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为了改良天津地区养殖黄颡鱼种质,提高经济和生态效益,本研究于2019年引进杂交黄颡鱼新品种‘黄优1号’,采用性状比较的方法,系统研究了试验鱼的生长、抗病和产氮、磷情况。结果表明:杂交黄颡鱼幼鱼生长速度、增重率显著高于普通黄颡鱼(P<0.05),饵料系数低于普通黄颡鱼,但差异不明显(P>0.05);杂交黄颡鱼的主要死亡病因为体表溃烂和烂鳃,体表溃烂发病情况与普通黄颡鱼无明显差别(P>0.05),烂鳃发病情况明显重于普通黄颡鱼(P<0.05),而其他疾病发病情况明显小于普通黄颡鱼(P<0.05),试验总成活率显著高于普通黄颡鱼;实验鱼体重增加1 kg,杂交黄颡鱼实验组尾水中氨氮、亚硝酸盐、总磷的增量均显著低于普通黄颡鱼(P<0.05),总氮的增量虽然也小于普通黄颡鱼实验组,但比较结果差异不显著(P>0.05)。因此,本研究认为杂交黄颡鱼‘黄优1号’的生长、抗病和单位增重产氮、磷量等性能较普通黄颡鱼优良,适合在天津地区推广养殖。 相似文献
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Giovenale Moirano Lorenzo Richiardi Mattia Calzolari Franco Merletti Milena Maule 《Zoonoses and public health》2020,67(1):54-61
In Italy, the first human case of West Nile Virus (WNV) infection was reported in 2008 and, since then, the number of cases has been steadily increasing. In this study, we describe the temporal and spatial pattern of WNV infection risk among humans in Italy, focusing on the human cases of West Nile Neuro‐invasive Disease (WNND) observed between 2008 and 2017. Incidence rates are estimated for each year and province under study. The incidence temporal trend is estimated using Poisson regression, and a spatio‐temporal cluster detection analysis is performed to detect high‐risk areas. In total, 231 WNND cases were notified in Italy between 2008 and 2017. The annual incidence rates increased during the study period (annual percentage change: 11.7%; 95%CI: ?0.9%; 26.1%). A geographical spread of the disease was observed during the study period throughout Northern Italy, with an increasing number of affected provinces. Provinces close to the Po River (the main river in the north of Italy) and the Oristano province (in the Sardinia Island) experienced the highest incidence rates during the study period. Our study shows a gradual, but rapid spread of WNND across Northern Italy from east to west and suggests the hypothesis that provinces close to Po River might present ecological and climatic conditions favourable to the virus circulation. 相似文献
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非洲猪瘟在我国流行已有两年多的时间,尽管很多科研团队都在致力于非洲猪瘟疫苗的研发,但尚未有治疗措施和有效的疫苗来控制该病。因此现阶段“生物安全”是控制非洲猪瘟最为有效,也是唯一的方法。文章总结出目前规模化猪场常见的感染风险有“人员流动、物品流动、车辆流动、水源流动、猪群流动”(即“五流”),并提出严格控制“五流”的生物安全防控措施(即“五流”生物安全防控),以减少外界病原与猪只的接触,稀释病原浓度,降低病原载量,最大程度地降低规模化养猪场感染疾病的风险。为当前规模化猪场建立有效的生物安全措施提供参考。 相似文献
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观赏植物种类繁多,在这些植物的育种、销售及栽培过程中,与植物病害相关的各种病原物也被广泛传播。因此,培育抗病品种一直是园艺育种工作者的重要目标性状之一。在粮食作物中,抗病育种方面已经投入了很大的人力物力,新的生物技术不断被用于作物新品种的培育。但对于观赏植物而言,这些新技术应用范围还极为有限。本综述对园艺植物抗病育种现状进行了总结,并对育种前景进行了预测。 相似文献
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Leptospirosis is a re-emerging and widespread zoonosis, worldwide distributed, due to a wide variety of wild and domestic animal species able to act as natural or accidental hosts. During last years, in Europe, as in Italy, wild boar (Sus scrofa) population is increased. This animal represents a reservoir for different etiological agents, such as Leptospira. The aim of this investigation was to evaluate the prevalence of Leptospira spp. in wild boar hunted in Liguria region (Italy) during two-year hunting seasons. From 611 hunted wild boar, kidneys were collected. DNA was extracted from each organ and different targets were used to detect pathogenic (lipL32 gene), intermediate (16S rRNA gene) and saprophytic (23S rRNA gene) Leptospira by Taqman-based RealTime-PCR assays. Overall, kidneys were sampled from 282 adults, 155 sub-adults and 174 young wild boar (in total 314 males and 298 females). By RealTime PCR 77 kidneys were positive and, among these, 74 resulted positive for pathogenic (96.10%) and 3 (3.90%) for intermediate Leptospira. No significant differences in pathogenic Leptospira infection ratio were detected between male (11.50%) and female (12.75%). Only 13 sub-adult animals (8.39%) resulted infected by pathogenic Leptospira; 23 young animals (13.22%) and 38 adult animals (13.47%) were positive. The results of this study confirmed the importance of wild boar in the epidemiology of leptospirosis, which is able to infect other animal species (domestic and wild) including humans. Rarely, intermediate Leptospira could be able to infect wild boar with a renal localization that can contribute to their shedding and circulation. 相似文献
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