الفهرس | Only 14 pages are availabe for public view |
Abstract Antibiotics are used by the poultry industry and poultry veterinarians to enhance growth and feed efficiency and reduce disease. Antibiotic usage has facilitated the efficient production of poultry, allowing the consumer to purchase, at a reas onable cost, high quality meat and eggs. Antibiotic usage has also enhanced the health and well-being of poultry by reducing the incidence of disease. Although these uses benefit all involved, unfortunately, consumer perceptions are that edible poultry tissues are contaminated with harmful concentrations of drug residues (Donoghue, 2003). Drugs used in food animals can affect the public health because of their secretion in edible animal tissues in trace amounts usually called residues. For example, oxytetracycline (Salehzadeh et al., 2006) and enrofloxacin residues (Salehzadeh et al., 2007) have been found above the maximun residual level in chicken tissues. Similarly, diclofenac residues were reported to be the cause of vulture population decline in Pakistan (Oaks et al., 2004). Some drugs have the potential to produce toxic reactions in consumers directly; for example, clenbutarol caused illness in 135 peoples as a result of eating contaminated beef in Spain in 1990. Other types of drugs are able to produce allergic or hypersensitivity reactions. For example, 2-β-lactam antibiotics can cause cutaneous eruptions, dermatitis, gastro-intestinal symptoms and anaphylaxis at very low doses. Such drugs include the penicillin and cephalosporin groups of antibiotics (Paige et al., 1997). Indirect and long term hazards include microbiological effects, carcinogenicity, reproductive effects and teratogenicity. Microbiological effects are one of the major health hazards in human beings. Antibiotic residues consumed along with edible tissues like milk, meat and eggs can produce resistance in bacterial populations in the consumers. This is one of the major reasons of therapeutic failures amongst such peoples. Certain drugs like 3 -nitrofurans and nitroimidiazoles can cause cancer in human population. Similarly, some drugs can produce reproductive and teratogenic effects at very low doses consumed for a prolonged period of time. One such example is vaginal clear cell adenocarcinoma and benign structural abnormalities of uterus with diethyl stilbesterol (Sundlof, 1994). Antibiotics are important in animal husbandry because they significantly enhance growth when added to animal feed, although European Union (EU) legislation has forbidden this practice since 2006 (European Commission, 2003). Several antibiotic families are used in veterinary medicine: B-lactams; Tetracyclines; Chloramphenicols; Macrolides; Spectinomycin; Lincosamide; Sulphonamides; Nitrofuranes; Nitroimidazoles; Trimethoprim; Polymyxins; Quinolones and Macrocyclics. Macrocyclics are characterized by their high selectivity as they are Introduction 2 chiral selectors (Ward and Farris, 2001). The extensive use of antibiotics has triggered the development of bacterial resistance (Novais et al., 2010), which, in recent years, has become an international concern (Teuber, 2001). Much attention has been paid to food-producing animals as potential source of antibiotic resistant bacteria in humans. As a result, there is increasing pressure on laboratories responsible for ensuring the safety of food for human consumption. Legislation regarding the control of antibiotic residues in live animals and animal products is given in Council Directive 96/23/EC (European Commission, 1996), and maximum residue limits (MRLs) have been established for different matrices, so fast, sensitive methodologies to determine antibiotic residues in food samples are critical in food safety control laboratories. In this field, Kantiani et al., (2009) presented a review on the analytical methods developed for penicillin and cephalosporin residues in milk and feed samples (Kantiani et al., 2009). Drugs used in food animals can affect the public health because of their secretion in edible animal tissues in trace amounts usually called residues. For example, oxytetracycline (Salehzadeh et al., 2006) and enrofloxacin residues (Salehzadeh et al., 2007) have been found above the maximun residual level in chicken tissues. Similarly, diclofenac residues were reported to be the cause of vulture population decline in Pakistan (Oaks et al., 2004). Some drugs have the potential to produce toxic reactions in consumers directly; for example, clenbutarol caused illness in 135 peoples as a result of eating contaminated beef in Spain in 1990. Other types of drugs are able to produce allergic or hypersensitivity reactions. For example, 2-β-lactam antibiotics can cause cutaneous eruptions, dermatitis, gastro-intestinal symptoms and anaphylaxis at very low doses. Such drugs include the penicillin and cephalosporin groups of antibiotics (Paige et al., 1997). Indirect and long term hazards include microbiological effects, carcinogenicity, reproductive effects and teratogenicity. Microbiological effects are one of the major health hazards in human beings. Antibiotic residues consumed along with edible tissues like milk, meat and eggs can produce resistance in bacterial populations in the consumers. This is one of the major reasons of therapeutic failures amongst such peoples. Certain drugs like 3-nitrofuransand nitroimidiazoles can cause cancer in human population. Similarly, some drugs can produce reproductive and teratogenic effects at very low doses consumed for a prolonged period of time. One such example is vaginal clear cell adenocarcinoma and benign structural abnormalities of uterus with diethyl stilbesterol (Sundlof, 1994 |