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

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.

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.

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.

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.