Assessing the nuclear level impacts upon exposure to Bispyribac–sodium and Carbosulfan in Poecilia reticulata and Aplocheilus parvus

Conventional chemical controlling, due to harmful effects on the environment and animal health, is less appreciated and discouraged today. The impacts to exposed organisms are multiple, but changes at nuclear level can result in long-term impacts to exposed populations. Such chemical exposure can also negatively impact fish that are intentionally introduced to aquatic systems for mosquito vector control. Hence, two types of fish, guppy (Poecilia reticulata) and dwarf panchax (Aplocheilus parvus) used for mosquito control, were tested to the sensitivity to insecticide, Carbosulfan, and weedicide, Bispyribac–sodium in the present study. Lethal average concentration (LC50)was measured for both chemicals. Gills and liver of moribund and survived fish were stained with Heamotoxyin and Eocin to determine the histological changes. Level of cell necrosis was calculated through terminal deoxynucleotidyl transferase-mediated d'UTP nick end labeling (TUNEL) method. The 96h acute LC50 value of Bispyribac-Sodium to A. parvus and P. reticulata were 1.280 mg L-1 and 2.370 mg L-1 respectively. The 96h acute LC50 value of Carbosulfan to A. parvus and P. reticulata were 0.315 mg L-1 and 0.028 mg L-1 respectively. Lamellar fusion, filament and lamellar epithelium proliferation, curling of secondary lamellae, hypoplasia and necrosis in gills were observed in treated fish. The percentage of damaged nuclei in the liver of treated A. parvus to Bispyribac–sodium indicated a significantly higher number of damaged nuclei in all treatments except in the lowest concentration (0.025–0.075 mg L-1) compared to control (P