Study of pathology of Diclobothrium armatum parasite in the gills of farmed Huso huso in Guilan

Diclobothrium armatum is  a host specific parasite , causing various severe damages to the gills , respiratory distress, loss of appetite, weight loss and chronic mortality in sturgeon. The purpose of this study was to identify the various damages caused by parasite invasion in gills of sturgeon. In this research 40 pieces of elephant species weighing 50 to 150 grams were harvested from sturgeon farms from early June until the end of September 2018. Fish were transferred to the aquatic animal health laboratory under the same biological conditions. Clinical laboratory examinations were performed on the skin, fins and gill tissue. They were also scientifically assisted to find out the causes of chronic deaths and the examination of the internal organs of young fish. After observing the parasites, they were isolated in the gills and placed in a 4% formalin solution, and the dehydration, clarification and coloring of them were carried out with Alum Carmine. At the same time, in order to gill pathology caused by parasites, after parasite separation, samples of gill tissue were also sampled and transferred to stabilize the Bowen solution. Then, after dehydration, clarification, paraffinization, cutting, and lamination, they were stained with Haematoxylin Eosin (H & E) method. The results of the clinical observations of the gill showed mucous secretions, gill tissue adhesions, and hyperemia.The results of microscopic studies in parasite-infected gill tissue samples: Adhesion in secondary gill lamela, degeneration, edema, necrosis, hyperemia, hemorrhage, hyperplasia, and destruction of gill tissue.