Thesis (M.Sc.)--Chulalongkorn University, 2004

In general, the toxicity testing of various chemicals is not the studies only in mammals but also in aquatic organisms. From the review, most of research on toxicity of distilled liquors was studied in mammals and a few recorded in aquatic organisms especially the fish. Therefore, the aim of this study was to investigate acute toxic and subchronic toxic of distilled liquors 30 degree on liver and kidney of Nile tilapia Oreochromis niloticus. Acute toxicity bioassay was performed by acute static toxicity test type to obtained the LC[subscript 50] at 96 hours. The median lethal concentration of distilled liquors was 15,751.21 ppm. From the calculation, sublethal concentration of subchonic toxicity studies was 964.30 ppm. One-month-old Nile tilapias were exposed to distilled liquors at sublethal concentration for 6 months. Liver and kidney of control group and treated group were sampled every month. Body weight and liver weight were recorded. Liver and kidney were processed for permanent slide and studied under light microscope. The results showed that the liver somatic indices of all treated fish in every month from 4th months to 6th months of experiment were higher than normal value and significantly different from the control group (p<0.05) and not significant different among treated groups of all experimental months. From histological studies, liver of treated fish exhibited histological changes that consisted of hydropic swelling, hyaline granules and lipid droplets accumulation, diffuse and focal necrosis, sinusoid dilatation and sloughing of blood vessels endothelium. Lymphocyte and granulocyte infiltration were seen in the inflammatory areas. Some damage area showed the regeneration of hepatocytes. Histological alterations of kidney consisted of glomerulus shrinkage, hydropic swelling of proximal tubular cells and hyaline granules accumulation, pyknotic nuclei, and karyolysis of proximal tubular cells. Tubular lumen showed the accumulation of cellular debris and protein cast. In conclusion, this research showed that distilled liquors 30 degree caused toxic effects on Nile tilapia liver and kidney and the severity of histopathological changes depended on the exposure time.