Cross-sectional study of antimicrobial-resistant bacteria in horses. Part 2: Risk factors for faecal carriage of antimicrobial-resistant Escherichia coli in horses

Reasons for performing study: The increasing prevalence of antimicrobial resistant bacteria such as antimicrobial‐resistant and extended spectrum β‐lactamase (ESBL)‐producing Escherichia coli represents a significant problem for human and veterinary medicine. Despite this, the risk factors for faecal carriage of such bacteria by horses in the UK, particularly those in the wider community, have not been well described. Objectives: To characterise the risk factors for faecal carriage of antimicrobial‐resistant E. coli amongst horses in the mainland UK. Methods: A cross‐sectional study of horses recruited by 65 randomly selected equine veterinary practices was conducted, with a faecal sample collected and self‐administered questionnaire completed by the horse owner. Faecal samples were cultured for antimicrobial‐resistant E. coli, with isolates confirmed as E. coli having their antimicrobial resistance profile determined. Multilevel, multivariable logistic regression models were used to investigate risk factors for the carriage of antimicrobial‐resistant E. coli in the sample population. Results: Faecal samples and completed questionnaires were obtained for 627 horses located on 475 premises. Recent hospitalisation, contact with specific types of nonequid animals, the type of premises, the surrounding land use, the reason for veterinary treatment received in the last 6 months and antimicrobial treatment in the previous 10 days were identified as risk factors for many of the antimicrobial‐resistance outcomes considered. Being stabled on the same yard as a recently hospitalised horse was identified as a risk factor for increased risk of carriage of ESBL‐producing E. coli. Conclusions and potential relevance: Increasing antimicrobial resistance may have significant health implications for the horse population of Great Britain. This form of epidemiological investigation highlights potential risk factors that may be controlled to limit the extent of the problem.     

土壤铜形态与环境因素的关系及其对黑麦草生长的影响

采用盆栽试验研究酸度与氮素水平对土壤易溶态铜形态的影响,以及土壤铜含量与形态对黑麦草生长的影响。结果表明,土壤水溶态铜、有机碳结合态铜、离子态铜与铜处理水平呈极显著正相关关系,相关系数分别达到0.70、0.96、0.61。土壤酸度影响土壤中各形态铜的含量,随pH值降低土壤水溶态铜、离子态铜均显著增加,在pH4.7土壤上二者的含量随铜处理浓度的不同分别为pH6.0土壤上的1.6～6.3倍和39～148倍,两种土壤上水溶态铜、离子态铜含量差异达显著水平。铜处理水平、水溶态铜、有机碳结合态铜、离子态铜含量均强烈影响黑麦草的生长和其对铜的吸收,牧草鲜重与各形态铜呈极显著负相关,相关系数分别为-0.73、-0.76、-0.71、-0.72,而植株铜含量则与各形态铜间呈极显著正相关关系,相关系数分别为0.61、0.87、0.56、0.87。土壤氮素水平影响土壤溶解有机碳的含量,但对土壤各种铜的形态及牧草对铜的吸收并无显著影响。     

Uterine biology in pigs and sheep

There is a dialogue between the developing conceptus (embryo-fetus and associated placental membranes) and maternal uterus which must be established during the peri-implantation period for pregnancy recognition signaling, implantation, regulation of gene expression by uterine epithelial and stromal cells, placentation and exchange of nutrients and gases. The uterus provide a microenvironment in which molecules secreted by uterine epithelia or transported into the uterine lumen represent histotroph required for growth and development of the conceptus and receptivity of the uterus to implantation. Pregnancy recognition signaling mechanisms sustain the functional lifespan of the corpora lutea (CL) which produce progesterone, the hormone of pregnancy essential for uterine functions that support implantation and placentation required for a successful outcome of pregnancy. It is within the peri-implantation period that most embryonic deaths occur due to deficiencies attributed to uterine functions or failure of the conceptus to develop appropriately, signal pregnancy recognition and/or undergo implantation and placentation. With proper placentation, the fetal fluids and fetal membranes each have unique functions to ensure hematotrophic and histotrophic nutrition in support of growth and development of the fetus. The endocrine status of the pregnant female and her nutritional status are critical for successful establishment and maintenance of pregnancy. This review addresses the complexity of key mechanisms that are characteristic of successful reproduction in sheep and pigs and gaps in knowledge that must be the subject of research in order to enhance fertility and reproductive health of livestock species.     

夏季采用湿帘通风系统的密闭式肉种鸡舍温热环境因子的变化

选择华南农业大学增城正大肉鸡发展中心的肉种鸡舍为研究对象,在夏季分别对该鸡舍的气温、气湿、风速等温热环境因子进行测定,用以评价该鸡舍采用的湿帘通风系统对鸡舍内温热环境因子的调节效果。结果表明,夏季采用湿帘通风系统的鸡舍平均舍温比舍外气温低3~4℃,相对湿度保持在80%左右;夏季采用湿帘通风系统可以有效地降低舍温,主要表现为前端降温效果明显,后部降温效果有所下降;中间比两侧的降温效果好。表明夏季采用湿帘通风系统对种鸡舍内的温热环境控制较好。     

温度和季节对四川白獭兔部分繁殖性状的影响分析

环境因素特别是温度、光照对家兔的繁殖力影响很大。为评估亚热带地区温度和季节对四川白獭兔繁殖性状的影响,对四川成都邛崃市某兔场2008-2009年的四川白獭兔种兔部分繁殖资料进行了相关性分析。结果表明:温度和季节对四川白獭兔的窝平均产仔数、初生仔兔死亡率的影响明显,夏季高温条件下四川白獭兔的窝平均产仔数最低为6.00只;而冬春季节较高,分别为6.19只和6.16只。夏季初生兔死亡率最高为0.07%,而秋季最低为0.03%。     

表观健康猪群携带猪链球菌2型毒力因子的分布特征

为了研究钦州市猪链球菌2型(SS2)的毒力因子分布特征,采用多重PCR方法对从我市健康猪扁桃体分离的11株SS2相关毒力基因——荚膜多糖(Cps2J),溶菌酶释放蛋白(Mrp),胞外蛋白因子(EF),溶血素(Sly),进行毒力基因检测。检测结果显示:毒力基因型为Mrp+epf+Sly+共有8株,毒力基因型为Mrp+epf+Sly-共有1株,这两种毒力基因型可归为强毒力基因型,占此次健康猪源毒株的81.8%;另外Mrp-epf-Sly-共有2株,属于弱毒和无毒基因型,占健康猪源毒株的18.2%。通过结果分析,预示我市目前SS2的主要流行菌株是同时具有4种毒力因子的高致病性菌株。     

桦木酸对小鼠免疫器官抗氧化能力的影响

本试验旨在研究桦木酸(BA)对小鼠免疫器官抗氧化能力的影响.选取健康的昆明系小鼠28只,随机分为4组(每组7只),每天每只分别按每千克体重0、0.25、0.50、1.00 mg的剂量给予BA,BA混悬于0.2 mL1％可溶性淀粉溶液中.以灌胃方式给予,每天灌胃1次,连续灌胃14 d后,检测各组小鼠脾脏和胸腺中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GHS-Px)活性,丙二醛(MDA)含量以及总抗氧化能力(T-AOC).结果表明:BA可使小鼠脾脏和胸腺中SOD、GSH-Px活性以及T-AOC升高,MDA含量降低.其中,每千克体重灌胃0.50 mg BA能显著或极显著提高脾脏和胸腺中GSH-Px活性和T-AOC(P＜0.05或P＜0.01),显著或极显著降低胸腺和脾脏中MDA含量(P＜0.05或P＜0.01);每千克体重灌胃1.00 mg BA能显著或极显著提高脾脏和胸腺中SOD活性、T-AOC以及脾脏中GSH-Px活性(P＜0.05或P＜0.01),极显著降低胸腺和脾脏中MDA含量(P＜0.01).由此得出,BA能有效地增强小鼠免疫器官的抗氧化能力.     

丁酸钠对断奶仔猪生长性能及免疫功能的影响

本试验旨在研究丁酸钠对断奶仔猪生长性能及免疫功能的影响。试验选用162头28日龄(8.25±0.18)kg断奶去势仔猪,随机分为6组,每组3个重复,每个重复9头猪。对照组饲喂基础饲粮,试验组分别在基础饲粮中添加0.01%抗生素(Ⅰ组)、0.10%丁酸钠(Ⅱ组)、0.10%丁酸钠+0.01%抗生素(Ⅲ组)、0.30%氧化锌+0.01%抗生素(Ⅳ组)和0.10%丁酸钠+0.30%氧化锌+0.01%抗生素(Ⅴ组)。试验期21 d。结果表明:1)Ⅲ、Ⅳ、Ⅴ组末重、平均日采食量和平均日增重显著高于对照组(P<0.05)。2)除Ⅰ组外,其他4个试验组的脾脏指数、胰脏指数、淋巴结指数均显著高于对照组(P<0.05);与对照组相比,各试验组免疫球蛋白G含量均显著升高(P<0.05),各试验组肠道黏膜免疫球蛋白A阳性(IgA+)细胞含量均有所上升,其中Ⅲ组上升最显著。3)Ⅲ、Ⅴ组的二胺氧化酶活性分别比对照组降低了46.22%和44.83%(P<0.05);Ⅲ、Ⅳ、Ⅴ组的皮质醇含量分别比对照组降低了43.13%、43.14%、47.01%(P<0.05)。结果提示,饲粮中添加丁酸钠能促进断奶仔猪生长和免疫器官发育,提高血清免疫球蛋白含量,刺激机体肠道黏膜分泌免疫球蛋白A阳性细胞,提高其免疫功能。此外,丁酸钠与抗生素一起使用对促进生长性能和降低腹泻率作用效果更明显。     

抗菌肽对蛋用仔公鸡生长性能、免疫指标及空肠组织相关细胞因子基因mRNA表达的影响

本试验旨在研究饲粮中添加不同水平天蚕素抗菌肽对海兰褐蛋用仔公鸡生长性能、免疫器官指数及空肠组织相关前炎性细胞因子基因mRNA相对表达水平的影响.选用336只1日龄健康海兰褐蛋用仔公鸡,随机分为7组,每组4个重复,每个重复12只鸡.7组试鸡分别饲喂基础饲粮(对照组),基础饲粮+150mg/kg金霉素(抗生素组),基础饲粮+150、200、250、300、350mg/kg抗菌肽(抗菌肽Ⅰ、Ⅱ、Ⅲ、Ⅳ、V组),试验期为42d.结果表明:1)抗菌肽Ⅲ、Ⅳ、V组平均日采食量显著低于对照组(P＜0.05),平均日增重各组之间差异不显著(P＞0.05),抗菌肽Ⅳ、V组料重比较对照组显著降低(P＜0.05).2)抗菌肽V组胸腺指数显著高于其他各组(P＜0.05),法氏囊指数较对照组、抗菌肽Ⅰ组显著提高(P＜0.05),抗菌肽Ⅳ、V组之间脾脏指数差异不显著(P＞0.05),与其他各试验组相比,抗菌肽V组脾脏指数显著升高(P＜0.05).3)抗菌肽V组白细胞介素-6基因mRNA相对表达水平较其他各组显著降低(P＜0.05),抗菌肽Ⅲ、Ⅳ、V组干扰素-Υ基因mRNA相对表达水平较对照组显著降低(P＜0.05),抗菌肽Ⅳ、V组肿瘤坏死因子-α基因mRNA相对表达水平较对照组显著降低(P＜0.05).综上所述,饲粮抗菌肽可不同程度提高蛋用仔公鸡生长性能、免疫器官指数,并能有效降低前炎性细胞因子基因的mRNA相对表达水平,以添加350mg/kg抗菌肽效果为最好.