2009_Book_FoodChemistry

9.5 Veterinary Medicines and Feed Additives 487
Table 9.10. Animal medicines (selected structural formulas are presented in Fig. 9.3)
Number Class of compounds
Example
Antibiotics
I Sulfonamides Sulfapyridine (Ia), Sulfathiazole (Ib)
II β -Lactams Amipicillin (IIa), Amoxycillin (IIb)
III Tetracyclines Tetraycline (IIIa), Oxytetracycline (IIIb)
IV Aminoglycosides Streptomycin (IVa), Dihydrostreptomycin (IVb)
V Macrolides Tiamulin (Vt)
VI Crinolines & Fluorochinolones Ciprofloxacin (VIa), Marbofloxacin (VIb)
Anthelmintics
VII Benzimidazoles Fenbendazole (VIIa), Mebendazole (VIIb)
VIII Tetrahydroimidathiazoles Levamisol (VIIIa), Morantel (VIIIb)
IX Avermectins Ivermectin (IX)
Coccidiostats
X Different classes Dicoquinat (Xa), Clopidol (Xb), Lasalocid (Xc)
only for therapy, but to a large extent for prophylaxis
and economic aims (e. g. to shorten animal
growth or feeding time; to abate the risk of
losses). Veterinary preparation residues in food
are ingested by humans in low amounts but continuously
and, hence, could be a health hazard.
This possibility was, for a long time, not carefully
examined. Therefore, as in the field of pesticides,
supporting and maintaining appropriate measures
(imposing legally binding regulations, analytical
control or supervision, elucidation of toxicological
problems) has the ultimate aim of protecting
human health.
A brief outline of some important groups of veterinary
medicines follows. Table 9.10 and Fig. 9.3
provide a review of their use and chemical structures.
9.5.3 Anthelmintics
In meadows and sheds, animals come into contact
with their excrements and subsequently with
worms in all developmental stages. Anthelmintics
are used against the resulting diseases caused by
worms.
9.5.4 Coccidiostats
The compounds of this class are added to animal
feed to combat coccidiosis diseases (such as enteritis
or cachexie) caused by protozoans living
as parasites in intestines. Poultry and rabbits are
the animals most often affected. Residues may be
found in eggs.
9.5.2 Antibiotics
Antibiotics are used prophylactically to stem infections,
e. g., in intensive mass animal farming
and in the therapy of infectious diseases. Since
they inhibit the growth of the microflora, which
is present in the digestive tract of livestock, feed
utilization is improved. The animals gain weight
faster. This application of antibiotics as growth
promoters is regarded critically in the EU and has
led to bans. A constant intake of antibiotics, even
at low doses, is a risk to human health since some
microorganisms may become resistant and allergic
reactions may develop.
9.5.5 Analysis
The aim of these analyses is:
• to detect medicines which are banned or
not approved, e. g., chloramphenicol (XIt),
nitrofurans (derivatives of 2-nitrofuran,
e. g., nitrofurantoin, XIIt), fattening aids
with estrogenic activity such as 17-estradiol
(XIIIt), diethylstilbestrol (XIVt), zeranol
(XVt).
• to check if the residue of an approved therapeutic
agent is still within the permissible upper
limit (MRL, cf. 9.1).