Investigation of some aspects of the Neuro-Morphometry of the African catfish (Clarias gariepinus)

Abstract

The brain is one of the most important organs, as it controls numerous bodily functions. Due to its crucial regulatory roles, the nervous system of fishes and especially the brain needs more research. Catfish (order Siluriformes or Nematognathi) are ray finned fish, named for their prominent whiskers (barbels), which resembles the whisker of a cat. The Nigerian cultured catfish (Clarias gariepinus) have small eyes and wide mouths, which suggest low dependence on vision, nocturnal activity, and predatory habits. Herein, we describe the gross morphology and morphometrics of the brain of Clarias gariepinus. Five apparently healthy adult catfish (Clarias gariepinus) without sex differences were used. Cranial nerves and spinal cord were severed as the brain case was removed, after which all the morphological descriptions were done. Ten morphometric parameters were also measured. The generated data were graphically illustrated with scatterplot and biplot, as well; the regression analysis showing the stepwise fit for the prediction of the brain weight from other measured parameters was also presented. The olfactory bulb is large, somewhat rounded and rostral. The cerebellumin all examined brain was the largest structure of the brain with a cerebellar length and width of 1.16±0.11 cm and 0.82±0.03, respectively. The optic tectum, lobusvagi, lobusfacialis and eminentiagranularis were also well developed but small in size. Although, the behavior of the catfish (Clarias gariepinus) is still unknown, the relative proportion of the cerebellum, optic tectum, eminentiagranularis, lobusfacialis and lobusvagi, might be related to carnivory and an enhanced capacity for food selection in this species. In conclusion, the report herein has helped to provide useful information for the first time on morphology of the brains of Clarias gariepinus cultured in Nigeria, for understanding of the neurobehaviour and habits of this species.