Effects of heavy metal(loid)s on lipid composition in mud crab Scylla paramamosain: A lipidomic approach

Heavy metal(loid)s (HMs) represent significant environmental and health threats due to their persistence, bioaccumulation, and ability to induce oxidative stress and lipid peroxidation (LPO) in aquatic organisms. Here, we present the first lipidome analysis of the mud crab Scylla paramamosain to examine associations between lipid profiles and 12 HMs across three contaminated estuaries in Guangdong Province. We observed pronounced sex-specific differences in both HMs concentrations and lipid composition (P < 0.05). The lipidome showed marked dysregulation of membrane lipids, with glycerophospholipids (52.33%) and sphingolipids (11.9%) predominating, alongside elevated energy-storage lipids such as triacylglycerols (24.35%). Major glycerophospholipid classes included phosphatidylcholines (7.7%), phosphatidylethanolamine (7.49%), phosphatidylserine (6.98%), and phosphatidylglycerol (5.31%), while within the sphingolipid fraction, carnitines (4.43%) and ceramides (>2.26%) were abundant, and saccharolipids such as MGDG were present at low levels (0.07%). Female crabs exhibited significantly higher HMs concentrations and lipid levels than males, with copper (Cu), iron (Fe), and zinc (Zn) being the most abundant. Notably, Cu, Fe, and lead (Pb) showed strong positive correlations with all lipid groups. The associated lipid alterations are consistent with mitochondrial dysfunction and oxidative stress-related pathways commonly linked to HMs exposure. Although sex- and site-specific differences cannot be attributed exclusively to HMs under field conditions. These findings demonstrate the sensitivity of lipidomic profiles to environmental contamination and highlight lipidomics as a powerful tool for assessing ecological risks in HM-contaminated estuarine systems.