Total and differential white blood cell counts in Caiman latirostris after in ovo and in vivo exposure to insecticides

Abstract

Agricultural activities associated mainly with soybean crops affect the natural environment and wildlife by habitat destruction and the extensive use of agrochemicals. The aim of this study was to evaluate immunotoxic effects of the insecticides cypermethrin (CYP) and endosulfan (END) in Caiman latirostris analyzing total blood cell count (TWBC) and differential white blood cell count (DWBC) after in ovo and in vivo exposure. Eggs (in ovo) and hatchlings (in vivo) from nests harvested in natural habitats were artificially incubated and reared under controlled conditions in the Proyecto Yacaré (Gob.Santa Fe/MUPCN) facilities. Exposure of embryos was performed by topication on the eggshell during the first stage of development. The treatments were distilled water (negative control; NC), ethanol (vehicle control; VC), four groups treated with different concentrations of CYP and four groups with END. In vivo exposure was performed by immersion; treatments were NC, VC, two groups exposed to CYP and two to END. After embryonic exposure to the insecticides, no differences were found in TWBC or DWBC among the neonates exposed to pesticides versus controls. In the in vivo scenario, similar results were obtained for TWBC, but DWBC data showed differences between NC hatchlings and CYP-1 hosts for heterophil, lymphocyte and monocyte levels, and between NC and END-1 hosts for lymphocyte and monocyte levels. Research on the effects of pesticide exposure on this species is of special interest not only to assess the impact on caiman populations, but also to further characterize the species as a potential sentinel of ecosystem health.