Brain Anatomy and Histology of Orange Spotted Grouper (Epinephelus coioides)

This research was carried out to identify the different layers and cells of orange spotted grouper brain for further toxicological experiments and defects brought by xenobiotics during exposure periods.The anatomy and histology of the brain of orange spotted grouper was illustrated and compared to mammals and other fishes. The preserved structures of teleosts brain species were different as compared to other orders of teleosts and mammals. The anatomy and histology of the olfactory tract, olfactory lobe, cerebrum, optic lobe, cerebellum, diencephalon and medulla were visualized by the stereoscope and optic microscope using haematoxylin- eosin staining method. Different layers of various parts of the brain were depicted and compared to other species. The telencephalon of E.coioides was lobulated. The cerebrum consisted of a single layer unlike the six layered neocortex in mammals. The epiphysis was situated internally within the tectal ventricle. The cerebellum was the most prominent part in this fish, which might not be seen in other orders of teleosts. The cerebellum consisted of corpus cerebelli and valvula cerebelli. The ganglionic layer of cerebellum possessed eurydendroid cells which did not exist in mammals.