为了研究湘黄鸡鸡蛋中氟苯尼考的残留消除规律,本试验采用氟苯尼考的标准治疗剂量拌料给药饲喂产蛋高峰期的湘黄鸡,连续用药5 d,从给药前1 d开始收集鸡蛋以备检测,连续收集30 d,使用液相色谱-串联质谱法测定鸡蛋中氟苯尼考及其代谢产物氟苯尼考胺的含量.结果表明,在停药第15天时,湘黄鸡鸡蛋中氟苯尼考、氟苯尼考胺的残留量低于现行农业农村部指定检测方法的检出限.

本实验建立饲料中环丙氨嗪含量的分析方法.试样采用 1%三氯乙酸/乙腈(20:80)溶液提取,经MCX固相萃取柱净化,采用磷酸缓冲盐+甲醇+乙腈(93:5:2)为流动相洗脱,C18 色谱柱(4.6×250 mm,5 μm)分离,在检测波长214 nm下进行测定,外标法定量.在浓度 0.2-50.0 mg/L范围内线性关系良好(R≥0.999),在 0.5 μg/kg、5 μg/kg和50 μg/kg添加水平下,平均回收率为75.3%-97.9%,相对标准偏差均少于10%,方法定量限0.5 mg/kg.该方法灵敏、简单、重复性好,适用于饲料中环丙氨嗪的测定.

在动物养殖过程中,抗生素滥用导致了动物源性食品药残超标和耐药细菌等严重问题.随着"无抗"养殖的推广,益生菌作为替代策略被用于动物养殖中.关注益生菌的主要功能和其作用机理,以及近年来在动物养殖等方面应用的研究进展,以期为益生菌在动物无抗养殖生产中的应用提供参考.

IntroductionGelsemium elegans (G. elegans) as a traditional medicinal plant used in livestock production. The use of G. elegans in veterinary clinics may pose safety risks to human health.ObjectivesThe aim of this study was to investigate tissue residue depletion in pigs fed G. elegans powder.MethodsA precise quantitation method and a simultaneous semi-quantitation method for multiple components independently of standards in pig tissues were developed for the first time. The two methods were validated in terms of specificity, LODs, LOQs, linearity, accuracy, precision, and matrix effects. They were then applied to a tissue residue depletion study after G. elegans powder at a dose of 2% per kg feed were fed to pigs.ResultsCompared with precise quantitation, the method validation results indicated that the semi-quantitation method was reliable and acceptable for multicomponent quantification independent of standards. Many G. elegans alkaloids are widely distributed in most tissues of pigs. Tissue residue depletion studies indicated that 14-hydroxygelsenicine, 11-hydroxygelsenicine, and gelsemoxonine could be used as potential residue markers, and pancreas, small intestine, and lung tissues could be considered as potential residue target tissues of G. elegans. In addition, both urine and plasma could be used to predict 14-hydroxygelsenicine and gelsemoxonine residues in the liver, pancreas, and small intestinal tissues of pigs.ConclusionThe developed semi-quantification method can be applied to monitor the application and residue of G. elegans. The results provide scientific evidence for evaluating the safety of animal-derived food from G. elegans for consumers and will be helpful for its application and future development.

Antibiotics have been extensively used to ensure the productivity of animals on intensive livestock farms. Accordingly, antimicrobial-resistant organisms, which can be transmitted to humans via the food chain, pose a threat to public health. The Enterobacterium antimicrobial resistance gene, blaNDM-1, is a transmissible gene that has attracted widespread attention. Here, we aimed to investigate the prevalence of Enterobacteriaceae carrying blaNDM-1 on an intensive pig farm. A total of 190 samples were collected from a pig farm in Hunan Province, China. Resistant isolates were selected using MacConkey agar with meropenem and PCR to screen for blaNDM-1-positive isolates. Positive strains were tested for conjugation, antimicrobial susceptibility, and whole-genome sequencing. Four blaNDM-1-positive Providencia strains were obtained, and multidrug resistance was observed in these strains. The structure carrying blaNDM-1 did not conjugate to E. coli J53 after three repeated conjugation assays. This suggests that, in intensive farming, attention should be focused on animal health and welfare to reduce the frequency of antibiotic usage. Carbapenem-resistant Enterobacteriaceae in the breeding industry should be included in systematic monitoring programs, including animal, human, and environmental monitoring programs.

Background Gelsenicine, one of the most toxic alkaloids of Gelsemium elegans Benth ( G. elegans), causes severe respiratory depression. However, its toxicity mechanisms are yet to be elucidated and no effective antidotes are available. Objective This study aimed to analyse the toxicity characteristics of gelsenicine. Methods Both acute and sub-acute toxicities were evaluated. Gelsenicine distribution and elimination in the central nervous system (CNS) and blood were observed. Effective antidotes for gelsenicine poisoning were screened. Results In the acute toxicity study, gelsenicine was highly toxic, and female rats exhibited greater sensitivity to gelsenicine than male rats (LD 50 0.520 mg/kg vs 0.996 mg/kg, respectively). Death was primarily caused by respiratory failure. However, in the sub-acute toxicity study, no significant organ damage was observed. Gelsenicine was easily absorbed from the gastrointestinal tract and penetrated the blood–brain barrier, reaching peak concentrations in the CNS within 15 min and rapidly decreasing thereafter. Flumazenil or diazepam combined with epinephrine reversed gelsenicine toxicity and significantly improved survival rate in mice. Conclusions Gelsenicine is a highly toxic substance that affects nerve conduction without causing damage; the potential toxic mechanism is possibly associated with GABAA receptors. Our findings provide insights into the clinical treatment of gelsenicine -related poisoning and its toxicity mechanisms.

使用高效液相色谱-串联质谱(HPLC-MS/MS)对猪尿中莱克多巴胺的测定进行不确定度分析,建立数学模型,探究影响测量结果的各种因素,对每个不确定度分量进行评估及计算.结果表明:当猪尿中莱克多巴胺含量测定结果为1.015 mg/L时,其扩展不确定度为0.0312 mg/L(k=2),其中,引入不确定度主要的影响因素是标准品配制及稀释、重复性操作及试样体积量取.在实际的检测中,应该严格控制实验条件,保证移取标准品配制的准确性,重复性操作及体积量取的规范性,以得到准确、可靠的测量结果.

目的:评定QuEChERS-液相色谱-串联质谱法测定猪肝中玉米赤霉醇含量的不确定度.方法:参照不确定度评测数学模型和方法学评价指标,构建相关统计分析模型,获得真值结果的离散程度,分析该方法在生产实践中的优劣,并分析其在应用过程中影响不确定值的主要因素,最终确定猪肝中玉米赤霉醇含量的扩展不确定度.结果:当猪肝中α-玉米赤霉醇、β-玉米赤霉醇残留量分别为9.49μg/kg、9.21μg/kg时,其扩展不确定度分别为1.04μg/kg、0.96μg/kg(k=2).结论:该方法测量误差较小,测量结果可信赖程度高.影响测量不确定度的主要来源是标准溶液的配制、标准曲线拟合和方法的添加回收,在实际检测应用中需加强控制.

建立高效液相色谱-串联质谱法(HPLC-MS/MS),同时检测鸡肉中恩诺沙星、环丙沙星、达氟沙星、沙拉沙星、诺氟沙星、培氟沙星、氧氟沙星、洛美沙星、金刚烷胺药物残留量.结果表明,9种药物在0.5～20μg/L浓度范围内具有良好的线性关系.检出限为0.1～0.5μg/kg,定量限为0.5～2μg/kg.样品添加回收率在70％～115％之间,相对标准偏差(n=6)为1.3％～12.2％.

使用高效液相色谱-串联质谱对预混合饲料中喹乙醇的测定进行不确定度分析,建立数学模型,对不确定度分量进行评估及计算.结果 表明,当饲料中喹乙醇含量测定结果为0.763 mg· kg-1时,其扩展不确定度为0.0244 mg· kg-1(k=2),引入不确定度主要的影响因素是前处理提取体积、重复性操作以及标准品配制.在实际的检测中,应严格控制试验条件,保证移取提取液体积、重复性操作的规范性及标准品配制的准确性,以得到准确、可靠的测量结果.

病死动物无害化处理产物肉骨渣的再利用是当今社会各界关注的热点问题之一.本研究收集连续高温法无害化处理病死猪产物肉骨渣产品,采用氨基酸自动分析仪测定其氨基酸含量,并与标准肉骨粉进行营养比较分析与评价.结果 表明:(1)与标准肉骨粉相比,病死猪无害化处理产物肉骨渣中除甘氨酸和组氨酸含量具有较大差异外,其余氨基酸含量差异不明显.(2)与标准肉骨粉相似,肉骨渣中含量最高的是谷氨酸,其次是甘氨酸氨酸、天冬氨酸、丙氨酸、亮氨酸和精氨酸.(3)肉骨渣与标准肉骨粉的氨基酸评分(AAS)、化学评分(CS)及氨基酸比值系数(RC)、必需氨基酸指数(EAAI)、氨基酸比值系数分(SRC)和生物价(BV)值无明显差异.综上所述,肉骨渣的氨基酸和必需氨基酸含量丰富,为连续高温法无害化处理产物肉骨渣资源化再利用提供理论基础.

Gelsemium elegans Benth (G. elegans) is highly toxic to humans and rats, but has insecticides and growth promoting effects on pigs and goats. G. elegans is widely used in livestock, but its in vivo dynamics are entirely unknown. Hence, we investigated the toxicokinetic profiles of G. elegans alkaloids after a single oral dose of G. elegans to pigs (1.0 g/kg) and rats (0.1 g/kg). The results indicated that rats were more susceptible to the toxicity of G. elegans than pigs. The toxicokinetic parameters of 22 and 6 components were obtained in pigs and rats, respectively. The components included 9 and 5 gelsedine-type alkaloids in pigs and rats, respectively. The T-max results of the 5 gelsedine-type alkaloids indicated that these alkaloids were rapidly absorbed in pigs and rats. The T-1/2 values of the 5 gelsedine-type alkaloids indicated that the elimination rates of these alkaloids in pigs were slower than those in rats. In addition, the C-max and AUC results indicated that the degrees of absorption and exposure of most alkaloids in pigs were higher than those in rats except GS-2. However, the C-max value of GS2 (11-methoxy-14-hydroxygelsenicine) in rats was greater than that of pigs, and the C-max value of 14-hydroxygelsenicine in pigs was merely greater than 3 times that of rats. The present results suggested that the cause of the toxicological differences species of G. elegans might be related to the degrees of absorption and exposure of gelsedine-type alkaloids, especially for the 14-hydroxygelsenicine and GS-2 in different animals.

为阐明金丝猴毛首线虫线粒体细胞色素c氧化酶Ⅰ亚基(cox1)基因部分(pcox1)序列的遗传变异情况,以长沙生态动物园金丝猴体内分离的毛首线虫作为研究对象,根据cox1序列构建其与其他毛首线虫的进化发育关系.使用PCR方法扩增金丝猴毛首线虫线粒体cox1,然后将所测得的序列应用Clustal X 1.81程序进行比对,最后用Mega 5.0程序NJ法绘制种系发育树.结果显示,本实验扩增获得的6条毛首线虫分离株cox1序列长度一致,均为411 bp,种内变异为0.种系发育分析结果表明,这6条毛首线虫分离株位于同一分支.鉴于金丝猴毛首线虫的cox1基因种内保守,而种间差异大(24.0％～34.1％),因此可以作为种间鉴定检测研究的遗传标记.本研究结果为进一步研究金丝猴毛首线虫的群体遗传结构奠定了基础.

蛋白质饲料原料极度匮乏,畜禽对饲料利用率低和养殖业产生大量排放物对环境造成的污染等,制约我国畜牧业的发展.随着理想蛋白质氨基酸营养平衡理论的发展,应用低蛋白日粮技术可在不影响猪生长性能的基础上提高蛋白利用率,减少氮排放﹑改善肠道形态与肠道菌群及降低仔猪腹泻.本文综述了低蛋白日粮概念﹑生物学功能及机制以及其在猪生产中的应用.

随着我国生猪产业的快速发展,我国已成为世界第一生猪产出国,在生猪产业快速发展的同时相应的配套无害化处理措施依然存在一些不足,特别是在非洲猪瘟疫情的背景下,病死猪如何无害化处理,如何减少其对生态环境的影响,本文主要针对病死猪无害化处理的现状与对策进行综合分析,为我国病死猪无害化处理提供一些理论依据.

近年来,湖南省各地建成并投产了多家畜禽无害化处理场.高温无害化处理后产生的肉骨渣主要用作有机肥料,产出价值不高.我们对省内多家畜禽无害化处理场的100批次肉骨渣样品进行了氨基酸含量测定.从实验结果看,肉骨渣的总氨基酸很高,特别是赖氨酸、苏氨酸、亮氨酸、苯丙氨酸、缬氨酸、蛋氨酸等必需氨基酸含量高.可以考虑利用肉骨渣生产高价值的氨基酸类饲料原料.

The multicomponent pharmacokinetic study of herbal medicine is a great challenge due to the low plasma concentrations, large range of concentration scales, lack of authentic standards and uncertain interactions of the components. The aim of this work was to explore the in vivo pharmacokinetics of herbal medicine independently of authentic standards using an integrated analytical strategy. First, ion pairs of multiple components were tuned and selected, and then major parameters were optimized for derivative multiple reaction monitoring (DeMRM) by LC-MS/MS, which was combined with characterization of the chemical profiles of the herbal medicine by LC-QqTOF/MS. Second, different concentrations of herbal extracts were employed instead of authentic standards to construct calibration curves for the semiquantitative determination of multiple components in plasma. Taking Gelsemium elegans as an example, in addition to the fully validated and sufficient methodological results, a total of 27 alkaloid components, major bioactive constituents of Gelsemium elegans, were simultaneously monitored in pig plasma. The concentration-time profiles and pharmacokinetic properties of these 27 components were characterized. The absolute quantification of three components was compared with the results obtained using authentic standards, and the method showed very similar analytical characteristics, such as linearity, precision, accuracy, and the values of the pharmacokinetic parameters Tmax, Vd, Cl and MRT. This analytical strategy was found to be capable of assessing herbal pharmacokinetics independently of specific authentic compounds for each component. This study was the first attempt to systematically reveal the in vivo pharmacokinetics of Gelsemium elegans. This strategy and methodology will find widespread use in the quantitative pharmacokinetic analysis of multiple components independently of standards for herbal medicine, among other applications.

Three monomers of G. elegans indole alkaloids (gelsemine, koumine and humantenmine) were simultaneously detected in porcine plasma for the first time with the development and validation of a sensitive and reliable LC-ESI-MS/MS method. Using a gradient mobile phase at a constant flow rate of 0.2 mL/min via electrospray ionization (positive ion mode) in a multiple reaction monitoring (MRM) scan, gelsemine, koumine and humantenmine were eluted, separated and detected at an appropriate retention time. The porcine plasma was prepared using protein precipitation with 1% formic acid-acetonitrile: methanol (2:1, v/v). Using matrix-matched calibration curves and weighted least squares linear regression, a good linearity (r(2) > 0.99) was achieved with a concentration range of 0.1-200 mu g/L for gelsemine, koumine and humantenmine; estimated LOD and LOQ values were 0.10 mu g/L and 0.2 mu g/L, respectively. The mean of the recoveries was in the range of 82.68-400.35% of porcine plasma at four different levels, and the intra-day and inter-day precision (CV) were lower than 15% with a range of 2.46-8.76% and 2.73-10.83%, respectively. The proposed method has proved to be suitable for accurate, quantitative determination of gelsemine, koumine and humantenmine in porcine plasma.

Tildipirosin is a new type of semi-synthetic macrolide antibiotic specially developed for use in ani-mals.Tildipirosin is designed and approved for respiratory diseases caused by Haemophilus parasuis,Acti-nobacillus pleuropneumoniae infections.Compared with tylosin,tildipirosin has better effect in the inhibi-tion of swine and bovine respiratory diseases and has the advantages of fast absorption,long half-life,high bioavailability and stable property,and furthermore,it is worth to deep development.However,it is still not approved for use in veterinary clinic in China since 2012.The paper summarized the synthesis research,anti-bacterial effect and mechanism,pharmacokinetics,detection residues and drug resistance research of tildipi-rosin for providing the references in pharmacy and application in veterinary clinic.

本试验对食品中亚硝酸盐与硝酸盐测定的前处理方法进行优化.比较了不同称样量、不同加样体积及稀释倍数对猪肉中高浓度亚硝酸钠含量测定的影响,并对优化后的方法进了仪器与人员比对试验.结果表明,优化后的方法结果准确可靠,重复性好,可适用于猪肉中高浓度亚硝酸钠的含量测定.