Lead Acetate-induced Histopathological Changes in the Gills and Digestive System of Silver Sailfin Molly (Poecilia latipinna)

This study aims to investigate the effects of a single sublethal concentration of lead acetate on the gills and digestive system of the silver mollies. After LC50 determination, twenty five mollies were randomly chosen and divided into two groups. The first one served as control; while the second group exposed to 0.8 mg lead acetate/liter of H2O for 96 h. Afterwards fish were anesthetized, dissected out and the gills, liver, pancreas, stomach and intestine were processed for paraffin embedding, stained with haematoxylin and eosin and examined by light microscopy. Lead acetate-exposed fish exhibited a decrease of swimming activity and brilliant silvery body color, accumulation of lead acetate on ovarian surface and an increased secretion of mucus from gills and skin. The gills showed hyperplasia, hypertrophy and destruction of the lamellar architecture, fusion of lamellae and lamellar clubbing. The livers showed disarrangement of hepatic cords, shrinkage of hepatocytes and dilatation of liver sinusoids and extravasation of blood. Hepatopancreas damage included loss of contact between hepatocytes and pancreocytes, lysis of pancreocyte membranes and appearance of pyknotic/apoptotic nuclei. The exocrine pancreas revealed necrosis, increased adipocytes and atrophy of pancreatic acini. The stomach exhibited irregularity, shrinkage and fusion of its microvilli, pyknotic/apoptotic nuclei of microvilli epithelium and atrophy of submucosal zone. The intestinal damage included fusion of intestinal microvilli, necrosis and irregularities of the microvilli cells, microvilli loss, flattening and hypertrophy. The study concluded that lead acetate exposure resulted in severe histopathological changes in the gills and in the selected digestive organs of silver mollies.