Abstract
Light and electron microscopic studies were carried out on the gills of grouper (Epinephelus malabaricus) fed diets supplemented with or without crystalline ascorbic acid for 12 weeks. Fish fed the diet without ascorbic acid supplementation showed various clinical signs such as haemorrhages of fins, deformed opercula and caudal fin erosion. Histological observations of the gills of scorbutic fish showed hyperplasia of epithelial cells of primary and secondary lamellae, fusion of secondary lamellae, gill cartilage distortion and detachment of the epithelium from the basal membrane of the secondary lamellae. By electron microscopy, degeneration of chloride cells, mucous cells and epithelium cells as well as hyperplasia and edema of epithelium cells were observed.
