BACKGROUND: Ensuring health quality of an agricultural or food product is of significance for consumers and could be a decisive factor in terms of attracting and maintaining the market for manufacturers.OBJECTIVES: The present study aimed to determine the residues of florfenicol antimicrobial agent in the edible tissue (muscle) of rainbow trout reared in Sepidan County (Fars Province, Iran).METHODS: 50 fresh fish were purchased from 7 farms in Sepidan County. The samples from lateral muscle were taken and kept at -18 °C until the residues drug tests were performed. The florfenicol concentration was measured through the high-performance liquid chromatography (HPLC).RESULTS: The mean of florfenicol residues in fish muscle reared in Sepidan County was significantly less than the drug products evaluation standard value (P<0.05). However, the concentration of this antibiotic sampled from one of the studied farms went beyond from standard value (1.12 µg.g-1). Of course, this difference was not significant (P>0.05).CONCLUSIONS: It seemed as though the residue levels of florfenicol in the purchased fish reached alarming levels. Meanwhile, it is possible that their average in an area would be within the range of food standards. Thus, it could be suggested that periodic monitoring be carried out continuously by the relevant institutions to ensure that consumer rights are more adequately met.

BACKGROUND: Antibacterial drug use in food producing animals, in addition to the very beneficial effects on the prevention, treatment, and control of infectious diseases, can lead to health risks including microbial resistance and drug residues. This survey was conducted due to the lack of information on the status of antibacterial drug use in dairy farms of Qom province. OBJECTIVES: To study the usage pattern of antibacterial drugs and compliance with public health- related measures in dairy cattle farms in Qom province. METHODS: In this study, 100 dairy herds were surveyed in three areas of Qom province including the southern part (Kahak), West (Jafar-abad and Khalajestan) and central part (Qom and the suburbs) using a questionnaire and direct interview. RESULTS: Injectable oxytetracycline, tylosin, penicillin + streptomycin were the most frequently used antibacterial products in dairy farms of Qom province (94%, 89% and 87%, respectively). A range of other antibacterial drugs showed high percentages of usage, as well. Among the 9 intramammary products, Tetranebalon®/Mastijet Forte® and Linconeocin MC® with 50% and 40% of frequency were the most commonly used products. Also, in a significant percentage of dairy farms, the milk collected from livestock treated with antibacterial drugs for mastitis (35%) or other illnesses (41%) was introduced into the milk reservoirs to be used in humans. CONCLUSIONS: In Qom province, there was an overuse of antibacterial drugs and high percentage of dairy farm units that did not follow the principles of rational drug therapy and the withdrawal times of milk and meat. This could be due to inadequate awareness of livestock workers regarding the public health implications of using these drugs and insufficient monitoring of veterinary authority in the province.

Introduction: Studies of anabolic hormone residues in the tissues of slaughter animals have been carried out in Poland for more than 25 years. During the period of 2011 to 2015, a total of 35 387 samples from different animal species were tested in the National Residue Control Programme for the presence of residues of compounds that cause hormonal effects, as listed in Annex 1 of Directive 96/23/EC. Material and Methods: The research was conducted in the National Reference Laboratory and eight regional laboratories in departments of veterinary hygiene located throughout the country. Urine, muscle tissue, serum, kidney fat, and drinking water were the targeted matrices. Test methods based on instrumental techniques such as gas and liquid chromatography coupled with mass spectrometry were applied, as well as enzyme-linked immunosorbent assays (ELISA). Results: The concentration of detected hormones exceeded the decision limits in 30 samples, the consequence of which was 41 non-compliances with current applicable criteria. The hormones found present pseudo-endogenous (nortestosterone and boldenone) only, while synthetic hormones were not identified. Conclusion: The non-compliant findings constitute a small percentage (0.085%) of the five-year analysis compilation. On this basis the related food produced in Poland can be accepted as safe for human consumption with regard to the hormone residues tested.

The occurrence of veterinary drug residues in chicken meat originating from 320 small and medium scale chicken slaughterhouses in Peninsular Malaysia was determined. 637 chicken meat samples were examined for tetracycline (TCs), sulphonamide (SAs) and quinolone residues using a microbiological inhibition test and was further confirmed using liquid chromatography mass spectrometry (LCMS/MS). The presence of TC residues were confirmed in 10 (1.6%) samples, and 1 (0.2%)sample was confirmed in compliance to the established maximum residue limit (MRL) for residues of quinolone. A total of 6 (0.9%) samples were above the MRL for TC. The samples were from Pulau Pinang, Terengganu and Kelantan. Among those tested in compliance, the main analytes found for TC and quinolone werechlortetracyclines (CTC), enrofloxacin and mixture of chlortetracycline (CTC) and oxytetracycline (OTC). No samples were found to contain sulfonamides residues.

OBJECTIVE To determine the pharmacokinetics of meloxicam in domestic hens and duration and quantity of drug residues in their eggs following PO administration of a single dose (1 mg of meloxicam/kg). ANIMALS 8 healthy adult White Leghorn hens. PROCEDURES Hens were administered 1 mg of meloxicam/kg PO once. A blood sample was collected immediately before and at intervals up to 48 hours after drug administration. The hens' eggs were collected for 3 weeks after drug administration. Samples of the hens' plasma, egg whites (albumen), and egg yolks were analyzed by high-performance liquid chromatography. RESULTS The half-life, maximum concentration, and time to maximum concentration of meloxicam in plasma samples were 2.8 hours, 7.21 μg/mL, and 2 hours, respectively. Following meloxicam administration, the drug was not detected after 4 days in egg whites and after 8 days in egg yolks. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that meloxicam administered at a dose of 1 mg/kg PO in chickens appears to maintain plasma concentrations equivalent to those reported to be therapeutic for humans for 12 hours. The egg residue data may be used to aid establishment of appropriate drug withdrawal time recommendations.

Monitoring of veterinary drug residues in chicken, swine and cattle was conducted in Peninsular Malaysia from 2010 to 2016. Tissue samples were collected from slaughterhouses and processing plants. A total of six groups of veterinary drugs were analysed in 8,708 samples using bioassay or immunoassay and LCMS method. The average violation rate was 3.4%, 2.5%, 1.9%, 0.8%, 1.6% and 2.7% for year 2010, 2011 and 2012, 2013, 2014, 2015 and 2016, respectively

Few antimicrobials are licensed for use in sheep in Canada, and the range of indications is narrow. Treatment in an “extra-label” manner may be ineffective. In addition, potentially harmful drug residues in food-animal products and antimicrobial resistance in bacteria may be associated with extra-label drug use (ELDU). No data had been documented on drug use, specifically antimicrobial use (AMU), in Ontario sheep, although it was thought that much use was extra-label. This study investigated AMU and ELDU on 49 lamb-producing Ontario sheep farms. Data were prospectively collected over 12 months from the participating farms, and farm-level practices were ascertained with a questionnaire. Treatment-level and farm-level variables were investigated for associations with rates of AMU by means of Poisson rate regression models fit with a generalized estimating equation to control for clustering at the farm level. Antimicrobials with high mean exposure rates included chlortetracycline (in feed), penicillins, and oxytetracycline. The exposure rate in lambs was significantly lower (P < 0.01) with antimicrobial treatment of systemic signs, respiratory disease, or wound or injury than with treatment of other reported diseases or conditions; it was also significantly lower with 3 or more lambing periods per year (α = 0.05). The exposure rate in adult sheep was significantly lower with treatment of 5 of the 6 most prevalent diseases or conditions (α = 0.05) and significantly higher with producer decision to treat and producer experience of 20 y or greater. Rates of using antimicrobials not licensed for use in sheep were high, as was extra-label use of licensed antimicrobials. Diseases reportedly treated most often with antimicrobials (e.g., systemic signs, mastitis) were significantly associated with lower rates of ELDU (α = 0.05). Compared with the rates in adult sheep, the mean rate of use of nonlicensed antimicrobials was similar in the lambs, whereas the mean rate of extra-label use of licensed antimicrobials was lower among the lambs. The results are useful in determining if public health concerns about antimicrobial use in Ontario sheep are warranted and in creating drug use and licensure strategies for the Canadian sheep industry.

Milk antimicrobial residues are a serious concern for the dairy industry. Residues of the tetracycline family of antimicrobials have been reported in market milk by investigators, using radioimmunoassay and microbial receptor technology (hereafter referred to as the Charm II test). In response to these reports, an investigation was conducted to determine the potential of 3 extra-label routes of oxytetracycline (OTC) administration to cause milk residues above the Food and Drug Administration safe value of 30 parts per billion (ppb). Lactating Holstein cows were administered OTC once by use of 1 of 3 routes: IV at 16.5 mg/kg of body weight (n = 6); IM at 11 mg/kg (n = 6); and intrauterine (IU) at 2 g in 500 ml of saline solution/cow (n = 6). Duplicate milk samples were collected at the milking prior to drug administration and for the next 13 milkings at 12-hour intervals. Concentrations of OTC in milk samples were analyzed by use of the Charm II test for tetracyclines (limit of OTC detection, approx 5 ppb) and were compared with concentrations determined by use of a high-performance liquid chromatography (HPLC) method (lower limit of OTC quantitation, approx 2 ppb). The potential for milk OTC residues above the Food and Drug Administration safe value of 30 ppb after treatment was considerably greater for the IV and IM routes, compared with the IU route. Mean peak OTC concentrations in milk at the first milking after treatment for the HPLC and Charm II tests were approximately 3,700 to 4,200 ppb for the IV route, 2,200 to 2,600 ppb for the IM route, and 186 to 192 ppb for the IU route, respectively. Pharmacokinetic analysis, based on milk OTC concentrations, indicated that the area under the curve (AUC) and milk maximal concentration (Cmax) differed significantly (P < 0.001) among routes of administration. The AUC was similar for IV and IM administrations; values for both were greater than the AUC for IU administration. The Cmax was greatest for IV, intermediate for IM, and least for IU administration. There were significant (P less than or equal to 0.01) differences in AUC between assay methods (Charm II vs HPLC) for the IV route. Concentrations of OTC in milk determined by the Charm II test were often greater than those determined by HPLC. Administration of OTC to lactating cows via these routes is extra-label drug use. Failure to withhold the product from early milkings of cows administered OTC by the IV or IM route should be considered a potential cause of OTC residues in market milk. Milk from nearly all cows contained OTC (< 30 ppb), the Food and Drug Administration safe level, by 120 hours after OTC administration. Use of appropriate withholding times and antibiotic residue testing is indicated to avoid OTC residues.

Using 7 penicillins (amoxicillin, ampicillin, methicillin, penicillin G, oxacillin, cloxacillin, and dicloxacillin), simultaneous and direct determination of residual penicillins in biological samples was carried out by use of bioassay and high-performance liquid chromatography with spectrophotometric or fluorometric detectors. By use of assay medium seeded with penicillin-sensitive Micrococcus luteus (ATCC No. 9341) as a test organism, we were able to detect penicillins even at low concentrations. All penicillins treated with 10 U of penicillinase/ml did not produce inhibition zones by disk testing, even at a concentration of 100 micrograms of penicillin/ml/assay plate. Using a mobile phase of acetonitrile:methanol:0.01M KH2PO4 (19:11:70, v/v/v; pH, 7.1), standard solutions of the penicillins were separated from each other by use of high-performance liquid chromatography analysis, producing symmetric peaks without tailing, each of which had a characteristic retention time. Simultaneous detection of residual penicillins in bovine serum, kidneys, and liver, for the 5 penicillins for which analysis was possible by use of the UV method, yielded recovery rates from 71.4 to 102.3%; for the 2 amino-penicillins, amoxicillin and ampicillin, which could only be detected by use of the fluorometric method, recovery rate ranged from 72.9 to 103%.

The pharmacokinetic properties of enrofloxacin were determined in broiler chickens after single IV and orally administered doses of 10 mg/kg of body weight. After IV and oral administrations, the plasma concentration-time graph was characteristic of a two-compartment open model. The elimination half-life and the mean +/- SEM residence time of enrofloxacin for plasma were 10.29 +/- 0.45 and 9.65 +/- 0.48 hours, respectively, after IV administration and 14.23 +/- 0.46 and 15.30 +/- 0.53 hours, respectively, after oral administration. After single oral administration, enrofloxacin was absorbed slowly, with time to reach maximal plasma concentration of 1.64 +/- 0.04 hours. Maximal plasma concentration was 2.44 +/- 0.06 micrograms/ml. Oral bioavailability was found to be 64.0 +/- 0.9%. Statistically significant differences between the routes of administration were found for the pharmacokinetic variables-half-lives of the distribution and elimination phase and apparent volume of distribution and volume of distribution at steady state. In chickens, enrofloxacin was extensively metabolized into ciprofloxacin. Residues of enrofloxacin and the major metabolite ciprofloxacin in fat, kidney, liver, lungs, muscles, and skin were measured in chickens that received an orally administered dose of 10 mg/kg once daily for 4 days. The results indicate that enrofloxacin and ciprofloxacin residues were cleared slowly. Mean muscle, liver, and kidney concentrations of the metabolite ciprofloxacin ranging between 0.020 and 0.075 micrograms/g persisted on day 12 in chickens after dosing. However, at the time of slaughter (12 days), enrofloxacin residues were only detected in liver and mean +/- SEM concentration was 0.025 +/- 0.003 micrograms/g.