转基因技术在畜牧兽医中的发展前景

通过简要叙述转基因动物研究的发展简史、研究现状和存在问题 ,对转基因动物育种、药物生物反应器、组织器官移植 ,以及基因治疗和免疫等前景进行了综述。在此基础上 ,从畜牧兽医角度出发提出了追踪发展趋势的几点思考。     

Aortic to caudal vena cava ratio measurements using abdominal ultrasound are increased in dogs with confirmed systemic hypertension

Chronically sustained systemic hypertension in dogs can damage the kidneys, eye, brain, heart, and vessels. In human medicine, systemic hypertension has been implicated as the most common risk factor for aorta dilation, which can progress to an aneurysm. Abdominal ultrasound has been commonly used to monitor the size of the abdominal aorta in people with systemic hypertension. In this retrospective cross‐sectional abdominal ultrasound study, evaluation of the size of the abdominal aorta relative to the caudal vena cava was performed in 18 control dogs and 128 dogs with confirmed systemic hypertension. Preexisting conditions contributing to systemic hypertension in these dogs were renal disease, hyperadrenocorticism, diabetes mellitus, adrenal tumors, and previous administration of phenylpropanolamine or palladia. The abdominal aorta and caudal vena cava were assessed from longitudinal images cranial to the trifurcation with measurements made from outer border to outer border of the walls, being careful not to compress the caudal vena cava that would alter its size. Our hypothesis was the ratio of the diameter of the abdominal aorta to caudal vena cava would be higher in dogs with systemic hypertension compared to dogs with normal blood pressure. The mean abdominal aorta‐caudal vena cava ratio was 1.028 in control dogs with a normal blood pressure and 1.515 in dogs with systemic hypertension. In dogs with confirmed systemic hypertension, the abdominal aorta was dilated compared to the caudal vena cava in the caudal abdomen. An increase in the abdominal aorta‐caudal vena cava ratio in a dog should raise suspicion for the presence of systemic hypertension and prompt evaluation of blood pressure.     

荷斯坦育肥牛日粮中添加碳酸氢钠的增重效果

荷斯坦育肥牛日粮中添加５０ｇ碳酸氢钠，观察增重效果，试验期５０ｄ。结果表明，试验组牛头均日增重比对照组提高１８．０％，差异显著。     

吡啶羧酸铬对肉鸭后期作用效果初探

选用21日龄樱桃谷鸭36只,采用有重复对照试验,比较饲粮中添加0．2×10－6吡啶羧酸铬对肉鸭生产性能、屠体品质和血液生化指标的影响。结果表明,吡啶羧酸铬对增重、饲料转化率无显著影响,对屠宰率、胸肌率和皮脂率亦无显著影响;但使心重、血清总甘油三酯显著降低,血清总胆固醇、高密度脂蛋白胆固醇显著增加。     

科尔沁地区的垦殖与荒漠化

不合理的开垦是我国北方土地沙质荒漠化的主要原因,北方农牧交错带45%的退化土地属这一类型.垦殖也是过去科尔沁地区沙地几度活化的主导因素.人类历史时期以来,科尔沁地区沙地的活化和稳定、垦殖期和弃耕期的环境特征的变化,再一次证明了这一点.     

Analysis of the mucosal microenvironment: factors determining successful responses to mucosal vaccines

The predominance of IgA antibodies in mucosal sites reflects a combination of high rate IgA isotype switching among precursor cells in induction sites, their selective localisation in mucosal effector tissues and vigorous proliferation of these cells after extravasation. Each of these steps leading to IgA expression at the mucosa is under cytokine control. This paper will address the role of cytokines in induction and expression of IgA responses, the contribution of various precursor cell subsets and their differential responses to cytokine signals and strategies for manipulating cytokine expression. With respect to IgA antibody production in the gut whereas IL-4 and TGF-beta have been implicated in isotype switching of precursor cells to IgA commitment, their subsequent localisation, proliferation and effector activity expression is dependent on IL-5 and IL-6 expression locally. Most IgA plasma cells in the intestine derive from cells of the B2 lineage in the Peyer's patch, but a subpopulation of cells derived from the peritoneal cavity (B1 cells) also contribute to the IgA plasma cell population in the intestinal lamina propria. Whereas IgA+ cells of the B2 lineage are IL-6 dependent but IL-5 independent, B1-derived IgA+ cells are IL-5 dependent and IL-6 independent. On the other hand, cell mediated immune responses in the gut are highly dependent on IFN-gamma production by both Th1 CD4 cells and CD8 cells and in enteric Salmonella infection IFN-gamma production is essential but antibody has little effect on this process.Therapeutic interventions based on the information emerging from these studies will lead to improved vaccination responses and correction of immunodeficiencies especially in young animals.     

乳牛体型性状线性评定数学模型的指导和应用

本文说明了乳牛体型性状线性评定的常规方法,在此基础上推导出了该评定方法的数学模型。该模型的提出,极大地简化了常规评定方法的繁琐计算,值得在乳牛业生产实践中推广使用。     

重庆市水产品质量安全现状及对策

我国是世界上最大的渔业生产国,其养殖产量占全世界养殖产量的2/3。我国也是水产品出口大国,2006年水产品出口量为301.5万吨,出口额93.6亿美元,占农产品出口总额的     

“黄白散”对兔接种RHD疫苗后免疫功能的影响

在注射兔病毒性出血症 (RHD)疫苗后 ,30只兔随机分为 2组 ,试验组兔饲喂含 1 5 %黄白散的饲料。从接种到第 1 80天 ,每组取兔 8只 ,每隔 1 5d采血 1次 ,检测血凝抑制 (HI)抗体 ;在接种前 1天及接种后 5、 1 0、 1 7、 2 4、 31、 41、 5 1d ,每组取兔 1 0只 ,采血检测ANAE+淋巴细胞百分率 ;在 1 80、 2 4 0、 30 0d时 ,每组分别取兔 5只做攻毒保护试验。结果表明 :2组兔HI抗体峰值分别为 7 3log2和 9 8log2 ,差异极显著 (P <0 0 1 ) ;试验组疫苗保护期可延长 60d ;试验组ANAE+率从第 1 0天至 5 1天与对照组比较 ,差异极显著(P<0 0 1 )。所以黄白散可增强兔接种RHD疫苗后的特异性免疫功能 ,增强RHD疫苗的免疫效果。     

Pyruvate kinase is necessary for Brucella abortus full virulence in BALB/c mouse

Brucellosis, caused by a facultative intracellular pathogen Brucella, is one of the most prevalent zoonosis worldwide. Host infection relies on several uncanonical virulence factors. A recent research hotpot is the links between carbon metabolism and bacterial virulence. In this study, we found that a carbon metabolism-related pyruvate kinase (Pyk) encoded by pyk gene (locus tag BAB_RS24320) was associated with Brucella virulence. Determination of bacterial growth curves and resistance to environmental stress factors showed that Pyk plays an important role in B. abortus growth, especially under the conditions of nutrition deprivation, and resistance to oxidative stress. Additionally, cell infection assay showed that Pyk is necessary for B. abortus survival and evading fusion with lysosomes within RAW264.7 cells. Moreover, animal experiments exhibited that the Pyk deletion significantly reduced B. abortus virulence in a mouse infection model. Our results elucidated the role of the Pyk in B. abortus virulence and provided information for further investigation of Brucella virulence associated carbon metabolism.