Clenbuterol Residues in Plasma and Urine Samples of Food-Producing Pigs During and After Subchronic Exposure to a Growth-Promoting Dose

The aim of the study is to evaluate the suitability of plasma and urine as matrices for clenbuterol residue determination during and after its subchronic administration at a growth-promoting dose to male pigs, using previously validated enzyme-linked immunosorbent assay (ELISA) as a screening method and liquid chromatography tandem mass spectrometry (LC-MS/MS) as a confirmation method. A high correlation coefficient between these analytical methods was obtained for both urine (R=0.9800) and plasma (R=0.9970) concentrations. Study results show the plasma and urine concentration to vary greatly during oral treatment with clenbuterol for 28 days. The peak urine concentration ((88.54±50.54) ng/mL) recorded on day 21 was 40-fold peak plasma concentration ((2.25±1.54) ng/mL). After withdrawal period, the peak urine clenbuterol concentration ((42.93±10.52) ng/mL) recorded on day 0 was 24-fold plasma concentration ((1.79±0.97) ng/mL). The maximum allowed concentration of 0.5 ng/g in the liver as a regulated matrix for control of clenbuterol abuse was achieved in plasma on day 3 ((0.52±0.26) ng/mL) and in urine on day 7 of treatment withdrawal ((0.45±0.11) ng/mL). Study results indicate that urine and plasma may be suitable matrices for the control of clenbuterol abuse during fattening of food-producing pigs but have a limited value because of the rapidly decreasing concentration upon treatment withdrawal, in plasma in particular

Ostaci klenbuterola u uzorcima plazme i urina tijekom i nakon subkroničnog izlaganja tovnih svinja dozi klenbuterola koja potiče rast

The aim of the study is to evaluate the suitability of plasma and urine as matrices for clenbuterol residue determination during and after its subchronic administration at a growth-promoting dose to male pigs, using previously validated enzyme-linked immunosorbent assay (ELISA) as a screening method and liquid chromatography tandem mass spectrometry (LC-MS/MS) as a confirmation method. A high correlation coefficient between these analytical methods was obtained for both urine (R=0.9800) and plasma (R=0.9970) concentrations. Study results show the plasma and urine concentration to vary greatly during oral treatment with clenbuterol for 28 days. The peak urine concentration ((88.54±50.54) ng/mL) recorded on day 21 was 40-fold peak plasma concentration ((2.25±1.54) ng/mL). After withdrawal period, the peak urine clenbuterol concentration ((42.93±10.52) ng/mL) recorded on day 0 was 24-fold plasma concentration ((1.79±0.97) ng/mL). The maximum allowed concentration of 0.5 ng/g in the liver as a regulated matrix for control of clenbuterol abuse was achieved in plasma on day 3 ((0.52±0.26) ng/mL) and in urine on day 7 of treatment withdrawal ((0.45±0.11) ng/mL). Study results indicate that urine and plasma may be suitable matrices for the control of clenbuterol abuse during fattening of food-producing pigs but have a limited value because of the rapidly decreasing concentration upon treatment withdrawal, in plasma in particular.Svrha je rada utvrditi prikladnost plazme i urina kao matriksa za određivanje ostataka klenbuterola tijekom i nakon subkroničnog davanja doze koja potiče rast muških svinja, primjenom prethodno validirane metode: ELISA kao screening metodu i tekućinsku kromatografiju s masenom spektrometrijom (LC-MS/MS) kao potvrdnu metodu. Primijenjenim analitičkim metodama određen je visoki korelacijski koeficijent u urinu (R=0,9800) i plazmi (R=0,9970). Rezultati istraživanja pokazali su da se koncentracije klenbuterola u plazmi i urinu značajno razlikuju tijekom 28 dana oralne primjene klenbuterola. Najveća koncentracija u urinu ((88,54±50,54) ng/mL), određena 21. dan, bila je 40 puta veća od najveće koncentracije određene u plazmi ((2,25±1,54) ng/mL). Nakon prestanka obrade, najveća koncentracija klenbuterola u urinu ((42,93±10,52) ng/mL) određena je 0. dan i bila je 24 puta veća od one određene u plazmi ((1,79±0,97) ng/mL). Maksimalno dopuštena koncentracija od 0,5 ng/g u jetri, kao regulatornom matriksu što se koristi u kontroli zlouporabe klenbuterola, u plazmi je određena 3. dan ((0.52±0.26) ng/mL), a u urinu 7. dan ((0,45±0,11) ng/mL) nakon tretmana. Rezultati istraživanja pokazuju da urin i plazma mogu biti prikladni matriksi u kontroli zlouporabe klenbuterola tijekom tova svinja, ali s ograničenom primjenom zbog naglog opadanja koncentracije nakon prestanka tretmana, a posebno u plazmi

Detection and characterisation of hepatitis E virus in naturally infected swine in Croatia

Hepatitis E is a viral zoonotic disease infecting swine worldwide. Since pigs represent a likely animal reservoir for the hepatitis E virus, the epidemiology of naturally occurring hepatitis E was investigated in Croatian swine herds. Nearly all tested animals were seropositive for antibodies against the hepatitis E virus (55/60, 91.7%). Active infection was detected in all age groups by RT-PCR of viral RNA in serum (8/60, 13.3%) and bile samples (3/37, 8.1%), which was further confirmed by histopathological findings of characteristic lesions in the livers of the infected animals. Three new strains of hepatitis E virus were isolated from Croatian pig herds. Phylogenetic analysis using median-joining networks clustered those Croatian strains with isolates from various parts of the world, indicating their likely origin in international trade. Similarity to human isolates implies a zoonotic potential of Croatian strains, which raises a public health concern, especially in the light of the high prevalence of hepatitis E in the herds studied