Cadmium Accumulation in the Goat Liver and Kidney Is Partially Promoted by the Upregulation of Metal Transporter Genes

SIMPLE SUMMARY: The pattern of cadmium (Cd) accumulation and the role of metal transport in tissues’ cadmium deposition using Cd from an organic source are not well-clarified in ruminants. The present study results clearly showed that dietary Cd exhibited different deposition rates between goat liver, kidney, and muscle. Cd concentration in the liver, kidney, and muscle of goats fed 1.07 mg Cd/kg of dry matter (DM) for 60 days remained within the scope of (1.0 mg/kg) the food safety standards of China (GB 2762-2017) and the European Commission Regulation 1881/2006 (amended by No. 629/2008). Dietary Cd promoted the expression of metal transporter genes in the liver and kidneys of goats. DMT1, ZIP8, and ZIP14 might play an imperative role in the uptake of Cd in the goat liver and kidney but not in the muscle. ABSTRACT: Metal transporters, including divalent metal-ion transporter-1 (DMT1), Zrt-/Irt-like protein 8 and 14 (ZIP8 and ZIP14), and ferroportin-1 (FPN1), reportedly participate in cellular cadmium (Cd) uptake, but those in farm animals remain unclarified. This study aimed to examine the growth, plasma biochemical indices, Cd accumulation, and expression of metal transporter genes in the liver, kidney, and muscle of goats exposed to rice paddies contaminated with different levels of Cd. Twenty-four goats were randomly assigned across three dietary treatments: 0.23, 0.63, and 1.07 mg of Cd/kg of dry matter (DM) for 60 days. The results showed that dietary Cd exposure increased (p < 0.05) both Cd accumulation and the mRNA expressions of metal transporter genes (DMT1, ZIP, and FPN1) in the liver and kidney but not in the muscle, suggesting dietary Cd exhibited different deposition rates between goat liver, kidney, and muscle. These outcomes suggest that high levels of dietary Cd stimulated the expression of metal transporter genes and thereby enhanced the uptake and accumulation of Cd in the goat liver and kidney. As such, higher Cd concentrations in the liver and kidney observed with Cd diets could be partly explained by upregulation of metal transport genes expression.