不同抗生素对肉用仔鸡生产性能的影响

本试验比较了不同抗生素对肉鸡生长速度和抗病力的影响。试验分为４个组，第１组采用正大肉鸡料５１０、５１１、５１３为对照组，第２、３、４组为试验组，分别添加土霉素、杆菌肽锌＋硫酸粘杆菌素、硫酸粘杆菌素，４个组饲粮营养成分的分析结果基本相同。２０００只爱拔益加肉鸡分４个处理，每个处理５个重复，每个重复１００只鸡。试验结果证明，４个组鸡只成活率有显著的差异（Ｐ＜０．０１），分别为８７．７％、９４．９％、９３．３％、８９．７％。４种料的增重效果也有较大的差异。土霉素组与杆菌肽锌＋硫酸粘杆菌素和硫酸粘杆菌素组比较，日增重依次提高１１．６％、１０．２％。料肉比组间差异极显著（Ｐ＜０．０１），以杆菌肽锌＋硫酸粘杆菌素料组为最低，其次为上霉素组、硫酸粘杆菌素组，正大组饲料报酬最高。增重的饲料成本依次为４．８３元／ｋｇ、４．５２元／ｋｇ、４．５５元／ｋｇ、４．７５元／ｋｇ。与产品效益相联系综合分析结果，杆菌肽锌＋硫酸粘杆菌素组饲料和硫酸粘杆菌素组饲料的经济效益较好。     

饲料添加剂的现状和前景(三)

四、抗生素 4.硫酸粘杆菌素和比考扎霉素硫酸粘杆菌素(Colistin Sulfate)硫酸粘杆菌素是出多粘杆菌变种、粘杆菌培养制成的,是以粘杆菌素A和粘杆菌素B为主要成分的多肽类抗生素之一。其1μg(效价)相当于30单位。对大肠杆菌和革兰氏阴性菌有抗菌力,因此除用于促进生长外,还可达到预防肠道感染的目的。使用情况粘杆菌素为人畜共有抗生素。日本在鸡、猪、牛的饲料中都有使用。美国及欧洲尚未作饲料添加剂。在台湾和东南亚地区已作为饲料添加剂使用。比考扎霉素(Bicozamyein) 比考扎霉素是由Streptomyces griseoflavus培     

鸡组织中硫酸粘杆菌素残留的微生物学检测方法研究

在国内首次以支气管炎博代特氏菌（Bordetella bronchiseptica）ATCC4617作为检测菌株，用PBS提取鸡肌肉组织，用5％硫酸提取鸡肝脏和肾脏组织中的硫酸粘杆菌素，应用一剂量法设计原理制备肌肉、肝脏和肾脏组织标准曲线。硫酸粘杆菌素检测限肌肉组织为0．15μg／g，肝脏和肾脏组织均为0．20μg／g，低于我国农业部和欧盟规定的粘杆菌素最高残留限量。肌肉、肝脏和肾脏组织标准曲线在0．025—6．4μg／mL范围内线性关系良好，r分别为0．9970、0．9994、0．9990，n=9。以高、低（300mg／L、60mg／L按效价计）两个剂量给鸡饮水给药，肌肉高、低剂量组均未检测出硫酸粘杆菌素残留，肝脏和肾脏低剂量组未检测出硫酸粘杆菌素残留，高剂量组0h有微量残留。     

硫酸粘杆菌素与甘氨酸联合用药的研究进展

近年来,由于耐药细菌的不断出现,粘杆菌素在临床上又重新受到兽医工作者的青睐。甘氨酸具有良好的抗炎、免疫作用,且对肝、肾功能具有一定保护作用。甘氨酸和硫酸粘杆菌素联合用药可以有效地拮抗内毒素引起的发热,并且降低单一药物的使用剂量,减轻硫酸粘杆菌素的毒副反应等。因此,与甘氨酸配伍制备增效降毒的硫酸粘杆菌素注射液,具有极大的发展前景和推广应用价值。     

硫酸粘杆菌素、活菌制剂及酶制剂对仔猪生长的影响

选用30日龄杜×长·大三元杂交商品仔猪40头,研究了硫酸粘杆菌素、活菌制剂及酶制剂在基础日粮中单独使用与配合使用对促进仔猪生长及防治腹泻的效果。结果表明,各试验组仔猪平均日增重比对照组有显著提高。其中以在基础日粮中添加硫酸粘杆菌素20mg/kg与添加活菌制剂200mg/kg配合使用效果最明显,比对照组提高了16.7%(P<0.05)。在饲料转化率方面,添加硫酸粘杆菌素20mg/kg不明显,添加硫酸粘杆菌素20mg/kg 活菌制剂200mg/kg和硫酸粘杆菌素20mg/kg 酶制剂1g/kg两组均比对照组有显著提高(P<0.05),从防治腹泻情况看,对照组仔猪腹泻率28%,添加硫酸粘杆菌素20mg/kg腹泻率8.5%,添加硫酸粘杆菌素20mg/kg 活菌制剂200mg/kg和添加硫酸粘杆菌素20mg/kg 酶制剂1g/kg两组未见腹泻。利用硫酸粘杆菌素,特别是将其分别与活菌制剂和酶制剂配合使用,对提高仔猪日增重和饲料转化率以及防止仔猪腹泻发生都有较好效果。     

高效液相色谱法测定饲料中硫酸粘杆菌素含量

本文提出了通过高效液相色谱法(HPLC)快速、简便测定饲料中硫酸粘杆菌素的含量。该方法首先用超声波法提取饲料中的硫酸粘杆菌素,通过旋转蒸发将提取液浓缩后,利用HPLC进行检测。结果表明,在最优检测条件下,提取液中硫酸粘杆菌素与杂质分离良好,其浓度为0.5～400μg/mL与峰面积呈线性相关(r=0.9967);饲料样品回收率87.3%～112.6%,变异系数(RSD)小于5%;其他饲料常规成分在实验条件下对硫酸粘杆菌素测定均无干扰,此方法的适用范围广,可满足饲料中硫酸粘杆菌素的检测。     

硫酸粘杆菌素对雏鸡红细胞的影响

通过测定红细胞C3b受体(C3bR)花环率和免疫复合物(IC)花环率,研究了不同添加剂量的硫酸粘杆菌素对雏鸡红细胞免疫功能的影响。试验分为5组,分别为I组(基础日粮对照组)、II组(基础日粮+20mg/kg硫酸粘杆菌素试验组)、III组(基础日粮+40mg/kg硫酸粘杆菌素试验组)、IV组(基础日粮+60mg/kg硫酸粘杆菌素试验组)和V组(基础日粮+80mg/kg硫酸粘杆菌素试验组),结果表明,随日龄和剂量增加,雏鸡红细胞C3b受体花环率和免疫复合物花环率下降,说明不同剂量硫酸粘杆菌素均可不同程度导致雏鸡免疫功能受损,其中80mg/kg添加组最为明显。     

抗菌肽替代硫酸粘杆菌素对断奶仔猪生长性能及腹泻的影响

试验通过在断奶仔猪的饲粮中添加抗菌肽和硫酸粘杆菌素,对比研究其对断奶仔猪生长性能和腹泻的影响。试验1组在饲粮中添加0.5%的抗菌肽制剂,试验2组在饲粮中添加0.5%的抗菌肽制剂和200mg/kg的硫酸粘杆菌素,对照组在饲粮中添加200 mg/kg的硫酸粘杆菌素,试验期20 d。试验结果显示,3组的头均日增质量分别为450、540和410 g,料肉比分别为1.47、1.45和1.58。可见抗菌肽对断奶仔猪促生长作用明显优于硫酸粘杆菌素,且两者具有协同效应,此外抗菌肽和硫酸粘杆菌均能有效防治仔猪腹泻。     

硫酸粘杆菌素(Colistin sulfate)对大肠杆菌的抗生素后效应

用微量稀释法潮定的硫酸粘杆菌素(colistinsulfate)对4株大肠杆菌的最小抑茵浓度(MIC)和最低杀菌浓度(MBC)。分剐为0．2～O．8mg／k和0．8～1．6mg／k。2MIC硫酸粘杆菌素对4株大肠杆菌作用2h后。l000倍稀释去除药物。硫酸粘杆菌素对4株大肠杆菌的抗生素后效应(PAE)在1．062-2．017h之间。64、32、16、8、4、2MIC硫酸粘杆菌素对大肠杆菌CMCC44103作用2h后。l000倍稀释去除药物。硫酸粘杆菌素PAE的平均值分别为0．517、2．487、2．037、1．727、1．467、1．057h。PAE与药物浓度呈正相关。     

微生态制剂肽菌素在断奶仔猪上的应用研究

试验在断奶仔猪日粮中添加肽菌素、硫酸粘杆菌素,通过测定断奶仔猪生长性能免疫器官指数及胃肠道p H等指标,探讨肽菌素在断奶仔猪生产上的应用效果。结果表明:肽菌素和硫酸粘杆菌素均能促进断奶仔猪生长,从增重改善程度看,1~28d全期1‰肽菌素组效果优于对照组和硫酸粘杆菌素组15.0%(P0.05)和9.5%(P0.05);全期1‰肽菌素组料重比均低于对照组和硫酸粘杆菌素组10.5%(P0.05)和5.26%(P0.05);1‰肽菌素组肝脏指数和脾脏指数分别比硫酸粘杆菌素组提高14.60%(P0.05)和12.45%(P0.05);1‰肽菌素组的胃和十二指肠的p H均低于对照组和硫酸粘杆菌素组21.21%(P0.05)和19.81%(P0.05)。综上所述,日粮中添加1‰肽菌素可促进断奶仔猪的生长性能、提高机体免疫力、降低胃肠道p H、控制断奶仔猪腹泻率,效果优于硫酸粘杆菌素。     

阿莫西林和硫酸粘菌素对猪鸡大肠杆菌和沙门氏菌的体外联合抗菌作用

探讨了阿莫西林与硫酸粘菌素对猪鸡的大肠杆菌和沙门氏菌的联合抗菌效果。采用微量稀释法分别测定阿莫西林与硫酸粘菌素单药对大肠杆菌和沙门氏菌的最低抑菌浓度（MIC）,采用棋盘稀释法测定阿莫西林与硫酸粘菌素联用对大肠杆菌和沙门氏菌的MIC并计算联合指数（FIC）。试验结果显示,对14株试验菌株体外联合抗菌呈协同与相加作用的占78.6%,呈无关作用的占21.4%,无拮抗作用,表明阿莫西林和硫酸粘菌素可联合应用于治疗猪鸡大肠杆菌和沙门氏菌感染。     

Rapid one-step enzyme immunoassay and lateral flow immunochromatographic assay for colistin in animal feed and food

Background: Colistin(polymyxin E) is a kind of peptide antibiotic which has been approved in animal production for the purposes of disease prevention, treatment, and growth promotion. However, the wide use of colistin in animal feed may accelerate the spread of colistin-resistance gene MCR-1 from animal production to human beings,and its residue in animal-origin food may also pose serious health hazards to humans. Thus, it is necessary to develop corresponding analytical methods to monitor the addition of colistin in animal feed and the colistin residue in animal-origin food.Results: A one-step enzyme-linked immunosorbent assay(ELISA) and a lateral flow immunochromatographic assay(LFIA) for colistin were developed based on a newly developed monoclonal antibody. The ELISA showed a 50%inhibition value(IC50) of 9.7 ng/m L with assay time less than 60 min, while the LFIA had a strip reader-based detection limit of 0.87 ng/m L in phosphate buffer with assay time less than 15 min. For reducing the non-specific adsorption of colistin onto sample vial, the components of sample extraction solution were optimized and proved to greatly improve the assay accuracy. The spiked recovery experiment showed that the recoveries of colistin from feed, milk and meat samples were in the range of 77.83% to 113.38% with coefficient of variations less than 13% by ELISA analysis and less than 18% by LFIA analysis, respectively. Furthermore, actual sample analysis indicated that the two immunoassays can produce results consistent with instrumental analysis.Conclusions: The developed assays can be used for rapid qualitative or quantitative detection of colistin in animal feed and food.     

Toxicity, bioavailability and pharmacokinetics of a newly formulated colistin sulfate solution

We formulated a new colistin sulfate injectable solution and tested its effectiveness, toxicity and pharmacokinetics in vivo on mice, rabbits, and piglets. When intramuscularly injected (i.m.) into rabbits at 0.5 mL per site, the 2.5% colistin sulfate solution caused no reaction at the injection site, but the 5.0% solution caused the muscle circumference to appear erythematic. Tested LD50 in CD-1 mice were 38.72 mg/kg for i.m. and 431.95 mg/kg for oral administration, respectively. At 15.0 mg/kg/day (i.m.) for 5 days, colistin sulfate caused obvious neurotoxicity to piglets with moderate granular degenerations in the epithelial tissues from kidney and liver. These toxic responses were not seen when colistin sulfate was injected at 10.0 mg/kg/day for 5 days. Pharmacokinetic studies revealed Cmax of 3.73 +/- 0.28 and 6.40 +/- 0.18 microg/mL, Tmax of 32 +/- 1.5 and 34 +/- 1.8 min, t(1/2beta) of 256 +/- 14 and 264 +/- 29 min, and absolute bioavailability of 95.94 and 88.45% for colistin sulfate intramuscularly injected to piglets at 2.5 and 5.0 mg/kg, respectively. Serum colistin sulfate concentration followed a two-compartment open model showing first-order absorption. The high bioavailability and the long-lasting serum retention time indicated that the new solution is suitable for i.m. in piglets with a recommended dose of 2.5 mg/kg injected twice daily.     

Effect of fishmeal replacement with spray-dried animal plasma and colistin on intestinal structure,intestinal microbiology,and performance of weanling pigs challenged with Escherichia coli K99

We evaluated spray-dried animal plasma (SDAP) as an alternative to antimicrobial medication with colistin sulfate in weanling pigs challenged with Escherichia coli K99. Forty-eight piglets weaned at 24 d of age were distributed into 12 pens, and each pen was assigned to one of four dietary treatments. All the piglets were given an oral dose of 5 x 10(7) cfu of E. coli K99 at weaning. The dietary treatments followed a factorial arrangement with two levels of SDAP (0 and 7%) and two levels of colistin (0 and 300 mg/kg of diet). The ADG and ADFI were measured on d 7 and 14 of trial. Three piglets from each treatment were killed on d 7 and 14 to remove the small intestine, and to obtain ileal and cecal digestive contents. The inclusion of SDAP improved ADG by 68 g (P < 0.05) and ADFI by 41 g (P < 0.10) in wk 1 of trial. During wk 2, SDAP improved ADG by 41 g (P < 0.10) and gain:feed ratio (G:F) by 25% (P < 0.01). On the other hand, whereas colistin had no effect on performance in wk 1, it improved ADG by 102 g (P < 0.01), ADFI by 62 g (P < 0.01), and G:F by 26% (P < 0.01) in wk 2. Over the 14 d of the trial, ADG was improved by 54 (P < 0.05) and 75 g (P < 0.05), and G:F was improved by 35 (P < 0.05) and 32% (P < 0.05) due to SDAP and colistin, respectively. There was interaction between colistin and SDAP for ADFI in wk 2 and between d 0 to 14 (P < 0.05), which indicates that their effects were not additive. The use of colistin was advantageous in the maintenance of the integrity of the intestinal mucosa of the pigs, as suggested by a small intestine that was 93 g heavier (P < 0.10) and with the tallest villi 106 microm longer (P < 0.10) than in pigs without colistin. The inclusion of SDAP in the diet favored the growth of lactobacilli in the ileum (P < 0.10) and the cecum (P < 0.05), whereas colistin reduced the number of enterococci in the cecum (P < 0.05) and of Escherichia coli both in the ileum and the cecum (P < 0.001). These results suggest that SDAP may be an alternative to medicated feed with antibiotics since it provided a level of protection against an experimental challenge with E. coli K99 similar to that obtained with colistin, an antibiotic of proven efficacy. The current situation in which the use of antimicrobials in animal feeding is being questioned should encourage further investigation into the use of SDAP as a means of preventing disease in pigs at weaning.     

Frequent use of colistin-based drug treatment to eliminate extended-spectrum beta-lactamase-producing <Emphasis Type="Italic">Escherichia coli</Emphasis> in backyard chicken farms in Thai Binh Province,Vietnam

Reports of livestock infections with extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-E) are increasing. Based on interviews conducted over a 6-month period, we found that veterinarians in the Vietnamese province of Thai Binh prefer to prescribe colistin-based drugs (CBD) in chicken farms. We aimed to clarify whether CBD use selects for strains of colistin-resistant ESBL-E. With the cooperation of seven local households, we detected ESBL-E in chickens’ feces after treating chickens with CBD. Phylogenetic groupings and the presence of CTX-M/AmpC genes were determined, and the multi-antibiotic susceptibility of isolates was analyzed. Our results showed that ESBL-E presented in seven chickens’ feces from two households. Seventy-two percent of ESBL-E isolates harbored CTX-M9 and the phylogenetic group A; the colistin minimum inhibitory concentration (MIC) of all isolated ESBL-E ranged from 0.064 to 1 μg mL^?1. Moreover, ESBL-E isolates were used to experimentally select for colistin resistance, and the effect of commercial CBD on ESBL-E was investigated. The results showed that an ESBL-E strain with a colistin MIC of 4 μg mL^?1 was able to grow in media with CBD. Although CBD treatment was effective, in vitro experiments demonstrated that ESBL-E can easily acquire colistin resistance. Therefore, restrictions on colistin use are necessary to prevent the emergence of colistin-resistant bacteria.     

The pharmacokinetics and tissue levels of polymyxin B, colistin and gentamicin in calves

Following a single intravenous injection of polymyxin B, colistin (5 mg/kg, each) and gentamicin (3 mg/kg) to calves, the decline in serum antibiotic concentration generally suggested a three-compartment (open system) pharmacokinetic model. Tissue binding is a dominant factor in the distribution and elimination kinetics of the drugs. Less than 65% of the dose of polymyxin B and colistin was recovered in the urine during 48 h after treatment. Concentrations of nonbound polymyxin B and colistin in the kidney, liver, lung, heart, and skeletal muscles were similar to total (free and bound) serum drug levels, but considerably higher concentrations were found, in bound form, in chloroform-ethanol extracts of these organs.
At 24 h after treatment, more than 50% of the doses of polymyxin B and colistin were present bound to the tissues; the largest amount was in the skeletal muscles. Gentamicin was concentrated in the kidney, predominantly in the free form. At 48 h after treatment the amount of gentamicin in the kidney was 6.3% of the administered dose, being more than five times greater than the corresponding amounts of polymyxin B and colistin.
The extent of tissue uptake of polymyxin B and colistin limits the usefulness of kinetic values, which are derived from the analysis of serum drug levels, for the purpose of designing dosage schedules. The strong affinity of the polymyxins to the muscle tissue, and gentamicin to the kidney, can result in drug residues persisting in the body for several weeks.     

羊肉中多黏菌素A和多黏菌素B液相色谱—串联质谱检测方法的建立

[目的] 建立一种液相色谱—串联质谱同步测定羊肉中多黏菌素A和多黏菌素B的方法。[方法] 样品经10%三氯乙酸水溶液—乙腈溶液提取,WCX固相萃取柱净化,0.1%甲酸水溶液作为流动相进行梯度洗脱,流速0.30 mL/min,多反应监测（MRM）正离子模式扫描,用液相色谱—串联质谱仪检测,基质添加标准溶液外标法定量。[结果] 多黏菌素A和多黏菌素B在5.0~110.0 μg/L浓度范围内呈良好线性关系,线性相关系数R>0.996,方法的定量限为0.50 μg/kg,3个添加水平的平均回收率为73.2%~115.6%,RSD≤10.0%。[结论] 该方法高效、准确,适用于羊肉样品中多黏菌素A和多黏菌素B的定量及确证检测。     

硫酸粘杆菌素的急性毒性及对小鼠骨髓细胞的微核效应

为评价国产硫酸粘杆菌素的安全性 ,进行了改良寇氏法测定LD50 小鼠骨髓细胞的微核试验。结果显示 ,国产硫酸粘杆菌素的LD50 为 71 1 45mg/kg ,属于低毒类化合物 ;小鼠骨髓微核试验结果为阴性 ,表明其不具致突变作用     

我国鸡源沙门氏菌的血清型分布和对黏菌素耐药性的研究

黏菌素是目前临床治疗多重耐药革兰阴性菌感染的重要药物之一,mcr-1基因的携带可介导黏菌素耐药性的产生和扩散。鸡源沙门氏菌作为重要的食源性病原菌,其血清型分布、对黏菌素的耐药性及mcr-1基因的携带对于公共卫生安全具有重要意义。研究对2014-2016年从全国12个省份成鸡分离的450株沙门氏菌进行了血清分型;用微量肉汤稀释法进行了对黏菌素的MIC检测;并用PCR方法对mcr-1基因的携带情况进行了调查。结果表明,鸡源沙门氏菌的优势血清型以肠炎、鸡白痢和鼠伤寒为主;肠炎沙门氏菌对黏菌素的耐药性最强(62.9%),其次为鸡白痢(50.5%)和杜伊斯堡(38.1%);鼠伤寒沙门氏菌对黏菌素最敏感(仅7.1%的菌株耐药);未检测出mcr-1基因阳性的沙门氏菌。研究结果为鸡源沙门氏菌感染的防控以及兽医临床黏菌素的使用和风险评估提供了技术参考。