不同周龄BWEL-SPF种鸡生理生化指标的测定

目的测定不同周龄的BWEL-SPF种鸡生理和生化指标,并对测定值进行t-检验。方法分别采用计数板法、血涂片法、血液全自动分析仪测定法、双缩尿法、溴甲酚绿法、酶比色法和硫氰酸汞比色法等测定了10、40和60周龄的雌、雄BWEL-SPF种鸡的生理生化指标,并对雌、雄差异进行了统计学分析。结果在所测定的生理生化指标中,不同周龄雌雄之间差异显著性表现项目不同,其中在10周龄时,只有总胆固醇(CHO)在雌、雄之间差异极显著(P<0.01);40周龄时,甘油三酯(TG)、在雌、雄之间差异极显著(P<0.01);总胆固醇(CHO)为雌、雄之间差异显著(P<0.05);60周龄时,出血时间(BT)、嗜碱性粒细胞(B)、单核细胞(M)、谷丙转氨酶(ALT)、葡萄糖(Glu)在雌、雄之间差异极显著(P<0.01),而凝血时间(CT)和甘油三酯(TG)在雌、雄之间差异显著(P<0.05),除此以外,其它生理生化指标在雌雄之间差异不显著。结论BWEL-SPF种鸡的生理和生化指标随周龄不同,在雌、雄之间的差异随之变化。     

Modulation of immune function by conjugated linoleic acid in chickens

This study was carried out to determine the effects of dietary supplementation with conjugated linoleic acid (CLA) on the immune response and fatty acid composition of the spleen in chickens. Three hundred male broiler chicks were randomly allotted into five dietary treatments with different inclusion levels of CLA (0, 5.0, 10.0, 15.0, 20.0 g pure CLA/kg). The relative weights of the thymus and bursa were significantly increased (p<0.05) in chickens fed 5.0 or 10.0 g CLA/kg diet compared with control chickens at age 21 days. Peripheral blood mononuclear cell (PBMC) proliferation and anti-NDV titers were enhanced in 10.0 g CLA/kg dietary treatments (p<0.05). CLA diets resulted in lower PGE₂ synthesis than the control diet (p<0.05). Dietary CLA readily incorporated into the phospholipids of immune tissues and altered the fatty acid composition of the spleen with increased LO (n-3) and decreased LA, AA (n-6) relative amounts in chicks. Negative correlation was observed between PGE₂ synthesis and lymphocyte proliferation at age 21 days (R ²= ? 0.677, p<0.05), but no correlation between PGE₂ synthesis and anti-NDV titres was observed. The results indicated that dietary CLA could enhance the immune response in chicks, which might be due to changes of eicosanoid production. However, the PGE₂-mediated effects cannot be accounted for solely by the overall effect of CLA on immune function.     

Reassortant Highly Pathogenic Influenza A(H5N6) Virus in Laos

In March 2014, avian influenza in poultry in Laos was caused by an emergent influenza A(H5N6) virus. Genetic analysis indicated that the virus had originated from reassortment of influenza A(H5N1) clade 2.3.2.1b, variant clade 2.3.4, and influenza A(H6N6) viruses that circulate broadly in duck populations in southern and eastern China.     

不同CTX-M亚群鸡大肠杆菌毒力基因的流行特征

目的了解CTX-M-1亚群,CTX-M-9亚群与不产CTX-M3类鸡源大肠杆菌毒力基因的流行特征.方法 从河南省不同地区分离获得CTX-M-1亚群鸡大肠杆菌33株,CTX-M-9亚群鸡大肠杆菌31株和不产CTX-M的鸡大肠杆菌23株,以多重PCR技术检测受试菌携带33种毒力基因的情况.结果 3类受试菌毒力基因的携带种类趋于一致,其中feoB,fimH,traT和sitA在3类菌中检出率均较高.CTX-M-1亚群鸡大肠杆菌中traT和irp-2基因和CTX-M-9亚群鸡大肠杆菌中iroN,iss和irp-2基因的携带著高于不产CTX-M菌株.CTX-M-1亚群鸡大肠杆菌中cvaC和sfaS的携带率高于CTX-M-9亚群,而iroN和iss的携带率低于CTX-M-9亚群.结论 结果表明CTX-M-1与CTX-M-9亚群大肠杆菌部分毒力基因的携带率明显高于不产CTX-M的菌株,CTX-M-9和CTX-M-1亚群鸡大肠杆菌携带的部分毒力基因差异明显,推测产CTX-M鸡大肠杆菌的致病力可能较强,且菌株的致病力可能还与其携带的CTX-M基因亚型有关.     

Bacteriophage Therapy to Reduce Colonization of Campylobacter jejuni in Broiler Chickens before Slaughter

Campylobacteriosis is the most commonly reported gastrointestinal disease in humans. Campybacter jejuni is the main cause of the infection, and bacterial colonization in broiler chickens is widespread and difficult to prevent, leading to high risk of occurrence in broiler meat. Phage therapy represents an alternative strategy to control Campylobacter in poultry. The aim of this work was to assess the efficacy of two field-isolated bacteriophages against experimental infections with an anti-microbial resistant (AMR) Campylobacter jejuni strain. A two-step phage application was tested according to a specific combination between chickens’ rearing time and specific multiplicities of infections (MOIs), in order to reduce the Campylobacter load in the animals at slaughtering and to limit the development of phage-resistant mutants. In particular, 75 broilers were divided into three groups (A, B and C), and phages were administered to animals of groups B and C at day 38 (Φ 16-izsam) and 39 (Φ 7-izsam) at MOI 0.1 (group B) and 1 (group C). All broilers were euthanized at day 40, and Campylobacter jejuni was enumerated in cecal contents. Reductions in Campylobacter counts were statistically significant in both group B (1 log₁₀ colony forming units (cfu)/gram (gr)) and group C (2 log₁₀ cfu/gr), compared to the control group. Our findings provide evidence about the ability of phage therapy to reduce the Campylobacter load in poultry before slaughtering, also associated with anti-microbial resistance pattern.     

The emergence of the infection of subgroup J avian leucosis virus escalated the tumour incidence in commercial Yellow chickens in Southern China in recent years

A total of 81 clinical cases of suspected tumours were submitted to our laboratory from Yellow chicken farms in southern China during the years 2010 through 2017. The tumour‐like tissue samples were closely examined for common oncogenic avian viruses in cell culture and further analysed using polymerase chain reaction (PCR). During 2010‐2012, Marek's disease virus (MDV) mono‐infection was found to be the dominant cause of the tumour incidences (52.4%, 11/21) followed by co‐infection of MDV+ALVs (19.1%, 4/21). Starting from the year 2013 the mono‐infection of avian leucosis virus subgroup J (ALV‐J) became the dominant agent of the tumour cases (83.3%, 5/6). During the most recent four years (2014‐2017), co‐infections involving ALV‐J and MDV or between ALV subgroups have increased (23.4% and 18.5%, respectively), but each of the co‐infections was still slightly lower than the ALV‐J mono‐infection incidence (33.3%). In contrast to the dominant MDV mono‐infection cases before 2013, more recently, the emerging ALV‐J mono‐infection and ALV‐J co‐infections were largely responsible for the occurrence of avian virus‐induced tumour incidences in the commercial local Yellow breeds of chickens in southern China. These results indicate that eradication measures against ALV on all chicken farms, especially on farms with the Yellow chickens, ought to be enhanced to reverse this trend.     

The Pathobiology of H7N3 Low and High Pathogenicity Avian Influenza Viruses from the United States Outbreak in 2020 Differs between Turkeys and Chickens

An outbreak caused by H7N3 low pathogenicity avian influenza virus (LPAIV) occurred in commercial turkey farms in the states of North Carolina (NC) and South Carolina (SC), United States in March of 2020. Subsequently, H7N3 high pathogenicity avian influenza virus (HPAIV) was detected on a turkey farm in SC. The infectivity, transmissibility, and pathogenicity of the H7N3 HPAIV and two LPAIV isolates, including one with a deletion in the neuraminidase (NA) protein stalk, were studied in turkeys and chickens. High infectivity [<2 log₁₀ 50% bird infectious dose (BID₅₀)] and transmission to birds exposed by direct contact were observed with the HPAIV in turkeys. In contrast, the HPAIV dose to infect chickens was higher than for turkeys (3.7 log₁₀ BID₅₀), and no transmission was observed. Similarly, higher infectivity (<2–2.5 log₁₀ BID₅₀) and transmissibility were observed with the H7N3 LPAIVs in turkeys compared to chickens, which required higher virus doses to become infected (5.4–5.7 log₁₀ BID₅₀). The LPAIV with the NA stalk deletion was more infectious in turkeys but did not have enhanced infectivity in chickens. These results show clear differences in the pathobiology of AIVs in turkeys and chickens and corroborate the high susceptibility of turkeys to both LPAIV and HPAIV infections.     

医用透明质酸钠防止肌腱粘连的实验与临床应用研究

用３６只莱亨鸡的第三趾屈肌腱部分切断后缝合修复；１８只在切断处鞘内注入医用透明质酸钠制剂（ＳＨＰ）为实验组，半数注入生理盐水为对照组。然后分期活杀，通过趾屈曲度、肌腱滑移距离、肉眼和电镜观察及肌腱粘连范围组织学评分。结果表明实验组肌腱愈合好、无粘连，而对照组肌腱与周围组织粘连，界限不清。在动物实验的基础上，临床应用ＳＨＰ于３４例肌腱修复和８７例骨科其它手术，术中将ＳＨＰ均匀薄层涂抹在相关部位上，经３，８个月及３年的随访观察，表明ＳＨＰ对促进肌腱愈合，防止术后肌腱、肌肉、神经根、硬脊膜等的粘连及改善它们的滑移和关节功能具有良好的效果。如果创口发生感染和坏死，则将严重影响ＳＨＰ的作用和效果     

两种靶细胞在ADCC检测中的比较

选用绵羊红细胞 (SRBC)和鸡红细胞 (CRBC)作为靶细胞 ,用微量比色法检测人外周血单个核细胞 (PBMC)的抗体依赖细胞介导的细胞毒 (ADCC)活性。结果测得靶细胞对绵羊红细胞细胞毒指数为 9 0 3± 6 74 % ,对鸡红细胞的指数为 31 77± 16 2 7%。经t检验 ,有显著性差异 (t =4 75,P <0 0 1)。在 10例配对比较中 ,经相关性检验 ,对两靶细胞的指数具有显著相关性 (r =0 7152 ,P <0 0 5) ;经t检验 ,对两靶细胞的指数具有极显著差异 (t=4 33,P <0 0 1)。相同条件下 ,对CRBC的指数比SRBC的指数高。故认为 ,用CRBC作为靶细胞检测人PBMC的ADCC活性较好。     

Ceftiofur Resistance in Salmonella enterica Serovar Heidelberg from Chicken Meat and Humans, Canada

The Canadian Integrated Program for Antimicrobial Resistance Surveillance describes a strong correlation (r = 0.9, p<0.0001) between ceftiofur-resistant Salmonella enterica serovar Heidelberg isolated from retail chicken and incidence of ceftiofur-resistant Salmonella serovar Heidelberg infections in humans across Canada. In Québec, changes of ceftiofur resistance in chicken Salmonella Heidelberg and Escherichia coli isolates appear related to changing levels of ceftiofur use in hatcheries during the study period, from highest to lowest levels before and after a voluntary withdrawal, to increasing levels after reintroduction of use (62% to 7% to 20%, and 34% to 6% to 19%, respectively). These events provide evidence that ceftiofur use in chickens results in extended-spectrum cephalosporin resistance in bacteria from chicken and humans. To ensure the continued effectiveness of extended-spectrum cephalosporins for treating serious infections in humans, multidisciplinary efforts are needed to scrutinize and, where appropriate, limit use of ceftiofur in chicken production in Canada.