产房内仔猪腹泻的原因及防治措施

仔猪腹泻是目前规模化养猪生产中最严重的仔猪疾病之一.产房内仔猪发生腹泻后,轻者可使患病仔猪体质下降和免疫功能减退从而导致其对其他疾病的抵抗力减弱,严重者可引起仔猪死亡,给养猪生产造成严重经济损失.     

Anatid herpesvirus 1 CH virulent strain induces syncytium and apoptosis in duck embryo fibroblast cultures

Anatid herpesvirus 1 (AHV-1) CH virulent strain was first isolated from an infected duck and it was found that this virus strain could induce cytopathic effect (CPE) in duck embryo fibroblast (DEF). Following AHV-1 infection, DEF showed morphological changes such as cell rounding, improved refractivity and detachment from the culture surface. However, its pathological characteristics were not adequately known. Related studies were performed and the results showed that syncytium formation could be observed as the other type of CPE in AHV-1 infection. Hematoxylin-eosin staining and 4’, 6-diamidino-2-phenylindole (DAPI) staining of infected DEF were each used to visualize the shape and distribution of chromatin within nuclei and nuclear fragmentation was observed. Chromatin condensation and margination, as well as formation of apoptotic bodies were observed by transmission electron microscopy (TEM). DNA ladder formation was detected in AHV-1 infected cells and apoptosis of the infected DEF was also detected by flow cytometry analysis of Annexin V-FITC/PI staining method. Therefore, it was suggested that AHV-1 virulent strain can induce syncytium and apoptosis in DEF. Syncytium formation and apoptosis observed in this study may contribute to the elucidation of AHV-1 pathogenesis.     

Phospholipase A<Subscript>1</Subscript> activity of crude enzyme extracted from the ovaries of skipjack tuna

The phospholipid class composition, fatty acid composition and phospholipase A₁ (PLA₁) activity from the ovaries of skipjack tuna were compared with those of six other species of marine fish. In the skipjack ovaries, the lysophosphatidylcholine (LPC) proportion for the phospholipid, the docosahexaenoic acid (DHA) percentage for the total fatty acids of the phospholipids and the PLA₁ activity of the crude enzyme were the highest among those of the seven species. The optimum pH and temperature for the PLA₁ activity of the crude enzyme from the skipjack ovaries were in the range of pH 6–7 and 20–30°C, respectively, and calcium ions were not required. As a substrate, phosphatidylcholine was more easily hydrolyzed than phosphatidylethanolamine by this enzyme, and the plasmalogen-type phospholipid was much lower than the acyl-type phospholipid. After a 6-h hydrolysis reaction of the purified phospholipid extracted from the mixed ovaries of skipjack and yellowfin tuna by this enzyme, the LPC ratio of the phospholipid increased from 20 to 72.6% and the percentage of DHA for the total fatty acids of the phospholipid also increased. Thus, skipjack ovaries might possibly be used as a source of PLA₁.     

多重PCR诊断猪细小病毒、伪狂犬病毒和圆环病毒Ⅱ型方法的建立和应用

根据GenBank中已发表的猪细小病毒(PPV)、猪伪狂犬病毒(PRV)和猪圆环病毒Ⅱ型(PCV2)等3种病毒基因序列,对各病毒基因区进行同源性分析,确定PPV VP2、PRV gB、PCV2 ORF1基因的保守区为各病毒的诊断靶序列.在建立各病毒单重PCR技术的基础上,优化多重PCR反应条件,建立了三种病毒的多重PCR技术.用78份临床病料对本研究多重PCR技术和单重PCR技术进行对比验证,结果显示,总符合率为97.4%以上.该方法特异性强、敏感性高,为PPV、PRV和PCV2临床诊断和流行病学调查等研究提供了新手段.     

水库不投饵网箱无公害养殖技术

2006年南阳市不投饵网箱养鱼发展到6万箱,是全国最大规模的淡水不投饵网箱养鱼基地。丹江口水库(河南境内)和鸭河口水库两座大型水库共有水面约70万亩,从2002年1月至2006年12月连续进行不投饵网箱养殖鲢鳙鱼试验,经过逐步实施严格的养殖生产技术和质量控制措施,所生产的水产品质量安全、无公害,目前两座水库均通过了国家农业部无公害水产品产地认定和产品质量认证。现将养殖技术总结如下:     

添加剂对番茄茎秆好氧堆肥发酵过程及氮素损失的影响

为研究减少在番茄茎秆好氧堆肥过程中氮素损失的途径,提高堆肥品质,以粉碎的番茄茎秆为原料,按物料干重分别加入5%的腐殖酸(T1)、氯化钙(T2)和过磷酸钙(T3),同时以不进行任何添加的堆体作为对照(CK),进行45 d的好氧堆肥试验。结果表明：3种添加剂均可降低堆肥过程中的氮素损失,同时减少了NH₃的挥发量;堆肥结束时,CK、T1、T2和T3处理的氮素损失率分别为18.04%、15.00%、12.65%和14.05%,累计NH₃挥发量为CK(1 648.11 mg/kg)>T1(1 330.35 mg/kg)>T3(995.35 mg/kg)>T2(528.11 mg/kg)。其中,添加氯化钙的处理保氮效果最好,与对照相比,氮素损失率低至12.65%,NH₃挥发量减少67.96%;各处理高温期均≥3 d,发芽指数≥80%,表明堆体已经腐熟,无植物毒性。综上,番茄茎秆好氧堆肥中添加氯化钙,对于减少堆肥过程中的氮素损失较为理想。本研究可为番茄茎秆好氧堆肥保氮工艺优化提供理论依据。     

山葡萄‘双红’、‘双优’在戈壁滩上栽培的表现

报道我国西部栽培的‘双红’和‘双优’两个山葡萄品种不埋土能正常越冬,调查、测定和分析这两个山葡萄品种在冬季寒冷、冬春又极干旱的西部戈壁滩上栽培的生产表现。两个山葡萄品种根系耐低温能力比欧亚种酿酒葡萄品种强,枝条保水能力更强,因此,在干旱荒漠的戈壁石砾地上不埋土能安全越冬和抗御春日多风和干旱。一年生枝条长势好,花芽能正常形成,但在开花季节花序干枯和脱落现象严重。‘双红’、‘双优’山葡萄表现生产性能差、果穗少、果穗小、穗重轻、果粒小,故产量低,仅为原产地的1／3,但其品质好,可溶性固形物高出3．9～4．6个百分点。为使‘双红’、‘双优’在河西戈壁滩上栽培,既不埋土又有较高的产量,提出一些解决措施。     

农用柴油发动机噪声污染分析

柴油发动机广泛应用于各类农业机械中,由其带来的噪声污染也日益严重.为研究柴油机的整机噪声,利用声强测试技术中的p-p法,对某型农用六缸柴油发动机进行实测.通过对发动机各包络面上声强分布和声功率测试结果的分析,确定了其噪声源的位置、声功率的大小、主要噪声频率及整机辐射强度,为控制柴油发动机噪声污染提供了理论依据.