Antimicrobial resistance in Enterococcus spp. and Escherichia coli isolated from poultry feed and feed ingredients

Poultry feed is at the start of the food safety chain in the "farm-to-fork" model, and might serve as a source of antimicrobial resistant bacteria present in poultry meat. Antimicrobial resistance was investigated in 1137 enterococci and 163 Escherichia coli strains recovered from 23 samples of commercial broiler feed and 66 samples of raw feeding materials taken over half a year timespan. Enumeration of enterococci and E. coli were also performed using traditional plating and fluorescent in situ hybridisation methods. Viable enterococci were detected in all feed samples and in 66% of samples of separate feed ingredients, while E. coli was present in 50% and 32% of feed and raw feeding materials, respectively. The median values (50th percentile) for plate and FISH counts for feeds were, respectively, 2.70 log CFU/g and 5.52 log cells/g for enterococci, and 0.15 log CFU/g and 6.00 log cells/g for E. coli. Among enterococci recovered from feed ingredients, resistance to rifampicin, erythromycin, nitrofurantoin, tetracycline, and ciprofloxacin was found in 59.8%, 21.6%, 21.2%, 18.0% and 6.9% of the isolates, respectively. A considerable proportion of the enterococci isolates obtained from broiler feed displayed resistance to tetracycline (69.1%), rifampicin (58.5%), erythromycin (52.9%) and nitrofurantoin (36.2%). Lower percentage of resistance was observed to chloramphenicol (4.6%), ciprofloxacin (3.9%), vancomycin (1.9%) and ampicillin (1.2%). Among E. coli recovered from feed ingredients and poultry feeds, resistance to ampicillin, tetracycline and streptomycin was found in 22.9%, 27.6% and 19.0% and in 22.4%, 41.4% and 17.0% of the isolates, respectively. These data show that feedstuffs and poultry feeds are extensively contaminated by resistant enterococci and, in a lesser extent, by E. coli, thus leading to their introduction in the farm environment.     

复合纳他霉素配方组合在饲料中应用研究

作为天然、高效、低毒、实用型防霉剂－纳他霉素已广泛用于食品、饮料、水果、肉制品中。由于纳他霉素主要对霉菌及酵母有抑制作用，对细菌无效，而在各种饲料贮藏期间细菌危害也很严重，对产品质量有很大影响。因此实验拟采用两种低成本、高效，低毒的防腐剂与纳他霉素配制成复合配方，对鱼用饲料进行防腐防霉抑菌实验。实验结果表明，所用复合配方有很好效果，使用10mg/kg复方制剂可抑制鱼饲料中各种细菌及霉菌的生长。     

液体饲料发展动向

近年来，世界各地的饲料厂使用液体饲料的数量正在不断增长，这种情况在工业化国家尤为明显。因为他们有输送、贮存散装液体饲料的设备可利用。在我国，液体添加技术还是一项新兴技术，而液体饲料的生产还刚刚起步，对于液体饲料的资源和应用技术等方面认识还不够，本文就液体饲料的应用作一概述。１液体饲料的优缺点液体饲料通常是指脂肪或植物油和含糖分的物质，除了这些主要成分外，也要增加微量成分。相对干物质而言，应用液体饲料具有以下好处。①液体饲料中养分的生物利用率较高。例如，脂溶性维生素可以以它的自然状态于液体脂肪中来…     

不确定度评定在饲料卫生学霉菌捡验中的应用

按GB/T 13092-1991规定进行霉菌检验,介绍了不确定度评定在饲料卫生学霉菌检验中的应用.结果表明,将重复性试验结果取对数后,用合并样本标准差计算霉菌检测结果的A类不确定度的程序很方便,所得的不确定度适用于多个样本.     

L—肉碱在家禽饲料营养中的应用

L－肉碱(L－Carnitine,β－羟基－γ－三甲胺基丁酸)又叫肉毒碱，是一种类维生素营养素，相当于B族维生素，具有多种生理功能，是哺乳动物必不可少的重要生理活性物质。其分子量为161.20，分左右旋消旋三种异构体D－型、L－型以及消旋型。D－型（右旋）肉碱由于肉碱乙酰转移酶（CAT）和肉碱脂肪酰转移酶（PTC）相互竞争抑制，能使右旋肉碱乙酰转移酶失活，故只有L－肉碱具有生理活性。商品肉碱王约含左旋肉碱50％。L－肉碱在生物体内主要存在于骨骼肌和心肌，且主要在成年动物体内由赖氨酸、蛋氨酸、烟酸、维生素B6、维生素C以及Fe2…     

酵母源生物饲料在家禽养殖中的应用

酵母是一种重要的单细胞微生物,与人们的日常生活和工业应用密切相关.酵母的生产和发展已经有200多年的历史.在美国,用酵母产品饲喂动物的历史已超过100年.这些产品包括在农场里制作的酵母发酵饲料、酿酒厂产生的酵母副产品以及专门为饲喂动物而生产的商业性酵母产品(龙凌,2001).酵母在饲料中最初作为单细胞蛋白产品替代饲料中部分鱼粉,不仅解决了部分地区蛋白资源紧缺的问题,也大大降低了饲料成本.随着酵母工业的发展和对酵母产品的研究不断加深,酵母及其相关产品在饲料工业中有了更广泛的应用,也展现出了广阔的应用前景.     

益生素在畜禽饲料中的应用

益生素（Ｐｒｏｂｉｏｔｉｃｓ）是“一种活的、能够有效促进肌体调节肠道内微生物平衡的微生物添加剂”（Ｆｕｌｌｅｒ,１９８８）。益生素也称活菌剂、生菌剂 ,其主要作用是在数量或种类上补充肠道内减少或缺乏的正常微生物 ,调节动物胃肠道微生物的平衡功能 ,维持胃肠道的正常生理功能。它是一种无毒、无副作用、无残留及无抗药性、不污染环境的新型饲用活菌制剂 ,因而被认为是绿色饲料添加剂 ,在畜禽饲料中将得到广泛应用。益生素作为饲料添加剂 ,其作用原理与抗生素正相反 ,是向动物消化道内导入对动物有益的活菌 ,帮助动物建立有利于…     

壳聚糖及其在家禽饲料中的应用

壳聚糖又称脱乙酰甲壳素聚氨基葡萄糖,是甲壳素脱乙酰后的产物。甲壳素是自然界中产量仅次于纤维素的天然产物,广泛存在于虾、蟹等甲壳动物外壳中。壳聚糖因具有优良的生物相容性,可被溶菌酶溶解,可生物降解,其代谢产物无毒,且能被生物体完全吸收等独特的理化特性,在医药、食品、化妆品、农业及环境等方面应用较为广泛。而壳聚糖作为一种极有潜力的饲料添加剂只是在近几年才开始进行研究开发的,本文将对近年有关壳聚糖在家禽饲料中的应用效果进行总结分析。1壳聚糖结构与理化性质壳聚糖是甲壳素脱乙酰后的产物,化学名称为β-(1,4)-2脱氧-D-…     

The immunogenicity and pathogenicity of Pasteurella multocida isolated from poultry in Indonesia

Of 13 field isolates of Pasteurella from chickens and ducks in Indonesia, 10 were confirmed as P. multocida subspecies multocida, one as P. multocida subspecies gallicida and one as P. multocida subspecies septica. Nine were capsular Type A four were Serotype 1, one was Serotype 4, one was Serotype 11, one was Serotypes 4,12, and the remaining six were untypable. Five isolates were pathogenic for mice and two were pathogenic for chickens. Both a trivalent vaccine which included local field isolates and an imported commercial vaccine, were efficacious in layer chickens against challenge with virulent reference and local field strains. Though not statistically significant, the protection provided by the trivalent vaccine against virulent field isolate challenge was slightly better and could provide an improvement over the currently used imported vaccine although further field trials are required. A bacterin vaccine produced from a Serotype 1 field isolate grown in the allantoic sac of embryonated chicken eggs provided chickens with good cross protection against heterologous serotype challenge.     

磷脂在猪禽饲料中的应用

磷脂在细胞膜功能、生物合成、生理代谢和免疫应答等方面发挥重要功能,为脂肪代谢所必需。饲料中补充磷脂可有效地改善畜禽脂肪消化和养分利用,提高其生产性能,且能够乳化饱和脂肪和减少脂肪添加量,降低饲料成本。本文综述了磷脂的生物学功能及其在畜禽生产上的应用。     

禽腺病毒家禽分离株的生物学特性

为了解禽腺病毒(FAV)家禽分离株的致病性,通过病毒凝集试验、电镜观察、细胞病变试验以及接种鸡胚或鸡体,研究了3株A型FAV分离株的生物学特性。结果表明,分离株具有腺病毒的典型形态,不能凝集鸡的红细胞;不引起鸡胚成纤维细胞的病变,可导致鸡胚肾细胞变圆、折光性增强;对SPF鸡胚无明显致病作用;以1.0×1010TCID50的剂量,经皮下注射和口服2种途径接种1日龄的SPF鸡,攻毒后未出现明显的临床症状,体重和免疫器官的重量基本不受影响,除肝脏出现一过性病变,大部分脏器基本无病变。因此,FAV分离株致病性低,生物安全性高,可能是较好的FAV载体。     

A serotypic survey of Pasteurella multocida isolated from poultry

One hundred forty-eight Pasteurella multocida isolates from four southeastern states and California were serotyped by a gel diffusion precipitin test. The isolates were predominantly from turkeys and chickens. Sixty-eight percent of the isolates had antigenic characteristics of serotypes 3 and 4 (3 X 4). In turkeys, 76% of the isolates were 3 X 4, and serotype 3 was second (17%) in frequency. In chickens, 54% of the isolates were 3 X 4 and 19% were serotype 1.     

Antimicrobial susceptibility of Enterococcus strains isolated from poultry faeces

We have investigated the resistance of Enterococcus isolated from poultry faeces to antibiotics commonly used as therapy of enterococcal infections. Identification was made by the method of Facklam and Collins. Minimal inhibitory concentrations of penicillin, ampicillin, vancomycin and teicoplanin were determined and high level aminoglycoside resistance was investigated. Genes codifying high level aminoglycoside resistance (HLAR) were determined by PCR. Fifty five Enterococcus strains were isolated (63.6% E. faecalis, 12.7% E. mundtii, 9.1% E. faecium, 7.3% E. casseliflavus, 3.7% E. durans and 3.6% E. hirae). None of the strains were resistant to VAN, TEC, P or AM. HLAR was found in 34.5% of strains for SM, 27.3% for KM and 7.3% for GM. The gene for the bifunctional enzyme was found only in one strain, that showed HLAR to GM and KM. Fourteen strains harboured the gene aph(3')-III, being 11 resistant to KM and STR, and three resistant to GM, KM and STR. The remaining six strains showed HLAR to STR, but were negative for the three genes tested by PCR. The gene ant(4'4") was not detected in any of the strains. No unexpected vancomycin resistance was detected. The resistance rates among poultry strains were lower than those found among human strains isolated from hospital patients in recent Canary studies.     

发酵饲料在家禽生产中的应用

饲料原料经过微生物发酵,可以降解抗营养因子和毒素,提高饲料利用率.发酵饲料对提高家禽生产性能、调节肠道菌群、维持肠道微生态平衡及增强机体免疫力具有积极作用.文章对发酵饲料的作用机理及其在家禽生产中的应用研究进行综述,对发酵饲料的应用前景进行展望,对发酵饲料与发酵工艺存在的问题进行探讨,为发酵饲料在家禽中的应用提供参考.     

Transfer of fat-soluble pesticides from contaminated feed to poultry tissues and eggs

1. Implementation of Good Manufacturing Practice and HACCP (Hazard Analysis Critical Control Points) in the production of poultry feed requires efficient tools for profiling risks associated with pesticide use in the production of crops for feed. 2. This paper describes a simple model that may be of use in the first tiers of risk profiling of feeds. 3. The model adequately reproduced the pattern of residues in fat and eggs of laying hens dosed with a selection of lipophilic pesticides that may be used in the production of crops for poultry feeds: deltamethrin, diflubenzuron, fipronil, lindane, piperonyl butoxide and spinosad. 4. Simulations suggest results derived from studies on laying chickens can be extrapolated to other laying birds. 5. Poultry meat production systems focus on maximising growth of birds giving rise to significant potential for dilution of residues that transfer to fat from feed. 6. Simulations of residues in fat of chickens, ducks, geese and turkeys exposed to a lipophilic pesticide with an elimination half-life of one day at 10 mg/kg body weight/d from hatching to typical market ages suggest residues in fat that are highest in turkeys > chickens > geese > ducks. 7. The model is of use in interpreting published dosing studies and predicting likely residues in birds at times after last exposure/dosing.