共查询到20条相似文献，搜索用时 46 毫秒
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《中国蜂业》2021,(6)
噻虫啉作为一种常见的新烟碱类杀虫剂,由于具有广谱性、高效性以及对哺乳动物低毒性等特点,在农业中的应用越来越广泛。噻虫啉在植物花粉花蜜中的残留不仅会对成年蜜蜂有危害,同时也会影响蜜蜂幼虫。目前针对噻虫啉对蜜蜂幼虫行为影响的研究还相对较少。本实验在蜜蜂幼虫阶段的食物中添加浓度为0.5、1.0mg/L的噻虫啉,记录噻虫啉暴露后幼虫的封盖率、化蛹率和出房率,并在蜜蜂出房当天测试其嗅觉联想学习和记忆行为。结果显示,1.0mg/L的噻虫啉会显著降低蜜蜂幼虫的化蛹率、羽化率,增加蜜蜂的死亡率,同时噻虫啉降低了蜜蜂出房后的学习效率和短时程记忆。结果说明蜜蜂幼虫阶段暴露亚致死浓度噻虫啉对蜜蜂的影响会延续到成年蜜蜂,进而影响整个蜂群的存活。 相似文献
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基于广西贵港市覃塘区黄练镇发生了大批量家蚕中毒死亡的现象,为了科学查找蚕中毒原因,通过实地走访调研,发现中毒家蚕的饲养农户共同之处是使用同种桑树肥料,对各种涉蚕物资进行农药残留检测。结果显示,桑树肥料中含有高浓度噻虫嗪,家蚕添食试验显示噻虫嗪的浓度大于0.001 56 mg/kg能够导致家蚕发生中毒;噻虫嗪16.5 mg/kg浓度根基施肥,40 d内采叶喂蚕可导致3龄蚕急性中毒,100 d后药物毒性消失。通过综合分析,认为桑园施用的肥料中残留有高浓度的噻虫嗪,其通过桑树根部吸收,传导到桑叶,导致家蚕农药中毒,继而引起大批量死亡。农药来源推测是甘蔗种植中使用噻虫嗪,农户购买的此批肥料使用了较多的甘蔗滤泥,导致肥料中噻虫嗪含量较高。针对噻虫嗪引起的家蚕农药中毒现象,建议更换新鲜无毒桑叶减少损失,可疑桑叶先行少量饲喂试验等措施,噻虫嗪肥料施肥后的桑树在100 d后再采叶喂蚕,可有效防止家蚕农药中毒的发生,减少经济损失。 相似文献
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《中国蜂业》2017,(4):20-22
新烟碱类杀虫剂(neonicotinoid insecticide)目前已经成为全球范围内应用最广泛的一类杀虫剂。此类杀虫剂通过作用于昆虫的乙酰胆碱受体,释放乙酰胆碱受体抑制剂,阻碍昆虫神经传导,影响昆虫正常生理行为,最终导致昆虫麻痹死亡~([1])。本文通过测定吡虫啉与噻虫胺两种新烟碱类杀虫剂对中华蜜蜂(Apis cerana cerana)24 h内半数致死剂量(median lethal dose,LD50)~([2]),评估此类杀虫剂对中华蜜蜂的急性致死毒性。并通过统计经过亚致死剂量(sub-lethal dose)处理的中华蜜蜂,经过2 h、24 h和48 h后的伸吻反应率,从而进一步探究新烟碱类杀虫剂对中华蜜蜂行为的影响。 相似文献
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欧洲投票禁止新烟碱类杀虫剂 总被引：2，自引：0，他引：2
《中国蜂业》2018,(9)
正4月底,欧盟委员会投票决定全面禁止新烟碱类杀虫剂。自2013年以来就已经实施限制,但新的裁定将禁令扩展到几乎所有户外化学品的使用。3种禁用的化学药品是吡虫啉、噻虫胺和噻虫嗪。这项禁令在2018年年底生效。最近有关新烟碱类杀虫剂对蜜蜂负面影响的实地研究对该决策产生重大影响。欧洲食品安全管理局的一份报告得出结论,杀虫剂对蜜蜂构成"高度急性风险"。 相似文献
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<正>基于欧洲食品安全局(EFSA)所做的风险评估,为保护种群数量减少的蜜蜂,2013年5月欧盟委员会(EC)通过了对三种新烟碱类杀虫剂——拜耳公司的噻虫胺和吡虫啉,先正达公司的噻虫嗪,在吸引蜜蜂或其他授粉者的农作物上禁用2年的决议。2013年8月,两家公司均对欧盟委员会提起诉讼。EFSA评估的重点是对蜜蜂暴露于杀虫剂的三条主要途径进行风险评估:施过药的植物花蜜和花粉中的农药残留;种植含杀虫剂的种子时或杀虫剂经颗粒施用时产生的尘埃;施过药的植物吐水液中的农药残留。他们发现,在这三种情况下均对蜜蜂生存构成威胁。 相似文献
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魏静 《四川畜牧兽医学院学报》2009,(4):28-32
在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。 相似文献
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本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。 相似文献
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REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air. 相似文献
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以国际标准强毒Ｒ株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离ＭＧ,并收集感染鸡所产蛋分离ＭＧ。结果表明,人工感染４８小时后上、下呼吸道及肺已被全面感染,９６小时气囊已被感染,１２０小时输卵管已能分离到ＭＧ,卵巢始终分离不到ＭＧ。人工感染鸡自１４４小时便能在其所产蛋中分离出ＭＧ。药物治疗能在７２小时内消除感染,油乳剂苗则需２４天后逐渐降低蛋内ＭＧ分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内ＭＧ,但以研制的种蛋浸泡剂药浴效果为最好。 相似文献
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Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF
Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo. 相似文献