Ractopamine and Clenbuterol Urinary Residues in Pigs as Food-Producing Animals

Jelka Pleadin1*, Ana Vulić1, Nina Perši1, Dinka Milić2 and Nada Vahčić3

1Laboratory for Analytical Chemistry, Croatian Veterinary Institute, Savska 143, HR-10000 Zagreb, Croatia

2Dubravica Swine Farm, Ltd., Pavla Štoosa 109, HR-10293 Dubravica, Croatia
3Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, HR-10000 Zagreb, Croatia

Article history:

Received January 17, 2011
Accepted April 21, 2011

Key words:

ractopamine, clenbuterol, ELISA, pig, urine


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.


*Corresponding author: 
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