The validity of two microbiological methods: Tube (Premi® Test) and Plate (Three Plate Test) Test for the detection of oxytetracycline (OTC) in poultry was done using Enzyme Linked Immunosorbent Assay (ELISA) immunoassay as gold standard. OTC was administered to two groups of birds: intramuscular drug administration (group A) and oral drug administration (group B). Liver and muscle tissue samples from birds in both groups were tested for the presence of OTCwith the Four Plate Test (FPT), Premi® Test and ELISA. For muscle tissues, FPT had a sensitivity of 71.4% and 60%, while Premi® Test had a sensitivity of 57% and 20% for intramuscular and orally treated birds, respectively. For the liver tissues, FPT had 87.5% and 83.5% while Premi® Test had 37.5% and 16.6% sensitivity for intramuscular and orally treated birds, respectively. The two tests had 100% specificity for OTC in tissues of birds from both treatment groups. There is a strong correlation (r = 0.93) between the inhibition zones of FPT and ELISA concentrations in OTC detection. FPT, therefore, has a higher sensitivity for OTC than Premi® Test.
Keywords: ELISA; Oxyteracycline; plate test; poultry; sensitivity; tube test.