Chlortetracycline Research Articles

Integrity of Sperm Cell Bali Bull Preserved at 5°C Using a Diluent Formulation of Extracted Red Fruit and Coconut Water

This study aims to determine the role of the best diluent in protecting the integrity of the spermatozoa membrane after storage using an alternative diluent formulation of red fruit extract (Pandanus Conoideus Lamk) and coconut water. An alternative diluent formulation featuring red fruit extract (Pandanus Conoideus Lamk) and coconut water was utilized. Fresh semen from Bali Bull was evaluated in the Integrated Field Laboratory, Department of Animal Science of Universitas Muhammadiyah Gorontalo. Bali bull sperm of high quality was diluted using a combination diluent containing red fruit extract (Pandanus Conoideus Lamk), green coconut water, and CEP-2 mixed with 10% egg yolk. Technical term abbreviations were explained at their initial use. Spermatozoa membrane integrity was assessed using the hypoosmotic swelling test (HOST), while chlortetracycline (CTC) fluorescent dye was used to evaluate spermatozoa capacitation and acrosome reaction. The randomized group design (RAK) was used in the research, consisting of four conditions and 10 replications. P0 served as the control group, which received CEP-2 plus 10% egg yolk. P1 was administered EBM diluent AK enriched with 15% KT, while P2 received EBM diluent AK plus 15% KT and fructose 1 mg/ml. P3 was given EBM diluent AK plus 15% KT and fructose 2 mg/ml. Analysis of variance was used to examine the resulting data. The findings indicated that CEP-2 plus 10% egg yolk diluent was more effective than the diluent formulations containing red fruit extract and coconut water. Spermatozoa with intact membranes and no capacitation remain high, while those with capacitation and acrosome reaction remain low.

Enhanced stability and conductivity of montmorillonite and sucrose loaded Fe-MOFs for degradation of chlortetracycline hydrochloride via electrochemically activated persulfate

Ferreous metal-organic frameworks (Fe-MOFs) have provided excellent platforms for the removal of refractory contaminants from water, whereas poor conductivity and intrinsically fragile limit applications in electrochemistry and heterogeneous catalyst, respectively. Hence, we synthesized a novel Fe-based MOFs(Mt@Fe-MOFs@C) obtained through introducing sucrose to improve conductivity and montmorillonite (Mt) to enhance cycling stability, and combined with persulfate (PS) and electrochemical (EC) method to remove chlortetracycline hydrochloride(CTC) from water environment. The electrochemical impedance spectroscopy (EIS) demonstrated Mt.@Fe-MOFs@C was more conductive than pure Fe-MOFs. Mt.@Fe-MOFs@C showed high electrocatalytic activity for degradation of CTC in EC/Mt.@Fe-MOFs@C/PS system. The mechanism study indicated that SO4•− and HO• played dominant role in the elimination of CTC. Mt.@Fe-MOFs@C also exhibited excellent reusability with 83% removal efficiency after 5 cycle degradation. This work demonstrated that Mt.@Fe-MOFs@C would have potential for electrochemical wastewater remediation.

Morpho-physiological, biochemical, and molecular responses of lettuce (Lactuca sativa L.) seedlings to chlortetracycline stress

Antibiotic contamination in soil is an emerging environmental problem due to its potential threat to the soil ecosystem. Among antibiotics, chlortetracycline (CTC) is widely used for livestock and accumulates in agricultural soil, leading to detrimental effects on various physiological and biochemical metabolic processes in crops. However, the adverse impacts of CTC on plants and their defensive mechanisms remain poorly understood. We aimed to investigate the physiological, biochemical, and molecular responses of lettuce to CTC toxicity and to understand better the regulatory mechanism influencing the growth and development of plants. In this study, lettuce seedlings were exposed to different CTC doses (0, 0.01, 0.1, 0.5, and 1 mg L–1) and grown for 4 weeks in a hydroponic system. The results showed that an initial CTC dose (0.01 mg L–1) induced a hormesis phenomenon in the seedling's growth accompanied by upregulation of anthocyanin production, and their biosynthesis and regulation-related genes (e.g., F3H, F3′H, DFR, UFGT, ANS, and MYB) were found upregulated. While increasing CTC doses displayed stimulated phenolic acid and flavonoid contents, it had negative impacts on plant growth and leaf fresh/dry biomass. A progressive increase in the contents of H2O2 and MDA in the plants was found as the CTC dose increased, while the relative water content (RWC) level decreased. The activities of antioxidant enzymes, like superoxide dismutase, catalase, ascorbate peroxidase, and peroxidase, displayed differential responses to CTC. In addition, CTC doses, especially at 0.5 and 1 mg L–1, tended to promote the production of abscisic acid and jasmonic acid, but salicylic acid remained unaltered. Overall, this study provides a new perspective insight into the toxic effects of CTC and the resilience mechanisms interlinked in lettuce plants' survival against antibiotic contamination.

Sulfur vacancy defects mediated CdZnTeS@BC heterojunction: Artificial intelligence-assisted self-enhanced electrochemiluminescence molecularly imprinted sensing of CTC

Environmental pollution caused by tetracycline antibiotics is a major concern of global public health. Here, a novel and portable molecularly imprinted electrochemiluminescence (MIECL) sensor based on smartphones for highly sensitive detection of chlortetracycline (CTC) has been successfully established. The high-performance ECL emitter of biomass carbon (BC) encapsulated CdZnTeS (CdZnTeS@BC) was successfully synthesized by hydrothermal. The enhanced ECL performance was ascribed to the introduction of the BC and increased the overall electrical conductivity of the nanoemitter, as well as increased the number of sulfur vacancies and doping on the surface of the emitter based on density functional theory calculations. An aniline-CTC molecular imprinted polymer was synthesized on the surface of the CdZnTeS@BC modified electrode by in-situ electropolymerization. The decrease in MIECL signal was attributed to the increase in impedance effect. The MIECL nanoplatform enabled a wide linear relationship in the range of 0.05–100 μmol/L with a detection limit of 0.029 μmol/L for spectrometer sensors. Interestingly, the light emitted during the MIECL reaction can be captured by a smartphone. Thus, machine learning was used to screen the photos that were taken, and color analysis was carried out on the screened photos by self-developed software, thus achieving a portable, convenient, and intelligent sensing mode. Finally, the sensor obtains satisfactory results in the detection of actual samples, with no significant differences from those of liquid chromatography.

Influence of phase structure of MnO2 for enhancing the electrochemical sensitivity of environmental pollutant chlortetracycline

Electrochemical sensing of chlortetracycline (CTC) using α and β- MnO2 nanowires has been studied. The influence of different phase structures (α and β) of MnO2 nanowires on the determination of chlortetracycline (CTC) was studied systematically. To enhance the sensitivity of MnO2, a high conductivity microporous carbon (MC) was employed as a support matrix for MnO2. The electrochemical sensing results illustrate that the α-MnO2 exhibited better electrochemical performance than β-MnO2. This better activity was correlated with its excellent properties like more exposed MnO6 edges, higher conductivity, and lowest average oxidation state . The kinetics study illustrated that the MnO2 modified electrodes perform much better than the bare electrodes. The number of electron transfer, electron transfer coefficient, and diffusion coefficient of CTC were calculated from the scan rate effect; the values are 1, 0.50, and 1.581 × 10−6 cm2 s−1 respectively. Amperometry was used to calculate the lowest detection limit (LOD) at a potential of 0.82 V. The α-MnO2/MC electrode exhibits a better linear range (1–55 µM) with a LOD value of 103 nM towards CTC. Furthermore, the proposed sensor exhibited better anti-interference ability towards KCl, kanamycin sulfate, zinc acetate, magnesium chloride, tetracycline, streptomycin sulfate, and oxytetracycline. The sensor's ability to accurately determine the level of CTC in samples of drinking water, tap water, poultry farm soil, and milk highlights its suitability for industrial applications. The developed sensor showed better reproducibility (RSD=0.45%) and repeatability (RSD=2.06%) towards CTC. Therefore, the proposed sensor can be used as a more practical platform for monitoring environmental contaminants.

Unraveling the synergistic effect of adsorption-photocatalysis in magnetically recyclable Fe3O4/metal-organic gels/sodium alginate beads for chlortetracycline hydrochloride elimination

The development of highly efficient and easily recyclable materials remains at the forefront of chlortetracycline hydrochloride (CTC) remediation. Herein, two magnetic metal-organic gels (Fe3O4/Fe-MOG and Fe3O4/Al-MOG) are constituted by an ultrafast room-temperature synthesis of MOGs on the surface of carboxylated Fe3O4, affording exceptional adsorption-photocatalysis abilities towards CTC under visible light irradiation, along with favorable magnetic separation capabilities. Meanwhile, the proposed synergistic mechanisms of adsorption-photocatalysis, the probable degradation pathways of CTC, and the underlying toxicity evaluation of intermediates are expounded. More importantly, we ingeniously develop Fe3O4/MOGs/SA beads with sodium alginate (SA) as the backbone and magnetic MOGs as the reaction center, which minimizes the loss of powdered Fe3O4/MOGs and ameliorates the recyclability. Attractively, Fe3O4/MOGs/SA beads achieve long-term continuous operation for CTC degradation in various water samples under visible light irradiation. Overall, this work highlights a new possibility for devising immobilized magnetic MOGs with adsorption-photocatalysis synergies in actual and large-scale wastewater remediation.

Highly dispersed Fe/SnS2/kaolinite composite for the enhanced photo-Fenton degradation of tetracycline hydrochloride

A novel Fe/SnS2/kaolinite (Fe/SK) composite photocatalyst was successfully prepared herein to degrade tetracycline hydrochloride (TCH) in a photo-Fenton system. 5%Fe/SK-20% achieved the best TCH degradation efficiency in the photo-Fenton system within 60 min (80.38%), which was considerably higher than that achieved using pure SnS2 (31.46%). The introduction of the kaolinite carrier increased the dispersion of SnS2 particles and exposed more reactive sites, while Fe doping improved the energy band structure of SnS2 and enhanced electron transfer. Furthermore, photogenerated e− promoted the Fe2+/Fe3+ redox cycle, which facilitated the continuous and efficient activation of H2O2. Liquid chromatography–mass spectrometry was employed to identify the intermediate products and propose the possible pathway for TCH degradation. Free-radical trapping experiment and electron paramagnetic resonance revealed that •OH was the primary active substance in the 5%Fe/SK-20%/visible (vis)/H2O2 system, while h+ and •O2− were the auxiliary substances. In addition to TCH, 5%Fe/SK-20% exhibited excellent degradation efficiency for various organic pollutants, such as oxytetracycline hydrochloride, chlortetracycline hydrochloride, rhodamine B, and methyl orange, in the vis/H2O2 system. This study provides new insights into the efficient decontamination of antibiotic wastewater by kaolinite-based photocatalysts in a photo-Fenton system.

Confined PbO2 nanoparticles in carbon nanotubes on boron-doped diamond substrate for highly efficient chlortetracycline degradation

Realizing highly efficient catalysis with high stability in complex chemical environments remains a major challenge for advanced oxidation processes. Here, confined lead dioxide (PbO2) nanoparticles in carbon nanotubes (CNTs) on boron-doped diamond (BDD) substrate is designed and fabricated as a heterogeneous catalyst for antibiotic treatment, achieving ultra-efficient degradation of chlortetracycline (CTC) with high reaction rate and stability. The maximum degradation rate of CTC reaches 98.8 % in 120 min, and it remains 91.0 % after ten cycles, which are significantly higher than that proposed by the contrast catalysts. The excellent degradation performance of this heterogeneous catalyst is mainly attributed to three factors: (i) the prepared PbO2 nanoparticles with an average size of 5 nm are confined in CNTs, providing more active sites and higher electron transfer rate; (ii) secondary pollution and catalyst deactivation of PbO2 are avoided by protecting CNTs; (iii) BDD shows strong capacity for mineralizing organic compounds related to the high oxygen evolution reaction potential. This finding provides a novel strategy for advanced oxidation processes in environmental remediation.

In-situ synthesis of MIL-100(Fe)@chitosan composite beads with hierarchical porous structure for efficient adsorption of chlortetracycline hydrochloride: Synthesis, performance and mechanisms

The widespread use of chlortetracycline hydrochloride (CTC) inevitably poses a potential threat to human health and the biological system, and its environmental pollution and ecotoxicological effects cannot be ignored. Herein, we adopted an in-situ growth method to immobilize the powder form of MIL-100(Fe) adsorbent into low-cost chitosan (CS) matrix for the CTC removal. Metal hydroxide (or metal oxide)/CS beads from the acid-dissolved/alkali-solidified self-sphering shaping method were employed as the substrates for MIL-100(Fe) immobilization, allowing it grow uniformly and stably. Notably, this strategy not only reduced the loss in the separation and regeneration process of powdery MIL-100(Fe), but also improved the adsorption capacity of the CS. Isotherm and kinetic studies showed that the Freundlich and PSO models can describe the experimental data better, respectively, and the maximum adsorption capacity of Langmuir can reach 578.03 mg g−1. Further, the performance of MIL-100@CS-2 composite beads was thoroughly explored by batch experiments and response surface methodology (RSM) to obtain the optimized operating conditions with the highest CTC removal rate. By combining the density functional theory (DFT) calculation with experimental analysis, the adsorption mechanisms of pore filling, hydrogen bonding, electrostatic interaction, π-π EDA interaction, and hydrophilic interaction were proposed. This work provides a reliable basis for the development of shaping adsorbents and has potential application prospects in the treatment of wastewater containing antibiotics.

Photodegradation of Antibiotic Drugs by BiVO4 Nanocomposites

BiVO4 and its composites were prepared and compared with tetracycline hydrochloride, chlortetracycline hydrochloride and hygromycin hydrochloride to simulate the target degradation species for photocatalytic degradation experiments. All the prepared samples were found to have strong degradation effects on the three antibiotics, and the composite photocatalysts GB, PB and PGB showed faster photocatalytic reaction rates and higher photocatalytic activity than the pure BiVO4. In addition, the degradation of each sample to each antibiotic solution was in accordance with the primary reaction kinetic equation. The UV detection of PGB degradation of antibiotics was also carried out, and the results showed that the catalyst has a strong oxidation ability to degrade antibiotics to small molecules.

Study of Sorption of Chlortetracycline Hydrochloride and Its Subsequent Determination by Capillary Zone Electrophoresis

Study of Sorption of Chlortetracycline Hydrochloride and Its Subsequent Determination by Capillary Zone Electrophoresis

Study of Sorption of Chlortetracycline Hydrochloride and Its Subsequent Determination by Capillary Zone Electrophoresis

The work deals with the development of an approach to the determination of chlortetracycline, which combines the preconcentration of the analyte with its subsequent determination by capillary zone electrophoresis. The conditions that ensure the lowest value of the limit of determination for chlortetracycline in aqueous solutions using a Kapel-105M capillary electrophoresis system (Lumex, Russia) are determined, i.e., temperature, time and pressure of sample injection, background electrolyte composition, and detection wavelength. It is shown that the stability of a chlortetracycline solution is maximum at a storage temperature of 0.5°С in the absence of buffer systems or in using a dilute ammonium acetate buffer solution. It is found that the recovery of chlortetracycline by strongly acidic cation exchangers KU-1, KU-2 is higher compared to that by KB-4 and KB-4P2, bearing weakly acidic functional groups. The conditions under which the recovery of the analyte by KU-1 from a phosphate buffer solution is about 90% are determined.

Preparation of nanofiber Co–BiVO4/Bi2O3 p-n heterojunction for high efficiency photocatalytic degradation of organic pollutants

In recent years, water pollution caused by organic pollutants and antibiotic residues has become increasingly serious, posing a serious threat to human health and ecosystems. In this paper, Co–BiVO4/Bi2O3 heterojunction was successfully prepared by electrospinning of Co3+ doped monoclinic BiVO4 nanofibers and Bi2O3. The photocatalytic degradation of chlortetracycline hydrochloride (CTC·HCl) and 2-mercaptobenzothiazole (MBT) in water was tested by simulating visible light conditions. The degradation efficiency of CTC·HCl by 3Co–BiVO4/Bi2O3-0.8 reached 90.5 % within 30 min, and the degradation rates were 3.93 and 7.06 times that of BiVO4 and Bi2O3, respectively. At the same time, the degradation efficiency of MBT by 3Co–BiVO4/Bi2O3-0.8 reached 97.7 % within 40 min, and the degradation rates were 8.93 and 41.80 times that of BiVO4 and Bi2O3, respectively. In addition, the photocatalytic performance of the catalyst and potassium persulfate (PS) co-system on pollutants was investigated. When 0.5 mM PS and a small amount of 3Co–BiVO4/Bi2O3-0.8 catalyst were added, the degradation efficiency of CTC·HCl and MBT could reach 87.6 % and 92.8 % in a short time. Furthermore, the work function and difference of the material were calculated by density functional theory (DFT), and the charge transfer mechanism of the p-n heterojunction was further determined. Finally, the intermediate products, degradation pathways and reaction mechanisms of MBT degradation were analyzed in detail by high performance liquid chromatography-mass spectrometry (HPLC-MS). Therefore, this study provides a potential effective way for the treatment of water pollution.

Impact of In-Feed versus In-Water Chlortetracycline and Tiamulin Administrations on Fecal Prevalence and Antimicrobial Susceptibilities of Campylobacter in a Population of Nursery Pigs.

Antimicrobial resistance (AMR) in bacteria is a major public health concern in the US and around the world. Campylobacter is an important foodborne pathogen that resides in the gut of pigs and is shed in feces, with the potential to be transmitted to humans. In pigs, the oral route, either in-feed or in-water, is by far the most common route of administration of antimicrobials. Because the distribution of the antibiotic in the gut and the dosages are different, the impact of in-feed vs. in-water administration of antibiotics on the development of AMR is likely to be different. Therefore, a study was conducted to compare in-feed vs. in-water administrations of chlortetracycline (CTC) and/or tiamulin on fecal prevalence and AMR profiles of Campylobacter among weaned nursery piglets. A total of 1,296 weaned piglets, allocated into 48 pens (27 piglets per pen), were assigned randomly to six treatment groups: Control (no antibiotic), in-feed CTC, in-water CTC, in-feed tiamulin, in-water tiamulin, or in-feed CTC and tiamulin. Fecal samples were collected randomly from 5 piglets from each pen during the pre-treatment (days 0, 7), treatment (days 14, 21), and post-treatment (days 28, 35) phases. Bacterial isolations and species identifications were conducted by culture and PCR, respectively. The microbroth dilution method with SensititreTM plates was used to determine the antimicrobial susceptibility and resistance of Campylobacter isolates. The results on resistance were interpreted based on the European Committee on Antimicrobial Susceptibility Testing (EUCAST) epidemiological cutoff values for Campylobacter. The overall prevalence of Campylobacter was 18.2% (262/1440). Speciation of Campylobacter isolates by PCR indicated the prevalence of only two species: Campylobacter hyointestinalis (17.9%; 258/1440) and C. coli (0.3%; 4/1440). Campylobacter isolates were resistant to tetracycline (98.5%), ciprofloxacin (89.3%), and nalidixic acid (60.3%). Neither the antibiotic nor the route of administration had an effect (p > 0.05) on the prevalence of AMR Campylobacter in the feces of piglets.

3D flower-like In2Se3/Bi2O2CO3 n-n scheme heterojunctions for visible-driven simultaneous degradation of multi-tetracyclines

ABSTRACT The purification of tetracycline wastewater using visible-light-driven heterojunction catalysts is a promising approach. In this study, a n-n type heterojunction, In2Se3/Bi2O2CO3, is synthesised through a solvothermal method by combining band-matched semiconductors. The resulting hybrid has a 3D hierarchical structure with abundant mesopores, facilitating rapid mass transfer. Notably, 5% In2Se3/Bi2O2CO3 hybrids demonstrate enhanced photocatalytic efficacy for simultaneous degradation of tetracycline hydrochloride (TCH) under visible light, including TCH blends with chlortetracycline (CTC) and oxytetracycline (OTC). This enhancement originates from the heterojunction interface, narrowing the band gap, increasing visible light absorption by Bi2O2CO3 (BOC), and creating an inherent electric field between BOC and In2Se3, separating electron-hole pairs. Mechanistic analysis identifies h+ and •O2 − radicals as primary contributors to the photocatalytic process, suggesting a plausible n-n mechanism. This innovative design shows promise for advancing hierarchical heterostructures in tetracycline removal.

Unveiling the inhibition of chlortetracycline photodegradation and the increase of toxicity when coexisting with silver nanoparticles

Silver nanoparticles (AgNPs) and antibiotics inevitably co-exist in water environment. Nonetheless, little is known regarding the interactions between AgNPs and antibiotics or the effects of AgNPs on environmental behavior of antibiotics, particularly on sunlight-driven transformation. In the present work, we found that AgNPs obviously inhibit the photochemical decay of chlortetracycline (CTC), and CTC boosts the dissolution of AgNPs. With the help of electron paramagnetic resonance (EPR) and quenching experiment, we ascertained that these results originated from the competition between AgNPs against CTC for capturing 1O2 generated from CTC photosensitization. 1O2 reacting with CTC contributed mostly to CTC photodegradation, while 1O2 as well reacting with AgNPs leads to release of Ag+. When compared to reaction of 1O2 with CTC, 1O2 is prone to react with AgNPs, based on lower Gibbs free energy of AgNPs reacting with 1O2. Therefore, upon CTC co-existing with AgNPs, the release of Ag+ was accelerated and the photodegradation of CTC was inhibited obviously. Furthermore, the accelerated release of Ag+ significantly increased their toxicity toward E. coli cells under simulate sunlight irradiation. Overall, the findings demonstrate how AgNPs interact with CTC and how these interactions affect the environmental behaviors of CTC or AgNPs, allowing more accurate assessments of the risk to ecosystems posed by AgNPs coexisting with antibiotics.

Construction of g- C3N4/Au/MgAl2O4 photocatalysts with different coupling methods to improve the photodegradation behavior and performance prediction

A novel g-C3N4/Au/MgAl2O4 (CN-Au-MAO) system have been developed to improve the photocatalytic activity of CN and MAO for the simulated sunlight -driven chlortetracycline hydrochloride (CTC-HCl) removal. The Au particles act as a surface plasmon resonance center to separate and accumulate electrons from the conduction band of CN and MAO, promoting the transfer of photo-generated carriers, thereby maintaining high oxidative capacities of MAO. The prepared photocatalysts revealed that the plasma resonance wavelength and photocatalytic efficiency of CN -Au -MAO photocatalysts strongly depend on the coupling order of CN, Au, and MAO. The effects of mass percentages of Au, CN and Au-CN, catalyst content, drug concentration and pH value on the degradation of CTC-HCl were explored in depth. The CN-Au-MAO photocatalysts exhibited a high photocatalytic efficiency of 92.56% toward the photodegradation of CTC-HCl with the optimum catalyst content of 1 g/L, drug concentration of 200 mg/L and pH= 11. The genetic algorithm was used to predict the photocatalytic activity of CN-Au-MAO photocatalyst, and the minimum data set that can effectively predict its photocatalytic activity was explored. The active species detection experiments, degradation pathways, and toxicity estimates were also performed. A reasonable mechanism of the CN-Au-MAO system was proposed. This work effectively solves the problem of coupling MAO with the noble metal particles, which makes MAO easy to hydrolyze, and the problem of predicting the effective minimum data set required for the photocatalytic activity through neural network algorithms.

A Molecularly Imprinted Electrochemical Sensor Based on TiO2@Ti3C2Tx for Highly Sensitive and Selective Detection of Chlortetracycline.

In view of the serious side effects of chlortetracycline (CTC) on the human body, it is particularly important to develop rapid, sensitive, and selective technologies for the detection of CTC in food. In this work, a molecularly imprinted electrochemical sensor with [Fe(CN)6]3-/4- as signal probe was proposed for the highly sensitive and selective detection of CTC. For this purpose, TiO2, which acts as an interlayer scaffold, was uniformly grown on the surface of Ti3C2Tx sheets through a simple two-step calcination process using Ti3C2Tx as the precursor to effectively avoid the stacking of Ti3C2Tx layers due to hydrogen bonding and van der Waals forces. This endowed TiO2@Ti3C2Tx with large specific surface, abundant functional sites, and rapid mass transfer. Then, polypyrrole molecularly imprinted polymers (MIPs) with outstanding electrical conductivity were modified on the surface of TiO2@Ti3C2Tx via simple electro-polymerization, where the pyrrole was employed as a polymeric monomer and the CTC provided a source of template molecules. This will not only provide specific recognition sites for CTC, but also facilitate electron transport on the electrode surface. The synergistic effects between TiO2@Ti3C2Tx and polypyrrole MIPs afforded the TiO2@Ti3C2Tx/MIP-based electrochemical sensor excellent detection properties toward CTC, including ultra-low limits of detection (LOD) (0.027 nM), a wide linear range (0.06-1000 nM), and outstanding stability, reproducibility, selectivity, and feasibility in real samples. The results indicate that this strategy is feasible and will broaden the horizon for highly sensitive and selective detection of CTC.

Absorption–Translocation of Veterinary Antibiotics in Rice Plants Introduced with Irrigation Water

Veterinary antibiotics (VAs) have been indiscriminately used in animal feed for the past five decades to increase and ensure profits with negligible environmental considerations. The VAs amoxicillin (AMX), chlortetracycline (CTC), and oxytetracycline (OTC), which can be unintentionally introduced by irrigation water during rice cultivation, were evaluated for their phytotoxic effects, absorption–translocation into plants, and soil residues using a randomized complete block design. It was found that exposure to VAs can severely affect the photosynthetic pathway of rice plants. The uptake and translocation of VAs by rice plants varied significantly. CTC and OTC translocated more easily than AMX, a member of the β-lactam class, which accumulated at the lowest concentration compared to CTC and OTC across all treatments. Rice yield was about 4.3–5.7% lower in the experimental plots that received fifty-fold the background levels of VAs compared to the control. The findings indicate that these widely used veterinary antibiotics can hamper crop production, leave residues in the soil, and constitute a risk to human health if introduced into the agro-ecosystem unintentionally.

PSIV-9 Describing the Consumption of Chlortetracycline-Containing Supplement Offered Free-Choice to Commercial Beef Cows on Pasture

Abstract Extensive beef cattle production systems depend on forage as the predominant nutrient source. However, mineral requirements are not always met solely through forage consumption. To maintain optimum animal productivity, beef cattle producers must provide mineral supplementation and free-choice supplements are most common. Free-choice supplement intake by grazing cattle is highly variable and is dictated by season, individual animal preference, supplement palatability and other factors. Variation in supplement intake is problematic for delivering medication such as chlortetracycline (CTC), which is aimed to mitigate the risk of bovine anaplasmosis in beef herds. Research investigating the relationship between individual animal attributes and supplement consumption in extensive settings is limited. Recently, adoption of technology such as a portable, self-contained individual feeding unit (SmartFeed; C-Lock Inc.) into supplementation programs has facilitated unprecedented data collection in grazing cattle. The study objectives were to describe the consumption patterns of a granular CTC-containing supplement and to evaluate the factors contributing to consumption variability by gestating cows on pasture. A total of 103 nonlactating, pregnant, crossbred cows were assigned to this experiment on d -28 and allocated to 1 of 3 pastures equipped with a SmartFeed unit to record individual supplement intake. Cows were offered dried distillers grains for 27 d of acclimation to the units (mean intake of 0.29 kg of supplement/cow daily; 74% of cows) before transition to a commercially available granular mineral supplement containing CTC for 46 d. Supplement was formulated such that a 630 kg cow must consume 113 g/d to receive the label CTC dose (1.1 mg/kg). Cow intake and unit visit frequency data were analyzed using a general linear model (PROC GLM) and differences evaluated using Least Squared Means. The runs test for serial randomness was used to evaluate clustering of feeding and non-feeding events. Feeding and non-feeding events during the 46-d observation period were not randomly distributed (P < 0.01), and the mean number of consecutive days a cow did or did not consume mineral supplement were 1.8 and 5.6 days, respectively. As cow age increased, visits to the feeding unit decreased and total supplement consumption also decreased (P < 0.01). According to supplement label instructions, each cow was expected to consume 5.2 kg of supplement in total over 46 d to receive the total recommended 32.2 g CTC dose. Mean supplement consumption was 40.5 g· cow-1· d-1, providing 0.25 g CTC· cow-1· d-1, and only 1.9% (2/103 cows) consumed enough supplement to receive the recommended dose. Collectively, results indicate that providing a granular free-choice supplement containing CTC is not an effective method of ensuring cows consume an adequate amount of supplement to receive CTC at the label-directed dose and frequency.