Effect of chicken manure amendment on lead burden in mice: exposure to lead‑spiked soil

Abstract

Purpose Adding organic soil amendments, like animal manure, can alleviate the mobility of lead (Pb). However, there is a scarcity of in vivo studies examining the impact of animal manure as a soil amendment on mammals.

Methods Six C57BL/6 mice per group were raised for 30 and 98 days on soil containing 3000 mg Pb/kg. On Pb-spiked soil, chicken manure (40 t/ha) was applied as an immobilizer. Pb concentrations in the tissues were analyzed using ICP-MS after microwave digestion. RT-PCR was used to measure the mRNA expression of antioxidant and cell apoptosis genes in the liver, kidneys, and brain.

Results When chicken manure was used as the immobilizer in Pb-spiked soil, Pb concentrations in the brain, kidneys, and lungs at day 30 were significantly different (p < 0.05) with reduction percentages of 28.58, 26.63, and 25.62, respectively. The brain, kidneys, liver, and bone, except for the lungs and trachea, also showed a similar reducing phenomenon on day 98, with percentages of 11.82, 4.63, 29.87, and 14.54, respectively. There was a significant difference in the levels of Nrf2, HMOX1, SOD1, CAT, BCL2, and Bax in the brain between Pb-exposed and remediated groups after 98 days of exposure.

Conclusions This study highlights that the utilization of chicken manure reduced Pb accumulation in tissues (6.25-28.58% at 30 days and 4.63-29.87% at 98 days). This reduction in Pb accumulation subsequently alleviated the body burden by activating antioxidant genes in the brain, notably HMOX1, SOD1, and CAT.