Efficacy, duration, and onset of immunogenicity of a West Nile virus vaccine, live Flavivirus chimera, in horses with a clinical disease challenge model

REASON FOR PERFORMING STUDY: West Nile virus (WNF) is a Flavivirus responsible for a life-threatening neurological disease in man and horses. Development of improved vaccines against Flavivirus infections is therefore important. OBJECTIVES: To establish that a single immunogenicity dose of live Flavivirus chimera (WN-FV) vaccine protects horses from the disease and it induces a protective immune response, and to determine the duration of the protective immunity. METHODS: Clinical signs were compared between vaccinated (VACC) and control (CTRL) horses after an intrathecal WNV challenge given at 10 or 28 days, or 12 months post vaccination. RESULTS: Challenge of horses in the immunogenicity study at Day 28 post vaccination resulted in severe clinical signs of WNV infection in 10/10 control (CTRL) compared to 1/20 vaccinated (VACC) horses (P<0.01). None of the VACC horses developed viraemia and minimal histopathology was noted. Duration of immunity (DPI) was established at 12 months post vaccination. Eight of 10 CTRL exhibited severe clinical signs of infection compared to 1 of 9 VACC horses (P<0.05). There was a significant reduction in the occurrence of viraemia and histopathology lesion in VACC horses relative to CTRL horses. Horses challenged at Day 10 post vaccination experienced moderate or severe clinical signs of WNV infection in 3/3 CTRL compared to 5/6 VACC horses (P<0.05). CONCLUSIONS: This novel WN-FV chimera vaccine generates a protective immune response to WNV infection in horses that is demonstrated 10 days after a single vaccination and lasts for up to one year. POTENTIAL RELEVANCE: This is the first USDA licensed equine WNV vaccine to utilise a severe challenge model that produces the same WNV disease observed under field conditions to obtain a label claim for prevention of viraemia and aid in the prevention of WNV disease and encephalitis with a duration of immunity of 12 months.     

Dietary supplementation with Acanthopanax senticosus extract enhances gut health in weanling piglets

The present study was conducted to investigate the effects of Acanthopanax senticosus extract (ASE) as a dietary additive on gut health in weanling piglets by examining diarrhea frequency, intestinal microbiota and morphology. A total of 96 Duroc× (Landrace × Yorkshire) piglets weaned at 21 days of age with an average initial body weight (BW) of 5.6 ± 0.4 kg were randomly assigned to 3 treatment groups with 4 duplicates of 8 piglets each. The piglets were fed basal diet to which had been added 0 or 1 g/kg of ASE, or 0.7 g/kg antibiotics, respectively. Fecal consistence was monitored twice daily and the frequency of diarrhea was calculated. On day 21 after the initiation of supplementation, 8 piglets were randomly selected from each treatment group (2 piglets per pen) and slaughtered. The jejunum, ileum, colon and cecum were then excised and fixed in 10% neutral formalin solution to determine villus height and crypt depth, after their contents were collected to determine microbiota. The results showed that dietary supplementation with ASE increased (P < 0.05) the density of bacterial populations that co-migrated with Lactobacillus amylovorus, Lactobacillus salivarius, Bacillus subtilis, and Clostridium lituseburens, but decreased (P < 0.05) those co-migrating with Staphylococcus aureus, Salmonella typhimurium, Ruminococcus forques, and E. coli O157:H7 in the PCR-DGGE profiling analysis when compared with the control group. The villus height of the duodenum, jejunum and ileum increased (P < 0.05) by 14.8, 13.7 and 10.0%, while the crypt depth decreased (P < 0.05) by 17.9, 9.1 and 12.1%, respectively, in response to dietary ASE supplementation. Additionally dietary supplementation with ASE or an antibiotic decreased (P < 0.05) the frequency of diarrhea by 55.6 and 52.2%, respectively, compared with the control group. In conclusion, these findings suggest that dietary supplementation with ASE could regulate the microbiota composition and maintain a normal morphology of gut mucosa in weanling piglets, thereby decreasing diarrhea that resulted from weaning stress.     

太湖鹅体尺测量及屠宰性能测定

对70日龄太湖鹅体尺及屠宰性能进行测定,并对相关参数进行相关性分析。结果表明,太湖鹅平均体斜长、龙骨长、胸深、胸宽、胫长、胫围、髋骨宽、半潜水长、颈长分别为26．23cm、12．03cm、10．31cm、9．94cm、8．42cm、4．38cm、6．01cm、49．08cm、35．85cm,除龙骨长、髋骨宽外,其它体尺指标公母间差异显著;平均屠宰率、全净膛率、半净膛率、胸肌率、腿肌率分别为87．84％、69．66％、78．31％、7．35％、18．74％,半净膛率、胸肌率公母间差异极显著（P〈0．01）,全净膛率公母间差异显著（P〈0．05）;体尺各指标间仅有半潜水长和髋骨宽呈负相关,屠宰性能各指标间存在高等或中等强度相关,胸肌重与胫长呈负相关。     

黄芪多糖对细小病毒感染犬血常规与脂质过氧化的影响及疗效研究

将临床收集确诊的40只细小病毒病犬分为黄芪多糖组和常规治疗组,对黄芪多糖是否具有治疗犬细小病毒病的作用进行试验研究,并以犬血常规变化来检验其疗效。结果表明：细小病毒病以2～5月龄犬发病较多,并以肠炎型为主。犬感染细小病毒后白细胞数、红细胞数、血红蛋白含量、红细胞压积均低于正常值范围。黄芪多糖能够升高病犬白细胞数、红细胞数、血红蛋白含量,除红细胞数外,在治疗第6天均恢复到正常水平。黄芪多糖能够升高病犬血清中SOD的活性,治疗第6天与基础值比较差异极显著（P〈0．01）;同时能够降低病犬血清中MDA的含量,在治疗第6天与基础值比较差异极显著（P〈0．01）,与健康对照组相近。黄芪多糖组治愈率为90％,常规治疗组治愈率为70％。     

粘度对超高温灭菌奶中脂肪球上浮的影响

基于物理反射模型的背反射光检测技术研究不同瓜尔胶添加量对超高温灭菌乳体系粘度及乳脂肪球的稳定性.以0.02%添加量(w/w)的K-卡拉胶作为乳蛋白稳定剂.蔗糖酯SE-15、羟基化改性大豆磷脂及分子蒸馏单甘酯按一定比例进行复配并以0.1%(w/w)进行添加以稳定乳脂肪,在此基础上分别添加0%、0.02%、0.03%、0.04%的瓜尔胶以增加超高温灭菌乳的粘度.分别测定了样品的粘度及顶部脂肪球的迁移动力学并比较4者之间的稳定动力学.实验结果表明,随着瓜尔胶添加量的增加,样品粘度亦随之增加,顶部的脂肪浮油速率呈降低趋势,瓜尔胶添加量为0.03%时样品的稳定性达到最大值.因此,增加粘度可以抑制乳脂肪球上浮速率、增加产品的稳定性.     

高钙牛奶稳定性研究

钙强化后的高钙牛奶可以提供更多利于人体的钙质,研究了制备高钙牛奶时所需要的钙源、乳化剂以及增稠剂,采用正交试验确定了复配稳定剂的成分及用量,并利用粒径分析仪对高钙牛奶稳定性进行了研究.     

序贯疗法治疗圈养黑猩猩支原体肺炎一例

肺炎支原体对于灵长类幼年黑猩猩的感染,与人类幼儿的临床表现和发病规律相似。该病例幼年黑猩猩早期症状偶见咳嗽,听诊肺部有湿性罗音,体温38.3℃。初步诊断为肺炎,用抗病毒药和抗生素头孢克洛治疗无效。随着病程发展,体温进一步升高到39℃以上,几乎无食欲。拍X光片和采血做支原体抗体检测,结果显示支原体感染强阳性。最终使用阿奇霉素采取＂停4喂3＂的序贯疗法治疗,即阿奇霉素输液3d——口服5d——停药4d——口服3d——停药4d——口服3d,其他则对症治疗。动物在治疗第7天时除偶见咳嗽,症状基本消除;治疗20d后,动物恢复健康。需要注意的是,治疗过程中一定要按照序贯疗法坚持用药治疗,防止疾病复发和减小用药的副作用。     

二次制粒加工对断奶仔猪生长性能和血液生化指标的影响

选用360头21日龄断奶仔猪,按制粒工艺、原料预处理不同,设计2因素2水平试验,研究断奶仔猪采食二次制粒颗粒饲料对生长性能和血液生化指标的影响,结果显示:试验全期,采用二次制粒工艺及膨化玉米、膨化豆粕原料的处理4组仔猪,平均日增重和体重最大,生长性能最佳。血清尿素氮测定结果显示:断奶第14 d,处理4和2组的仔猪血清尿素氮显著低于(P<0.05)处理1和3组;断奶第28 d,处理1组仔猪血清尿素氮显著高于其他三个处理组。血清皮质醇测定结果显示:断奶第14 d,处理4组仔猪血清皮质醇显著低于其他三组。本试验证明,在选择膨化玉米与膨化豆粕优质饲料原料的基础上,采用二次制粒工艺,尤其先将鱼粉与膨化玉米、膨化豆粕进行第一次高温制粒,对降低仔猪断奶应激,改善生长性能有良好的效果。     

奶牛TMR饲料的研究进展

介绍了全混合日粮的概念,指出了使用全混合日粮的必要性;并对全混合日粮在奶牛生产中的应用进行了论述,提出全混合日粮是奶牛集约化养殖的必然趋势。     

气相色谱/质谱法测定饲料中三唑仑的含量

本实验建立了检测饲料中三唑仑的气相色谱/质谱法。样品经有机溶剂提取,阳离子固相萃取小柱净化后注入气相色谱质谱仪进行测定,并且经质谱确证。结果表明,三唑仑在0.1～5.0μg/mL范围内具有良好的线性关系,方法的回收率、精密度较高。