Lip histology of the adult farmed African Catfish (<i>Clarias gariepinus</i>)

Abstract

The lip histology of the adult farmed African catfish was investigated to fill the knowledge gap in available literature especially those from commercial concrete tanks. This microanatomy is important as the lip is the principal organ involved in prehension. The lip epidermis was lined by stratified squamous epithelium containing PAS and AB positive mucous cells, and occasional eosinophilic club cells. Some melanocytes were seen at the basal epithelial layer and subepithelium. Pectinate ligament of dense regular connective tissue was seen attaching the epithelium to the deep dermal dense regular connective tissue. This deep dense regular connective tissue was seen ventral to the subepithelial loose areolar connective tissue. In the lower lip, the core contained skeletal muscle fibres in varying directions, elastic cartilage, and bone. This core provides anchorage for the horny pad teeth. Abundant nerve fibres were observed in the deep connective tissue layers. No taste bud was observed. This microanatomical observation suggests an organ involved in prehension and tearing of feed; protractibility, protection but no gustatory function.

Keywords: Pectinate ligament, mucous cells, club cells, Histology, lip.