Next-generation effects of fetal and lactational exposure to the neonicotinoid pesticide clothianidin on the immune system and gut microbiota.

Recently, the effects of exposure to clothianidin (CLO) on the thymus and gut microbiota have become clear, but no report has examined its next-generation impacts. Pregnant C57BL/6N mice were administered a no-observed-adverse-effect-level dose of CLO until weaning. We examined CLO's effects on the gut microbiota and immune organs of dams and their 3- and 10-week-old male offspring. CLO administration led to several alterations of the top 30 bacterial genera in the gut microbiota in dams and 3-week-old mice. Compared to controls, 10-week-old mice had more thymic Hassall's corpuscles, and both dams and 10-week-old mice had fewer macrophages. These results suggest that fetal and lactational CLO exposure may affect the immune system and gut microbiota of the next generation.