Levels of total mercury in the muscle (29 samples) and liver tissue (15 samples) of bluefin tuna (<i>Thunnus thynnus</i>) weighing 100&minus;300 kg were determined by cold vapour atomic absorption (AA) spectroscopy. Tunas were previously captured in the waters of Malta, towed to the farm in the Adriatic Sea and fattened with defrosted herring and sardine for the period of 6 to 7 months. The purpose of the investigation was to determine the magnitude of mercury contamination and to ascertain whether the concentrations in muscle tissue exceeded the maximum level defined by the European Commission Decision (1 &mu;g/g wet weight). Total mercury concentrations in the muscle tissue of tunas ranged from 0.49 to 1.809 (median 0.899 &mu;g/g wet weight) while in the liver tissue it was from 0.324 to 3.248 (median 1.165 &mu;g/g wet weight). Total mercury concentrations in six samples of sardine ranged from 0.050 to 0.072 &mu;g/g wet weight while two samples of herring contained 0.020 and 0.053 &mu;g/g wet weight. Twelve out of 29 (41%) muscle samples of tuna contained mercury above the maximum level defined by the European Commission Decision. It is generally believed that mercury levels in Mediterranean fish are higher than those of the other seas or oceans due to numerous deposits of mercury ores and metallic mercury in surrounding countries.

The concentrations of total mercury in muscle (17 samples), liver (16 samples) and kidney tissues (16 samples) of both bottlenose (<I>Tursiops truncatus</I>) and striped dolphins <I> (Stenella coeruloalba</I>) were analyzed by cold vapour atomic absorption (AA) spectroscopy. The dolphins were found dead at different locations along the east Adriatic over a 10-year period starting in 1990. In this study, the magnitude of mercury contamination of dolphins which are indicators of contamination of the Adriatic as well as the Mediterranean Sea was determined. Our results represent the first investigation of heavy metal concentrations in dolphins sampled along the Croatian coast of the Adriatic Sea. Total mercury levels were high, ranging from 1.51 to 136.7 mg/kg in muscle, from 2.04 to 143.1 in kidney and from 10.35 to 1 833 mg/kg in liver tissues (expressed as wet weight). These results were examined for differences based upon age and tissue type. A high correlation was observed between total mercury concentration and age, and adult dolphins (10 samples) contained statistically significant higher concentrations of mercury compared to juvenile (seven samples) dolphins. Mercury concentrations were generally the highest in liver tissue. The presence of high mercury levels in dolphins is attributed to natural as well as anthropogenic sources.

Chickens were vaccinated against Marek's disease intramuscularly at one day of age. Enrofloxacin was given ad libitum in the drinking water at concentrations of 50, 100 and 250 mg/L from 8 days to 13 days of age when the animals were killed and the activities of cytochrome P-450 enzymes in the liver were measured. Vaccinated non-treated chickens served as a positive control. A negative control group was neither vaccinated nor treated. Vaccination decreased the activity of aniline hydroxylase and ethylmorphine N-demethylase in the positive control group. Subsequent application of enrofloxacin in the lowest concentration (50 mg/L) decreased, while that given at the highest level (250 mg/L) significantly increased the activity of the same microsomal enzymes. Relative liver weights and concentrations of proteins in 9000 × g supernatant were not affected by vaccination or treatment.

Fertile Nick Chick eggs were injected with 0.05, 0.1, 0.5 and 5 p.p.m. of PCB (Aroclor 1254) on day zero and were incubated until the 14th day of incubation. Nick Chick cockerels, one day old, were fed different levels of PCB in their diet for two weeks. The levels of PCB used were 0.1, 1, 5, 100 and 200 p.p.m. Key gluconeogenic enzyme activities were measured in the liver of both experimental groups. In the liver of chick embryos and growing chickens the decrease of the activity of all key gluconeogenic enzymes, with the exception of G6P-ase in embyronic liver, and FDP-ase in that of growing chickens, was estimated. The inhibited gluconeogenesis may account for the embryonic death in eggs contaminated with PCB's.

Poisoning with acetylcholinesterase inhibitors in dogs is described. Diagnosis is confirmed by presence of carbofuran, chlorpyrifos and their metabolites in livers of poisoned dogs