Oxytetracycline Residues Research Articles

Impact of Oxytetracycline on Apis mellifera Colonies: Preliminary Results on Residues and Antibiotic Resistance

Abstract We tested two summer protocols for oxytetracycline (OTC) administration on beehives to evaluate: toxicity for the bees, residues in honey and presence of genes encoding for OTC antibiotic resistance in bacteria isolated from the gut of adult bees. In July 2020, eighteen healthy colonies were divided into three groups. Two OTC treatment protocols - long and short, were devised, and one group was left untreated. We did not detect any toxicity on adult bees or brood but found OTC residues in the honey of the nest up to seven months after both treatments (210.3±221.2 µg/kg after long protocol; 216.2±238.4 µg/kg after short protocol), even in the untreated group (up to the mean 75.8±173.2 µg/kg). Antibiotic resistance genes were found, even in the untreated group, possibly due to the long exposure to antibiotics. More in-depth studies should be performed to verify how the long-term persistence of antibiotics impacted the beehive during the inactive season.

Novel and Highly Sensitive Electrochemical Sensor for the Determination of Oxytetracycline Based on Fluorine-Doped Activated Carbon and Hydrophobic Deep Eutectic Solvents.

Residues of oxytetracycline (OTC), a veterinary antibiotic and growth promoter, can be present in animal-derived foods; their consumption is harmful to human health and their presence must therefore be detected and regulated. However, the maximum residue limit is low, and consequently highly sensitive and accurate detectors are required to detect the residues. In this study, a novel highly sensitive electrochemical sensor for the detection of OTC was developed using a screen-printed electrode modified with fluorine-doped activated carbon (F-AC/SPE) combined with a novel deep eutectic solvent (DES). The modification of activated carbon by doping with fluorine atoms (F-AC) enhanced the adsorption and electrical activity of the activated carbon. The novel hydrophobic DES was prepared from tetrabutylammonium bromide (TBABr) and a fatty acid (malonic acid) using a green synthesis method. The addition of the DES increased the electrochemical response of F-AC for OTC detection; furthermore, it induced preconcentration of OTC, which increased its detectability. The electrostatic interactions between DES and OTC as well as the adsorption of OTC on the surface of the modified electrode through H-bonding and π-π interactions helped in OTC detection, which was quantified based on the decrease in the anodic peak potential (E pa = 0.3 V) of AC. The electrochemical behavior of the modified electrode was investigated by cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. Under optimum conditions, the calibration plot of OTC exhibited a linear response in the range 5-1500 μg L-1, with a detection limit of 1.74 μg L-1. The fabricated electrochemical sensor was successfully applied to determine the OTC in shrimp pond and shrimp samples with recoveries of 83.8-100.5% and 93.3-104.5%, respectively. In addition to the high sensitivity of OTC detection, the proposed electrochemical sensor is simple, cost-effective, and environmentally friendly.

Dynamics impacts of oxytetracycline on growth performance, intestinal health and antibiotic residue of grouper in exposure and withdrawal treatment

Little is known about the effects of oxytetracycline (OTC) on marine fish. Using juvenile pearl gentian grouper (Epinephelus fuscoguttatus♀ × E. lanceolatus♂), we investigated the effects of 56 days dietary oxytetracycline (OTC; OTCD) exposure (80 mg/kg body weight/day) on fish growth performance, intestinal health and antibiotic residue. Meanwhile, the alteration of intestinal health status and antibiotic residue after 7 (O7) or 14 days (O14) OTC withdrawal treatment were explored. We also assessed the potential human health risks based on target hazard quotient (THQ). The results showed that OTC exposure had no effects on growth rate parameters but caused liver and intestine atrophy. OTC exposure impaired the intestinal health by distorting intestinal morphological features, inducing oxidative stress, repressing immune function, triggering NF-κB-mediated inflammatory response and apoptosis, while 7 days OTC withdrawal treatment improved intestinal health status and 14 days OTC withdrawal treatment further improved it. In addition, the order of OTC residue in tested tissues after OTC exposure was: liver > kidney > spleen > muscle > intestine. OTC residue was significantly decreased in all tissues along with the increasing of withdrawal treatment period. Adults and children consuming the edible tissues (muscle) of OTC-treated or withdrawal-treated pearl gentian grouper would not experience any previous health risk as the THQ < 1 in all group.

Accumulation and depletion of oxytetracycline (OTC) and oxolinic acid (OXA) in Pompano, Trachinotus blochii

Accumulation and depletion including withdrawal period for oxytetracycline (OTC) and oxolinic acid (OXA) in pompano (Trachinotus blochii) were determined following oral administration. Pompano were cultured in 250-L fiberglass tanks in a flow-through system provided with aeration. Observed average temperature was 30oC; salinity was 30 ppt. Fish were starved for 2 days then fed with OTC medicated diet (75mg/kg fish/day) or OXA medicated diet (30 mg/kg fish/day) 3 times a day for 10 successive days at 2% body weight and thereafter switched to regular diet for 45 days. Muscle and blood samples were taken at regular intervals during and after cessation of medication. OTC residues in the muscle and blood were analysed using the high performance liquid chromatography (HPLC). Peak OTC accumulation was observed at day 10 of treatment. Higher OTC accumulation was observed in the muscle (0.88+0.27 µg/g) than in the blood (0.3+0.09 µg/ml). OXA accumulation peaked on day 5 of treatment; higher OXA accumulation was observed in the muscle (0.11+0.06 µg/g) compared to blood (0.005+0.0001 ug/ml). Withdrawal period at 30oC for OTC in pompano muscle was 19 days (570 degree-days) and 17 days (510 degree-days) in the blood. For OXA, the withdrawal period in pompano muscle and blood at 30oC temperature was 3 days (90 degree-days).

Characteristics of oxytetracycline stress-sensitive microbe-dissolved organic matter component interactions during composting

Dissolved organic matter (DOM) has important impacts on the transportation of antibiotics through chemical and biological processes in composting. The interaction between DOM and antibiotics is reciprocal. The interaction between DOM ligands and antibiotics could be characterized based on a technique combining parallel factor analysis (PARAFAC) and microbial community structure analysis. However, PARAFAC cannot reveal the dynamic changes in each DOM peak in one PARAFAC component under antibiotic stress. In this study, two-dimensional correlation spectroscopy (2DCOS) combined with PARAFAC and bacterial community diversity analyses were employed to reveal the effects of oxytetracycline (OTC) stress and the key microorganisms on the transformation of different fluorescent peaks from DOM PARAFAC components during chicken manure composting. The results showed that OTC inhibits the transformation between DOM PARAFAC components by inhibiting the core microbial activities involved in the transformation of DOM components. Protein-like components (C1 and C2) were more sensitive to OTC residue, and components with a high humification degree promoted the degradation of OTC. The interaction between special DOM PARAFAC components and certain bacteria affects the degradation of OTC. The DOM PARAFAC components A2(C1), B1(C2), B2(C2) and Z1(C4) enhanced OTC degradation by stimulating the genera Pseudomonas, Glycomyces and Hyphomicrobium. With these promising results, the true effect of DOM PARAFAC components on the degradation of OTC can be revealed, which is helpful for addressing antibiotic contamination to improve the bioavailability of compost products.

Tetracycline residues in tilapia and catfish tissue and the effect of different cooking methods on oxytetracycline and doxycycline residues

Fish such as tilapia (Oreochromis niloticus) and catfish (Clarias gariepinus) is an important source of high biological value animal protein. Fish can be exposed to antimicrobials in intensive aquaculture systems or exposed to remnants of the antimicrobials released to various water bodies via drainage systems. This study aimed at screening for antimicrobial residues in two major fish species commonly consumed in Egypt, namely, tilapia, and catfish, either in wild or cultured fish using a microbial inhibition assay. Besides, quantitative estimation of tetracycline (oxytetracycline and doxycycline) residues in the edible fish muscles was carried out using the solid phase extraction (SPE) technique and high-performance liquid chromatography with photodiode-array detection (HPLC-PAD). In addition, the effects of different cooking methods (pan-frying, grilling, and microwaving) on oxytetracycline and doxycycline residues in tilapia and catfish were investigated. The microbiological inhibition assay revealed that 2, 24, 18, and 32% of the examined wild tilapia, cultured tilapia, wild catfish, and cultured catfish, respectively, contained antibiotic residues. Cultured tilapia, wild catfish, and cultured catfish had mean concentrations of oxytetracycline residues of 0.147 ± 0.067, 0.106 ± 0.046, and 0.313 ± 0.044 µg/g. 3 (6%), 4 (8%), and 9 (18%) of the sampled cultured tilapia, wild catfish, and cultured catfish exceeded the established maximum permissible limits (MPL) of tetracycline (0.100 ng/g). The mean concentrations of doxycycline residues were 0.276 ± 0.045, 0.026 ± 0.004, and 0.070 ± 0.010 µg/g in cultured tilapia, wild catfish, and cultured catfish, respectively, with 2 (4%) of the cultured tilapia exceeding the MPL of doxycycline. Consumption of fish with high residual levels of tetracyclines might pose potential health risks to consumers. In an experimental trial, heat treatment of tilapia and catfish could significantly reduce both oxytetracycline and doxycycline residues, particularly grilling had the highest reduction rates.

Microbiological contamination, antimicrobial residues, and antimicrobial resistance in raw bovine milk in Lebanon

A total of 195 raw milk samples were collected over two consecutive years from 48 milk sources in Lebanon. Collected samples were examined for microbiological quality and antibiotic susceptibility. Results revealed non-conformity with local and international standards, in 96% of samples for total aerobic mesophilic bacteria (TAMB), 81% for total coliform (TC), 17% for Staphylococcus aureus (S. aureus), 35% for Salmonella spp., and 65% for Escherichia coli (E. coli). Antimicrobial residues of oxytetracycline, tetracycline, ciprofloxacin, sulfamethazine, and doxycycline were below the maximum residue limits (MRL). On the other hand, E. coli isolates showed resistance to tetracycline (41%), doxycycline (39%), nalidixic acid (20%), and ciprofloxacin (3%), while S. aureus isolates were found resistant to doxycycline (63%), and tetracycline (51%). For Salmonella spp., isolates were found to be resistant to doxycycline (12%), tetracycline (6%), and nalidixic acid (4%). In conclusion, sampled milk shows high levels of pathogenic bacteria and antimicrobial resistance.

Conformational fixation induced fluorescence turn-on of oxytetracycline coordinated on aluminum-based metal-organic frameworks for ultrasensitive sensing application

Since the abuse of oxytetracycline (OTC) has brought serious environmental problems, it is of great practical significance to develop sensitive OTC fluorescent probes to quantify environmental OTC residues. Herein, the aluminum-based metal-organic framework MIL-53(Al) with microflower morphology and plentiful surface open aluminum sites (denoted as FMIL-53(Al)) was tailored via an acetic acid-assisted solvothermal method and subsequently exploited for ultrasensitive detection of OTC. Compared with conventional hydrothermally synthesized MIL-53(Al), FMIL-53(Al) possesses a larger specific surface with plentiful open aluminum sites, which can selectively coordinate with OTC to fix the molecular conformation. The coordinated OTC molecules undergo a transition from twisted-conformation to extended-conformation, accompanied by an increase in fluorescence quantum yield. As a fluorescent probe, the detection limit of FMIL-53(Al) for OTC is estimated as low as 0.94 nM. Finally, the FMIL-53(Al)-based probe can be applied for the detection of OTC in water samples of fish farm pond, and a portable test paper was successfully fabricated for on-site visual identification of OTC. This work not only demonstrates a novel morphology of MIL-53(Al) for OTC ultrasensitive sensing but also provides an example of morphological engineering to optimize the performance of MOF-based fluorescence sensors.

Histopathological changes and tissue residue concentrations of monosex Nile tilapia (Oreochromis niloticus, L) fries exposed to oxytetracycline.

The current study evaluated the biosafety of oxytetracycline (OTC) exposure for 30 days in monosex Oreochromis niloticus fries. The fries were exposed to OTC for 3 h/day for 30 days at 350 (0.5X), 700 (1X), 2100 (3X), 3500 (5X), and 7000 (10X) mg/L and compared with control (0X). The OTC exposure at 5X and 10X concentrations caused 100% mortality within 4 days and 5 min, respectively. The mortalities recorded in 0.5X, 1X, and 3X groups were 3.33 ± 1.15%, 14.67 ± 1.15%, and 47.33 ± 11.37% on day 30, respectively. The feed intake was decreased up to 23.33% in the 3X group during the exposure period. The OTC residue levels on 30-day exposure were 216.53 ± 14.71, 450.56 ± 44.31, and 1141.26 ± 63.64 μg/kg, which reduced to 40.40 ± 3.25, 76.68 ± 2.77, and 95.61 ± 5.13 μg/kg after 15 days of termination of exposure in the 0.5X, 1X, and 3X groups, respectively. The histopathological changes observed in the 1X group were epithelial detachment, desquamation of secondary lamellar epithelium, lamellar fusion, and inflamed cartilaginous core in the gills, alteration in the integrity of gut mucosa, degeneration of muscularis mucosae and necrosis in the intestine, the disintegration of the nephritic tubule, necrosis, and glomerulopathy in the kidney, and dilated vascular duct, necrotized hepatic tissue, diffused hepatic parenchyma, vacuolation, and fatty changes in the liver. The OTC exposure induced marked tissue changes histologically in a dose- and time-dependent manner, which undoubtedly reduced the growth of tilapia.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10499-022-00892-w.

Inspection of antimicrobial remains in bovine milk in Egypt and Saudi Arabia employing a bacteriological test kit and HPLC-MS/MS with estimation of risk to human health.

Veterinary medicine uses antibiotics randomly for treatment and growth promotion. Milk of dairy animals contains substantial quantities of antibiotics that have harmful effects on health. It is therefore necessary to test commercially available milk using immunological, chromatographic, or microbiological methods to confirm the absence of antibiotic residues. This study aims to perform a microbiological test, followed by a quantitative confirmation analysis, on raw milk to assess the presence of antibiotic residues. Tests were conducted on 200 milk samples collected from markets and farms in Saudi Arabia and Egypt. The microbial inhibitor test (Delvotest SP-NT) revealed that 40 samples were positive for antibiotic residues. The positive samples were further tested using liquid chromatography-tandem mass spectrometry (LC-MS/MS) as a confirmatory quantitative test for 29 antibiotics that belong to five groups: tetracyclines, sulfonamides, fluoroquinolones, macrolides, and lactamases. Only four samples tested positive for oxytetracycline residues above the maximum residue limit. Based on these results, researchers suggest a monitoring system that considers both microbial and HPLC-MS/MS methods when detecting antibiotic residues in bovine milk. The analysis of risk to human health revealed that antibiotic residues at the detected levels do not pose any health risks to consumers.

Quantification of antibiotic residues in raw and layers hen eggs by rp-hplc

Antibiotics (Oxytetracycline &amp; Enrofloxacin) residual levels in raw and layered samples are to be quantified using RP-HPLC. The antibiotic (oxytetracycline and enrofloxacin) residual levels in raw and layers hen egg samples were evaluated qualitatively by high performance liquid chromatography in this investigation, which used one hundred randomly selected samples (HPLC). C18 (Hypersil ODS-BPS, 250 4.6mm; 5) was used for the separation at a flow rate of 1 ml/min in a mobile phase of 0.1 percent formic acid: acetonitrile (50:50, v/v). At a detection wavelength of 350 nm, the residues were measured. Found oxytetracycline residues, which indicate widespread usage of antibiotics on farms and a lack of application of required withdrawal durations, were detected in samples. Because of this, the antibiotic residues found in broiler hen eggs have been reduced. Restrictive methods and stricter restrictions should be implemented to prevent the presence of abuse residues prior to marketing, according to these findings.

Kill two birds with one stone: Selective and fast removal and sensitive determination of oxytetracycline using surface molecularly imprinted polymer based on ionic liquid and ATRP polymerization

Oxytetracycline (OTC) residue in food and environment has potential threats to ecosystem and human health, thus its sensitive monitoring and effective elimination are very important. In this work, a new molecularly imprinted polymer (MIP) composite was prepared through atom transfer radical polymerization by using OTC as template, gold nanoparticles modified carbon nanospheres (Au-CNS) as supporter, ionic liquids (IL) as functional monomer and cross-linking agent. The obtained MIP-IL@Au-CNS composite was characterized by Fourier transform infrared absorption spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. It displayed high imprinting factor (5.50) and adsorption capacity (56.7 mg g−1), and could achieved the adsorption equilibrium in short time (about 15 min). Results also illustrated that the adsorption process basically conformed to the quasi-second-order kinetic model and Freundlich model, and MIP-IL@Au-CNS could be recycled at least 5 times. Furthermore, a sensitive OTC electrochemical sensor was developed by combining MIP-IL@Au-CNS with IL-modified carbon nanocomposites (IL@N-rGO-MWCNT). The resulting sensor demonstrated a linear response to OTC in the wide range of 0.02–20 μM, and the detection limit was down to 5 nM. It also had the advantages of high selectivity, fast elution/regeneration and simple construction procedure. The sensor had been applied to the detection of real samples, and acceptable recovery (96.4%−106%) and RSD (3.2%−6.2%) were obtained. This work expands the application of IL-based MIP in pollutant monitoring and enriching.

Development of a UPLC-FLD method for quantitative analysis of three tetracyclines and two fluoroquinolones in chicken muscle

A sensitive, rapid and efficient ultra-performance liquid chromatography-fluorescence detection (UPLC-FLD) method was established for detecting tetracycline (TC), oxytetracycline (OTC), doxycycline (DOX), enrofloxacin (ENR) and ciprofloxacin (CIP) residues in chicken muscle. Moreover, the fluorescence detector output signals were processed by dual-channel detection. The samples were extracted with a mixture of acetonitrile and 0.1 M citric acid containing 100 mM magnesium chloride (1:1, V/V, adjusted the pH to 5.0 with ammonia) using liquid-liquid extraction (LLE) and purified by Oasis PRiME hydrophilic-lipophilic balance (HLB) solid-phase extraction (SPE) cartridges (60 mg/3 mL). The target compounds were separated on an ACQUITY UPLC BEH C18 (100 mm × 2.1 mm, 1.7 μm) chromatographic column using a mobile phase composed of acetonitrile and 0.1 M malonic acid solution containing 50 mM magnesium chloride hexahydrate, and the pH was adjusted to 5.5 by adding ammonia. The limits of detection (LODs) and limits of quantification (LOQs) of the five target compounds in chicken muscle were 0.1–13.1 μg/kg and 0.4–39.4 μg/kg, respectively. The recoveries of the five target compounds in chicken muscles were above 87.33 % when the spiked concentrations were at the LOQ, 0.5 maximum residue limit (MRL), 1.0 MRL and 2.0 MRL. The intraday relative standard deviations (RSDs) were less than 4.91 %, and the interday RSDs were less than 5.13 %. Ultimately, this novel detection method was successfully applied to the quantitative analysis of TC, OTC, DOX, ENR and CIP in 20 commercial chicken samples from local supermarkets.

Comparative effects of ferric hydroxide and (semi) conductive iron oxides on the anaerobic digestion of oxytetracycline-contaminated dairy manure

Additives, such as iron oxides, have been used in anaerobic digestion (AD) to promote direct interspecies electron transfer and to boost methane yield. However, the function of additives in the AD of antibiotic-contaminated organic wastes remained unclear. In this study, the effects of ferric hydroxide and (semi) conductive iron oxides, namely hematite and magnetite, on the AD of oxytetracycline (OTC)-contaminated dairy manure were investigated. Each iron oxide was assigned to a set of experiment where 0.25 g/L of OTC was added to 1 L batch digesters, while the concentration of iron oxide was varied from 0.08 to 0.34 g/L. Generally, magnetite was the most effective iron oxide to enhance methane yield in OTC-free dairy manure followed by ferric hydroxide and hematite. However, when the manure was contaminated with OTC, higher methane yield was observed in ferric hydroxide followed by hematite, while the lowest was with magnetite. In all digesters, the highest methane yield was observed with ferric hydroxide at 0.08 g/L, which was 1.43-fold of that with OTC and without iron oxides. The kinetic studies of methane yield demonstrated that the addition of iron oxides in the AD of OTC-contaminated dairy manure did not shorten the lag phase period despite the increase of methane yield. Thus, the increase of methane yield with ferric hydroxide was attributed to the possible formation of Fe-OTC complex, which attenuated the inhibition of OTC. A strategy to recover OTC residue in the AD was proposed using magnetite, a ferromagnetic particle, and high gradient magnetic separator.

Evaluation of Oxytetracycline Residue in Muscles and Organs of Broiler Birds in Sokoto Metropolis

Evaluation of Oxytetracycline Residue in Muscles and Organs of Broiler Birds in Sokoto Metropolis

Oxytetracycline residues in bovine muscles, liver and kidney tissues from selected slaughter facilities in South Western Uganda

BackgroundDue to high disease burden and poor animal health services in Uganda, administration of antimicrobials particularly oxytetracycline (OTC) is often done by farm owners and workers without any prescription. This results in misuse of OTC with consequent high chances of antibiotic residues and antimicrobial resistance hence posing public health threat. The degree of public health threat from OTC use is not well established due to limited published data on antibiotic residues and usage in livestock production in Uganda. This study comparatively determined OTC residue levels in 318 samples of bovine muscles, liver and kidney tissues from Kiruhura, Mbarara and Ntungamo districts of South Western Uganda during dry and wet seasons.ResultsThe results revealed that the overall OTC residues positivity levels was 74.84% while the district wise rates were 56.88%, 84% and 84.52% for Kiruhura, Mbarara and Ntungamo, respectively. The mean OTC residue levels in bovine muscles, liver and kidney tissues were above the recommended maximum residue limits of 200, 600 and 1200 µg/kg, respectively as established by FAO/WHO. Of the collected samples, 72.41% (236/318) had OTC residues in concentrations above the recommended maximum residue limits. Wilcoxon signed rank test results showed that change in the seasons did not cause any significant changes in the liver OTC residue levels for all the districts, though this was significant for muscles from Kiruhura and Mbarara districts. Unacceptably high OTC levels were found in the muscles, liver and some kidney samples: Kiruhura muscles and liver samples had mean OTC concentrations of 1094 ± 378 µg/kg and 967 ± 198 µg/kg; Mbarara muscles, liver and kidney samples had mean OTC mean concentrations of 668 ± 163 µg/kg, 3778 ± 1140 µg/kg and 12,576 ± 1630 µg/kg, respectively while Ntungamo samples had mean OTC concentrations of 586 ± 123 µg/kg and 5194 ± 1463 µg/kg in muscle and liver tissues.ConclusionsThe results of this study indicated that there are unacceptably high OTC residue levels in bovine tissues consumed in South Western Uganda. This poses a public and veterinary health threat to consumers of these bovine tissues.

A Wake-Up Call: Determination of Antibiotics Residue Level in Raw Meat in Abattoir and Selected Slaughterhouses in Five Local Government in Kano State, Nigeria

The frequent use of antibiotics may result in drug residues that can be discovered at varying quantities in animal products such as milk or meat. Various persons have perceived the presence of pharmaceutical residues in food above the MRLs globally. Antibiotics residues are present in food, which can endanger human health by causing antibiotic sensitivity, allergic reactions, microflora imbalance, bacterial resistance to antibiotics in microorganisms, and financial loss to the food industry. Farmers around the world utilize them on a sporadic basis for both preventative and curative purposes. This study assessed the antibiotics residues in raw meat sold in 6 slaughter houses in Kano States. The study is a descriptive cross-sectional study involving six (6) major slaughterhouse in Kano state. Muscle, Kidney and liver samples were collected from each slaughterhouse. The antibiotic residues in the meat samples were analysed using high performance liquid chromatography (HPLC) for tetracycline, ciprofloxacin and oxytetracycline residue results were presented in charts and tables. Out of a total of 18 beef samples analyzed during this study, 15 (83%) of the total samples had detectable levels of tetracycline residues from which 6(33.3%) had tetracycline residues at violative levels above the WHO/FAO maximum residue limits (MRLs), out of those 18 beef samples analyzed during this study, 6(33%) of the total samples had detectable levels of oxytetracycline residues from which 3(17%) had oxytetracycline residues at violative levels above the WHO/FAO maximum residue limits (MRLs) and out of those 18 beef samples analyzed during this study, 12(67%) of the total samples had detectable levels of ciprofloxacin, all levels are below the WHO/FAO maximum residue limits (MRLs). This high level of tetracycline and oxytetracycline residues in greater proportion of meat destined for human consumption at violative levels could be as a result of the indiscriminate use and misuse of veterinary drugs as commonly practiced among livestock producers and marketers without observing withdrawal period prior to slaughter. These results indicate that consumers may be predisposed to health hazards and hinder international meat trade from Nigeria. Regulatory authorities should therefore ensure compliance with good agricultural practices including withdrawal period of drugs used for treatment of food animals.

Determination of Tetracycline Residues in Kidney and Muscle of Beef Cattle Slaughtered in Dire Dawa and Harar Municipal Abattoirs, Eastern Ethiopia.

Background:Antibiotics are among the most widely used drugs in farm animals for therapeutic and prophylactic purposes. However, the antibiotic residues in meat are a serious public health concern due to their harmful effects on consumer health. Besides this problem, there is limited information on the level of the antibiotic residues, including tetracycline residues. Therefore, this study was aimed to determine the tetracycline residues in the kidney and muscle samples of beef cattle in Harar town and Dire Dawa city.Methods:A study was conducted on 500 randomly selected carcass (250 kidney and 250 muscle samples) slaughtered at Dire Dawa and Harar municipal slaughterhouses between December 2018 and December 2019. The samples were collected aseptically and screened for tetracycline residues by thin layer chromatography. Then, presumptive positive samples were analyzed using high-performance liquid chromatography to get a quantitative outcome. Descriptive statistics were used to determine the frequency, mean, or standard deviation to determine the summary values and distribution of the outcomes. Finally, the data was analyzed using SPSS version 21 software.Results:Out of 500 samples, oxytetracycline residues were detected in 84% of the samples. However, tetracycline and doxycycline were not detected in all samples. Among the kidney and muscle samples collected from Dire Dawa and Harar abattoirs, 109 (87.2%) and 101 (80.8%) were positive for oxytetracycline, respectively. Oxytetracycline residue levels in Dire Dawa ranged from 57 to 607 µg/kg for the kidney and 10.14 to 435 µg/kg for muscle samples. Among the samples collected from Harar, the concentration of oxytetracycline residues ranged from 16 to 433 µg/kg and 6 to 435 µg/kg for kidney and muscle samples, respectively, at Harar slaughterhouses. About 22.0% of muscle samples collected from Dire Dawa and 17.8% from Harar town had oxytetracycline residues above maximum residue limits.Conclusions:In general, the study revealed that oxytetracycline residues were prevalent among tetracycline residues analyzed from kidney and muscle samples in the study areas. Thus, there is a risk of consumer exposure to these antibiotic residues that may have human health effects. Therefore, awareness creation and strict regulation is needed by the regulatory authorities for the use of antimicrobial drugs in the livestock industry.

Screening of oxytetracycline &amp; chlortetracycline residues in poultry feeds in Bangladesh

A total of 112 poultry feed samples were screened for oxytetracycline and chlortetracycline antibiotic residues by thin-layer chromatography (TLC). The samples were collected from Natore, Naogaon, Rangpur and Comilla districts of Bangladesh. Poultry feed samples were classified according to their product type (homemade, commercial) and types of poultry feed (broiler feed, layer feed and sonali feed). All the homemade poultry feed samples (100%) tested positive for oxytetracycline and chlortetracycline antibiotic residue when screened. About 95% of commercial poultry feed tested positive for antibiotic residue in all four districts. In this study, the positive screening for oxytetracycline and chlortetracycline antibiotic residue in broiler, layer and sonali poultry feed types are 98%, 95% and 90%, respectively. This study also observed that antibiotic residue remained in feed samples irrespective of temperature and time as they had been stored for about a year at room temperature. From this study, it was revealed that the use of antibiotics in poultry feeds was extensive. Moreover, the duration of sustaining in poultry feed also raised concerns regarding their use and effect on the environment. This study has also increased the concern about the strict monitoring of the use of antibiotics in the poultry industry.

Chromatographic analysis of bromhexine and oxytetracycline residues in milk as a drug analysis medium with greenness profile appraisal

Tetracyclines are frequently employed in animal husbandry. Bromhexine is a mucolytic drug that improves the efficacy of tetracyclines. It has been reported that residues of tetracyclines in milk may have negative effects on humans. Two versatile and accurate methods were developed for concurrent analysis of oxytetracycline (OTC) and bromhexine (BR) residues in spiked milk samples. Sample preparation was carefully considered for extraction and cleanup using the ecofriendly chemicals acetic acid, 0.1 N EDTA and ethanol or methanol. The first method was a TLC-densitometric method in which TLC plates previously treated with 10% EDTA (pH 9 with 40% sodium hydroxide) were used as a stationary phase. A solvent mixture of methanol : methylene chloride : 2% aqueous acetic acid (8 : 2 : 0.5, by volume) was the developing system, and detection was carried out at 254 nm. Metformin was used as the internal standard, and linearity was achieved in the ranges of 0.2-10 and 0.04-2 μg per band for OTC and BR, respectively. The second method was a RP-HPLC method; separation was performed on a C18 column using an isocratic mixture of ethanol : 7.5% aqueous acetic acid (70 : 30, v/v). Separation was achieved within 10 minutes, and linearity was proven in the ranges of 0.05-50 and 0.05-30 μg mL-1 for OTC and BR, respectively. Diclofenac sodium was used as an internal standard. The proposed methods were validated in accordance with the FDA Center for Veterinary Medicine guidelines. Moreover, the performance and health and environmental impacts of the methods were evaluated using several greenness metrics, namely, the National Environmental Methods Index (NEMI), modified NEMI, Green Analytical Procedure Index (GAPI), Analytical Eco-Scale and Analytical GREEnness (AGREE) metric approaches. All the obtained results proved the validity of the developed methods concerning its performance and ecological effects. The methods can be used to investigate the presence of OTC residues in various marketed milk samples to maintain public health.