Pathological (Histological and Ultrastructural) Study in Stomach and Intestine ofHeteropneustes fossilis (Bloch) to Excel Mera 71, a Glyphosate-Based Herbicide

Abstract

Effects of glyphosate-based commercial herbicide, Excel Mera 71 were performed to evaluate the pathological responses in stomach and intestine of Heteropneustes fossilis (Bloch) for duration of 30 days both under rice field and laboratory concentrations. Under light microscopy, stomach showed distortion in columnar epithelial cells (CEC), lamina propria (LP) and gastric glands under both conditions, but the severity of responses were more pronounced under laboratory condition. Severe fragmentation in mucosal folds (MF) and epithelial cells, and excessive mucus secretion were observed under scanning electron microscopic (SEM) study in laboratory study but alterations in stratified epithelial cells and microridges structure were not prominent under field; while deformation in mitochondria and endoplasmic reticulum and cytoplasmic vacuolations were seen under transmission electron microscopic (TEM) observation in both the conditions, but less severe in field study. Intestine showed distortion and fatty deposition in lamina propria, lifting of CEC and loss of brush border structures in laboratory study, while damage only at the tip of the mucosal villi and CEC were observed under field study through light microscopic observation. Under SEM study, degeneration in CEC and excessive mucus secretion over CEC were prominent, while under TEM study deformation and necrosis in mitochondria, severe cytoplasmic vacuolation, necrosis, cytosolic disorganization, and loss of cellular compartmentation were observed in laboratory study, but intestinal epithelium showed normal appearance under field observation. Therefore, present investigation depicted that long-term glyphosate exposure caused stronger pathological alterations under laboratory condition compared with field study and finally, displayed responses could be considered as indicators of herbicidal contamination in aquatic environment.