Histological observations on the dendretic organ of the farmed adult African catfish (Clarias Gariepinus) from eastern Nigeria

The histology of the accessory respiratory organ of the African catfish - dendretic organ was investigated to reveal its microanatomy. The data obtained will provide baseline data for further investigative research and assist fish pathologists. The histology showed that the tubular shaped dendretic organ was covered by stratified squamous epithelium containing periodic acid-Schiff (PAS) and alcian blue (AB) positive mucous cells. On most surfaces, the epithelial cells were organized into columns with mucous cells placed in-between the epithelial cell columns. At the tip of the surface, capillaries were lined by endothelium at the surface epithelium/air contact area. The subepithelial layer was of loose connective tissue containing adipose tissue and occasional blood vessels. The core of the dendretic organ contained elastic cartilage surrounded by a dense layer of perichondrium. Elastic fibres were observed the territorial and inter-territorial spaces