Majallah-i ̒Ilmī-i Shīlāt-i Īrān (Jan 2017)
Histopathological study as bio-indicators for evaluation of water quality in rainbow trout fish farms along the Baram Springs of Lordegan
Abstract
The purpose of this study was to evaluate histopathological changes in gills, spleen, liver, kidney and intestine of farmed rainbow trout in four different stations along the Barm Springs (Lordegan, Iran). In this study, at least 15 fish from each farm were captured and following autopsy, sampling was carried out from the gills, liver, spleen and intestine of fish. After tissue sectioning, samples were stained with hematoxylin and eosin. Tissues were studied at 400X magnification. Gill lamellae that sticking together, gill hyperplasia, exfoliation of gill epithelium, epithelial necrosis and hypertrophy and swelling of gill lamellae, hypertrophy and liver lipoid degeneration, glomerular degeneration, degeneration of collecting duct of urinary system, increasing volume of the lumen space, shrinking of glomerular size, increasing in melanomacrophage centers, disorganization of ellipsoids in the spleen, necrosis of epithelial cells and exfoliation of the mucosal layer of intestine were the major histopathological alterations which were observed in the fourth (less than 20% of the group) and the third (a few of fish) group. The results of this study showed that these alterations may be due to increasing amounts of chemicals in downstream water. Therefore, these histopathological changes can be used as appropriate biomarkers for assessing water quality.
