Toxic Effects of Combined Molecule from Novaluron and Diflubenzuron on Paramecium caudatum

2 Abstract: The struggle against the agricultural ravagers was increased in few last years; many products were appeared and destined to kill the harmful insects, of which we did not know their effects on ecosystem and non-target animals. In present work, we try to investigate the ecotoxicological effects of a combined molecule from Novaluron and diflubenzuron; two Insect growth Regulator (IGR) pesticides, on ecosystem and biomasses by the estimation of the growth and respiratory metabolism of Paramecium caudatum as a non-target aquatic organism exposed to these pesticides. The pesticides are tested in vitro by the addition of four concentrations (5,10,15 and 20µg/ml) in strictly controlled conditions, to the culture medium before/after apparition of the protozoan. Paramecium population growth was evaluated by optic density at 600nm method, for the cells number we use the account under an optical microscope, the generation time and number were evaluated, also we evaluated the respiration of Paramecium population by oxygen electrode. Treatment with 5, 10, 15 and 20µg/ml of the molecule affects the growth (proliferation) of Paramecium caudatum in concentration-dependent manner; also it increases the generation time and response percentage in concentration-dependent manner. The respiratory metabolism of protozoan is perturbed at four concentrations, noting that the oxygen consumption was increased at 10 and 15µg/ml, contrarily to the other two concentrations, which they had an inhibition effect especially for 20µg/ml of pesticide.