This study was carried out to analyze the architecture of the skin of the upper lip
region in silver carp fishes using light, scanning, and transmission electron microscopies.
The skin was composed of epidermis, dermis, and hypodermis. The epidermis of the
upper lip was characterized by the presence of large number of metachromatic mucous
goblet cells, which showed positive reaction with Periodic Acid–Schiff (PAS), Alcian
blue (AB), and toluidine blue. The electroreceptive lateral line system was organized
into ampullary and tuberous organs. The scanning electron microscopy showed that
the surface of the skin of upper lip was covered by microridges and characterized by
the presence of taste buds and openings of lateral line system. As observed by transmission
electron microscopy, the cytoplasm of the epidermal layers appeared electrondense
except for the superficial layer, where the cytoplasm was electron-lucent and
contained many vacuoles and few profiles of rER. Moreover, the epidermis contained
rodlet cells and stem cells. Few organelles were found within the cytoplasm of club
cells. Neutrophils and eosinophilic granular cells were also demonstrated as important
immune cells in the epidermis of the upper lip. Furthermore, lymphocytes and basophils
could be identified with macrophage in the epidermal layer of the upper lip. Numerous
telocytes were demonstrated between the collagen fibers of the dermis and bundles of
myelinated nerve fibers. In conclusion, the skin of the upper lip region of silver carp displayed
many sensory and immunological characteristic features.