ABSTRACT
Growth promoters include a wide range of substances that are generally used in farm animals for therapeutic and prophylactic purposes. These substances can be administered in the feed or in the drinking water. In some cases, the residues may proceed from contaminated animal feedstuffs.1 Anabolic promoters have been administered in the United States to meat-producing animals, where estradiol, progesterone, and testosterone are some of the allowed substances. The regulations in 21 Code of Federal Regulations Part 556 provide the acceptable concentrations of residues of approved new animal drugs that may remain in edible tissues of treated animals.2 Other countries allowing the use of certain growth promoters are Canada, Mexico, Australia, and New Zealand. However, the growth promotion of farm animals through the use of substances having a hormonal action (17β-estradiol, testosterone, progesterone, zeranol, trenbolone acetate, and melengestrol acetate) was prohibited through Directive 81/602/EEC while the use of growth promoters including the administration of synthetic and/or natural hormones was ofcially banned in the European Union through Directive 88/146/EC due to concerns about harmful effects on consumers.3,4
Growth promoters increase growth rate and improve efciency of feed utilization and thus contribute to the increase in protein deposition that is usually linked to fat utilization, which means a reduction in the fat content in the carcass and an increase in meat leanness.5-8 In addition, some fraudulent practices consist in the use of low amounts of several substances like β-agonists (clenbuterol) and corticosteroids (dexamethasone) and/or anabolic steroids, mixtures known as “cocktails,” that have a synergistic effect and exert growth promotion9 but making its analytical detection more difcult.
