Evaluation of abamectin toxicity on some biochemical constituents and osmoregulation in freshwater fish Oreochromis niloticus [Tilapia niloticus]

ABSTRACT

Indiscriment use of pesticides have been elevated the risk of contamination in environment and aquatic organisms. Considering to the previous fact, the present study was done to investigate the alterations of some blood constituents and ionic regulation; as well as the histopathological alterations in tissues of gills and kidneys of freshwater fish, Oreochromis niloticus, following prolonged exposure to sub-lethal concentrations of abamectin insecticide at 14 days. The obtained results showed that abamectin treatment caused hypotriglyceridemia and hyperglycemia in fish exposed to the high concentration [103.68 micro gL[-1]]. In addition, hypercholesterolemia was detected in abamectin-exposed fish [by 50.48 and 103. 68 micro gL[-]] after 14 days of exposure. Also, a marked increase in the creatinine level was observed in abamectin-exposed fish by 103.68 micro gL-1 on day 14, with a significant decline in the level of sodium ions [Na[+]] and a significant elevation in the level of chloride ions [Cl[-]] in fish exposed to low concentration [50.48 micro gL[-1]] of abamectin. In contrast, a significant decrease in the level of chloride ions [Cl[-]] was detected in the high concentration of abamectin. Marked decrease in the level of plasma bound calcium [B.Ca] with hypoproteinemia and hypophosphatemia were recorded in fish exposed to low concentration [50.48 micro gL[-1]] of abamectin. On the contrary, a marked enhancement in the triiodothyronine level [T3] was noticed in fish following exposure to 50.48 micro gL[-1] of abamectin. The histopathological studies on the gills and kidneys revealed necrosis of lamella and infiltration of acidophils leukocyte in gills with degenerative changes in kidney tubules were observed at both concentrations of abamectin