洞庭湖湿地虉草替代大白菜对肉兔生产性能的影响

试验采用48只青年期(40～45日龄、体重约800 g)发育良好、健康无病的新西兰肉兔,随机分为4组:1组饲喂基础日粮,2～4组分别用占日粮5%,15%和25%的虉草Phalaris arundinacea代替日粮中等量的大白菜,试验期35 d.试验结果表明:各组间兔的日增重、屠宰率、料肉比等指标差异均不显著(P＞0.05),可见虉草代替大白菜不影响兔的生长,以15%的替代量的3组增重效果最佳,经济效益最好.     

微量元素氨基酸螯合物在养鸡生产中的应用

微量元素氨基酸螯合物是微量元素添加剂更新换代的优良产品,应用前景广阔。文章概述了微量元素氨基酸螯合物的营养特性、代谢机制、添加方式及其在养鸡生产中的应用。     

几种绵羊常用粗饲料GI的测定及其代谢能模型化研究

在测定5类9种粗饲料及3个混合粗饲料的常规成分基础上,实测了它们的粗饲料分级指数(GI):大青山草地早熟禾3.4758、沙打旺3.3731、苜蓿1.7202、混粗C21.1797、青干草1.1029、混粗C10.7852、羊草0.5684、玉米青贮0.4152、玉米秸0.1985、谷草0.1728、混粗D0.0805、苏丹草0.0687,并就GI与饲料相对值(RFV)对粗饲料品质的分级进行了比较,表明GI要优于RFV,同时证明:GI还可以用于混合粗饲料的优化与牧草刈割期的确定。研究并建立了预测粗饲料代谢能(ME)的模型:ME(MJ/kg)=-11.7492 0.5959IVDM(D%)-0.0044[IVDM(D%)]2,其中IVDMD为体外干物质消化率。     

Differential gene expression of Eph‐ephrin A1 and LEPR‐LEP with high or low number of embryos in pigs during implantation

The objective of this study was to ascertain whether mRNA and protein expressions of implantation‐related genes (erythropoietin‐producing hepatocellular receptor–ligand A1, Eph‐ephrin A1 and leptin receptor–leptin, LEPR‐LEP) differed between pigs with high and low number of embryos, and whether these differences in gene expression might affect embryo implantation. Experimental pig groups (n = 24) for high and low number of embryos were prepared by altering the number of eggs ovulated in pre‐pubertal gilts treated with 1.5 × (High) or 1.0 × (Low) PG600 ([400 IU PMSG + 200 IU hCG]/dose, AKZO‐NOBEL). Gilts expressing oestrus were artificially inseminated twice and maintained in breeding and gestation until the reproductive tract was collected on day 22 of pregnancy. At slaughter, the reproductive tracts from each pregnant gilt from each treatment were immediately processed to collect samples for RNA and protein analysis. Within each gilt, three conceptus points were sampled, one from each horn and then a random conceptus within the tract. At each conceptus point, endometrial attachment site, chorion–allantois and embryo were collected and immediately frozen in liquid nitrogen. Number of corpus luteum (CL) (35.4 vs. 12.6) and total embryo number (18.8 vs. 10.2) were greater in the high‐embryo compared to the low‐embryo group, respectively (p < .05). Real‐time qPCR results showed that Eph‐ephrin A1 mRNA expression was less in the high‐embryo (p < .05) compared to the low‐embryo group. In addition, Western blotting analysis indicated that Eph‐ephrin A1 and LEP protein expression at endometrial attachment site in high‐embryo was less (p < .05) compared to low‐embryo group. It was also noted that mRNA expression of Eph‐ephrin A1 and LEPR‐LEP was greater in pregnant than non‐pregnant gilts (p < .05). Moreover, mRNA expression of Eph‐ephrin A1 (p < .05) and LEPR‐LEP was greatest at endometrial attachment site among all three tissues. There was a positive correlation between expressions of Eph‐ephrin A1, LEPR‐LEP and embryo length with the correlation coefficient 0.31–0.59. For Eph‐ephrin A1, the highest correlation coefficient appeared between Eph A1 expression and normal embryo number, between ephrin A1 expression and embryo length. For LEPR‐LEP, the highest correlation coefficient appeared between LEPR‐LEP expression and ovary weight (0.79 for both, p < .05), followed by embryo length and weight. The results of this study suggest that low expression of Eph‐ephrin A1 and LEPR‐LEP is somehow related to increased embryo number during implantation and that endometrial attachment site might be the main target tissue of these gene products. Yet, the increased expression of Eph‐ephrin A1 and LEPR‐LEP appeared associated with increased embryo growth (length and weight) and ovary weight, Eph‐ephrin A1 and LEPR‐LEP might play roles in the regulation of embryo implantation in pigs.     

紫茎泽兰对萨能奶山羊血常规及重要脏器病理学的影响

紫茎泽兰(Eupatorium adenophorum)在中国作为入侵物种,可造成食草动物中毒死亡,并给畜牧业带巨大的损失。为研究反刍动物采食紫茎泽兰后的中毒机理,本研究探讨了日粮中添加不同剂量的紫茎泽兰对萨能奶山羊(Saanen goat)血常规及肝、脾、肾的病理学影响。选择16只5~6月龄健康萨能奶山羊,随机分成对照组(日粮中未添加紫茎泽兰)和试验Ⅰ、Ⅱ、Ⅲ组(日粮配比中分别添加紫茎泽兰40%、60%和80%),每组4只。试验Ⅰ、Ⅱ、Ⅲ组分别饲喂含40%、60%和80%紫茎泽兰的混合日粮3个月,每两周检测一次血常规,试验末屠宰奶山羊,并观察其肝、肾、脾的病理学变化。结果表明,与对照组相比,各试验组血液中的白细胞(white blood cell,)和中性粒细胞(neutrophil,NEUT)均显著升高(P0.05),试验后期极显著高于对照组(P0.01);而各试验组血液中淋巴细胞(lymphocyte,LY)与血红蛋白(hemoglobin,HGB)均呈下降趋势,试验后期均极显著低于对照组(P0.01)。肝和脾肿大,肝组织出现淤血,肝细胞发生水泡变性及脂肪变性等,肾组织伴有出血、坏死、颗粒变性及水泡样变性的现象。因此,本研究结果说明紫茎泽兰对萨能奶山羊血液指标有显著影响,且长期摄入紫茎泽兰可引起动物肝、肾、脾等主要实质器官不同程度的损伤。     

社会网络方法在兽医流行病学中的应用

为揭示社会网络方法在兽医流行病学领域的发展趋势,通过对国内外文献进行检索分析,以"社会网络分析或社会网络""兽医学或动物"为关键词,在CNKI和PubMed数据库中检索并整理2000—2017年的相关文献,随后运用内容分析法,从研究主体、研究病种、数据获取、软件应用、指标计算以及数据验证等多个角度,比较国内外社会网络方法在兽医流行病学中的应用。结果显示:社会网络分析起源于20世纪30年代,2005年才被应用到兽医流行病学领域,此后研究热度不断上升,尤其在美国、英国和澳大利亚等国家,且在其带领下逐渐形成了不同国家和学科间的交流体系;研究者更倾向于有重大影响力的动物卫生事件研究;兽医流行病网络研究中可利用的数据和质量有限,因而限制了社会网络方法在兽医流行病学领域的发展;社会网络分析中,使用R软件的占比最高,其次为UCINET软件;社会网络方法虽在兽医流行病学领域起步晚,但研究深度已完成了从理论研究到网络分析及应用的过渡;研究指标仍局限在通过利用网络基本概念和测度来研究个体网络,缺乏对整体网络动态模式的研究。研究结果提示,社会网络方法在兽医流行病学领域的应用还很有限,研究者需要通过加强理论与实际的结合,构建网络时空模型,控制关键点,从而为疫病监测和防控做准备。     

Research Progress on Bacterial Resistance in Environment

Antibiotic resistance genes have become a recognized environmental pollutant, threatening the ecological safety and human health. The application of antibiotics in the clinical and animals breeding, making the environmental microorganisms living with the impact of the residue of antibiotics and elements of resistance genetic and leading to antibiotic resistant bacteria to gain a competitive advantage and destroyed the stability of ecosystem. In this paper, we expounded the concept of resistance gene transmission by the view of macro environment. Through analyzing the mechanism of resistance development,environmental pollution caused by drug resistance and the impact of environmental microorganism for drug resistance, we clarified the key role of the environment in the development of the characteristics of bacterial resistance and analysis environmental resistance.Such as the ecological diversity of flora, the types and the spread of resistant bacteria, the residues of antibiotics and the transmission of the resistance genes.     

鳢肠对棉铃虫生长发育的影响

通过饲料混毒法测定鳢肠对棉铃虫生长发育的影响。结果表明,随饲料中鳢肠比例的加大和棉铃虫幼虫取食时间的延长,鳢肠对棉铃虫幼虫的生长发育具有明显的抑制作用。幼虫取食鳢肠比例高的饲料后,棉铃虫蛹质量显著降低,但羽化率和单雌日均产卵量与对照处理差异不显著;给棉铃虫幼虫饲喂鳢肠明显延长了幼虫和成虫历期,但对蛹历期的影响较小。