Disposition of norfloxacin in broiler chickens and turkeys after different methods of oral administration

Norfloxacin was administered orally to chickens and turkeys at 15 mg/kg body weight by pulse dosing at 24 h intervals and by continuous dosing at 100 mg/L in drinking water for five days. Blood samples were taken serially. Plasma norfloxacin concentrations were determined by high-performance liquid chromatography. The plasma norfloxacin concentrations increased slowly during continuous dosing and reached the MIC(90) (250 ng/mL) for Gram-negative pathogens by 12 h in chickens and 18 h in turkeys. The steady-state plasma concentration was attained in 36 h and remained at approximately 776.67+/-33.23 ng/mL in chickens and 682.50+/-28.55 ng/mL in turkeys. After pulse dosing, the plasma norfloxacin concentrations increased rapidly and exceeded the MIC(90) at 2 h in both species and remained above MIC(90) for 8 h in chickens and 6 h in turkeys. Pulse dosing provided half the steady-state concentration that was achieved by continuous dosing, 365.32+/-39.31 ng/mL in chickens and 306.03+/-32.26 ng/mL in turkeys, during the dosing interval of 24 h. Data for daily pulse dosing suggested that every administration corresponded to a single, daily repeated bolus administration although pulse dosing produced higher plasma concentrations more readily. Continuous and pulse dosing are both rational for the administration of norfloxacin to flocks of chickens and turkeys. We recommend that treatment be commenced with a pulse oral dose administered over a 4 h period and maintained by continuous oral medication for three to five consecutive days.     

Treatment of experimentally induced Pasteurella multocida infections in broilers and turkeys: comparative studies of different oral treatment regimens

Experimental fowl cholera was induced in 60 healthy 10-week-old broiler chickens and 8-week-old turkeys by intramuscular inoculation with approximately 80 colony-forming units (cfu) of Pasteurella multocida X-73 strain and with approximately 70 cfu of P. multocida P-1059 strain, respectively. This method of infection proved to be useful for evaluating the efficacy of anti-microbial medication, by measuring mortality, weight gain, pathological responses and frequency of re-isolation of P. multocida. The efficacies of two different dosing methods, continuous and pulse dosing, were compared. Using the continuous-dosing method, norfloxacin was administered to drinking water at 100 mg/l for 5 days in chickens. Efficacies were slightly improved compared with pulse dosing at 15 mg/kg bodyweight for the same length of time. The opposite was observed in turkeys, to the degree of control of mortality and maintenance of weight gain.     

Pharmacokinetics of norfloxacin and its N-desethyl- and oxo-metabolites in broiler chickens.

Norfloxacin was given to 2 groups of chickens (8 chickens/group) at a dosage of 8 mg/kg of body weight, IV and orally. For 24 hours, plasma concentration was monitored serially after each administration. Another group of chickens (n = 30) was given 8 mg of norfloxacin/kg orally every 24 hours for 4 days, and plasma and tissue concentrations of norfloxacin and its major metabolites desethylenenorfloxacin and oxonorfloxacin were determined serially after the last administration of the drug. Plasma and tissue concentrations of norfloxacin, desethylenenorfloxacin, and oxonorfloxacin were measured by use of high-performance liquid chromatography. Pharmacokinetic variables were calculated, using a 2-compartment open model. For norfloxacin, the elimination half-life (t1/2 beta) and the mean +/- SEM residence time for plasma were 12.8 +/- 0.59 and 15.05 +/- 0.81 hours, respectively, after oral administration and 8.0 +/- 0.3 and 8.71 +/- 0.23 hours, respectively, after IV administration. After single oral administration, norfloxacin was absorbed rapidly, with Tmax of 0.22 +/- 0.02 hour. Maximal plasma concentration was 2.89 +/- 0.20 microgram/ml. Oral bioavailability of norfloxacin was found to be 57.0 +/- 2.4%. In chickens, norfloxacin was mainly converted to desethylenenorfloxacin and oxonorfloxacin. Norfloxacin parent drug and its 2 major metabolites were widely distributed in tissues. Considerable tissue concentrations of norfloxacin, desethylenenorfloxacin, and oxonorfloxacin were found when norfloxacin was administered orally (8 mg/kg on 4 successive days). The concentration of the parent fluoroquinolone in fat, kidneys, and liver was 0.05 micrograms/g on day 12 after the end of dosing.     

Effect of ochratoxin A on Escherichia coli-challenged broiler chicks

A study was conducted to evaluate the effects of ochratoxin A (OA) on Escherichia coli-challenged broiler chickens. Day-old broiler chicks were separated into two groups of 92 chicks each, with one group fed a control mash diet, and the other fed a mash diet containing 2 ppm OA. On day 14, each group was further separated into two groups, with one group inoculated with E. coli O78 (1 x 10(7) colony-forming units/0.5 ml), whereas the other group was not inoculated with E. coli. After E. coli inoculation on day 14, four birds from each group were euthanatized at 1, 2, 3, 5, 7, 10, 14, and 21 days postinoculation. Escherichia coli infection caused dullness, depression, huddling, and diarrhea. Mortality was 14.3% in chicks infected with E. coli but fed no OA. Mortality increased to 35.7% in chicks fed OA and infected with E. coli. Decreased body weight and reduced feed intake were observed in chicks fed OA, and the effects were more pronounced in chicks fed OA and infected with E. coli. Increased serum levels of aspartate aminotransferase, alanine aminotransferase, uric acid, and creatinine and decreased levels of total proteins, albumin, globulins, calcium, and phosphorus were observed in OA-fed birds. Escherichia coli infection did not cause significant alteration in any of the serum biochemical parameters. The presence of OA in poultry rations increased mortality and the severity of an E. coli infection.     

Comparative toxicity of coniine, an alkaloid of Conium maculatum (poison hemlock), in chickens, quails, and turkeys

Coniine, an alkaloid of Conium maculatum (poison hemlock), was administered by gavage to immature chickens, quails, and turkeys at 0, 25, 50, and 100 mg/kg body weight. At 25 mg coniine/kg body weight, clinical signs were observed only in quails (2/10) and consisted of excitement, depression, hypermetria, seizures, opisthotonos, and flaccid paralysis. Chickens (9/10) and quails (8/10) dosed at 50 mg/kg body weight were affected, and several birds of each species died (2/10 and 5/10, respectively). Turkeys (7/10) were affected only when dosed at 100 mg/kg body weight, and quails (6/10), turkeys (4/10), and chickens (10/10) died at this dose. There were no gross or microscopic lesions. Coniine was detected in skeletal muscle and liver of birds dying after ingestion and was present in some survivors 7 days post-treatment.     

禽大肠杆菌外膜蛋白、脂多糖疫苗的免疫保护试验

为探讨禽源性大肠杆菌外膜蛋白 (OMPs)、脂多糖 (L PS)对禽大肠杆菌病的免疫保护作用 ,从禽源性大肠杆菌0 37株提取 OMPs、L PS后 ,分别以含 2、1mg OMPs的油乳剂苗于 2、4周龄时各 2次免疫易感鸡 ,在免疫鸡 5周龄时以 10 8菌落形成单位 (CFU) 0 37株攻毒 ,结果免疫后、临攻毒前 (5周龄 ) 2组鸡的平均体重分别为 0 .96 kg和 0 .87kg,攻毒后 2个组的免疫保护效力分别为 94.74%和 78.95 %;以含 0 .2 5、0 .12 5 mg L PS的油乳剂苗同法免疫后攻毒 ,结果免疫后、临攻毒前其平均体重分别为 1.10 kg和 0 .98kg,免疫效力分别为 36 .84%和 31.5 8%;以含 1.2 5 mg OMPs 0 .12 5 m g L PS的油乳剂苗同法免疫后攻毒 ,该组鸡相应日龄的平均体重为 0 .88kg,免疫效力为 84.2 1%;以含 2 .5× 10 9CFU/ m L 灭活的全菌油乳剂苗免疫后攻毒 ,该组鸡 5周龄时的平均体重为 0 .88kg,免疫保护效力为 78.95 %。上述结果表明 ,OMPs是禽大肠杆菌病的主要免疫保护性抗原 ,而 L PS为次要免疫保护性抗原。     

Quantitative resistance level (MIC) of bacterial pathogens (Escherichia coli, Pasteurella multocida, Pseudomonas aeruginosa, Salmonella sp., Staphylococcus aureus) isolated from chickens and turkeys: national resistance monitoring by the BVL 2004/2005

In the study 2004/2005, the current quantitative resistance level of Escherichia coli, Pasteurella multocida, Pseudomonas aeruginosa, Salmonella sp. and Staphylococcus aureus from chickens and turkeys was determined for the first time within the framework of the National Resistance Monitoring of the Federal Office of Consumer Protection and Food Safety (BVL).The objective was to implement a valid database on the basis of which the development and spread of resistance can be evaluated and monitored. During the investigation period from January 2004 to February 2005,927 strains were collected and 857 (92%) bacteria strains which corresponded to the specifications of the study protocol were tested with the broth microdilution method to determine the in vitro susceptibility (minimum inhibitory concentration) to 22 to 28 antimicrobial agents or antibiotic combinations. The results document a prevalence of resistance that exceeds that of bacterial pathogens of other animal species, especially in the case of tetracycline. Apart for S. aureus, clinical resistance to fluoroquinolones can still be considered low in poultry pathogens (E. coli approx. 2%). By applying the MICG of 4 mg/L for enrofloxacin, a susceptibility of approximately 78 % was calculated for S. aureus. A comparison of the prevalence of resistance between chickens and turkeys, showed that a slightly higher prevalence of resistance can be expected in turkeys. Differences between the susceptibility data of chicks and adult animals could only be found in turkeys. In the case of E. coli, the prevalence of resistance of strains isolated from adult turkeys was up to 10% higher than those isolated from chicks for the corresponding antimicrobial agents. It must be pointed out that the number of E. coli strains from adult turkeys was much higher (n = 194) than the number from turkey chicks (n = 21). The results indicate clearly that in a resistance monitoring system it is necessary to categorise poultry by animal species (chicken, turkey) as well as by production stage and type (broiler, laying hen), so that the epidemiology of resistance can be correctly represented and evaluated. This information is the basis for the development of long-term management options for minimizing antibiotic resistance. Furthermore, the knowledge of prevailing resistance levels in Germany is a valuable tool for veterinary practitioners when determining an empirical therapy.The data collected by the BVL make an important contribution to the optimisation of the safety of food from animals, and thus to improving consumer protection.     

Immunogenic potency of an oil-emulsified Escherichia coli bacterin

Immunogenicity of an oil-emulsified Escherichia coli (O1:K1) bacterin with an aqueous-phase-to-oil-phase ratio of 1:4 was evaluated in chickens. Chickens were vaccinated subcutaneously with 0.5 ml of the bacterin at 4 and 6 weeks of age. At 8 weeks, the vaccinated chickens and unvaccinated controls were challenged via air sacs with 10(4) colony-forming units (CFU) of homologous E. coli. Vaccinated chickens were protected against active respiratory infection in that they (a) gained body weights comparable to those in unvaccinated, unchallenged chickens, (b) suffered no morbidity or mortality, (c) had gross lesions so mild that the scored values were comparable statistically to the 0 lesion scores of the negative controls, and (d) did not yield E. coli when their heart blood, pericardial sacs, livers, and air sacs were cultured. Unvaccinated challenged chickens had severe respiratory distress, suffered 36% mortality, and had average air sac, pericardial sac, and liver lesion scores significantly (P less than or equal to 0.05) different from both the vaccinated and negative control chickens. Also, the challenge strain of E. coli only was isolated from the affected tissues of 5 of 14 chickens. Protection against active respiratory infection was again demonstrated in a second experiment, though the challenge dose was 1.06 X 10(6) CFU of E. coli. The immunity, however, was partially overcome, as the vaccinated chickens gained less body weight and the scored values for lesions in the air sacs, pericardial sacs, and livers were significantly higher than those of the negative controls (P less than or equal to 0.05).     

Coccidiosis: a radiological study of sulphaquinoxaline distribution in infected and uninfected chickens

Using scintillation counting and autoradiographical techniques, the whole-body distribution in week-old uninfected chickens of the anticoccidial agent sulphaquinoxaline (SQ) labelled with ³⁵S was established at various time intervals after a single oral dose either alone or following continuous in-feed medication with unlabelled SQ, and after a single intravenous dose. The distribution was also established in chickens infected with the coccidia Eimeria acervulina or E. tenella , after a single oral dose of radiolabelled SQ administered either alone or following continuous in-feed medication with unlabelled SQ, as for uninfected chicks. In all uninfected chicks, SQ was rapidly absorbed from the gut and was distributed to all tissues. It appeared at high concentrations in the bile and kidneys 0.5 h after dosing. In chickens that had previously received unlabelled SQ in the diet, a radiolabelled dose maintained steadier tissue concentrations than the sharp rise and fall detected after a single oral dose. Intravenous dosing of uninfected chicks showed that SQ was secreted by the crop, gizzard and caecal epithelia into their lumina. Infection with E. acervulina or E. tenella coincided with an overall 3.5-fold sustained increase of SQ concentration in chick tissues. An updated hypothesis including these new observations for the anticoccidial mode of action of SQ in chickens is expounded.     

Evaluation of a Mycoplasma gallisepticum strain exhibiting reduced virulence for prevention and control of poultry mycoplasmosis.

Two experiments were conducted to evaluate the virulence and vaccination efficacy of a Mycoplasma gallisepticum (MG) isolate designated MG Intervet 6/85. Virulence of the strain was determined by evaluation of airsacculitis scores following aerosol exposure to the isolate before and after 10 sequential passes in either commercial broiler chickens or commercial turkeys. Two-week-old specific-pathogen-free chickens were vaccinated by aerosol exposure. The birds were challenged with the R' strain of MG at either 4 or 8 weeks post-vaccination. Efficacy was evaluated by airsacculitis scores determined 21 days after challenge. Ten repetitive back-passes of the isolate in chickens and turkeys did not substantially increase the virulence. Virulence for both chickens and turkeys was minimal, while protection elicited by aerosol vaccination in young chickens against virulent R' strain was significant (P less than or equal to 0.05) compared with unvaccinated controls.     

Escherichia coli colonization of the trachea in poultry: comparison of virulent and avirulent strains in gnotoxenic chickens

In chickens, virulent Escherichia coli strains express their pathogenicity in the respiratory tract. A quantitative comparison of tracheal colonization by virulent and avirulent E. coli was carried out in gnotoxenic chickens after intestinal implantation. Two-week-old axenic chicks reared in isolators were inoculated per os with various associations of identified E. coli strains. No clinical sign of disease was observed in any of the chicks, despite the presence of virulent strains in all the intestines and most of the tracheas. The virulent organism reached greater population sizes in the trachea and feces of monocontaminated chicks and of chicks contaminated simultaneously with a virulent and an avirulent strain. In holoxenic chicks, identified virulent and avirulent strains were outnumbered by the E. coli population of the intestinal flora previously established and could not be recovered from the tracheas of most chicks.     

Toxicity of seeds of three Aesculus spp to chicks and hamsters

Seeds of horse chestnut (Aesculus hippocastanum), Ohio buckeye (A glabra), and yellow buckeye (A octandra) were tested for toxicity to 2-week-old Leghorn chicks and adult female Syrian hamsters. The LD50 of the water soluble portion of alcoholic extracts of horse-chestnut seeds (for hamsters and chicks) and of dried, powdered seeds (chicks only) was determined. The LD50 for a single dose of extract from horse-chestnut seeds was 10.6 mg/g of body weight for chicks and 10.7 mg/g of body weight for hamsters. The LD50 for chicks given 2 consecutive daily doses of horse-chestnut seed was 6.5 mg/g. Toxic signs included depression, muscular incoordination, paralysis, coma, and death. Extracts of seeds of Ohio buckeye were nontoxic to chicks and hamsters when fed at 80 mg/g. One of 5 hamsters died after dosing for 5 days with 80 mg/g of extract of seeds of yellow buckeye/g.     

Tracheal mucus transport rate and bacterial clearance in turkeys exposed by aerosol to La Sota strain of Newcastle disease virus

Tracheal mucus transport rate (TMTR) and quantitative clearance of aerosolized Escherichia coli from the trachea, lung, and air sac were measured in healthy unanesthetized turkeys and in turkeys exposed by aerosol to a La Sota vaccine strain of Newcastle disease virus (NDV). The TMTR of uninfected turkeys was 42.4 +/- 14.7 cm/min. The TMTR of NDV-infected turkeys was depressed on days 3 through 7 postexposure (PE); depression was significant (P less than or equal to 0.05) on day 7 PE. Tracheal E. coli clearance in NDV-infected turkeys was reduced on days 4 through 9 PE, significantly so on day 5 PE (P less than or equal to 0.01). Depression of TMTR and tracheal E. coli clearance were associated histologically with replacement of normal pseudostratified columnar epithelium by 3 to 8 layers of immature nonciliated cells. E. coli clearance by the lung and air sac of NDV-infected turkeys was depressed on days 5 through 9 PE.     

氟罗沙星对鸡败血支原体和大肠杆菌混合感染的疗效

以人工诱发鸡败血霉形体和大肠杆菌混合感染模型,评价氟罗沙星的疗效。按每升水加入２５ｍｇ、５０ｍｇ及１００ｍｇ氟罗沙星及５０ｍｇ环丙沙星的用量给病鸡饮水给药,连续５天,对混合感染鸡的治愈率分别是８６．７％、９０．０％、９０．０％及８３．３％,而感染对照组的死亡率为６３．３％;用药组的相对增重率分别为１０１．３％、１０５．７％、１０７．２％及１０２．４％,均显著高于感染对照组（５８５．５％,Ｐ〈０．０１）     

Response to Eimeria tenella of chickens selected for high or low antibody response and differing in haplotypes at the major histocompatibility complex.

Sublines of chickens selected for high antibody (HA) or low antibody (LA) response that differed at the major histocompatibility complex (MHC) were tested for response to Eimeria tenella. In Expt. 1, the first exposure to E. tenella was natural (in floor pens), and chicks were challenged orally 21 days later with 0, 928, or 1855 oocysts. In Expt. 2, chicks were reared in wire-floored batteries, vaccinated orally with 928 oocysts, and challenged orally 12 days later with 15,844 oocysts. Corticosterone (20 mg/kg) was mixed with feed from 24 hr before vaccination to 120 hr after vaccination in Expt. 2. In Expt. 1, LA chicks had more-severe cecal lesions but gained relatively more body weight after challenge than did HA chicks. In Expt. 2, cecal lesions were least severe in HA chicks that had been fed corticosterone, most severe in LA chicks fed corticosterone, and intermediate in chicks that were not fed corticosterone. No differences in response to E. tenella occurred as a result of haplotypes at the MHC.     

Protective effects of sugar cane extracts (SCE) on Eimeria tenella infection in chickens

The effects of oral administration of sugar cane extracts (SCE) on Eimeria tenella oocysts infection in chickens were studied with 2 different experiments. In Experiment 1, 3-week-old inbred chickens (MHC; H.B15) were inoculated into the crop with SCE (500 mg/kg/day) for 1 day or 3 consecutive days, and then challenged with E. tenella sporulated oocysts (2 x 10(4) cells/chicken). In Experiment 2, 1-week-old chickens were orally administered SCE at the same dose for 3 consecutive days, and then initially infected with E. tenella sporulated oocysts (2 x 10(3) cells/chicken). At 2 and 3 weeks of age, these chickens were immunized intravenously with the mixed antigens of sheep red blood cells (SRBC) and Brucella abortus (BA). At 4 weeks of age, chickens were challenged with E. tenella sporulated oocysts (1 x 10(5)/chicken). Challenged chickens with E. tenella oocysts showed markedly decreased body weight gain/day, severe hemorrhage and great number of shedding oocysts in feces and high lesion scores. Oral administration of SCE and initial infection with oocysts (2 x 10 (3)/chicken) resulted in a remarkable improvement in body weight gain/day, hemorrhage, the number of shedding oocysts and lesion score, compare to other infected groups. In addition, SCE-inoculated chickens with the initial infection showed a significant increase in antibody responses against SRBC and BA and also improvement in decreased relative proportions of Bu-1a(+) and CD4( )cells in cecal tonsil lymphocytes of E. tenella-challenged chickens. Cecal tissues of chickens administered SCE and initially infected with E. tenella oocysts showed lower numbers of schizonts, gametocytes and oocysts than those of infected control chickens. These results suggest that SCE have immunostimulating and protective effects against E. tenella infection in chickens.     

喉支康对实验性鸡败血霉形体和大肠杆菌混合感染的疗效

以人工诱发鸡败血霉形体和大肠杆菌混合感染模型，评价复方制剂－喉支康水溶性粉的疗效。按每升水加入20，40，80mg喉支康的用量给病鸡饮水给药，连续5d，对混合感染鸡的治愈率分别是70．0％，93．3％，96．7％，而感染对照组的死亡率为63．3％；上述用药组的增重效果极显著高于感染对照组（P＜0．01）。     

Resistance of broiler chickens to Escherichia coli respiratory tract infection induced by passively transferred egg-yolk antibodies

Egg-yolk antibodies induced by immunizing hens with selected Escherichia coli antigens were evaluated for their ability to protect broiler chickens against respiratory/septicemic disease caused by avian pathogenic E. coli (APEC). Seven groups of broiler breeder hens were vaccinated three times, 1 week apart with live E. coli, killed E. coli, E. coli antigens [lipopolysaccharide (LPS), type 1 pilus adhesin (FimH), P pilus adhesin (PapG), aerobactin outer membrane receptor (IutA)] or phosphate buffered saline (PBS). An O78 APEC strain was used for preparation of all the antigens. Egg yolk immunoglobulins (IgY) were purified from eggs of each group and antibody activity in serum and purified IgY was determined by enzyme-linked immunosorbent assay (ELISA). IgY (100mg) was injected intramuscularly into 11-day-old broiler chickens, which were challenged 3 days later with homologous (O78) or heterologous (O1 or O2) E. coli by the intra-air sac route. Mortality was recorded and surviving chickens were euthanized 1 week after the challenge and examined for macroscopic lesions. Passive antibodies against all antigens except FimH were protective (90-100%) against the homologous challenge, but only anti-PapG and anti-IutA were effective against heterologous challenge. Anti-PapG IgY provided the greatest protection against the three serogroups of E. coli used for challenge. Hence vaccination of broiler breeders to induce anti-PapG and anti-IutA antibodies may provide passive protection of progeny chicks against respiratory/septicemic disease caused by APEC.     

Persistent hypoglycemia is induced by tolbutamide administration in broiler chickens fed a low-carbohydrate diet

With a view to gaining an insight into the regulatory mechanism of blood glucose concentrations specific to the chicken, an experimental induction of hypoglycemia was conducted by single or sequential administration of tolbutamide in broiler chickens fed a standard or low-carbohydrate diet. A single dosing of tolbutamide at levels of 25-200 mg/kg body weight decreased plasma glucose concentrations for 2 to 8 h after the dosing in chickens fed either diet. No significant rise in plasma insulin concentration was observed for 2 to 24 h after the single dosing of tolbutamide in chickens on either diet, with the exception of a significant rise when chickens on the standard diet received 100 mg tolbutamide. However, a transient increase of plasma insulin concentration was observed only in the 20 min immediately after the single dosing. Persistent hypoglycemia that was sustained for 5 days, with no significant changes in plasma insulin concentration, was induced by sequential dosing (3 times per day for 5 days, every 8 h) of tolbutamide (100 and 200 mg/kg body weight) in chickens fed the low-carbohydrate diet. In these chickens, the consistently low concentration of plasma glucose, with small diurnal variations, was evidenced by the determination of plasma glucose every 3 h in day 4/5 of the tolbutamide dosing. In chickens fed the standard diet, on the other hand, the low plasma glucose concentrations for 5 days were accompanied by significant diurnal fluctuations. Chickens with persistent hypoglycemia showed slight decreases in plasma non-esterified fatty acids (NEFA) concentration and only slight changes in blood D-3-hydroxybutyrate (3HB) concentration. The present study shows that the persistent hypoglycemia with normoinsulinemia, in the main, is induced by tolbutamide dosing in chickens fed a low-carbohydrate diet, and that the blood concentrations of NEFA and 3HB, alternatives of energy source in animals, are only slightly changed or not at all in hypoglycemic chickens.     

恩诺沙星对鸡大肠杆菌病及葡萄球菌病的药效研究

就畜禽专用氟喹诺酮类抗菌药恩诺沙星对鸡人工感染大肠杆菌病及葡萄球菌病的药效进行了研究。结果表明，恩诺沙星、氯霉素对大肠杆菌Ｏ７８的ＭＩＣ分别为０．０５、１．６０ｍｇ／Ｌ；恩诺沙星、红霉素对金黄色葡萄球菌Ｃ５６０５株的ＭＩＣ分别为０．２、３．２ｍｇ／Ｌ。人工发病试验中，恩诺沙星内服以５、１０、２０ｍｇ／ｋｇ剂量或肌注以２．５、５、１０ｍｇ／ｋｇ剂量，每天给药２次，连用３ｄ，对鸡大肠杆菌病及葡萄球菌病均有较好的疗效，其中对大肠杆菌病的疗效明显优于氯霉素