3. Result
3.1. Microscopical and histopathological observations
The external clinical symptoms of L. vannamei with black gill infection were observed as black colour appearance on the surface of the gill.
The normal gill of L. vannamei, and conidia of attached fungal were encapsulated at the base of the gill observed in the infected shrimp under light microscope (Fig. 1). The results of histological examination evidenced that the normal gill lamella.
Cross-section of haemocoel in gill tissue, and encapsulated hyphae were observed in the gills and at the base of the gills haemocytic infiltration is surrounded by large amounts of substances caused by coagulation necrosis (Fig. 2).