Histological and histochemical studies of the skin of some fresh-water teleost fishes

The present work conducted on 28 specimens of adult fresh water fishes collected from the Nile River [at Giza and El Qanater]. Four types of fresh water fishes were used Bayad [Bagrus bayad], Karmout [Clarias lazera], Nile Eel [Anguilla vulgaris] and Bolti [Tilapia nilotica]. The epidermis could be divided into three distinct layers. There were lymph spaces between the germinal cells. Various types of unicellular glands in the epidermis as sacciform glands in Bayad and Karmout; club cells in the epidermis of Nile Eel and mucous cells in the epidermis of all fishes. The mucous cells gave positive reaction to both PAS and AB stains. The sacciform slime secreting gland were unicellular glands surrounded by the epidermal cells themselves. The secretory materials they contained were PAS and AB negative. The club cells were recorded in the epidermis of Nile Eel. They were large in size, wedged between the epidermal cells. The contents of the glands were negatively reacted to both PAS and AB stains. The dermis was formed of spongy layer [stratum spongiosum] and compact layer [stratum compactum]. In the spongy layer the blood vessels occur forming, just under the basement membrane, a dense sub-epithelial net. A layer of pigment cells, supplied with blood capillaries in the loose connective tissue below the basement membrane and a second layer at the deeper part of the dermis were noticed. The epidermis of Bayad, Karmout and Bolti contained taste buds. The taste buds appeared flask-shaped and were embedded in the epidermis