Ultrastructural Alterations in Oreochromis niloticus Exposed to Glyphosate-Based Herbicide, Excel Mera 71

Oreochromis niloticus was exposed to Excel Mera 71 for 30 days both at field and laboratory conditions to investigate ultrastructural responses in stomach and intestine through light, Scanning and Transmission Electron Microscopy (SEM and TEM). Stomach showed damage in mucosal folds and gastric glands, fusion of gastric folds under laboratory condition but clumping of nucleus at the base of epithelial cell was observed in field. SEM study displayed cellular lysis, fragmentation of epithelial cells under laboratory condition, while excessive mucin droplets were observed in field. TEM displayed severe deformed mitochondria and Endoplasmic Reticulum (ER), vacuolation but under field condition vacuolations were prominent. Degenerative changes in Columnar Epithelial Cells (CEC) and lamina propria in intestine were observed under light microscopy but under field condition only damage in CEC were seen, while SEM study showed degeneration in CEC and microridge and huge mucus secretion under both conditions. Swelling of mitochondria, deformation and fragmentation in ER were seen under TEM in both conditions, but in field the degree of damages were comparatively less. Results clearly disclosed that responses were more profound in laboratory condition than field and these responses could be considered as potential biomarkers of exposure of agrochemicals like Excel Mera 71.