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主要介绍筛面物料的运动规律和试验方法的研究现状,分析了几种现有的筛分装置的工作原理,研究了现有的振动筛结构及工作参数的优化方案。同时,基于现有的研究成果为残膜机械的研究工作提供几点建议。 相似文献
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Xiao-ying He Li-bing Ma Xiao-ning He Wan-tong Si Yue-Mao Zheng 《Journal of veterinary science (Suw?n-si, Korea)》2016,17(2):145-152
Previous studies have established a bovine mammary gland epithelia cells in vitro model by the adenovirus-mediated telomerase (hTERT-bMGEs). The present study was conducted to confirm whether hTERT-bMGEs were effective target cells to improve the efficiency of transgenic expression and somatic cell nuclear transfer (SCNT). To accomplish this, a mammary-specific vector encoding human lysozyme and green fluorescent protein was used to verify the transgenic efficiency of hTERT-bMGEs, and untreated bovine mammary gland epithelial cells (bMGEs) were used as a control group. The results showed that the hTERT-bMGEs group had much higher transgenic efficiency and protein expression than the bMGEs group. Furthermore, the nontransgenic and transgenic hTERT-bMGEs were used as donor cells to evaluate the efficiency of SCNT. There were no significant differences in rates of cleavage or blastocysts or hatched blastocysts of cloned embryos from nontransgenic hTERT-bMGEs at passage 18 and 28 groups (82.8% vs. 81.9%, 28.6% vs. 24.8%, 58.6% vs. 55.3%, respectively) and the transgenic group (80.8%, 26.5% and 53.4%); however, they were significantly higher than the bMGEs group (71.2%, 12.8% and 14.8%), (p < 0.05). We confirmed that hTERT-bMGEs could serve as effective target cells for improving development of somatic cell cloned cattle embryos. 相似文献
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Effect of urea supplementation on performance and safety in diets of Dorper crossbred sheep 下载免费PDF全文
B. Wang T. Ma K.‐D. Deng C.‐G. Jiang Q.‐Y. Diao 《Journal of animal physiology and animal nutrition》2016,100(5):902-910
This study was conducted to evaluate the efficacy and safety of dietary urea in sheep rations having a 50:50 concentrate:roughage ratio. Sixty‐four Dorper × thin‐tailed Han crossbred ram lambs with an average body weight of 30.8 (±0.02) kg were randomly divided into four groups of 16 sheep each, and each group was fed one of the following diets: a basal diet (CON), or CON supplemented with 0.5% (0.5UTM), 1.5% (1.5UTM) or 2.5% (2.5UTM) urea. Growth performance, carcass characteristics, non‐carcass offals, meat quality and peptic tissue lesions were assayed. The average daily weight gains for CON, 0.5UTM, 1.5UTM and 2.5UTM were 216, 218, 200 and 170 g, respectively, with the CON and 0.5UTM groups higher than 2.5UTM group (p < 0.05). Sheep from the 2.5UTM treatment had a significantly lower dry matter intake (1.29 kg/day) than those from the CON and 0.5UTM treatments (1.42 and 1.43 kg/day, p < 0.05), and the feed conversion ratio in the 2.5UTM group was the highest (p < 0.05). Carcass characteristics, including shrunk body weight, empty body weight, hot carcass weight, dress percentage, and the absolute or relative weight (% body weight) of heart, liver, spleen, lung and kidney, were not altered by the treatments (p > 0.05). The muscular pH of 2.5UTM was higher than that of CON (5.68 vs. 5.52, p < 0.05), and shear force in 0.5UTM was lower compared with CON and 2.5UTM (p < 0.05). The anatomical structure lesions in kidneys became more serious with the increasing dietary urea concentrations, with the 2.5UTM animals showing the most severe lesions compared with CON animals. Therefore, supplementary urea as a non‐protein nitrogen source for sheep should not exceed 1.5% of ration having a 50:50 concentrate:roughage ratio to ensure efficacy and safety. 相似文献
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为实现对玉米黄花叶病毒(maize yellow mosaic virus,MaYMV)的血清学检测,丰富该病毒的检测方法,将编码MaYMV运动蛋白(movement protein,MP)的基因连接到原核表达载体pDBHis-MBP上,将构建成功的原核表达质粒转化到大肠杆菌Escherichia coli中诱导表达融合蛋白,将纯化后的融合蛋白对新西兰大白兔Oryctolagus cuniculus进行免疫并制备MaYMV MP多克隆抗血清,并采用Western blot对抗血清的效价、灵敏度和特异性进行检测。结果显示,利用成功构建的原核表达载体经诱导表达获得分子量大小约为62 kD的融合蛋白,纯化后对新西兰大白兔进行免疫获得MaYMV MP抗血清,该抗血清的效价为1∶128 000,灵敏度为1∶32,且该抗血清能够特异性地检测到本氏烟Nicotiana benthamiana中瞬时表达的MaYMV MP,而不与马铃薯卷叶病毒属Polerovirus及黄症病毒属Luteovirus的其他病毒发生血清学交叉反应,证明该抗血清具有良好的特异性。表明本研究制备的MaYMV MP抗血清能特异性... 相似文献
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2021年,沂南县推进动物疫病强制免疫“先打后补”工作,依托“鲁牧云”信息平台,通过强化组织领导,加强政策宣贯,强化人员培训,放开强免疫苗经营渠道,提供抗体检测无偿服务等措施,提升了养殖场户“先打后补”的积极性、自主性、灵活性,强化了养殖场户动物防疫主体责任,满足了养殖场户疫苗多样化需求。但由于 “先打后补”补助金额少、社会化服务不规范、基层动物防疫体系弱化、缺少配套工作经费等原因,部分养殖场户实施“先打后补”的积极性不高。建议通过规范社会化服务组织,强化培训水平,提高补助标准,强化三级(县乡村)基础设施建设,升级“鲁牧云”等措施,确保“先打后补”政策惠及更多养殖场户。 相似文献