Acute toxicity of ochratoxin-A in marine water-reared sea bass (Dicentrarchus labrax L.).

The toxic effects of ochratoxin-A (OTA) on sea bass, Dicentrarchus labrax L., have not been previously documented. A flow-through bioassay test system was conducted in two series and a total 180 of adult marine-reared sea bass was used to estimate the acute oral 96 h median lethal concentration (LC(50)) value and behavioral changes of OTA. The data obtained were statistically evaluated using Finney's Probit Analysis Method developed by EPA. The 96 h LC(50) value for adult D. labrax was found to be 277 microg kg(-1)bwt with 95% confidence limits of 244-311 microg kg(-1)bwt. This value was calculated to be 285 microg kg(-1) bwt with Behrens-Karber's method. The two methods were relatively comparable. The acute dietary 96 h LC(50) of OTA is 9.23 mg kg(-1) diet. Additionally, the behavioral changes of sea bass were primarily observed as nervous and respiratory manifestations. We concluded that sea bass is a species highly sensitive to OTA making them a useful experimental model for aquatic mycotoxigenic problems.

Subacute intoxication of a deltamethrin-based preparation (Butox) 5% EC) in monosex Nile tilapia, Oreochromis niloticus L.

The monosex Nile tilapia, Oreochromis niloticus L., was exposed to subacute concentration (1.46 microg/l) of a pyrethroid insecticide, deltamethrin for 28 consecutive days. Behavioural, clinical, haematological, serum biochemical and histopathological consequences were assayed at a regular interval of 7 days. The abnormal behavioural responses and toxic symptoms were described. Exposure to deltamethrin not only significantly decreased lymphocyte and basophile percentages, total leucocytic and total erythrocytic counts, haemoglobin percentage and packed cell volume value, but also caused serious effects in the form of hypoproteinaemia, hypoalbuminaemia, hypercholesterolaemia, hyperglycaemia and significantly increased serum aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase activities. Moreover, the histopathological results indicated that the haemobiotic organs were affected by deltamethrin, primarily liver and gills. Our data suggest that subacute exposure to deltamethrin exerts a serious metabolic distress on the fish corresponding to the exposure period. In addition, the assayed parameters and histopathological findings can be as good biomarkers of pyrethroid ecosystem pollution.