Tissue residue depletion of oxytetracycline after repeated intramuscular administration of Oxysentin 100 in sheep.

The depletion profile of oxytetracycline was studied in healthy sheep after intramuscular administration of Oxysentin 100, given at a dose of 10 mg oxytetracycline per kg body weight once daily for 5 consecutive days. Five medicated sheep were slaughtered at 0, 2, 4, 6, 9 and 12 days postmedication, and injection site, muscle, fat, liver and kidney tissues were sampled and analysed using a liquid chromatographic method, which was fully validated for oxytetracycline and 4-epi-oxytetracycline. At day 0 postmedication, the concentrations of oxytetracycline marker residue (sum of oxytetracycline and 4-epi-oxytetracycline) in all tissues examined were at the mg/kg level. At day 2 postmedication, the concentrations of oxytetracycline marker residue in all injection site and kidney samples examined were higher than the corresponding maximum residue limits (MRLs) established by the European Union, while the concentrations in muscle and liver tissues of two and three out of five animals examined, respectively, were below the corresponding MRLs. At days 4 and 6 postmedication, concentrations of oxytetracycline marker residue above the MRLs were found only in the injection site, whereas at day 9 postmedication, all observations were below the corresponding MRLs.

Cymothoid parasite Ceratothoa parallela inflicts great losses on cultured gilthead sea bream sparus aurata in Greece.

For the first time Ceratothoa parallela (Otto, 1828), a cymothoid isopod, is reported parasitizing cage-cultured gilthead sea bream Sparus aurata, in Greece. The specimens observed are larvae (Pullus secundus). They were found in the branchial and buccal cavity of young gilthead sea bream of 2 g mean body weight, upon introduction in the cages in an intensive cage farm facility. The species was previously known from several species of wild fish, particularly Sparidae (chiefly Boops boops) in the Mediterranean Sea, Adriatic Sea and Atlantic Ocean. However, this is the first documentation of this parasite in cage-cultured gilthead sea bream. Serious lesions were macroscopically visible and typical of a crustacean infection. The cumulative mortality over a 2 mo period was over 50%. The parasitic problem was not successfully dealt with due to high stocking densities and the non removal of the dead fishes, resulting in constant reinfection.

First record of Emetha audouini, a cymothoid isopod parasite, from cultured sea bass Dicentrarchus labrax in Greece.

For the first time, Emetha audouini (Milne Edwards, 1840), a cymothoid isopod, is reported parasitising cage cultured sea bass Dicentrarchus labrax L., 1758 in Greece. The specimens observed are larvae (Pulli II). They were found in great numbers in the buccal and branchial cavity of young (3.5 m.o. old) sea bass, in an intensive cage farm facility. This parasite is certainly transferred to sea bass from wild populations of Sparidae or Centracanthidae. Serious lesions were visible and typical of a crustacean infection, with extensive and deep skin damage in the head area. The cumulative mortality, over a 2 wk period, was 10.75%. The parasitic problem was successfully dealt with by optimization of management practices rather than use of costly and dangerous chemotherapeutants.