Risks to farm animals from pathogens in composted catering waste containing meat

Uncooked meat may contain animal pathogens, including bovine spongiform encephalopathy, foot-and-mouth disease virus, African swine fever virus and classical swine fever virus, and to prevent outbreaks of these diseases in farm animals, the disposal of meat from catering waste is controlled under the Animal By-Products Regulations. This paper estimates the risks to farm animals of grazing land on to which compost, produced by the composting of catering waste containing meat, has been applied. The factors controlling the level of risk are the separation of the meat at source, the efficiency of the composting process, and the decay and dilution of the pathogens in soil. The net pathogen destruction by the composting process is determined largely by the degree of bypass, and to accommodate the possibility of large joints or even whole carcases being discarded uncooked to catering waste, a time/temperature condition of 60 degrees C for two days is recommended. Where data are lacking, worst-case assumptions have been applied. According to the model, classical swine fever virus constitutes the highest risk, but the assessment shows that a two-barrier composting approach, together with a two-month grazing ban, reduces the risk to one infection in pigs every 190 years in England and Wales. This work defined the operational conditions for the composting of catering waste as set out in the Animal By-Products Regulations 2003 (SI 1482).     

Isolation and identification of a bacteriophage capable of infecting Streptococcus suis type 2 strains

Streptococcus suis (S. suis) type 2 infection is considered to be a major problem worldwide in the swine industry. Studying phages of S. suis type 2 would be crucial for understanding the ecology and evolution of the Gram-positive bacteria. However, at the present, very little is known about them. An S. suis type 2 bacteriophage, named SMP, was isolated from nasal swabs of healthy Bama minipigs and was characterized at the microbiological and molecular levels. Phage SMP had an isometric head of 50 nm, a noncontractile tail of approximately 135 nm, and a linear double-stranded DNA genome. The host range of phage SMP was limited to 2 of 24 S. suis type 2 strains tested. The genome of phage SMP contained 36,216 bp with an average G+C content of 41.6%.     

猪致病性大肠杆菌O9菌蜕的制备及免疫保护力

通过PCR方法克隆噬菌体PhiXl74的融菌基因E,将其与温控表达载体pBV220连接,成功构建温控融菌表达盒,设计扩增温控表达盒的2对引物,使其5′端分别与lacZ基因敲除基因的首尾50bp基因同源,使用Red系统同源重组,使用麦康凯平板筛选、PCR鉴定白色菌落,温控诱导融菌蛋白的表达,制备大肠杆菌O9的菌影,并对其融菌效率及免疫保护力进行了初步研究。结果显示,成功构建了温控融菌表达盒,经同源重组成功获得猪致病性大肠杆菌O9温控融菌株,温控表达溶菌蛋白能够成功抑制细菌的增殖,并使活菌数下降3个指数,对小鼠安全性好,皮下免疫组攻毒保护率达到71.43%。     

Utilization of phosphorus and certain other minerals from swine waste and broiler litter

Two trials were conducted with 15 wethers surgically equipped with duodenal and ileal cannulas to study the utilization of P, Ca, Mg, Cu, Fe and Zn from swine waste and broiler litter. For each trial, animals were fed a low-P basal diet until serum inorganic P averaged 5.5 mg/dl; then they were allotted at random to the following 50% DM ensiled diets: low-P basal, basal + swine waste, basal + broiler litter, basal + dicalcium phosphate and basal + soybean meal. Each trial consisted of a 7-d preliminary period, a 7-d collection of feces and urine and 6-d sampling of duodenal and ileal digesta and feces. Apparent P absorption was not different (P greater than .05) between sheep fed waste-supplemented diets (37%) and those fed the conventionally supplemented diets (28%). Phosphorus absorption, calculated by difference, tended (P less than .1) to be higher from the waste supplements (59%) than from dicalcium phosphate and soybean meal (37%). Less (P less than .05) Ca was absorbed from the waste diets (.62 g/d) than from the conventional diets (1.28 g/d). More (P less than .05) Cu (mg/d) was absorbed from the waste diets, but no difference was found when absorption was expressed as percentage of intake. Broiler litter and swine waste were good sources of available P and Mg for ruminants.     

猪场生物安全系统要点

建立生物安全体系是猪场防控疾病的前提,也是最经济有效的疫病防治措施。2018年我国发生非洲猪瘟以来,疫情对我国生猪养殖业带来深刻影响,在未来很长一段时间内该病都将是我国猪场的常态化疾病。非洲猪瘟疫情发生后,我国养猪业创新性地提出了系列生物安全防控技术,建立了能够有效应对疫情常态威胁的生物安全技术体系,两年多来的防控实践证明了这些生物安全防控手段的有效性。文章总结了猪场生物安全体系建设和管理中的关键环节及注意事项,希望可以为猪场非洲猪瘟防控提供参考。     

利用随机肽库鉴定猪瘟病毒E2蛋白抗原表位

利用噬菌体随机12肽库对抗猪瘟病毒（classical swine fever virus CSFV）糖蛋白E2特异的单抗A11进行表位鉴定，经过4轮筛选后，随机挑取10个噬菌体克隆作竞争ELISA检测。结果表明，10个克隆中除4号克隆外，其余9个均能抑制原核表达的E2蛋白和A1l单抗之间的抗原抗体反应，抑制率在35％～64％；DNA测序表明，所有产生竞争抑制作用的8个噬菌体克隆的12肽序列均舍有XXWRXXXL核心序列，而没有抑制作用的克隆则不含该核心序列；Western-blot试验证明，所挑阳性克隆均能被单抗A11识别。多序列比较发现，该核心序列与猪瘟病毒E蛋白的28～35位氨基酸TTWKEYSH有一定的同源性，人工合成的含有部分核心序列氨基酸的多肽可以与单抗A11反应，表明单抗A11所针对的抗原表位位于CSFVE2蛋白的28～35位氨基酸。     

High dietary copper improves odor characteristics of swine waste

We conducted two experiments to determine the effects of dietary copper concentration and source on odor characteristics of swine waste. In both experiments, 192 weanling gilts and barrows were allotted to 24 pens. Pens were randomly assigned to one of six dietary treatments, consisting of control (10 ppm Cu as cupric sulfate, CuSO4), 66 or 225 ppm Cu as CuSO4, or 33, 66, or 100 ppm Cu as cupric citrate (Cucitrate). An antibiotic was included in the diets for Exp. 1, but not Exp. 2. On d 28, fecal samples were randomly obtained from one pig per pen and stored at -20 degrees C until preparation and evaluation by an odor panel. The odor panel consisted of 10 individuals, and each panelist evaluated the odor intensity, irritation intensity, and odor quality of the samples. In Exp. 1, the odor and irritation intensity of the feces were lower (P < .05) from animals consuming diets containing 225 ppm Cu as CuSO4 and 66 or 100 ppm Cu as Cu-citrate compared to the control. The odor quality of the waste from animals consuming diets containing 225 ppm Cu as CuSO4 and 66 or 100 ppm Cu as Cu-citrate was improved (P < .05) compared to the 33 ppm Cu treatment. In Exp. 2, the odor intensity of the feces of pigs receiving diets supplemented with all concentrations of Cu-citrate was lower (P < .05) than that of feces from the control animals. Irritation intensity of the feces was not affected by treatment. Odor quality of waste of pigs supplemented with 225 ppm Cu from CuSO4 and all concentrations of Cu-citrate was improved (P < .05) compared to that of waste of the control pigs. Two gilts and two barrows from each nursery pen in Exp. 1 were continued through the growing-finishing phase on their respective experimental diets. The growing-finishing phase lasted 103 d, and fecal samples were randomly obtained from one pig per pen at the completion of the phase. During the growing-finishing phase, the odor intensity and the irritation intensity of the feces were lower (P < .05) from pigs supplemented with 66 and 225 ppm Cu as CuSO4 and 66 and 100 ppm Cu from Cu-citrate than from the control pigs. The odor quality of the waste was improved (P < .05) in all animals receiving supplemental Cu. These data indicate an improvement in odor characteristics of swine waste with the supplementation of Cu. In addition, lower concentrations of an organic nonsulfate Cu source resulted in similar odor characteristics of swine waste as 225 ppm CuSO4.     

H1N1猪流感病毒血凝素蛋白抗原表位的筛选及其抗原性分析

本研究旨在对H1N1猪流感病毒血凝素蛋白抗原分子的模拟表位进行分离鉴定并分析其抗原性。用抗H1N1猪流感病毒血凝素蛋白小鼠血清IgG对噬菌体随机12肽库进行筛选,3轮亲和筛选后,特异性噬菌体得到了有效富集;对随机挑选的47个噬菌体克隆用ELISA进行鉴定,其中40个为阳性;对40个阳性克隆测序得到3种不同氨基酸序列;用Western blotting对获得的3个不同序列的噬菌体克隆进行抗原性分析,显示这3种噬菌体插入短肽能和H1N1猪流感病毒感染小鼠血清特异性结合。结果表明,本试验获得了3种H1N1猪流感病毒血凝素蛋白模拟抗原表位,它们都具有明显的抗原性,为H1N1猪流感病毒的疫苗研究和诊断奠定了基础。     

Antimicrobial resistance in Salmonella enterica serovar Typhimurium from human and animal sources in Italy

Salmonella Typhimurium strains isolated in Italy in the period 2002-2004 from human and animal sources were examined for their antimicrobial susceptibility. Resistance to tetracycline (T, 73.6%), sulfonamides (Su, 73.3%), ampicillin (A, 67.6%), streptomycin (S, 65.4%) and chloramphenicol (C, 32.3%) were frequently observed. Resistance to ciprofloxacin was only observed in a swine strain, but most human strains resistant to nalidixic acid showed reduced susceptibility to that drug (MIC > or = 0.125 mg/l). Overall, 64% of the strains were resistant to four or more drugs. The most common resistance profiles were ACSSuT, prevalent in strains belonging phage type DT104 and ASSuT, prevalently associated with strains unable to be typed.     

Age-related variations in serum concentrations of the third component of complement in swine

Single radial immunodiffusion was used to determine the concentration of the third component of complement (C3) in serum from swine in the following age groups; 36 to 60 hours (neonates), 6 to 7 weeks (weanlings), 4 to 5 months (adolescents) and greater than 1 year (adults). Mean serum C3 concentrations, expressed as the percentage of pooled reference sera from 15 adult swine for the 4 groups were 23, 123, 119, and 98%. With the exception of mean values for weanlings and adolescents, all comparisons of group means were significantly different. Regression models were developed to estimate serum C3 concentration in neonates as a function of litter size, birth weight, and total serum IgG concentration. Increases in birth weight and litter size were accompanied by increased serum C3 concentration, possibly reflecting ontogenic variation of the complement system at the end of gestation. Passive transfer of colostral immunoglobulins, as measured by total serum IgG concentration, was inversely related to serum C3 concentration in neonatal swine, suggesting that colostral absorption of C3 has minimal impact on complement activity in neonatal swine.     

Clinical and Pathological Observations on the Experimental Passage of Swine Dysentery

The length of incubation for 36 eight and 12 week old swine in eight experimental passages averaged 11 days and ranged from five to 24 days. The duration of diarrhea for 24 of these swine averaged 6.4 days and ranged from two to 19 days. The consistent macroscopic lesion was a colitis and, subsequently, a typhlitis. In the swine euthanized on the first day of diarrhea, the colitis was most intense in the coils near the apex of the colon and, frequently, these swine had a hyperemia of the fundus of the stomach. The amount of visible blood in the colon varied. Organisms identified microscopically and ultrastructurally as spirochetes were observed commonly in the feces and the mucosal glands of the colon of swine with a diarrhea, but not in the adjacent mesenteric lymph nodes. These spirochetes which were the most numerous on the first day of diarrhea, could not be isolated and propagated in vitro. Swine which recovered naturally or were medicated at the height of a diarrhea, developed a resistance to swine dysentery. Colon from infected swine remained infectious when stored at -77°C for nine months but not when stored at -16°C. Feces from infected swine were not infectious after lyophilization and storage at -12°C.     

Characterization of Salmonella Typhimurium isolates associated with septicemia in swine

Salmonella Typhimurium is frequently isolated from pigs and may also cause enteric disease in humans. In this study, 33 isolates of S. Typhimurium associated with septicemia in swine (CS) were compared to 33 isolates recovered from healthy animals at slaughter (WCS). The isolates were characterized using phenotyping and genotyping methods. For each isolate, the phage type, antimicrobial resistance, and pulsed-field gel electrophoresis (PFGE) DNA profiles were determined. In addition, the protein profiles of each isolate grown in different conditions were studied by Coomassie Blue-stained sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblot. Various phage types were identified. The phage type PT 104 represented 36.4% of all isolates from septicemic pigs. Resistance to as many as 12 antimicrobial agents, including some natural resistances, was found in isolates from CS and WCS. Many genetic profiles were identified among the PT 104 phage types. Although it was not possible to associate one particular protein with septicemic isolates, several highly immunogenic proteins, present in all virulent isolates and in most isolates from clinically healthy animals, were identified. These results indicated that strains associated with septicemia belong to various genetic lineages that can also be recovered from asymptomatic animals at the time of slaughter.     

金黄色葡萄球菌烈性噬菌体的分离鉴定和最佳保存方法研究

基于细菌rRNA区域序列的PCR技术,通过设计特异性引物从奶样中快速、准确地鉴定奶牛乳房炎主要致病菌金黄色葡萄球菌。采用金黄色葡萄球菌与挤奶前从奶牛乳房上洗刷下来的污水经过3次富集的方法,通过双层琼脂平板法,分离纯化得到了强裂解性的奶牛乳房炎主要致病菌金黄色葡萄球菌的噬菌体。本试验分离的是可收缩尾的噬菌体,其头部为二十面体,约50 nm×62.5 nm,尾部长约187.5 nm,尾宽约37.5 nm,有尾鞘、基板等结构。纯化后在双层琼脂平板上形成的噬菌斑大而整齐,边缘光滑,透明,直径约2 mm,具有明显的强裂解性噬菌体特性,通过测定,该噬菌体的最佳感染复数为0.01,效价大于10⁹ PFU/mL。对噬菌体的不同保存方法进行比较,结果表明,将噬菌体置于-80 ℃加入7% DMSO冷藏是较好的保存方法。     

Serological detection of phage infection in Chlamydia psittaci recovered from ducks

Antiserum prepared against a phage which infects a Chlamydia psittaci isolate recovered from domestic ducks was used to screen other recent avian C psittaci isolates by indirect immunofluorescence. Two more phage infected strains from ducks were discovered. However, phage was not detected in every isolate examined from common source ducks, although such birds are likely to be infected with the same C psittaci strain. Moreover, phage could not always be demonstrated by indirect immunofluorescence in McCoy cell monolayers infected with the phage-containing strain. The results suggest that phage infection is probably an integral part of duck chlamydiosis in the United Kingdom at present, but that the infection is often cryptic.     

产志贺毒素多重耐药大肠杆菌噬菌体的生物学特性及全基因组分析

为探明大肠杆菌噬菌体的生物学特性和全基因组特征,本研究以在广西某猪场污水中分离得到的1株产志贺毒素且多重耐药的大肠杆菌GXEC010为宿主菌,同时在污水中分离到1株具有裂解作用的噬菌体,并通过透射电镜观察、最佳感染复数测定、一步生长曲线绘制、热敏感性与酸碱度稳定性评估、杀菌试验及全基因组测序等方法分析该噬菌体的生物学特性与基因组特征。结果表明,分离纯化得到能高效裂解大肠杆菌GXEC010的噬菌体,命名为vB_EcoM_BP10,其噬菌斑呈清晰透明,边缘光滑整齐;该噬菌体的最佳感染复数为1;一步生长曲线结果显示,感染宿主菌潜伏期为5 min,爆发期为65 min,爆发量为51;可耐受温度范围为30~60 ℃,在pH为5~8的环境中能维持稳定性;噬菌体杀菌试验结果显示,感染复数（MOI）为1时噬菌体vB_EcoM_BP10具有良好的杀菌效果。全基因组测序结果表明,噬菌体vB_EcoM_BP10基因组总片段长度为52 288 bp,GC含量为44.16%,含有71个阅读框（ORF）。GO功能注释表明,噬菌体vB_EcoM_BP10可参与小分子代谢、细胞氮化合物代谢等生物学过程中,具备核苷酸转移酶活性、离子结合、DNA结合等分子功能。与Escherichia phage ST32、 Enterobacteria phage phiEcoM-GJ1的亲缘关系较近。综上所述,噬菌体vB_EcoM_BP10具有清晰的宿主受体特异性,良好的热稳定性和酸碱稳定性,本研究结果能为有效防控产志贺毒素多重耐药大肠杆菌奠定一定的理论基础。     

Phage therapy reduces Campylobacter jejuni colonization in broilers

The effect of phage therapy in the control of Campylobacter jejuni colonization in young broilers, either as a preventive or a therapeutic measure, was tested. A prevention group was infected with C. jejuni at day 4 of a 10-day phage treatment. A therapeutic group was phage treated for 6 days, starting 5 days after C. jejuni colonization of the broilers had been established. Treatment was monitored by enumerating Campylobacter colony forming units (CFU) and phage plaque forming units (PFU) from caecal content. Counts were compared with control birds not receiving phage therapy. A clear 3 log decline in C. jejuni counts was initially observed in the therapeutic group, however, after 5 days bacterial counts stabilized at a level 1 log lower than that of the control group. Colonization of C. jejuni in the prevention group was delayed by the treatment and after an initial 2 log reduction, colonization stabilized within a week at levels comparable to the therapeutic group. The CFU and PFU counts displayed opposing highs and lows over time, indicative of alternating shifts in amplification of bacteria and phages. There were no adverse health effects from the phage treatment. Two different phages were combined as therapeutic treatment of Campylobacter positive chickens challenged at the age approaching broiler harvest. This again resulted in a significant decrease in Campylobacter colonization. We conclude that phage treatment is a promising alternative for reducing C. jejuni colonization in broilers.     

In situ hybridization for the detection and localization of swine Chlamydia trachomatis

Gnotobiotic piglets were inoculated intralaryngeally with swine Chlamydia trachomatis strain R33 or orally with swine C. trachmatis strain R27. Archived formalin-fixed, paraffin-embedded tissues from piglets euthanatized 4-7 days postinoculation were examined by in situ hybridization for C. trachomatis nucleic acid using a nonradioactive digoxigenin-labeled DNA probes that targeted specific ribosomal RNA or omp1 mRNA molecules of the swine C. trachomatis strains. Positive hybridization signals were detected in bronchial epithelial cells, bronchiolar epithelial cells, pneumocytes, alveolar and interstitial macrophages, and jejunal and ileal enterocytes. Chlamydia-infected cells had a strong signal that was confined to the intracytoplasmic inclusions. Positive hybridization signals were not detected in tissue sections from an uninfected control piglet or in C. psittaci-infected sheep placenta. The morphology of host cells was preserved despite the relatively high temperature required in parts of the incubation procedure. The data indicate that in situ hybridization can be used to detect swine C. trachomatis in formalin-fixed, paraffin-embedded tissue specimens.     

餐厨废弃物营养价值及饲料安全性研究进展

随着人们生活质量的提高,餐饮行业发展迅速,产生大量餐厨废弃物（food waste,FW）,严重影响粮食安全并对环境造成污染。目前,FW的资源化利用受到广泛关注,饲料化技术可实现资源价值再生,符合环境可持续性发展的要求,具有经济可行性。FW营养丰富,含有：14.93%~94.20%干物质（DM）、13.53%~42.90%粗蛋白质（CP）、3.89%~31.57%粗脂肪（EE）、0.24%~16.50%灰分（Ash）、2.07%~30.70%粗纤维（CF）、6.72%~38.90%中性洗涤纤维（NDF）、5.29%~25.20%酸性洗涤纤维（ADF）。FW安全性包括物理安全性、生物安全性及化学安全性。FW物理安全性在收集和预处理过程中可以得到保证。FW生物安全性问题主要集中在未经处理的FW容易滋生细菌,如沙门氏菌、大肠杆菌,以及未煮熟的FW饲喂动物可引起口蹄疫、猪瘟及传染性海绵状脑病等疾病的发生。FW化学安全性主要是要求其毒素、农药、重金属等含量要符合卫生标准,同时要注意其中抗营养因子、亚硝酸盐、洗涤剂等的影响。总体上,FW营养价值较高,能在一定程度上满足动物生长的需求,但其生物安全性问题限制了其饲料化应用与发展。     

Development of allele-specific primer PCR for a swine TLR2 SNP and comparison of the frequency among several pig breeds of Japan and the Czech Republic

In the present study, we have developed an allele-specific primer-polymerase chain reaction (ASP-PCR) for genotyping a single nucleotide polymorphism (SNP) of swine Toll-like receptor 2 (TLR2) (C406G), which is related to the prevalence of pneumonia caused by Mycoplasma hyopneumoniae. We also compared the allele frequency among several pig breeds of Japan and the Czech Republic. Allele-specific primers were constructed by introducing 1-base mismatch sequence before the SNP site. The swine TLR2 C406G mutation was successfully determined by the ASP-PCR using genomic DNA samples in Japan as previously genotyped by a sequencing method. Using the PCR condition determined, genomic DNA samples from pig blood obtained from 110 pigs from 7 different breeds in the Czech Republic were genotyped by the ASP-PCR. The genotyping results from the ASP-PCR were completely matched with the results from the sequencing method. The allele frequency of the swine TLR2 C406G mutation was 27.5% in the Czech Republic and 3.6% in Japan. The C406G mutation was only found in the Landrace breed in Japan, and was almost exclusively found in the Landrace breed in the Czech Republic as well. These results indicated the usefulness of ASP-PCR for detecting a specific SNP for swine TLR2.