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Dubravica, Croatia

Vulic A.,Croatian Veterinary Institute | Pleadin J.,Croatian Veterinary Institute | Persi N.,Croatian Veterinary Institute | Milic D.,Dubravica Swine Farm Ltd. | Radeck W.,EU and National Reference Laboratory
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences | Year: 2012

Ractopamine is a β 2-adrenergic agonist, which reduces fat deposition and promotes muscle growth in animals for meat production. In the European Union countries, systematic monitoring and control of this contaminant residue is regularly performed by use of validated analytical methods of detection in different biological materials. The aim of the present study was to assess persistence of ractopamine in retina as a pigmented tissue by determination of its residues using UPLC-MS/MS as a quantitative confirmatory method after pig exposure to a ractopamine dose of 0.51mg/kg b.w. Experimental group (n=9) of pigs were orally administered ractopamine for 28 days and then randomly sacrificed (n=3) on days 1, 3 and 8 of treatment discontinuation, whereas control animals (n=3) were left untreated. Study results showed mean ractopamine residue concentrations of 110.36μg/kg, 67.11μg/kg and 89.93μg/kg on days 1, 3 and 8 after withdrawal, respectively, indicating high accumulation of ractopamine in retina despite a low dose applied. These data pointed to high affinity of ractopamine for binding to the pigmented segment of the eye, thus supporting the use of pigmented tissues as matrices in the regulatory monitoring of this β 2-adrenergic agonist. © 2012 Elsevier B.V. Source


Pleadin J.,Croatian Veterinary Institute | Persi N.,Croatian Veterinary Institute | Mitak M.,Croatian Veterinary Institute | Terzic S.,Croatian Veterinary Institute | And 3 more authors.
Bulletin of Environmental Contamination and Toxicology | Year: 2012

The objective of this study was to investigate the effect of ochratoxin A (OTA) on serum biochemical parameters of pigs during subchronic treatment with 300 μg OTA/kg of feed for 30 days. OTA treatment resulted in significantly higher (p < 0.05) serum levels of creatinine, urea, potassium and alkaline phosphatase, and significantly lower levels of glucose and total protein. These changes in serum biochemical parameters in treated pigs were indicative of impaired liver and kidney function caused by OTA exposure. © Springer Science+Business Media, LLC 2012. Source


Pleadin J.,Croatian Veterinary Institute | Vulic A.,Croatian Veterinary Institute | Persi N.,Croatian Veterinary Institute | Milic D.,Dubravica Swine Farm Ltd. | Vahcic N.,University of Zagreb
Food Technology and Biotechnology | Year: 2011

The aim of the study is to determine residual ractopamine (RCT) and clenbuterol (CLB) concentrations in urine during and after their administration in anabolic dose to male pigs. RCT and CLB residues were determined using previously validated enzyme-linked immunosorbent assay (ELISA) as a quantitative screening method. Hydrolysis of urine samples with β-glucuronidase showed significantly higher (p<0.05) RCT residues. Study results showed RCT and CLB urine concentrations to vary greatly during oral treatment for 28 days, with maximal RCT and CLB concentration recorded on day 25 ((327.4±161.0) ng/mL) and day 20 ((68.4±32.2) ng/mL), respectively. RCT concentration of (57.1±10.6) ng/mL and CLB concentration of (38.8±20.1) ng/mL were measured on day 0 of treatment withdrawal; on day 7 of treatment withdrawal, the measured concentration of RCT ((5.0±0.9) ng/mL) was 20-fold of CLB concentration ((0.3±0.2) ng/mL). Study results indicate that the excretion of RCT and CLB in pig urine could clearly point to their abuse in pigs as food-producing animals, in particular when using sample hydrolysis with β-glucuronidase on RCT determination. Source


Pleadin J.,Croatian Veterinary Institute | Vulic A.,Croatian Veterinary Institute | Persi N.,Croatian Veterinary Institute | Vahcic N.,University of Zagreb | Milic D.,Dubravica Swine Farm Ltd.
7th International Congress of Food Technologists, Biotechnologists and Nutritionists, Proceedings | Year: 2011

Ractopamine and clenbuterol are β-adrenergic agonists that increase the rate of weight gain and feed conversion. If used in meat production, they promote muscle growth of treated animals by increasing nitrogen retention, protein synthesis and lipolysis, and suppressing lipogenesis. They can be illegally used during fattening of farm animals, thus implying a risk to consumers of meat and meat products. For residue surveillance of both substances, it is essential to choose appropriate matrices and use high sensitivity analytical methods in the analysis of suspect tissues. The aim of the study was to compare residue levels and accumulation potential of ractopamine and clenbuterol in pig tissues, liver and kidney (n=24), after subchronic repeat administration of clenbuterol and 10-fold dose of ractopamine. Ractopamine and clenbuterol residues in both matrices were determined using validated enzyme- linked immunosorbent assay (ELISA) as a quantitative screening method. Method validation showed good mean recoveries (R >70%) with acceptable inter- and intra-day relative standard deviations (RSD <10%) for both analytes and matrices. Immediately after the last dose of β-agonists, the maximal determined ractopamine concentration in the kidney (42.44 ng/g) was 2-fold that measured in the liver (20.66 ng/g) and was comparable with maximal concentration of clenbuterol in the liver (47.43 ng/g). Considering the dose difference, study results pointed to higher accumulation of clenbuterol residues in both matrices, suggesting the liver to have a significantly higher accumulation potential for clenbuterol residues and kidney for ractopamine residues. The results also suggested these tissues to be appropriate matrices to detect ractopamine and clenbuterol abuse in meat production. Source


Pleadin J.,Croatian Veterinary Institute | Persi N.,Croatian Veterinary Institute | Vulic A.,Croatian Veterinary Institute | Milic D.,Dubravica Swine Farm Ltd. | Vahcic N.,University of Zagreb
Meat Science | Year: 2012

The objective of this study was to measure residual ractopamine concentrations in tissues of pigs as experimental animals after treatment with dietary ractopamine for 28 consecutive days. Ractopamine was administered orally to the experimental group (n = 9) in a dose of 0.1. mg/kg body mass per day, whereas control animals (n = 3) were left untreated. Treated pigs (60. kg) were sacrificed on days 1, 3 and 8 of treatment discontinuation and residues were determined in kidney, liver, muscle, brain and heart tissues using previously validated enzyme-linked immunosorbent assay (ELISA) as a quantitative screening method. Validation showed good mean recoveries (approx. 70-90%) with acceptable inter- and intra-day relative standard deviations (RSD < 13%), demonstrating the method efficiency in determination of ractopamine tissue concentrations. The highest ractopamine concentration on day 1 (24. h) after the last exposure was recorded in the kidney (12.49 ± 7.96. ng/g), followed by the liver (7.21 ± 2.73. ng/g), heart (1.26 ± 0.12. ng/g) and brain (0.63 ± 0.05. ng/g); at this time of withdrawal, residues were not detected in the muscle. Ractopamine was depleted rapidly from all study tissues, with mostly no detectable residues on day 8 of withdrawal. © 2011 Elsevier Ltd. Source

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