Pharmacokinetics of tobramycin in ducks and sex-related differences

The aims of the present study were to determine the disposition of tobramycin after single intravenous (IV) and intramuscular (IM) injections in ducks, and to establish any sex-related differences. Tobramycin sulfate was administered as a 2.5% water solution in a cross-over design at a dose of 5 mg/kg to 12 healthy ducks (six males and six females). Concentrations of the drug in serum were determined by a microbiological assay. The serum pharmacokinetic values for tobramycin were best represented using a one- or two-compartment open model, depending on the method of administration. Non-compartment analysis was also performed after IV administration. Tobramycin had a low degree of distribution and a relatively fast elimination. The mean volume of distribution in ducks (males and females) was higher than that reported in pigeons but lower than in chickens, with a slower rate of elimination. The IM injection resulted in a fast and complete absorption. The rate of elimination after IM administration was about twice as slow as in other avian species. Sex-related variations in tobramycin pharmacokinetics were similar to those reported for kanamycin and apramycin in hens and roosters.     

鸡源耐安普霉素大肠杆菌耐药表型研究

进行了安普霉素耐药大肠杆菌耐药表型的研究.采用常规方法和生化鉴定管对有过安普霉素用药史的鸡场分离的鸡源病原性大肠杆菌进行鉴定,并用试管二倍稀释法测定其最低抑菌浓度(MIC),筛选出鸡源安普霉素耐药大肠杆菌;采用药敏纸片法研究了这些耐药菌对安普霉素等14种抗菌药物的敏感性.共筛选出7株对安普霉素耐药的鸡源性大肠杆菌,这些耐药菌株全部对安普霉素、妥布霉素、奈啶酸、多西环素和阿莫西林耐药;大部分对庆大霉素、链霉素、卡那霉素、壮观霉素也呈现耐药.对新霉素的耐药较低,对阿米卡星高度敏感.部分交叉耐药现象的存在揭示对安普霉素等氨基糖苷类药物产生耐药性的菌株,其他抗生素也可能对它们失去疗效.     

微生物浊度法测定安普霉素及其制剂效价的研究

以金黄色葡萄球菌为试验菌,抗生素检定培养基Ⅲ号为试验用培养基,制成菌悬液。将硫酸安普霉素稀释成不同的浓度加入菌悬液中,37 ℃培养3～4 h,确立浓度的对数值与相对应的吸光度呈直线相关的线性范围,并对所建立的浊度法进行准确度、精密度、专属性及适用性等验证。结果表明,安普霉素的浓度在2.9～7.2 U/mL之间,其浓度的对数值与相对应的吸光度呈直线相关,相关系数r＝0.9988。经t检验,安普霉素浓度的对数值与相对应的吸光度回归效果显著。所建立的浊度法平均回收率为99.82%,平均可信限率为2.48%,相对标准偏差（RSD）为1.86%。管碟法与比浊法所测结果无显著差异。因此,本方法具有可信限率低、灵敏度高、精密度高、快速等优点,可用于硫酸安普霉素及其制剂的效价测定。     

Comparison of the pharmacokinetics of five aminoglycoside and aminocyclitol antibiotics using allometric analysis in mammal and bird species

The allometric equations relating the half-life, the volume of distribution and the total body clearance of gentamicin, amikacin, tobramycin, kanamycin and apramycin to body weight for mammalian and mammalian + avian species were defined. Literature data were used as a source of comparative pharmacokinetic data. For all antibiotics examined half-life intercepts ranged from 0.49 to 1.66, slopes from 0.05 to 0.45, volume of distribution intercepts--0.13-0.75, slope-- 0.77-1.41, total body clearance intercepts--0.88-8.8 and slope--0.62-1.04. A better relationship between pharmacokinetic parameters and body weight was shown when all values were included in the allometric analysis. Different values of intercept and slope between birds and mammals were found in gentamicin and apramycin studies. In some cases, slopes and intercepts changed when all values of pharmacokinetic parameters were included. We conclude that small difference exist between pharmacokinetics of gentamicin, amikacin, tobramycin, kanamycin and apramycin. The allometric equations shown in our study provide a basis to estimate dose intervals for mammals and birds for which specific information is lacking.     

Interspecies variations in plasma half-life of ampicillin, amoxycillin, sulphadimidine and sulphacetamide related to variations in body mass.

The relationships between the half-lives during the elimination phase (t1/2 minutes) of ampicillin, amoxycillin, sulphadimidine and sulphacetamide and body mass (W, kg) between species of mammals and birds were examined using data from the authors' experiments and collected from the literature. Linear regression of the log half-lives of ampicillin, amoxycillin and sulphadimidine following intravenous injection on the log body mass for a variety of species of mammals and birds revealed significant correlations (r = 0.7709, n = 8, r = 0.7712, n = 8, r = 0.7749, n = 10). The interspecies relationships were described by the allometric equations t1/2 = 31.3 W0.16, t1/2 = 32.7 W0.12 and t1/2 = 129.2 W0.28, respectively. These equations may be of value for estimating dose intervals in species for which no relevant pharmacokinetic data are available.     

禽Ⅰ型副粘病毒各种禽源分离株的免疫原性

分别制备了源于鸡、鹅、鸽、鹌鹑、孔雀、画眉鸟、珍珠鸡的禽型副粘病毒(APMV-1)7个强毒分离毒株和商品弱毒疫苗株克隆30(C30)的灭活油乳剂苗,并用这8种灭活油乳剂苗和C30株的活疫苗分别在鸡、鹌鹑、鹅和鸽进行了免疫及交叉攻毒保护试验。免疫后(PI)分别测定试验禽血清的新城疫病毒(NDV)血凝抑制(HI)抗体的滴度,并于PI 5周用强毒株进行攻毒。结果表明,鸽的HI抗体几何平均滴度(MAT)为9.00~10.0 log2,鸡的为7.13~7.63 log2,鹌鹑的为5.00~5.13 log2,鹅对灭活油乳剂苗的为5.63~6.38 log2、而对C30株活疫苗的仅为3.38log2;除了C30株活疫苗免疫鹅提供的保护率比较低(20%)外,8种油乳剂苗都能对同源或者异源强毒株的攻毒提供比较高的保护率(66.75%~100%)。研究结果表明,经典疫苗株C30与近年来从各种不同禽类分离的致病性APMV-1野毒株之间、不同禽源分离株之间的抗原性,以及各种不同禽源分离株的之间的免疫原性差异均不大。     

Tissue and intracellular distribution of rhodanese and mercaptopyruvate sulphurtransferase in ruminants and birds

Cyanide detoxification is catalysed by two enzymes: rhodanese [thiosulphate: cyanide sulphurtransferase, E.C. 2.8.1.1], and 3-mercaptopyruvate sulphurtransferase [3-MST, EC. 2.8.1.2]. In the present work, the activity of the two enzymes in the crude extracts of different tissues and in the mitochondrial and cytosolic fractions of tissues from some ruminants (camels, cattle and sheep) and birds (chickens and pigeons) have been compared. Rhodanese activity was almost exclusively present in the mitochondrial fraction. In ruminants and chickens the highest activity of rhodanese was found in the liver, followed by the kidney. In pigeons, however, the enzyme activity was the highest in the kidneys. In camels' tissues, the rhodanese activity was significantly (P < 0.05) lower than in cattle or sheep, and the enzyme activities in the two latter species were similar. The activity of 3-MST in the crude extract of tissues from camels was similar to that in sheep, but higher than that in cattle. The enzyme activity was equally distributed between the mitochondrial and cytosolic fractions in the liver and kidneys of camels, cattle and sheep.     

内蒙古巴彦淖尔市畜禽寄生虫病调查

为了查清巴彦淖尔市辖区内畜禽寄生虫的感染、分布情况、流行与危害程度,提高防治效果,开展了本次畜禽寄生虫感染调查。调查采取生前临床检查、血液学检查、动物解剖、收集虫体、分类鉴定等方法,在全市7个旗、县、区,共66个乡镇选取羊386只(其中绵羊238只、山羊148只)、牛12头、骆驼8峰、猪11头、马驴8匹、鸡16只、兔10只,于实验室内解剖收集虫体,进行分类鉴定。调查结果显示,羊感染内外寄生虫53个种,牛、骆驼26个种,马属动物39个种,猪8个种,鸡5个种,兔7个种;畜禽寄生虫病在巴彦淖尔市较为普遍,感染率较高,危害也较为严重。本次调查不仅为我市进一步防治畜禽寄生虫病提供了依据,而且也对其他地区防治寄生虫病及寄生虫感染具有参考价值和指导作用。     

Comparative pharmacokinetics of enrofloxacin in mice, rats, rabbits, sheep, and cows.

OBJECTIVE: To compare pharmacokinetic variables of enrofloxacin (ENR) after IV administration in mice, rats, rabbits, sheep, and cows and to perform allometric analysis of ENR. ANIMALS: 47 mice, 5 rats, 5 rabbits, 5 sheep, and 5 cows. PROCEDURE: Serially obtained plasma samples were assayed for ENR concentration, using high-performance liquid chromatography. In vitro plasma protein binding was determined by ultrafiltration. Plasma ENR concentration versus time curves were fitted by use of nonlinear least-squared regression analysis. Pharmacokinetic variables were correlated further with body weight. RESULTS: In all species studied, the best fit was obtained for a two-compartment open model; ENR half-life ranged from 89 minutes in mice to 169 minutes in cows. Volume of distribution was large in all species studied, with values ranging from 10.5 L/kg in mice to 1.5 L/kg in sheep. Body clearance ranged from 68.1 ml/min/kg for mice to 4.6 ml/min/kg for sheep. Unbound ENR was found to be (mean +/- SD) 58+/-2, 50+/-6, 50+/-2, 31+/-2, and 40+/-3% in plasma of mice, rats, rabbits, sheep, and cows, respectively. The only pharmacokinetic variables that could be correlated with body weight were elimination half-life, clearance, and volume of distribution. Allometric exponents denoting proportionality of half-life, body clearance, and volume of distribution with body weight were 0.06, 0.82, and 0.90, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: An allometric approach could provide a suitable method for determining a scale for ENR pharmacokinetics among various mammalian species. This would faciliatate the administration of appropriate doses of ENR to all animals.     

Limited susceptibility of pigeons experimentally inoculated with H5N1 highly pathogenic avian influenza viruses

An experimental infection study was performed using pigeons reared for racing or meat production in Japan and clade 2.2 and 2.3.2 isolates of H5N1 highly pathogenic avian influenza virus to evaluate the possible role of pigeons in virus transmission to poultry. In experiment 1, when 20 pigeons were intranasally inoculated with high or low viral doses, no inoculated pigeon exhibited clinical signs for 14 days. Drinking water and almost all swab samples were negative for virus isolation. Virus isolation was positive in 3 oral swab samples from 2 pigeons from day 2 through 4 postinoculation, but viral titers of positive samples were extremely low. Immunohistochemical analysis for virus detection was negative in all tissue samples. Along with seroconversion in a limited number of pigeons postinoculation, these results suggest that pigeons have limited susceptibility to the virus used for experimental infection. In experiment 2, when uninoculated chickens were housed with virus-inoculated pigeons, all pigeons and contact chickens survived for 14 days without exhibiting any clinical signs. According to serological analysis, the chickens did not exhibit seroconversion after close contact with inoculated pigeons. Our data suggest that the risk posed by pigeons with respect to the transmission of the H5N1 highly pathogenic avian influenza virus to poultry would be less than that for other susceptible avian species.     

Allometric analysis of thiamphenicol disposition among seven mammalian species

The pharmacokinetics of thiamphenicol (TAP), a broad-spectrum antibiotic, was determined in male mice, rats, rabbits, dogs, pigs, sheep and calves. The relationship between the main pharmacokinetic parameters of TAP and body weight (W) was studied across these seven mammalian species, using double-logarithmic plots. The experimental values of volume of distribution (Vss), clearance (Cl) and elimination half-life (t(1/2)beta) were plotted, and extrapolated values were determined from corresponding allometric equations. These parameters were fitted to the following equations: Vss=0.98W0.92, Cl=15.80W0.76 and t(1/2)beta=0.94W0.20, and present good correlation (Vss: r2=0.997, P < 0.001; Cl: r2=0.976, P < 0.001, t(1/2)beta: r2=0.852, P < 0.005), that is expected of a drug eliminated primarily by renal glomerular filtration, with insignificant hepatic metabolism. For the t(1/2)beta, the extrapolated and observed values were similar. The extrapolated values of Cl were close to the experimental values, except for the mouse and pig mean percent error [(M.E.) equal to 62 and 119%, respectively], while the extrapolated and observed values for the Vss were very similar. The comparison between experimental and extrapolated values suggests that it could be possible to extrapolate, with good prediction, the kinetic parameters of this drug for mammalian species, using allometric scaling, except for the species that eliminate the drug by a combination of renal excretion and hepatic metabolism.     

A comparative study of pigeons and chickens experimentally infected with PPMV-1 to determine antigenic relationships between PPMV-1 and NDV strains

To compare the pathogenicity of PPMV-1 in pigeons and chickens, both species of birds were experimentally infected with strain pi/CH/LHLJ/110822, which was isolated from a pigeon in China. The clinical signs, gross lesions, and histopathological changes were observed in pigeons inoculated with pi/CH/LHLJ/110822. The morbidity and mortality rates were 80% and 70% in pigeons, respectively, whereas there were no clinical signs or gross lesions in chickens inoculated with the same strain. The viral loads in tissue samples were detected by real-time RT-PCR, indicating that six tissue samples (i.e., kidney, lung, brain, trachea, Harderian glands, and proventriculus) had detectable viral RNA in all dead pigeons, and significant differences in viral loads between pigeons and chickens were observed in several tissue samples (i.e., Harderian glands, proventriculus, duodenum, pancreas, small intestine, and large intestine) on 3 days post-inoculation (dpi) and in brain tissue on 7 dpi. In general, viral loads in pigeons were higher than those in chickens, whereas antibody titers in pigeons were lower than those in chickens. These results showed differences in pathogenicity, efficiency of viral RNA replication, and humoral immunity, indicating different susceptibilities between the host species. Additionally, the cross hemagglutination inhibition assay and cross virus neutralization tests demonstrated that pi/CH/LHLJ/110822 antigenicity was different from those of strains La Sota and F48E9.     

青海省畜禽寄生虫虫种资源与分布

本文简要介绍青海省畜禽寄生虫虫种资源与分布,并对绵羊主要线虫虫卵和幼虫在天然草场的生活力进行了观察。迄今从该省牛、羊、马、猪、鸡、免等畜禽检出寄生虫301种,隶属于6门,9纲,22目,58科,97属。     

Seroprevalence of ovine progressive pneumonia virus in various domestic and wild animal species, and species susceptibility to the virus

Ovine progressive pneumonia is caused by a lentivirus of known infectivity only for sheep and goats. Virus susceptibility of 11 other species of animals was examined. Species included cattle, chickens, deer, dogs, goats, hamsters, horses, mice, pigs, rabbits, and rats. Of these species, only goats and rabbits could be experimentally infected with the virus. The infection in rabbits was acute, and virus did not persist or induce antibody production as it does in sheep and goats. Sera obtained from several people working in close contact with the virus and from several wild species, with unknown exposure history, were tested for antibodies to viral antigens. All results were negative. Knowledge of the host range of this virus is important for scientific studies and for virus eradication programs.     

Prevalence and characteristics of intimin- and Shiga toxin-producing Escherichia coli from gulls,pigeons and broilers in Finland

The role of birds as sources of Shiga toxin-and intimin-producing Escherichia coli was studied. Fecal samples from live gulls (n=86), pigeons (n=33) and broiler chickens (n=199) from 23 flocks were analyzed for stx and eae by PCR. No stx positive samples were detected. In contrast, eae E. coli were highly prevalent among gulls (40%), and was also found in pigeons (7%) and chickens (57% of the flocks contaminated). The eae positive isolates were analyzed genetically and O-serogrouped. One isolate from a pigeon was found to have stx (2f). The isolates of gulls differed from those of pigeons and chickens, and all eae E. coli isolates from birds differed from human pathogenic strains by the lack of EHEC-hlyA and bfp/EAF as well as distribution of O-serogroups. Thus, birds cannot be regarded as important carriers of zoonotic stx or eae E. coli in Finland.     

Neutralizing antibody to bovine rotavirus in various animal species

A total of 288 serum samples were collected from 12 species of animals in various localities of Japan from 1975 to 1977. Neutralizing antibody to bovine rotavirus was found in serum samples from all the species, viz., horses, cattle, sheep, goats, pigs, dogs, rabbits, guinea pigs, rats, mice, chickens and human beings. The incidence of neutralizing antibody in titers of 1 : 2 or higher ranged from 31 to 100%, and high incidences exceeding 70% were obtained in horses, cattle, sheep, pigs, dogs, rabbits and human beings. High titers were most common in horses, cattle, sheep and pigs. These serological results suggest that rotaviruses occur commonly in these species of animals.     

Isolation of different serovars of Salmonella enterica from wild birds in Great Britain between 1995 and 2003

Postmortem examinations were carried out on the carcases of 779 wild birds. Salmonellosis was a common cause of death in greenfinches (Carduelis chloris), house sparrows (Passer domesticus) and chaffinches (Fringilla coelebs), and was also responsible for the deaths of other birds such as goldfinches (Carduelis carduelis), feral pigeons and different species of gulls. Most cases of salmonellosis in finches occurred between January and March, whereas salmonellosis in house sparrows tended to occur between October and March. Salmonella Typhimurium DT40 and DT56 (variant) predominated in finches and sparrows, DT41 and DT195 were the most common strains isolated from gulls, and DT2 and DT99 were recovered from feral pigeons. These "wild bird" strains of Salmonella made up less than 0.5 per cent of the isolates of Salmonella recovered from cattle, sheep, pigs, chickens or turkeys in Great Britain over the same period, but they made up nearly 3 per cent of the isolates from more extensively reared avian livestock such as gamebirds, ducks and geese.     

Turbidimetric measurement of immunoglobulin G in serum using an automatic centrifugal analyser

Turbidimetry and radial immunodiffusion techniques are compared for measuring the average amounts of IgG in serum from healthy sheep, swine and chickens using different rabbit antisera. The correlation coefficients (r) between the IgG values measured by the two techniques, were high; r greater than 0.97. Turbidimetric measurement was found to be a reliable, rapid and simple method for IgG determination in serum.     

Relationships between kidney mass and body size in some Anseriformes

Relationships between kidney mass (KM) and body mass (BM), body length (BL), and sternum length (SL) were studied in adults of both sexes of 4 Mergini anseriforms: Clangula hyemalis (n = 74), Melanitta fusca (n = 29), M. nigra (n = 15), and Somateria mollissima (n = 8). The following indices were established for the four species and for the Mergini tribe: KM/BM (as per cent body mass), KM/BL, and KM/SL. Additionally, allometric equations describing the relationships studied were developed for the tribe using mean kidney weights and body parameters of males and females of the species examined. The KM/BM indices for several anseriform tribes (i.e. Anserini, Anatini, Aythyini and Mergini), differing in food and feeding modes, were determined, based on the literature data and those obtained in this study. In addition, an allometric equation describing the kidney weight-body weight relationship in the Anseriformes order was developed as log KM = 0.797 log BM-1.346 (n = 22). The relative kidney size in the sea duck species studied showed significant intra- and interspecific differences. In addition, clear between-tribes differences in KM/BM were revealed. The highest value (1.57%) of the index is typical of the Mergini, grouping diving carnivorous sea ducks, while the lowest index (0.65%) is typical of the Anserini, a tribe which groups non-diving herbivorous birds.     

Genetic resistance to gastrointestinal nematode parasites in Rh?n sheep following natural infection.

Genetic parameters of resistance to gastrointestinal nematodes were estimated in Rh?n sheep, a local sheep breed in Germany. In the first year, a total of 131 lambs (born between January and February 1998) from five rams were evaluated. Faecal egg counts (FEC) (n=1528) were measured in all lambs every 2 weeks until 4 months of age and every 4 weeks until 12 months of age in female lambs. In the second year, a total of 129 lambs (born between January and February 1999) from the same rams were evaluated. FEC (n=645) were measured in the lambs every 4 weeks until 5 months of age. Blood was taken in both years at the time of faecal sampling from the jugular vein and haematocrit was measured. Heritabilities for log(10)(FEC+25) were between 0.11 and 0.44. Heritabilities for the corresponding haematocrits were between 0.19 and 0.26 depending on the number of samples taken in account. A significant negative correlation was estimated for the parameters of FEC and daily weight gain (r=-0.57). The results confirm the feasibility of genetic selection in Rh?n sheep for resistance to nematode parasites in an environment where Trichostrongylus spp./Teladorsagia spp., Haemonchus contortus and Cooperia spp. are the dominant species. Breeding decisions can be based on one or two samples depending on the mean values and ranges of FEC and haematocrit, respectively.