Contribution of the FilmArray Respiratory Panel in the management of adult and pediatric patients attending the emergency room during 2015-2016 influenza epidemics: An interventional study.

AIM: To evaluate the contribution of a multiplex PCR for respiratory viruses on antibiotic and antiviral prescription, ancillary test prescription, admission and length of stay of patients. METHODS: Two hundred ninety-one adult and pediatric patients visiting the emergency department during the 2015-2016 influenza epidemic were prospectively included and immediately tested 24/7 using the FilmArray Respiratory Panel. The results were communicated to the practitioner in charge as soon as they became available. Clinical and biological data were gathered and analyzed. FINDINGS: Results from the FilmArray Respiratory Panel do not appear to impact admission or antibiotic prescription, with the exception of a lower admission rate for children who tested positive for influenza B. Parameters that account for the clinical decisions evaluated are CRP level, white blood cell count, suspected or proven bacterial infection and, for adult patients only, signs of respiratory distress. Length of stay is also not significantly different between patients with a positive and a negative result. A rapid influenza test result permits a more appropriate prescription of oseltamivir.

Prospective evaluation of diagnostic tools for respiratory viruses in children and adults.

AIM: To compare the performances of molecular and non-molecular tests to diagnose respiratory viral infections and to evaluate the pros and contras of each technique. METHODS: Two hundred ninety-nine respiratory samples were prospectively explored using multiplex molecular techniques (FilmArray Respiratory Panel, Clart Pneumovir), immunological techniques (direct fluorescent assay, lateral flow chromatography) and cell cultures. FINDINGS: Molecular techniques permitted the recovery of up to 50% more respiratory pathogens in comparison to non-molecular methods. FilmArray detected at least 30% more pathogens than Clart Pneumovir which could be explained by the differences in their technical designs. The turnaround time under 2 hours for the FilmArray permitted delivery of results when patients were still in the emergency room.

Pharmacokinetics of florfenicol in turkey plasma, lung tissue, and pulmonary epithelial lining fluid after single oral bolus or continuous administration in the drinking water.

Florfenicol (FF) is registered for treatment of bovine and swine respiratory diseases. Although, turkeys often suffer from bacterial respiratory tract infections, there is no registered formulation based on FF for poultry available in Europe. The aim of this study was to evaluate the pharmacokinetic behavior of FF in turkeys in plasma, lung tissue, and pulmonary epithelial lining fluid (PELF).The concentration and pharmacokinetic characteristics of FF in plasma, lung tissue, and PELF in turkeys were determined, either after a single oral bolus (30 mg/kg body weight, BW) or during and after continuous drinking water medication (30 mg/kg BW/d for 5 d). Plasma, lung tissue, and PELF samples were collected at different intervals after administration, and FF was quantified by liquid chromatography-tandem mass spectrometry. After single bolus administration, FF was rapidly absorbed in plasma (the time to maximum concentration, tmax, was 1.02 h) and distributed to the respiratory tract (mean tmax = 1.00 h). The mean t1/2el in plasma and lung tissue was similar, around 6 h, whereas it was slightly higher in PELF, namely, 8.7 hours. After oral bolus dosing, the mean maximum concentration in plasma was twice as high as in the lung tissue, 4.26 µg/mL and 2.64 µg/g, respectively, while in PELF it was much lower, 0.39 µg/mL. During continuous drinking water medication, lung FF concentrations were slightly higher than plasma concentrations, with lung/plasma ratios of 2.01 and 1.27 after 24 h and 72 h, respectively. FF was not detected in PELF during continuous drinking water medication.

Influence of mycotoxin binders on the oral bioavailability of tylosin, doxycycline, diclazuril, and salinomycin in fed broiler chickens.

The presence of mycotoxins in broiler feed can have deleterious effects on the wellbeing of the animals and their performance. Mycotoxin binders are feed additives that aim to adsorb mycotoxins in the intestinal tract and thereby prevent the oral absorption of the mycotoxin. The simultaneous administration of coccidiostats and/or antimicrobials with mycotoxin binders might lead to a reduced oral bioavailability of these veterinary medicinal products. This paper describes the influence of 3 mycotoxin binders (i.e., clay 1 containing montmorillonite, mica, and feldspars; clay 2 containing montmorillonite and quartz; and yeast 1 being a modified glucomannan fraction of inactivated yeast cells) and activated carbon on the oral bioavailability and pharmacokinetic parameters of the antimicrobials doxycycline and tylosin, and the coccidiostats diclazuril and salinomycin. A feeding study with 40 15 day-old broilers was performed evaluating the effects of long-term feeding 2 g mycotoxin binder/kg of feed. The birds were randomly divided into 5 groups of 8 birds each, i.e., a control group receiving no binder and 4 test groups receiving either clay 1, clay 2, yeast 1, or activated carbon mixed in the feed. After 15 d of feeding, both the control and each test group were administered doxycycline, tylosin, diclazuril, and salinomycin, consecutively, respecting a wash-out period of 2 to 3 d between each administration. The 4 medicinal products were dosed using a single bolus administration directly in the crop. After each bolus administration, blood was collected for plasma analysis and calculation of the main pharmacokinetic parameters and relative oral bioavailability (F = area under the plasma concentration-time curve (AUC0-8 h) in the test groups/AUC0-8 h in the control group)*100). No effects were observed of any of the mycotoxin binders on the relative oral bioavailability of the coccidiostats (i.e., F between 82 and 101% and 79 and 93% for diclazuril and salinomycin, respectively). Also, no significant effects could be noticed of any of the mycotoxin binders on the relative oral bioavailability of the antimicrobials doxycycline and tylosin (i.e., F between 67 and 83% and between 43 and 104%, respectively).

Study of the immunomodulatory properties of gamithromycin and dexamethasone in a lipopolysaccharide inflammation model in calves.

The aim of this study was to define the in vivo immunomodulatory properties of the macrolide antibiotic gamithromycin in calves, with respect to the acute phase response. Additionally, the corticosteroid dexamethasone was included as a positive control immunomodulatory drug. Both drugs, as well as their combination,were studied in a previously developed inflammation model,which was initiated by an intravenous lipopolysaccharide (LPS) challenge (0.5 µg/kg body weight). Twenty-four 4-week-old male Holstein Friesian calves were randomized into four groups: no pharmacological treatment (n = 6) or a pharmacological treatment with gamithromycin (n= 6), dexamethasone (n= 6) or their combination (n= 6) 1 h prior to LPS administration. Blood collection and clinical scoring were performed at regular time points until 72 h post LPS challenge. Plasma concentrations of selected cytokines (tumour necrosis factor-α (TNF-α) and interleukin 6 (IL-6)) and acute phase proteins (serum amyloid A and haptoglobin) were subsequently determined. Gamithromycin did not have any beneficial effect on the LPS-induced clinical signs (dyspnea, fever, anorexia and depression), nor on the studied inflammatory mediators. In the dexamethasone and combination groups, the occurrence of dyspnea and fever was not prominently influenced, although the calves recovered significantly faster from the challenge. Moreover, dexamethasone significantly inhibited the levels of TNF-α and IL-6, suggesting a key role for these cytokines in sickness behaviour. In conclusion, unlike dexamethasone, gamithromycin did not directly reduce cytokine release in an LPS inflammation model in calves.

Multiplex analysis of pro-inflammatory cytokines in serum of Actinobacillus pleuropneumoniae-infected pigs.

Porcine pleuropneumonia is a severe respiratory disease caused by Actinobacillus (A.) pleuropneumoniae. The aim of the present study was to analyze serum samples of A. pleuropneumoniae-infected pigs for TNF-α, IL-1ß and IL-6 using a cytometric bead array (CBA) 3-plex assay and additionally for IL-6 using ELISA. The CBA 3-plex assay was successfully validated for use in serum. The limits of detection varied between 0.012 and 0.333 ng/mL, and the inter- and inter-assay coefficients of variation were <5% and <10%, respectively. Increased levels were observed for all 3 cytokines following experimental infection with A. pleuropneumoniae. Mean peak concentrations of TNF-α and IL-6 were recorded at 12h and at 10h p.i., respectively. For IL-6, similar concentration-time profiles were observed with CBA and ELISA. It is proposed that this immuno-assay can be applied for the screening of immunomodulatory properties of drugs and vaccine adjuvants in infection, inflammation and vaccination.

In vivo porcine lipopolysaccharide inflammation models to study immunomodulation of drugs.

Lipopolysaccharide (LPS), a structural part of the outer membrane of Gram-negative bacteria, is one of the most effective stimulators of the immune system and has been widely applied in pigs as an experimental model for bacterial infection. For this purpose, a variety of Escherichia coli serotypes, LPS doses, routes and duration of administration have been used. LPS administration induces the acute phase response (APR) and is associated with dramatic hemodynamic, clinical and behavioral changes in pigs. Pro-inflammatory cytokines, including tumor necrosis factor α (TNF-α), interleukin (IL)-1 and IL-6 are involved in the induction of the eicosanoid pathway and the hepatic production of acute phase proteins, including C-reactive protein (CRP), haptoglobin (Hp) and pig major acute phase protein (pig-MAP). Prostaglandin E2 (PGE2) and thromboxane A2 (TXA2) play a major role in the development of fever and pulmonary hypertension in LPS-challenged pigs, respectively. The LPS-induced APR can be modulated by drugs. Steroidal and nonsteroidal anti-inflammatory drugs ((N)SAIDs) possess anti-inflammatory, antipyretic and analgesic properties through (non)-selective central and peripheral cyclooxygenase (COX) inhibition. Antimicrobial drugs, especially macrolide antibiotics, which are commonly used in veterinary medicine for the treatment of bacterial respiratory diseases, have been recurrently reported to exert clinically important immunomodulatory effects in human and murine research. To investigate the influence of these drugs on the clinical response, production of pro-inflammatory cytokines, acute phase proteins (APP) and the course of the febrile response in pigs, in vivo LPS inflammation models can be applied. Yet, to date, in vivo research on the immunomodulatory properties of antimicrobial drugs in these models in pigs is largely lacking. This review provides acritical overview of the use of in vivo porcine E. coli LPS inflammation models for the study of the APR, as well as the potential immunomodulatory properties of anti-inflammatory and antimicrobial drugs in pigs.

Enantioselective pharmacokinetics of ketoprofen in calves after intramuscular administration of a racemic mixture.

The pharmacokinetic properties of ketoprofen were determined in 4-week-old calves after intramuscular (i.m.) injection of a racemic mixture at a dose of 3 mg/kg body weight. Due to possible enantioselective disposition kinetics and chiral inversion, the plasma concentrations of the R(-) and S(+) enantiomer were quantified separately, using a stereospecific HPLC-UV assay. A distinct predominance of the S(+) enantiomer was observed, as well as significantly different pharmacokinetic parameters between R(-) and S(+) ketoprofen. More in specific, a greater value for the mean area under the plasma concentration-time curve (AUC(0→∞)) (46.92 ± 7.75 and 11.13 ± 2.18 µg·h/mL for the S(+) and R(-) enantiomer, respectively), a lower apparent clearance (Cl/F) (32.8 ± 5.7 and 139.0 ± 25.1 mL/h·kg for the S(+) and R(-) enantiomer, respectively) and a lower apparent volume of distribution (V(d)/F) (139 ± 14.7 and 496 ± 139.4 mL/kg for the S(+) and R(-) enantiomer, respectively) were calculated for the S(+) enantiomer, indicating enantioselective pharmacokinetics for ketoprofen in calves following i.m. administration.

Pharmacokinetics of oral transmucosal and intramuscular dexmedetomidine combined with buprenorphine in cats.

Plasma concentrations and pharmacokinetics of dexmedetomidine and buprenorphine after oral transmucosal (OTM) and intramuscular (i.m.) administration of their combination in healthy adult cats were compared. According to a crossover protocol (1-month washout), a combination of dexmedetomidine (40 µg/kg) and buprenorphine (20 µg/kg) was given OTM (buccal cavity) or i.m. (quadriceps muscle) in six female neutered cats. Plasma samples were collected through a jugular catheter during a 24-h period. Plasma dexmedetomidine and buprenorphine concentrations were determined by liquid chromatography-tandem mass spectrometry. Plasma concentration-time data were fitted to compartmental models. For dexmedetomidine and buprenorphine, the area under the plasma concentration-time curve (AUC) and the maximum plasma concentrations (Cmax ) were significantly lower following OTM than following i.m. administration. For buprenorphine, time to reach Cmax was also significantly longer after OTM administration than after i.m. injection. Data suggested that dexmedetomidine (40 µg/kg) combined with buprenorphine (20 µg/kg) is not as well absorbed from the buccal mucosa site as from the intramuscular injection site.

Development and validation of an LC-MS/MS method for the toxicokinetic study of deoxynivalenol and its acetylated derivatives in chicken and pig plasma.

This study aims to develop an LC-MS/MS method allowing the determination of 3-acetyl-deoxynivalenol, 15-acetyl-deoxynivalenol, deoxynivalenol and its main in vivo metabolite, deepoxy-deoxynivalenol, in broiler chickens and pigs. These species have a high exposure to these toxins, given their mainly cereal based diet. Several sample cleanup strategies were tested and further optimized by means of fractional factorial designs. A simple and straightforward sample preparation method was developed consisting out of a deproteinisation step with acetonitrile, followed by evaporation of the supernatant and reconstitution in water. The method was single laboratory validated according to European guidelines and found to be applicable for the intended purpose, with a linear response up to 200ngml(-1) and limits of quantification of 0.1-2ngml(-1). As a proof of concept, biological samples from a broiler chicken that received either deoxynivalenol, 3- or 15-acetyl-deoxynivalenol were analyzed. Preliminary results indicate nearly complete hydrolysis of 3-acetyl-deoxynivalenol to deoxynivalenol; and to a lesser extent of 15-acetyl-deoxynivalenol to deoxynivalenol. No deepoxy-deoxynivalenol was detected in any of the plasma samples. The method will be applied to study full toxicokinetic properties of deoxynivalenol, 3-acetyl-deoxynivalenol and 15-acetyl-deoxynivalenol in broiler chickens and pigs.

Pharmacokinetics of gamithromycin after intravenous and subcutaneous administration in pigs.

The aim of this study was to investigate the pharmacokinetic properties of gamithromycin in pigs after an intravenous (i.v.) or subcutaneous (s.c.) bolus injection of 6 mg/kg body weight. The plasma concentrations of gamithromycin were determined using a validated high-performance liquid chromatography-tandem mass spectrometry method, and the pharmacokinetics were noncompartmentally analysed. Following i.v. administration, the mean area under the plasma concentration-time curve extrapolated to infinity (AUCinf) and the mean elimination half-life (t1/2λz) were 3.67 ± 0.75 µg.h/mL and 16.03 h, respectively. The volume of distribution at steady state (Vss) and the plasma clearance were 31.03 ± 6.68 L/kg and 1.69 ± 0.33 L/h.kg, respectively. The mean residence time (MRTinf) was 18.84 ± 4.94 h. Gamithromycin administered subcutaneously to pigs demonstrated a rapid and complete absorption, with a mean maximal plasma concentration (Cmax) of 0.41 ± 0.090 µg/ml at 0.63 ± 0.21 h and a high absolute bioavailability of 118%. None of the reported pharmacokinetic variables significantly differed between both administration routes.

Pharmacokinetics of gamithromycin after intravenous and subcutaneous administration in broiler chickens.

Gamithromycin is a new macrolide antibiotic that is only registered for use in cattle to treat respiratory disorders such as bovine respiratory disease. The aim of this study was to determine the pharmacokinetics of gamithromycin in broiler chickens. Gamithromycin (6 mg/kg of BW) was injected intravenously (IV) or subcutaneously (SC) to six 4-wk-old chickens in a parallel study design, and blood was collected at different time points postadministration. Quantification of gamithromycin in plasma was performed using an in-house validated liquid chromatography-tandem mass spectrometry method and the pharmacokinetics analyzed according to a 2-compartmental model. Following IV administration, the mean area under the plasma concentration-time curve (AUC0→∞), and α and ß half-life of elimination (t1/2el α and t1/2el ß) were 3,998 h•ng/mL, 0.90 h, and 14.12 h, respectively. Similar values were obtained after a SC bolus injection, i.e., 4,095 h•ng/mL, 0.34 h, and 11.63 h, for AUC0→∞, t1/2el α, and t1/2el ß, respectively. The mean maximum plasma concentration (889.46 ng/mL) appeared at 0.13 h. Gamithromycin showed a large volume of distribution after IV as well as SC administration, 27.08 and 20.89 L/kg, respectively, and a total body clearance of 1.61 and 1.77 L/h•kg, respectively. The absolute bioavailability was 102.4%, showing that there is a complete absorption of gamithromycin after a SC bolus injection of 6 mg/kg of BW.

Chronic exposure to the mycotoxin T-2 promotes oral absorption of chlortetracycline in pigs.

The aim of this study was to investigate whether T-2 toxin, a potent Fusarium mycotoxin, affects the oral absorption of the antibiotic chlortetracycline in pigs. Animals were allocated to blank feed without T-2 toxin (controls), feed containing 111 µg T-2/kg feed, T-2-contaminated feed supplemented with a yeast-derived feed additive, or blank feed supplemented solely with the feed additive, respectively. After 21 days, an intragastric bolus of chlortetracycline was given to assess potential alterations in the pharmacokinetics of this commonly used antibiotic. A significantly higher area under the plasma concentration-time curve and maximal plasma concentration of chlortetracycline was observed after intake of T-2-contaminated feed compared with control. Thus, exposure to T-2-contaminated feed can influence the oral bioavailability of chlortetracycline. This effect could have consequences for the withdrawal time of the drug and the occurrence of undesirable residues in edible tissues.

Development of a HPLC-UV method for the quantitative determination of four short-chain fatty acids and lactic acid produced by intestinal bacteria during in vitro fermentation.

A rapid and sensitive HPLC-UV method for the quantitative determination of four short-chain fatty acids (SCFAs) and lactic acid (LA) produced during in vitro fermentation is presented. Extraction of SCFAs from supernatants of bacterial cultures is aggravated due to their polarity and volatility. Detection can only be performed at a short, non-selective UV wavelength (210nm), due to the lack of any significant chromophore. Therefore special attention was paid to the optimization of the sample preparation procedure and the HPLC-UV conditions. The final extraction procedure consisted of a liquid-liquid back extraction using diethylether. Prior to HPLC-UV analysis the samples were acidified (pH<2) in order to improve retention of the SCFA's and LA on the Hypersil Gold aQ column. Matrix-matched calibration graphs were prepared for all analytes of interest (range 0.5-50mM) and correlation and goodness-of-fit coefficients were between 0.9951-0.9993 and 3.88-8.27%, respectively. Limits of detection and quantification ranged from 0.13 to 0.33mM and 0.5 to 1.0mM, respectively. The results for the within-day and between-day precision and accuracy fell within the ranges specified. The reported validated method has been successfully used for the in vitro screening of supernatants of bacterial cultures for the presence of butyric acid, aiming to select for butyric acid-producing bacteria. In addition, the method has been used to determine the production pattern of selected fatty acids by bacterial species isolated from human feces and chicken caeca.

The mycotoxin T-2 inhibits hepatic cytochrome P4503A activity in pigs.

Mycotoxins are toxic metabolites produced by fungi that readily colonize crops. After ingestion, these mycotoxins can compromise intestinal health, and once entering the blood stream, even affect the liver and its metabolizing enzymes. It was therefore the aim of the present study to investigate the effect of T-2 toxin, an emerging and potent Fusarium mycotoxin, on the enzymatic activity of cytochrome P4503A (CYP3A) metabolizing enzymes in the liver of pigs. In addition, a yeast-derived feed additive that claims to bind T-2 toxin was included in the study to evaluate its efficacy. Our results demonstrated that a 14-days intake of T-2 toxin contaminated feed at a dose of 903 µg/kg feed, whether or not combined with the mycotoxin binder, results in a substantial inhibition of the CYP3A activity in the liver of pigs. This result may be of importance for animal health, the pharmacokinetics and the withdrawal time of drugs that are substrate of CYP3A enzymes, and consequently can be a threat for public health with respect to tissue residues of these drugs.

Toxic effects of dietary exposure to T-2 toxin on intestinal and hepatic biotransformation enzymes and drug transporter systems in broiler chickens.

The effects of the mycotoxin T-2 on hepatic and intestinal drug-metabolizing enzymes (cytochrome P450) and drug transporter systems (MDR1 and MRP2) in poultry were investigated during this study. Broiler chickens received either uncontaminated feed, feed contaminated with 68µg/kg or 752µg/kg T-2 toxin. After 3weeks, the animals were euthanized and MDR1, MRP2, CYP1A4, CYP1A5 and CYP3A37 mRNA expression were analyzed using qRT-PCR. Along the entire length of the small intestine no significant differences were observed. In the liver, genes coding for CYP1A4, CYP1A5 and CYP3A37 were significantly down-regulated in the group exposed to 752µg/kg T-2. For CYP1A4, even a contamination level of 68µg/kg T-2 caused a significant decrease in mRNA expression. Expression of MDR1 was not significantly decreased in the liver. In contrast, hepatic MRP2 expression was significantly down-regulated after exposure to 752µg/kg T-2. Hepatic and intestinal microsomes were prepared to test the enzymatic activity of CYP3A. In the ileum and liver CYP3A activity was significantly increased in the group receiving 752µg/kg T-2 compared to the control group. The results of this study show that drug metabolizing enzymes and drug transporter mechanisms can be influenced due to prolonged exposure to relevant doses of T-2.

Hepatic and intestinal CYP3A expression and activity in broilers.

Cytochrome P450 is involved in drug metabolism. Subfamily CYP3A shows a degree of similarity across different animal species. However, little information is available about its expression and activity in broiler chickens. A RT-PCR method was developed for the quantification of CYP3A37 expression in the liver and small intestine of broilers. A higher expression in the jejunum was observed compared with that in the ileum. In the liver, a significantly lower expression compared with that in the jejunum was noticed. Thus, the role of the small bowel in drug metabolism cannot be neglected in broilers. CYP3A activity was studied in vitro using midazolam as a substrate. Two protocols for the preparation of intestinal microsomes were compared. Mincing of the tissues before ultracentrifugation seemed to be more appropriate than a protocol based on ethylenediaminetetra-acetic acid separation. CYP3A activity revealed to be the highest in the duodenum with a decreasing trend towards the ileum. Activity in liver was comparable to duodenal activity.

Development of a liquid-chromatography tandem mass spectrometry and ultra-high-performance liquid chromatography high-resolution mass spectrometry method for the quantitative determination of zearalenone and its major metabolites in chicken and pig plasma.

A sensitive and specific method for the quantitative determination of zearalenone (ZEN) and its major metabolites (α-zearalenol (α-ZEL), ß-zearalenol (ß-ZEL), α-zearalanol (α-ZAL), ß-zearalanol (ß-ZAL) and zearalanone (ZAN)) in animal plasma using liquid chromatography combined with heated electrospray ionization (h-ESI) tandem mass spectrometry (LC-MS/MS) and high-resolution Orbitrap(®) mass spectrometry ((U)HPLC-HR-MS) is presented. The sample preparation was straightforward, and consisted of a deproteinization step using acetonitrile. Chromatography was performed on a Hypersil Gold column (50 mm × 2.1 mm i.d., dp: 1.9 µm, run-time: 10 min) using 0.01% acetic acid in water (A) and acetonitrile (B) as mobile phases. Both mass spectrometers were operated in the negative h-ESI mode. The method was in-house validated for all analytes: matrix-matched calibration graphs were prepared and good linearity (r≥0.99) was achieved over the concentration range tested (0.2-200 ng mL(-1)). Limits of quantification (LOQ) in plasma were between 0.2 and 5 ng mL(-1) for all compounds. Limits of detection in plasma ranged from 0.004 to 0.070 ng mL(-1). The results for the within-day and between-day precision, expressed as relative standard deviation (RSD), fell within the maximal RSD values (within-day precision: RSD(max)=2((1-0.5logConc)) x 2/3; between-day precision: RSD(max)=2((1-0.5logConc))). The accuracy fell within -50% to +20% (concentrations <1 ng mL(-1)), -30% to +10% (concentrations between 1 and 10 ng mL(-1)) or -20% to +10% (concentrations >10 ng mL(-1)) of the theoretical concentration. The method has been successfully used for the quantitative determination of ZEN in plasma samples from broiler chickens and pigs. α-ZEL and ß-ZEL were the only metabolites that could be detected, but the concentrations were around the LOQ levels. The intact ZEN-glucuronide conjugate could be detected using the (U)HPLC-HR-MS instrument. A good correlation (r(2)=0.9979) was observed between the results for ZEN obtained with the LC-MS/MS and (U)HPLC-HR-MS instruments. The results prove the usefulness of the developed method for application in the field of toxicokinetic analysis and for exposure assessment of mycotoxins.

Transfer of the coccidiostats monensin and lasalocid from feed at cross-contamination levels to whole egg, egg white and egg yolk.

Recent legislation has addressed the unavoidable carry-over of coccidiostats and histomonostats in feed, which may lead to the presence of residues of these compounds in eggs. In this study, laying hens received cross-contaminated feed at a ratio of 2.5%, 5% and 10% of the therapeutic dose of monensin and lasalocid for broilers. The eggs were collected during the treatment and depletion period and were analysed using liquid chromatography-tandem mass spectrometry. The different egg matrices were separated and analysed during the plateau phase. High lasalocid concentrations, which exceeded the maximum residue level, and low monensin concentrations were found in whole egg. Plateau levels were reached at days 7-9 for lasalocid and at days 3-5 for monensin. For lasalocid, the highest concentrations were measured in egg yolk; residue concentrations in egg white were very low.

Transfer of flubendazole and tylosin from feed at cross-contamination levels to various poultry matrices.

Residues of veterinary drugs and feed additives used extensively in animal husbandry are sometimes found in edible matrices. In this study, broilers received experimental feed, containing either flubendazole or tylosin, at cross-contamination levels of 2.5%, 5%, and 10% of the therapeutic dose to determine the transfer ratio of these molecules from feed to poultry matrices. Breast and thigh muscle and liver samples were collected during treatment and depletion periods and then analyzed using liquid chromatography-tandem mass spectrometry. The parent molecule flubendazole and its 2 major metabolites were quantified. After 3 to 5 d, a plateau phase was reached, and a few days after withdrawal of the experimental feed, a depletion of residues was noted. Significant difference between both muscle types was noted for flubendazole. Strong metabolization of flubendazole in the liver was seen. For tylosin, no residue concentrations above the limit of quantification could be detected in muscle. None of the residue concentrations for either molecule exceeded the corresponding maximum residue limits.