Sophie Danyi

Analysis of EU priority polycyclic aromatic hydrocarbons in food supplements using high performance liquid chromatography coupled to an ultraviolet, diode array or fluorescence detector

High performance liquid chromatography coupled to an ultraviolet, diode array or fluorescence detector (HPLC/UV-FLD) has been used to set up a method to detect the 15(+1) EU priority polycyclic aromatic hydrocarbons (PAHs) in food supplements covering the categories of dried plants and plant extracts excluding oily products. A mini validation was performed and the following parameters have been determined: limit of detection, limit of quantification, precision, recovery and linearity. They were in close agreement with quality criteria described in the Commission Regulation (EC) No 333/2007 concerning the PAH benzo[a]pyrene in foodstuffs, except the not fluorescent cyclopenta[c,d]pyrene for which the UV detection leads to a higher limit of detection. Analysis of twenty commercial food supplements covering mainly the class of dried plants was performed to evaluate their PAHs contamination levels and to test the applicability of the method to various plant matrices. Fifty percent of analyzed samples showed concentration exceeding 2 microgkg(-1) for one or more PAHs.

Antigenic and genomic identity between simian herpesvirus aotus type 2 and bovine herpesvirus type 4.

Herpesvirus aotus type 2 (HVA-2) was isolated from a culture of kidney cells from a healthy owl monkey (Aotus trivirgatus). Bovine herpesvirus type 4 (BHV-4) is frequently isolated from diseased and even healthy cattle and occasionally from sheep, wild ruminants and cats. The two viruses are related antigenically, as was revealed by an indirect fluorescent antibody test using polyclonal antisera from experimentally infected rabbits or monoclonal antibodies raised against six BHV-4 proteins, three of which were glycosylated. The genome structures of the two viruses consist of a unique central sequence flanked at both ends by G + C-rich tandem repeats. Restriction maps (produced using EcoRI, BamHI and HindIII) of these two viruses were nearly identical but the unique sequence of the HVA-2 genome possessed two additional BamHI sites. Four genomic regions of variable size were detected, two located in the unique part, one in the repetitive part and one in the left junction between the unique and the repeated part of the genome; these slight variations were similar to those observed between various BHV-4 isolates. These results suggest that HVA-2 and BHV-4 belong to the same virus species; HVA-2 could be either a BHV-4 contaminant of owl monkey kidney cell cultures or an isolate from an owl monkey accidentally infected with BHV-4.

Validation of a two-plate microbiological method for screening antibiotic residues in shrimp tissue

Microbiological inhibition screening tests could play an important role to detect residues of antibiotics in the different animal food products, but very few are available for the aquaculture products in general, and for shrimps in particular. A two-plate microbiological method to screen shrimp for residues of the most commonly used antibiotics has been developed and validated according to criteria derived from the European Commission Decision 2002/657/CE. Bacillus subtilis was used as a sensitive strain to target antibiotics. Culture conditions on Petri plates (pH of medium) were selected to enhance the capacity of antibiotic detection. Antibiotic residues were extracted from shrimps using acetonitrile/acetone (70/30, v/v) before application on Petri plates seeded with B. subtilis. The method was validated using spiked blank tissues as well as antibiotic treated shrimps with enrofloxacin and tetracycline, two antibiotics often found to be used in shrimp production. For tetracyclines and (fluoro)quinolones, the detection capability was below the maximum residue limit (MRL), while it was around the MRL for sulfonamides. The specificity of the microbiological screening was 100% in all cases while the sensitivity and accuracy was 100% in almost all cases. The capacity of the method to detect contaminated samples was confirmed on antibiotic treated shrimps, analyzed in parallel with a confirmatory method (Liquid Chromatography coupled to mass spectrometry (LC-MS)).

Adverse effects of enrofloxacin when associated with environmental stress in Tra catfish (Pangasianodon hypophthalmus).

The aim of this study was to assess the adverse effects of enrofloxacin (EF) on Tra catfish, Pangasianodon hypophthalmus, in relation with density stress. Fish were held at 40, 80 or 120 fish m(-3) and fed with pellets containing either 1 g kg(-1) EF or no EF. Antibiotic exposure lasted 7d and all fish were fed without EF for another 7-d recovery period. Fish were sampled at 3, 7, 8, 10 and 14 d after the beginning of EF exposure. Lipid peroxidation (LPO) and total glutathione (GSH) levels, catalase (CAT), glutathione-s-transferase (GST) and acetylcholine-esterase (AChE) activities were assessed in gill, brain, liver and muscle. At day 7, LPO levels in gills of EF-fish reared at low or high density were significantly more than 5-fold higher than their respective control. On the contrary, LPO in gills of EF-fish reared at medium density was significantly 3-fold lower than the control fish. Similarly, CAT activities in gills of EF-fish reared under low or high density were higher than in their control groups, while this activity was lower in EF-fish of the medium density group. AChE activities in muscles of EF-fish reared at low or high density were lower than controls at days 3 and 7, respectively. These results suggest that EF exposure may lead to disorders like lipid peroxidation and neural dysfunction in fish. However, when reared under lower stress condition (medium density), they may cope better with EF-induced stress than chronically stressed fish (low or high density).

Determination and kinetics of enrofloxacin and ciprofloxacin in Tra catfish (Pangasianodon hypophthalmus) and giant freshwater prawn (Macrobrachium rosenbergii) using a liquid chromatography/mass spectrometry method

Determination and kinetics of enrofloxacin and ciprofloxacin in Tra catfish (Pangasianodon hypophthalmus) and giant freshwater prawn (Macrobrachium rosenbergii) using a liquid chromatography/mass spectrometry method. J. vet. Pharmacol. Therap. 34, 142-152. The fluoroquinolones enrofloxacin (EF) and ciprofloxacin (CF) residues were investigated in the edible tissues of two important Asian aquacultured species such as Tra catfish (Pangasianodon hypophthalmus) and giant freshwater prawn (Macrobrachium rosenbergii) using a sensitive liquid chromatography-electrospray ionization-tandem mass spectrometry method. Fish and prawn were treated with medicated feed with multiple doses of EF, in field conditions. A validation study of the analytical method was realized in terms of linearity, specificity, precision (repeatability and within-laboratory reproducibility), recovery and decision limit (CCα). The time needed before the antibiotic disappears from animal tissues or reach the maximum residue limit (MRL, 100μg/kg) was assessed. The concentration values of EF detected in Tra catfish tissue were between the MRL and 2×MRL concentrations, according to the fish density, 7days following the end of the enrofloxacin treatment (20mg/kg body weight per day, for seven consecutive days). The concentration value of ER in prawn tissue was lower than the MRL and the limit of quantification (LOQ, 14μg/kg) 5 and 7days after the stop of the EF treatment (50mg/kg body weight per day, for five consecutive days), respectively. The mean detected levels of CF was much lower in comparison with that of EF, indicating that only a small part of EF is metabolized into CF (<5%) in both Tra catfish and prawn.

Comparison of proteins of simian herpesvirus aotus type 2 and bovine herpesvirus type 4.

Genomes of herpesvirus aotus type 2 (HVA-2) and bovine herpesvirus type 4 (BHV-4) have previously been shown to be closely similar. Moreover, preliminary serological data indicated that HVA-2 is antigenically related to BHV-4. To extend this study, structural components of four BHV-4 strains and HVA-2 were compared by SDS-PAGE, radioimmunoprecipitation and Western blotting. The overall pattern of structural proteins was the same for HVA-2 and BHV-4 but variations were observed in electrophoretic profiles of glycoproteins, mainly of the two major ones (gp6/gp10/gp17 and gp11/VP24). Variations between HVA-2 and BHV-4 glycoproteins were greater than those observed among BHV-4 strains.