芒雀麦苗期抗旱性划分成3个级别,其中抗旱性较强的有9份材料,抗旱性较弱有6份材料,抗旱性居中的有5份材料。20份无芒雀麦种质材料苗期抗旱性排序结果为ZXY06P-1621抗旱性最强,ZXY05P-1171最弱。不同抗旱级别种质材料的光合特性表现为:随着持续干旱胁迫延续,其光合速率(P_n)、蒸腾速率(T_r)和气孔导度(G_s)均呈下降趋势,复水后迅速上升;而CO₂浓度的变化趋势则呈相反变化趋势,且在整个胁迫过程中变化差异不显著。干旱胁迫下抗旱性强的材料能够保持较高的光合性能。     

家蚕谷胱甘肽-S-转移酶研究进展

谷胱甘肽-S-转移酶在内外源有毒物质的代谢中起着重要作用。家蚕既是重要的经济昆虫,也是重要的模式生物。家蚕作为鳞翅目昆虫的模式生物,研究家蚕谷胱甘肽-S-转移酶,对于阐明谷胱甘肽-S-转移酶与杀虫剂抗性的关系,防治农林害虫有着重要的理论意义。本文就谷胱甘肽-S-转移酶在家蚕中的研究现状作了归纳,希望对今后谷胱甘肽-S-转移酶的研究能有所帮助。     

单播草坪匍匐翦股颖溶磷菌筛选及溶磷能力的初步研究

对西安地区单播草坪匍匐翦股颖根际联合固氮菌进行分离的基础上,采用PKO无机磷培养基和蒙金娜有机 培养基对匍匐翦股颖根际分离的联合固氮菌(共获得188种分离物)中具有溶磷能力的菌株(占29.3％),通过对菌株溶 磷圈大小的测定,最终筛选出溶磷能力较强菌株4株,分离物溶解无机磷D/d值在1.324~3.014之间;而溶解有机磷的能力 在1.239~2.156之间。     

结缕草属杂交后代抗寒性评价

以结缕草(Zoysia Willd.)杂交后代为材料,以Z014(马尼拉)、Z129(青岛结缕草)及Z077(“兰引3号”结缕草)为对照,以电解质外渗法和地下茎恢复性生长评价其抗寒性,分析抗寒性、枯萎期及青绿期的回归关系。结果表明:叶片电解质外渗率半致死温度(LT₅₀)的变化范围为-5.78~-8.26℃,其中22-2、40-2和40-8的半致死温度均低于对照;叶片半致死温度由低到高,即抗寒性由强到弱依次为22-2>40-2>40-8>Z077>Z129>Z014>40-5>31-3>18-1>18-4>37-1>22-3;地下茎恢复生长试验结果表明,杂交后代在-6℃时全部致死,在-2℃处理后均可以恢复生长,恢复生长的百分率变异较大(14.7%~100%),其中31-3与40-2超过Z014与Z077,22-2超过Z077;供试材料间叶片和地下茎抗寒性的测定结果一致;回归分析结果表明,叶片的半致死温度、青绿期及枯萎期相关不显著。