Ultra Structure of Excretory Organ (Kidney) in Juvenile Grouper, Epinephelus coioides

In order to study of kidney tubules, twenty specimen of 45 days old juvenile grouper (Epinephelus coioides) were prepared after proper biometry. Five mm thick sections were removed from the middle and posterior end of the kidney and fixed in Bouin and glutaraldehyde. The routine procedures of preparation of tissues were followed for light and transmission electron microscopic study. In macroscopic observations, it was observed that kidney was located retroperitoneal and attached to the vertebral column with an average length of 4±0.2 cm. The microscopic results showed that nephrons consisted of glomerules, proximal, distal and collective tubules. The proximal tubules were detectable with their brush border. Distal tubules had cuboidal cells with round nucleus that were positioned in the middle part of the cell. The lumen of these tubules were PAS negative due to lack of brush border. Collecting tubules were also PAS negative as their cuboidal cells lacked brush border and their ellipsoid to round nuclei were positioned central to the cell. TEM analyses of sections showed more details of tubules structure, e.g. plasma membrane showed an extensive system of depressions in all tubules, except in collecting tubules.