鸡胚发育过程中垂体促乳素的表达及其细胞的发育

利用免疫荧光标记方法研究了鸡胚发育过程中垂体促乳素(PRL)细胞的发生。结果表明，在鸡胚发育的第14.5天可观察到有少量PRL免疫荧光阳性细胞散在分布于腺垂体前叶。随着胚龄的增加，垂体PRL细胞的体积逐渐增大。细胞直径从第14.5天的6.83μm增加到第20.5天的11.24μm，胞核直径从4.27μm增加到5.99μm。PRL细胞占腺垂体细胞总数的百分比在胚胎发育的第14.5天为0.86％，第20.5天增加到18.85％，并且分布于整个腺垂体前叶。细胞多呈索状排列或团状分布。研究结果表明。鸡胚垂体催乳素细胞的增殖、分化和对PRL的分泌功能主要发生和建立于胚胎发育后期。     

大黄鱼冰鲜杂鱼饲料中细菌多样性研究

为研究大黄鱼（Larimichthys crocea）冰鲜杂鱼饲料中细菌的多样性,用细菌通用引物构建了细菌16S rRNA基因克隆文库。从文库中随机挑选125个克隆子进行限制性片段长度多态性（ RFLP）分析,得到82个不同的RFLP 带型。对部分代表性克隆子进行测序,得到23条有效序列。序列同源性分析和系统进化分析结果表明,大黄鱼冰鲜杂鱼饲料中细菌主要分为3大类群,其中γ-变形菌纲（γ-Proteobacteria）细菌占据明显地优势地位,约占所分析克隆子数的84.4％;其次是黄杆菌纲（Flavobacteria）细菌,约占10.9％;还有少量的梭杆菌纲（Fusobac-teria）细菌,约占4.7％。γ-变形菌纲细菌中以嗜冷杆菌（Psychrobacter sp.）最多,其次是发光杆菌（Photobacteri-um）。     

山药酸奶工艺的研制

以新鲜牛奶为原料,加入熟化后的山药汁经处理后通过正交试验,再添加山药果粒加工而研制出一种气味浓郁、口感爽滑、酸甜可口,集酸奶和山药的营养保健于一体的新型发酵饮料.     

我国生猪生产的波动性研究

本文针对生猪产量数据存在的问题,对肉类市场放开至第一次农业普查期间的生产数据进行了调整,在此基础上运用趋势分解法描述了改革开放后我国生猪生产的波动情况,进而对历史数据所描述的波动特征表示置疑,认为我国生猪生产存在明显的周期性,最后提出当前我国生猪生产急需采取的一些必要措施,以建立生猪供给安全长效机制。     

Selection and Evaluation of Indexes Commonly Used to Determine Contamination with T-2 Toxin in Pacific White Shrimp Litopenaeus vannamei by the Grey Relational Method

Abstract

The objectives of the present study were to evaluate the effects of different concentrations of the mycotoxin T-2 toxin in feed on muscle performance in the Pacific white shrimp Litopenaeus vannamei, evaluate indexes of physiological variables that indicate T-2 toxin contamination in the shrimp using the grey relational method, and determine the dose–response relationships between T-2 toxin and the indexes. Of the 6 physical, 7 biochemical, and 17 nutritional indexes examined, the values of the grey relational coefficients were highest for the hepatopancreas: body weight ratio (HBR), alanine aminotransferase (ALT) activity, and serine (SER) content (0.83, 0.68, and 0.82, respectively). Therefore, the HBR, ALT activity, and SER content were selected as appropriate indexes for contamination of Pacific white shrimp muscle with T-2 toxin. Based on their dose–response relationship curves, mean effective doses of 1.45, 1.69, and 1.33 mg of T-2 toxin/kg of feed were obtained for the HBR, ALT activity, and SER content, respectively. These results offer technical reference points for the evaluation and control of T-2 toxin in shrimp feed.

Received April 28, 2016 accepted April 9, 2017 Published online July 26, 2017     

Mapping B-cell linear epitopes of NS3 protein of bovine viral diarrhea virus

Bovine viral diarrhea virus (BVDV) is a member of the genus Pestivirus within the family Flaviviridae. NS3 is one of the immunodominance regions of the BVDV viral proteins. To identify the potential B-cell linear antigenic epitopes within BVDV NS3 region, serial overlapping truncations covering the whole region were expressed and purified, and screened by multistep of Western-blot. We found (₁VCKKITEHERCHVNI₁₅), (₂₀AFFGVMPRGTTPRAPVR₃₆), (₄₆RRGLETGWAYTHQGGI₆₁), (₂₈₁EGDMATGITYASYGYFC₂₉₇), (₄₂₆YSGEDPANLRVVTSQSPYVVVATNAIESGV₄₅₅) and (₄₈₁FIVTGLKRMAVTVGEQA₄₉₇) can be recognized by the BVDV infected bovine serum. These proteins have been confirmed by indirect enzyme-linked immunosorbent assay (I-ELISA). The results of this study might open new perspectives on the structure and antibody–antigen reaction of the non-structural proteins and may aid in the clinical application as well.     

The 2009 pandemic (H1N1) viruses isolated from pigs show enhanced pathogenicity in mice

Since the emergence of the 2009 pandemic (H1N1) virus (2009/H1N1) in April 2009, cases of transmission from humans to pigs have been reported frequently. In our previous studies, four 2009/H1N1 variants were isolated from pigs. To better understand the phenotypic differences of the pig isolates compared with the human isolate, in this study mice were inoculated intranasally with different 2009/H1N1 viruses, and monitored for morbidity, mortality, and viral replication, cytokine production and pathological changes in the lungs. The results show that all isolates show effective replication in lungs, but varying in their ability to cause morbidity. In particular, the strains of A/swine/Nanchang/3/2010 (H1N1) and A/swine/Nanchang/F9/2010 (H1N1) show the greatest virulence with a persisting replication in lungs and high lethality for mice, compared with the human isolate A/Liaoning /14/2009 (H1N1), which shows low virulence in mice. Furthermore, the lethal strains could induce more severe lung pathological changes and higher production of cytokines than that of other strains at an early stage. Amino acid sequence analysis illustrates prominent differences in viral surface glycoproteins and polymerase subunits between pig isolates and human strains that might correlate with their phenotypic differences. These studies demonstrate that the 2009/H1N1 pig isolates exhibit heterogeneous infectivity and pathogencity in mice, and some strains possess an enhanced pathogenicity compared with the human isolate.     

土壤—作物资源多目标优化配置分析

本文提出一种多目标土壤—作物资源优化配置的数量化分析方法,并对江苏省东海县土壤资源进行优化配置。结果表明：白浆土、岭砂土、包浆土、紫砂土等岗岭低产土应稳定小麦面积,压缩玉米面积,优先发展春花生、大豆、水稻;洼地砂姜黑土、水稻土应发展小麦—水稻和小麦—玉米两熟制,并适时换茬;介于上述两类土壤间的潮棕壤亚类和潮土类应大力发展小麦—花生两熟制。     

成年高原藏羊精索血管分布的形态学研究

对13头成年高原藏羊的睾丸采用血管铸型、常规石蜡切片结合扫描电镜观察,研究在高寒低氧环境中,藏羊睾丸精索血管分布的形态学特点.结果表明藏羊精索睾丸动脉螺旋卷曲并发出分支分布到附睾,睾丸动脉表面覆盖蔓状静脉丛;回流睾丸血液的集合静脉纵向走行形成静脉网包裹在睾丸表面,汇集至睾丸门附近形成特殊的“束袋口”构筑,紧缩回笼汇集形成蔓状静脉丛;精索部动脉和静脉各自形成三级分枝,小静脉及静脉毛细血管网与动脉滋养血管小分支之间形成广泛的吻合支.藏羊精索部血管形成了特殊的高原适应性微形态结构.     

不同饲养密度对地面平养蛋鸡福利状况和生产性能的影响

试验旨在通过研究地面平养模式下不同饲养密度对蛋鸡行为、外观、血液应激指标及生产性能的影响,筛选保证蛋鸡福利状况及生产性能的最大饲养密度,为我国推广地面平养模式蛋鸡福利养殖奠定理论基础。将780只苏禽绿壳蛋鸡按舍内密度分为四组,其中地面平养分为低密度组(6只/m^2)、中密度组(8只/m^2)、高密度组(10只/m^2),笼养组为对照组,每组3个重复。试验期为18~27周龄,蛋鸡行为学数据均采用视频录像收集,在27周龄末进行翅静脉采血和福利外观评价,统计分析24~27周龄生产性能。结果显示:笼养蛋鸡的产蛋率,攻击、刻板等非福利行为均显著高于平养组(P<0.05),脚垫损伤、羽毛评分、应激激素浓度(CORT、ACTH)显著低于平养组(P<0.05)。地面平养各组间,高密度组蛋鸡料蛋比显著高于低、中密度组(P<0.05);低、中密度组蛋鸡行走和休息时间比例均显著高于高密度组(P<0.05);低密度组蛋鸡啄羽行为显著低于高密度组(P<0.05),但与中密度组差异不显著(P>0.05);低、中密度组蛋鸡脚垫损伤、背羽损伤显著低于高密度组(P<0.05);高密度组蛋鸡血清中CORT和ACTH浓度显著低于低、中密度组(P<0.05)。由此可见,平养蛋鸡比笼养蛋鸡行为表现更积极,羽毛覆盖度更好,但应激水平和足部损伤较高、生产性能较低;在试验场地模式下,推荐8只/m2为最佳饲养密度。