Estimation of Acute Toxicity of Ammonium Sulphate to a Fresh-Water Catfish,Heteropneustes fossilis II. A Histopathological Analysis of the Epidermis

摘要

The toxicity of 4000 ppm(96h LC50 value)of the inorganic fertilizaer ammonium sulphate on the epidermis of Heteropneustes fossilis(H.fossilis)at different intervals of time has been studied.The destruction induced by the ammonium salt is massive.Secretion of a copious amount of slime from the goblet mucous cells leading to their exhaustion and/or shedding and subsequent disappearance is perhaps the first reaction to the toxicity of the irritant.Later,the polygonal epithelial cells of the outermost layer show cyclic stages of necrosis and sloughing followed by their regeneration and repair.The contents of the club cells show enormous shrinkage and condensation with subsequent replacement of their areas with a hazy substance.In the earlier stages of exposure,regeneration takes place quickly,side by side with the degenerative changes at different stages of experimentation.Later after 8 50 10d,the degenerative changes slow down and the epideris appears identical to that of the normal skin.Goblet mucous cells also showed several cyclic increases followed by decreases in number and activity.