H5N1 亚型禽流感病毒NS1的克隆和原核表达

利用RT-PCR技术扩增了一株H5N1亚型禽流感病毒(AIV)的NS1基因,克隆到pGEM T-easy载体上,经序列测定和分析正确后,将该基因插入到pET-32a载体中构建原核表达载体pET-NS1,阳性重组质粒转化BL21感受态细胞,用1mmol/L的IPTG诱导和SDS-PAGE电泳后获得了分子质量约为51ku的NS1融合蛋白。通过Western-blotting发现NS1蛋白可与H5N1亚型AIV单因子血清反应。为建立H5N1亚型AIV野毒株和疫苗株的特异性鉴别方法奠定了基础。     

高铜对雏鸭肝氧化状态及肝细胞凋亡的影响

将360只1日龄天府肉鸭随机分为6组,分别以对照日粮（Cu8mg／kg）和高铜日粮（Ⅰ组：Cu100mg／kg;Ⅱ组：Cu200mg／kg;Ⅲ组：Cu400mg／kg;Ⅳ组：Cu600mg／kg;Ⅴ组：Cu800mg／kg）饲喂6周,研究日粮铜水平对雏鸭肝氧化状态及肝细胞凋亡的影响。结果显示,与对照组比较,Ⅳ组和Ⅴ组肝铜锌SOD和谷胱甘肽过氧化物酶活性降低（P〈50．01）,Ⅲ组、Ⅳ组和Ⅴ组羟自由基和丙二醛含量显著升高（P〈0．01）,Ⅰ组和Ⅱ组肝铜锌SOD和谷胱甘肽过氧化物酶活性升高（P〈0．01）。高铜组肝细胞凋亡率随日粮铜水平的升高而增加。表明,日粮铜水平为400mg／kg以上时可引起肝抗氧化功能降低和肝细胞凋亡率升高。     

品种和体重对猪肌肉生长抑制素表达的影响

本文旨在研究猪的体重和品种对其背最长肌的肌肉生长抑制素基因表达的影响,并对猪100kg时的胴体性状与肌肉肌肉生长抑制素基因表达量的相关性进行分析。试验采用荧光定量PCR方法,以β-actin基因为内标,研究不同体重(20、50和100kg)和品种(汉普夏猪和长白×撒坝猪)对猪背最长肌的肌肉生长抑制素基因表达的影响,同时考察试验猪在100kg时的胴体肉质指标。结果表明:①猪背最长肌中肌肉生长抑制素的表达随体重的增加呈上升的趋势(P>0.05);②相同体重条件下长撒猪背最长肌中肌肉生长抑制素表达均显著高于汉普夏猪(P<0.05),其中20kg时达到极显著水平(P<0.01);③肌肉生长抑制素的表达与瘦肉率呈极显著的负相关(P<0.01),与背膘厚则呈极显著的正相关(P<0.01),与滴水损失和肌内脂肪的相关性不显著(P>0.05)。本研究结果表明猪背最长肌的肌肉生长抑制素基因的表达量随体重增加而提高,品种间差异显著,并且肌肉生长抑制素基因的表达与瘦肉率、背膘厚存在显著的相关性。     

黑米发酵乳饮料的研制

以黑米和牛奶为主要原料,研制出集黑米和酸奶的保健功能于一体的新型保健饮料——黑米发酵乳饮料。采用正交试验筛选出最优组合。结果表明,黑米发酵乳饮料的最佳质量配比为：牛奶添加量55%、黑米添加量6%、蔗糖添加量4.5%。制备该黑米乳饮料的最佳发酵工艺条件为：保加利亚乳杆菌和嗜热链球菌混合菌种接种量3.5%、发酵时间5.5 h、温度4 2℃。     

Effect of dietary supplemental nicotinic acid on growth performance,carcass characteristics and meat quality in three genotypes of chicken

The effects of dietary supplemental nicotinic acid (NA) on growth performance, carcass characteristics and meat quality were investigated in three genotypes of chicken. Fast‐growing AA (Arbor Acres) broilers were compared with two genotypes of a slow‐growing local breed, Beijing‐You, that had undergone selection for and against intramuscular fat content respectively (BJY+IMF and BJY?IMF). The treatments were arranged 3 × 4 factorial completely randomized design. Day‐old females (n = 624) were allocated to four treatments with six replicates per treatment and fed diets (basal contained ～25 mg NA/kg) supplemented with 0, 30, 60 and 120 mg NA/kg. A sample of 72 birds from each genotype was slaughtered at market time (8 weeks of age for AA and 16 weeks of age for BJY). The breast muscles of AA broilers were darker, had less redness and yellowness, lower drip loss and higher shear force as compared to the BJY genotypes (p < 0.01). The highest drip loss and the lowest shear force among the three genotypes were apparent in BJY+IMF (p < 0.01). Increasing supplementation from 0 to 60 mg NA/kg tended to increase average daily gain (ADG), average daily feed intake, width of intermuscular fat band, thickness of subcutaneous fat (including skin) and percentage of abdominal fat but, for most variables, values decreased slightly with 120 mg NA/kg. Increasing supplementation to 60 mg NA/kg decreased (quadratic, p < 0.001) drip loss, but it increased at 120 mg NA/kg. The present results indicate that (i) the AA broilers fed corn–soybean meal based‐diets require approximately 60 mg NA/kg to maximize ADG and meat product yield and decrease the drip loss of breast muscle; (ii) the addition of 30 mg NA/kg meets the requirement of BJY genotypes; and (iii) there seems to be no beneficial effect of NA supplementation on chicken meat quality except for limiting the drip loss.     

Vaccination of chickens with a chimeric DNA vaccine encoding Eimeria tenella TA4 and chicken IL-2 induces protective immunity against coccidiosis

A fusion DNA vaccine co-expressed Eimeria tenella TA4 and chicken IL-2 (chIL-2) was constructed and its efficacy against E. tenella challenge was observed. TA4 gene of E. tenella and chIL-2 gene were cloned into expression vector pcDNA3.1 and pcDNA4.0c in different forms, producing vaccines pcDNA3.1-TA4-IL-2, pcDNA3.1-TA4 and pcDNA4.0c-IL-2. The expression of aim genes in vivo was detected by RT-PCR and western blot. Animal experiment was carried out to evaluate the immune efficacy of the vaccines. Results indicated these DNA vaccines were successfully constructed and the antigen genes could be expressed effectively in vivo. The animal experimental results showed that DNA vaccines could obviously alleviate cecal lesions, body weight loss and increase oocyst decrease ratio. The ACI of pcDNA3.0-TA4-IL-2 group was 192, higher than that of pcDNA3.1-TA4 group. The results suggested that TA4 was an effective candidate antigen for vaccine and co-expression of cytokine with antigen was an alternative method to enhance DNA vaccine immunity.     

松辽黑猪胰岛素样生长因子Ⅱ基因PCR-SSCP多态性分析

采用PCR-SSCP技术检测胰岛素样生长因子Ⅱ(IGF-Ⅱ)基因外显子3和外显子4在松辽黑猪中的单核苷酸多态性,同时研究该基因对松辽黑猪部分重要生长、胴体性状的影响。结果表明:3对引物中,只有p3的扩增片段存在多态性。p3的扩增片段在松辽黑猪中检测到AA、AB和BB 3种基因型;测序分析发现BB型与AA型相比在IGF-Ⅱ基因(AY044828)第21585 bp处有G→C突变,松辽黑猪AA、AB和BB基因型频率分别为0.6956、0.2609和0.0435。AA基因型对瘦肉率(P<0.05)、日增重(P<0.05),BB基因型对平均背膘厚(P<0.01)有正遗传效应,对其他性状差异不明显。     

SYBR Green Ⅰ实时荧光PCR检测网状内皮增生症病毒方法的建立

根据禽网状内皮组织增生症病毒(REV)长末端重复序列LTR基因保守区域设计并合成一对引物,建立基于SYBR GreenI模式的实时荧光PCR方法(Real-timePCR)。以常规PCR产物为标准品建立标准曲线,并对方法的特异性、敏感性、可重复性以及再现性、检出率进行评价。结果表明,该方法只从REV阳性样本检出扩增信号,不与其它病原出现交叉反应;熔解温度为86.8±0.5℃,无引物二聚体;扩增产物片段大小为270bp,与预期大小相符,测序结果证实为REV靶序列;在1.01×102～1.01×109拷贝之间呈现良好的线性关系,相关系数为0.999,扩增效率为99.7%,最低可检测101拷贝/反应阳性标准品,比常规PCR敏感103倍;组内变异系数、组间变异系数分别为4.80%～5.72%、0.75%～3.87%;对16例临床疑似病例进行检测,阳性率为81.25%(13/16),随机抽取7份阳性扩增产物进行测序,证实为REV序列。本研究建立的SYBR GreenI实时荧光PCR特异性强、通量高、灵敏度高、检测速度快,为REV的快速检测、分子流行病学调查以及监测REV污染疫苗情况提供新方法。     

退化高寒草甸上高原鼠兔的扩散研究

在高寒草甸上高原鼠兔是必不可少的生态关键种,同时由于密度过高又加剧着高寒草甸的退化.应加强对高原鼠兔种群动态的管理,使其保持适当的密度和适当的时空分布,发挥其关键物种的作用,但不对高寒草甸造成破坏.为此有必要掌握高原鼠兔的扩散规律.通过高原鼠兔的扩散试验得到了以下结果:环境容纳量K和植被高度h有如下关系:K={6.2237h 17.2237(h＜4.8717) 47.5438(h=4.8717) -4.0654h 67.3494(h＞4.8717);高原鼠兔月扩散距离为32.16 m;高原鼠兔对原有栖息地留恋的量α为0.3371.     

强化动物饲养场的规范化管理打造畜禽养殖科学发展示范区

2006年7月,胡锦涛总书记来唐山市视察时,提出了把曹妃甸地区建设成为科学发展示范区的要求。赵勇书记来乐亭考察调研时,为乐亭确定了建设"全国一流的工业强县、全国一流的农业富县、全国一流的海洋经济大县、全国一流的文化名县"的发展目标。建设全国一流的农业富县,畜牧发展至关重要。