鸡蛋中兽药残留形成过程及防控措施分析

应用药物治疗产蛋期蛋鸡的感染性疾病时,常会引发鸡蛋中的兽药残留问题。这些残留的兽药会直接危害消费者的生命健康（如过敏反应等）,此外,还会诱导人体内的细菌产生耐药性,造成人类感染性疾病的治疗困难。本文结合鸡蛋的形成过程,对鸡蛋中兽药残留的特点、形成过程及防控措施进行了详细分析。     

鸡蛋中兽药残留的危害、检测方法与防控措施

鸡蛋中的兽药残留主要是指抗生素类药物、合成抗菌药物、抗球虫药物以及农药等,以上药物都是蛋鸡饲养过程中的常用药,因其价格低廉、广谱抗菌、抗菌效果良好等优点被广泛应用,容易造成兽药残留,对人体健康产生直接危害。加之细菌容易对这些药物产生耐药性,可经由食物链导致人类感染耐药菌株,尤其是鸡蛋中兽药残留会造成人体内敏感细菌形成耐药性,这已经被全世界关注。现概述鸡蛋中兽药残留的危害、检测方法及防控措施。     

蛋鸡大肠杆菌病的防控要点

大肠杆菌是环境寄生菌,一般多不致病,但经常与其他致病微生物混合感染,使得病情复杂。在养鸡过程中经常大量、长期地使用多种抗生素治疗大肠杆菌病,使得大肠杆菌产生严重的、多重的耐药性。同时,鸡蛋中的药物残留也直接威胁着人类的健康,具有"三致"作用。所以蛋鸡大肠杆菌的防控具有重要的公共卫生安全意义。本文从侵袭蛋鸡的大肠杆菌血清型、大肠杆菌的理化特性、致病过程、临床症状、防控等方面分析了蛋鸡大肠杆菌病防控要点。     

蛋鸡场大肠杆菌病防治效果分析

蛋鸡大肠杆菌病的治疗,主要依赖抗生素或合成抗菌药物,但是耐药性问题比较突出。本文以江苏省海安县集约化蛋鸡场为例,对大肠杆菌病的流行病学调查、耐药性检测和微生态制剂防治大肠杆菌病以及取得的经济效益进行了分析。     

规模化蛋鸡场流感的防控

流行性感冒是规模化鸡场经常发生的传染性疾病,由禽流感病毒感染所引起,寒冷季节本病高发,多与鸡舍通风不良有关,另外,候鸟迁徙对本病的扩散也有着重要影响。本病可导致蛋鸡出现严重的呼吸道症状,同时产蛋率和蛋重下降,蛋壳质量变差,料蛋比上升,死亡率升高。预防本病必须做好鸡群的疫苗免疫,加强鸡场管理和生物安全建设;产蛋期治疗本病禁止使用化学药物,防止出现药物残留等食品安全问题,可采用中药配合生化制品治疗。     

蛋鸡疾病的诊治分析

人们对肉蛋食品需求的增加推动了蛋鸡养殖业向规模化集约化养殖的发展。规模化养殖在增加养殖户经济效益保障人们对鸡蛋的需求的同时,也伴随着鸡病增大的风险。疾病防控技术能够预防病毒、细菌等病原微生物,降低蛋鸡传染病。因此针对蛋鸡养殖及疾病防控技术进行探析,以保证蛋鸡及产品的质量。     

2013年规模化猪场细菌性疾病流行状况与防控对策

目前,规模化猪场细菌病常年不断发生,特别是猪群中发生各种病毒病时,往往都出现细菌病的混合感染或继发感染,导致猪群发病率与死亡率增高,造成重大经济损失。尤其是在当前猪群中免疫抑制性疾病普遍存在;病原体不断发生变异,新的血清型不断出现;滥用抗生素造成细菌耐药性增高,导致＂超级细菌＂的出现;加之生物安全措施不健全、     

蛋鸡养殖不可忽视“六净”工作

<正>生物安全是防控各种传染病较有效的方法,而环境清洁、卫生是生物安全中重要的环节。要想搞好蛋鸡生产,鸡舍内外环境、设备用具、日粮、饮水、蛋鸡本身和饲养人员等清洁卫生工作较重要,只有坚持不懈、认真和细致地去做好这"六净"工作,蛋鸡养殖才能取得事半功倍的效果。一净:鸡舍内外环境的清洁、卫生每天对鸡舍周围进行清扫,每周对舍外环境、道路消毒1次,消毒药用10%的漂白粉或0.5%的     

辽宁朝阳一规模化蛋鸡饲养场兽药减量化模式

近年来,我国规模化养殖方兴未艾,智能化养殖发展势头良好,集团化、全产业链布局正在形成。然而,快速发展的养殖业却也饱受诟病,其原因之一就是抗菌药物使用过多导致的细菌耐药性和药物残留问题突出。"今天不采取行动,明天就无药可用"的担忧绝不是危言耸听,减抗已是大势所趋。为此,本文介绍了辽宁省朝阳市双塔区勤德利牧业有限公司规模化蛋鸡饲养场在兽药减量化道路上形成的适合自身特点的发展模式:得天独厚的自然环境,安全智能的饲养环境、优质健康的饲料标准、科学有效的疾病防控、严格的生物安全管理体系,以供参考。     

技术支撑是家禽业健康发展的关键——华牧公司五项技术规程专家论证会侧记

受河北省科学技术厅委托,石家庄市科学技术局组织并主持,邀请家禽领域专家组成论证委员会,于2010年8月8日对石家庄华牧牧业有限责任公司、河北农业大学及河北省畜牧兽医研究所承担的《蛋鸡规模化健康养殖关键技术集成与示范》项目实施过程中所形成的“标准化蛋鸡舍建设”、“商品蛋鸡饲养管理”、“商品蛋鸡饲料营养”、“商品蛋鸡场疫病防治”、“鸡蛋质量追溯体系”五项关键技术规程进行了论证。     

Antimicrobial resistance in Swiss laying hens, prevalence and risk factors

Antimicrobial resistance is an emerging concern to public health, and food-producing animals are known to be a potential source for transmission of resistant bacteria to humans. As legislation of the European Union requires to ban conventional cages for the housing of laying hens on the one hand, and a high food safety standard for eggs on the other hand, further investigations about the occurrence of antimicrobial resistance in alternative housing types are required. In this study, we determined antimicrobial resistance in indicator bacteria from 396 cloacal swabs from 99 Swiss laying hen farms among four alternative housing types during a cross-sectional study. On each farm, four hens were sampled and exposure to potential risk factors was identified with a questionnaire. The minimal inhibitory concentration was determined using broth microdilution in Escherichia coli (n=371) for 18 antimicrobials and in Enterococcus faecalis (n=138) and Enterococcus faecium (n=153) for 16 antimicrobials. All antimicrobial classes recommended by the European Food Safety Authority for E. coli and enterococci were included in the resistance profile. Sixty per cent of the E. coli isolates were susceptible to all of the considered antimicrobials and 30% were resistant to at least two antimicrobials. In E. faecalis, 33% of the strains were susceptible to all tested antimicrobials and 40% were resistant to two or more antimicrobials, whereas in E. faecium these figures were 14% and 39% respectively. Risk factor analyses were carried out for bacteria species and antimicrobials with a prevalence of resistance between 15% and 85%. In these analyses, none of the considered housing and management factors showed a consistent association with the prevalence of resistance for more than two combinations of bacteria and antimicrobial. Therefore we conclude that the impact of the considered housing and management practices on the egg producing farms on resistance in laying hens is low.     

蛋鸡兽用抗菌药使用减量化养殖现状与研究对策

不合理使用抗菌药严重威胁到蛋鸡养殖健康,引起鸡蛋中药物残留和细菌耐药性产生风险,影响鸡蛋食品安全和公共卫生安全。本文基于我国自2018年起开展的涵盖蛋鸡养殖的兽用抗菌药使用减量化行动,从蛋鸡养殖的减量化现状、问题、对策等方面进行综述,以期为推动蛋鸡兽用抗菌药使用减量化养殖提供参考。     

蛋鸡抗菌药使用减量化养殖中的全链条综合措施

为有力推动国家兽用抗菌药使用减量化行动落实落地,结合蛋鸡养殖生产特点,提出科学有效、实操性强的减抗养殖全链条综合措施,包括蛋鸡减抗养殖基本要求、抗菌药使用减量化养殖技术要求、抗菌药使用减量化评估等,旨在促进蛋鸡养殖企业切实提高生物安全水平和科学饲养水平,切实有效降低抗菌药的使用,确保蛋鸡健康养殖,有效促进蛋鸡养殖业高质量发展。     

Antimicrobial resistance of commensal Escherichia coli from dairy cattle associated with recent multi-resistant salmonellosis outbreaks

The use of antimicrobial drugs in livestock is suspected to contribute to bacterial antimicrobial resistance (AR) development. Dairy farms experiencing recent outbreaks of salmonellosis involving multi-resistant (MR) Salmonella strains were compared to control farms with respect to AR among bovine commensal E. coli isolates. For most antimicrobials tested, the percentage of AR E. coli isolated from salmonellosis-affected farms was significantly higher than that from control farms. Calf E. coli from both case and control farms had greater levels of AR than cow isolates. Commensal E. coli isolates from case farms and calves tended to more frequently be MR. These data are consistent with the existence of higher antimicrobial selection pressure on farms with recent salmonellosis outbreaks, however, the directionality of the relationship remains to be elucidated. An improved understanding of the epidemiology of AR bacteria in livestock production, both at the herd and molecular level, is essential to mitigate risk to public health and food safety.     

Estimations of repeatability and heritability of egg albumen antimicrobial activity and of lysozyme and ovotransferrin concentrations

1. The repeatability and heritability of growth inhibition by egg albumen of two major pathogenic bacteria, a Gram-negative (Salmonella Enteritidis) and a Gram-positive (Staphyloccocus aureus) and of two antimicrobial albumen proteins, lysozyme and ovotransferrin, were estimated in commercial pedigree hens. 2. Repeatability was evaluated in 100 egg-type hens at the beginning, middle and end of the laying cycle on eggs collected for 3 weeks. Heritabilities were estimated at 36 to 40 weeks of age on 400 pedigree hens (2 eggs/hen), which were the offspring of 25 sires each mated with 4 dams. Ovotransferrin and lysozyme were quantified by ELISA. Salmonella Enteritidis (S.E.) and Staphyloccocus aureus (S.A.) were inoculated into a sample of sterilised albumen and enumerated after incubation. 3. Total protein content in albumen decreased with age of laying hens, whereas there were increases in lysozyme or ovotransferrin concentrations and in the bacteriostatic effect of albumen. 4. Repeatability for bacterial growth in albumen ranged from 0.29 to 0.39 for the number of S.E. (log cfu/ml) one day post inoculation (p.i.) but was lower and more variable at 5 d p.i. or for S.A. number. It ranged from 0.27 to 0.38 for S.E. and S.A. number at the mid period of the laying cycle. Repeatabilities were low and variable for total egg albumen protein or lysozyme and ovotranferrin concentrations (0 to 0.22). 5. Negative phenotypic correlations were observed between lysozyme concentrations and S.E. number but that between lysozyme and S.A. number was not significant. 6. Heritabilities were low (0.01 to 0.09) for protein traits. They were 0.11 for S.A. number and 0.16 for S.E. number one day p.i. 7. It appears to be more efficient to select on global bacterial growth than on specific antimicrobial proteins. The most promising trait is the number of S.E. one day p.i.     

Effects of inulin on performance, egg quality, gut microflora and serum and yolk cholesterol in laying hens

1. The present study was conducted to investigate the effects of inulin on laying hens. A total of 360 Brown Nick laying hens were divided randomly into 6 groups of 60 with 6 replicates of 10 hens and fed on diets containing 0 (control), 0·1, 0·5, 1·0, 1·5 or 2·0% inulin during the 4-week trial. 2. Dietary supplementation of inulin reduced cholesterol concentration (mg/g yolk) and content (mg/egg) in eggs. Cholesterol content in eggs decreased linearly with increasing levels of dietary inulin level. 3. Supplementation of inulin in diets decreased coliform bacteria counts and pH in the caecum. The lowest coliform bacteria counts (6·30 ± 0·03 log10 cfu/g) and pH (6·47 ± 0·01) were obtained in the 2·0% inulin group, the two indices decreasing by 21·6% and 3·0% respectively, compared with the control group. Coliform bacteria count and pH were changed linearly in accordance with increasing levels of dietary inulin level. Caecal Bifidobacteria counts were increased in the 2·0%-inulin group. 4. Inulin supplementation of layer diets did not appear to have any adverse effects on laying rate, egg weight, feed intake, feed conversion efficiency, cracked-egg rate, eggshell thickness or Haugh unit compared with the control laying hens. 5. Therefore, dietary supplementation with inulin may lead to the development of low-cholesterol chicken eggs as demanded by health-conscious consumers.     

Antimicrobial use in Belgian broiler production

The use of antimicrobials in production animals has become a worldwide concern in the face of rising resistance levels in commensal, pathogenic and zoonotic bacteria. In the years 2007 and 2008 antimicrobial consumption records were collected during two non consecutive production cycles in 32 randomly selected Belgian broiler farms. Antimicrobials were used in 48 of the 64 monitored production cycles, 7 farms did not use any antimicrobials in both production cycles, 2 farms only administered antimicrobials in one of the two production cycles, the other 23 farms applied antimicrobial treatment in both production cycles. For the quantification of antimicrobial drug use, the treatment incidences (TI) based on the defined daily doses (the dose as it should be applied: DDD) and used daily doses (the actual dose applied: UDD) were calculated. A mean antimicrobial treatment incidence per 1000 animals of 131.8 (standard deviation 126.8) animals treated daily with one DDD and 121.4 (SD 106.7) animals treated daily with one UDD was found. The most frequently used compounds were amoxicillin, tylosin and trimethoprim-sulphonamide with a mean TI(UDD) of 37.9, 34.8, and 21.7, respectively. The ratio of the UDD/DDD gives an estimate on correctness of dosing. Tylosin was underdosed in most of the administrations whereas amoxicillin and trimethoprim-sulphonamide were slightly overdosed in the average flock.     

我国动物源细菌耐药状况、存在问题和对策

动物源细菌耐药性问题不仅关系到动物的用药安全,也与公共卫生安全密切相关,日益引起各国的关注。中国兽医药品监察所从事动物源细菌耐药性检测工作10余年,对我国动物源细菌的耐药性状况进行了系统的调查。本文从动物源细菌耐药性监测工作的重要性、我国动物源细菌的耐药性状况、存在的问题以及应对策略四个方面进行了综述,以期对我国的动物源细菌耐药性监测工作起一定的参考作用。     

广西地区禽致病性大肠杆菌的耐药性分析

禽致病性大肠杆菌(APEC)是一种能引起鸡、火鸡和其他鸟类肠外感染的致病性大肠杆菌,可以导致肉鸡气囊炎、败血型全身感染、蜂窝织炎和蛋鸡输卵管炎、腹膜炎。为了了解广西地区禽致病性大肠杆菌的耐药表型以及耐药基因的携带情况,本实验室对2019年从广西分离到的69株APEC采取K-B药敏纸片法进行药敏试验,药敏结果显示,69株APEC对氧氟沙星(56.5%)、恩诺沙星(69.6%)、氟苯尼考(79.7%)、氨苄西林(91.3%)、四环素(98.6%)耐药率较高,而对美罗培南、丁胺卡那霉素、呋喃妥因均不耐药;其中,多重耐药现象严重,对10种抗菌药物以耐4种、5种、6种的情况居多。同时用PCR扩增的方法对其耐药基因,包括碳青霉稀类、β-内酰胺类、氨基糖苷类、黏菌素类、喹诺酮类、四环素类在内的6大类共计17种耐药基因进行了检测。特别值得关注的是,发现了7株携带mcr-1基因的多黏菌素耐药APEC。药敏纸片法检测菌株的耐药表型和耐药基因存在一定关联度。本研究可为养禽场临床用药提供参考,同时为减缓耐药菌传播、降低对人类健康和公共卫生安全威胁提供依据。     

Comparison of the prevalence of Salmonella infection in layer hens from commercial layer farms with high and low rodent densities

A comparison on the prevalence of Salmonella infection in layer hens from commercial layer farms with high and low rodent densities was investigated. Out of 280 laying hens sampled from three commercial layer farms with high rodent densities, Salmonella enterica subsp. enterica serovar Enteritidis (Salmonella Enteritidis) was isolated from 20 (7.14%) hens and Salmonella enterica subsp. enterica serovar Infantis (Salmonella Infantis) from three (1.07%) hens. In contrast, layer hens sampled from four commercial layer farms with low rodent densities were negative for any salmonellae. Significant differences (P < 0.05) in the isolation rates of Salmonella from various organs of infected layer hens were also noted. For Salmonella Enteritidis, liver (55.0%) and the oviduct (55.0%) had the highest isolation rates while all Salmonella Infantis isolates were from the oviduct. Pulsed field gel electrophoresis (PFGE) analysis of BlnI-digested chromosomal DNA of Salmonella Enteritidis isolated from layer hens and rodents showed similar patterns. PFGE analysis of Salmonella Infantis isolated from layer hens, rodents, eggs, and the environment yielded identical patterns. In this study, the significantly higher prevalence rate (P < 0.05) of Salmonella Enteritidis and Salmonella Infantis in layer hens from high rodent density farms could be attributed to the high rodent population density. The persistent Salmonella Enteritidis and Salmonella Infantis infection inside layer houses may have been amplified by the increasing numbers in the rodent population over the years, which increased the opportunity for environment-rodent-chicken interaction and the transmission of salmonellae to chickens. Monitoring of salmonellae from rodents inside poultry premises is recommended to be an effective additional tool in the assessment of the Salmonella status of layer flocks.