Residue Depletion of Ractopamine and Its Metabolites in Swine Tissues, Urine, and Serum

• Published in: Journal of agricultural and food chemistry Vol. 55; no. 11; pp. 4319 - 4326
• Main Authors: Qiang, Zhiyi, Shentu, Fenqin, Wang, Bing, Wang, Jianping, Chang, Jianyu, Shen, Jianzhong
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 30.05.2007
• Subjects: Adrenergic beta-Agonists - blood; Adrenergic beta-Agonists - pharmacokinetics; Adrenergic beta-Agonists - urine; Animal productions; animal tissues; Animals; bioavailability; Biological and medical sciences; blood serum; chemical analysis; chemical residues; Chromatography, High Pressure Liquid; detection; excretion; feed additives; fluorescence; Food industries; food safety; Fundamental and applied biological sciences. Psychology; high performance liquid chromatography; Kidney - metabolism; Liver - metabolism; livestock production; meat quality; metabolites; Muscle, Skeletal - metabolism; Phenethylamines - blood; Phenethylamines - pharmacokinetics; Phenethylamines - urine; pork; ractopamine; swine; Swine - blood; Swine - metabolism; Swine - urine; swine feeding; temporal variation; Terrestrial animal productions; urine; validity; Vertebrates; Urine; Biological fluid; Farming animal; Ractopamine; Metabolite; HPLC chromatography; HPLC-FLD; Pig; swine; Tissue; Vertebrata; Meat animals; Mammalia; Residue; Serum; residue depletion; Artiodactyla; Ungulata
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf070167c

Ractopamine hydrochloride is a β-adrenergic leanness-enhancing agent approved for use in swine in the United States. Depletion of ractopamine and its metabolites from animal tissues, urine, and serum is of interest for the detection of illegal use. The objectives of this study were to measure the residues of ractopamine in swine incurred samples after treatment with dietary ractopamine for 28 consecutive days. An efficient and sensitive analytical method was developed for the detection of parent ractopamine and its metabolites in swine tissues, urine, and serum by HPLC-FLD. After extraction, enzymatic digestion, and solid-phase cleanup of the samples, ractopamine residues were determined by liquid chromatography (LC) with fluorescence detector. The limits of detection (LOD) for tissues, urine, and serum were 1 ng g-1, 0.5 ng mL-1, and 0.5 ng mL-1, respectively. Recoveries ranged from 70.5 to 94.5% for samples fortified at 1−50 ng g-1 or ng mL-1. Sixty pigs were fed twice daily for 28 consecutive days with feeds containing 18 mg kg-1 ractopamine HCl. The residue concentrations in urine, liver, and kidney were 650.06 ng mL-1, 46.09 ng g-1, and 169.27 ng g-1, respectively, compared with those in muscle, fat, and serum (4.94 ng g-1, 3.28 ng g-1, and 7.48 ng mL-1, respectively) at the feeding period of 7 days. The residue concentrations at withdrawal period of 0 days in all edible tissues were lower than tolerance values established by the FDA and MRL values listed by the JECFA. These data support the withdrawal time of 0 days established by the FDA for ractopamine used as feed additive in swine. Keywords: Ractopamine; swine; HPLC-FLD; residue depletion