Investigation of oxytetracycline use and abuse: determination of its residues in meat consumed in Dodoma and Morogoro municipalities
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Date
2004
Authors
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Journal ISSN
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Publisher
Sokoine University of Agriculture
Abstract
In spile of oxytetracycline (OTC) being a widely used drug in livestock production in
Tanzania for many years, there is no published information on its use and occurrence of its
residues in the meat consumed in the country. This study was aimed at establishing the
mode of OTC use, the occurrence and levels of its residues in the meat consumed in
Dodoma and Morogoro regions. The mode of OTC use was studied by the administration
of a questionnaire to respondents in some of the slaughter cattle catchment areas. The
residue occurrence levels were accomplished by analysis of 131 muscle, liver and kidney
samples by using the high performance liquid chromatography (HPLC) technique. OTC
sample extraction was done using a pH 4.0 Mcllavaine-EDTA buffer and cleanup by
application on Supelclean LC-18 solid phase extraction (S.P.E.) cartridges. OTC
quantification was done by using an ATIUNICAM H.P.L.C. system with an electron
capture UV detector set at 350nm. The separation of OTCs was carried out by an RP 8-10
Lichrosorb (4.6 mmd x 25cm) column and a Methanol: Acetonitrile: O.OlMaq. Oxalic
Acid mobile phase in the ratio 1:2:7 V/V/V, respectively. The study established a high
degree of OTC abuse of use especially by the livestock keepers through overdosing by as
much as 10-20 times the recommended therapeutic doses, use of wrong routes of
administration, arbitrary drug combinations and non-observance of the OTC withdrawal
period. Out of the 131 beef samples analysed, 54 (41.2%) had detectable OTC residues.
Furthermore 41 (31.3%) samples had violative OTC residues levels compared to the
FAO/WHO 1999 OTC maximum residue levels (MRLs) of 0.2 mg/kg (muscle), 0.6 mg/kg
(liver) and 1.2mg/kg (kidney).
Violative OTC residues ranged from 0.52 mg/kg to
8.98mg/kg of tissue. The 31.3% violative samples, coupled with the high mean OTC
residue concentrations observed were very significant compared to those of other countries. It is an indication of the seriousness of the OTC abuse problem with its
attendant residue occurrence and harmful effects on public health, our international trade
of animal products and the environment. Deliberate steps need to be taken by the state to
redress the situation before it gets worse.
Description
Degree of Master of Veterinary Medicine
Keywords
Oxytetracycline use and abuse, Meat consumed- Dodoma municipalities, Meat consumed-Morogoro municipalities, Dodoma municipalities, Morogoro municipalities