沉积物源镉在福寿螺体内的富集及其对生理特性的影响OA

To elucidate the accumulation and elimination patterns of sedimentary cadmium(Cd)in Pomacea canaliculata and its toxic effects,this study conducted a sediment exposure experiment in which snails were exposed to Cd-contaminated sediment(2.51 μg·g-1)for 14 days,followed by a 14-day depuration period in uncontaminated sediment(0.04 μg·g-1).Cd content in different tissues,as well as the activities of superoxide dismutase(SOD),catalase(CAT),glutathione S-transferase(GST),and glutathione(GSH)content in the visceral mass,were measured.The structure and predicted functional changes of the gut microbiota were analyzed based on 16S rRNA amplicon sequencing.The results showed that the visceral mass had the strongest Cd accumulation capacity,reaching 0.11 μg·g-1 after 14 days of exposure,without reaching equilibrium.After depuration,Cd residue in the shell remained significantly higher than the initial level.SOD and CAT activities in the Cd-exposed group were significantly higher than those in the control group,while GST activity and GSH content were significantly reduced.Cd stress significantly decreased the Chao1,Observed features,and Shannon indices of the gut microbiota,leading to significant structural separation,characterized by increased abundances of Firmicutes and Fusobacteriota and a decreased abundance of Proteobacteria.Functional prediction revealed that Cd exposure significantly enhanced the biosynthesis pathways of amino acids such as L-isoleucine and L-valine but inhibited the synthesis pathways of lipids such as mannose and oleate.In conclusion,sedimentary Cd can significantly accumulate in the visceral mass of P.canaliculata,induce oxidative stress,reduce gut microbiota diversity,alter its community structure,and reshape metabolic functions,demonstrating multi-level toxic effects of Cd on benthic organisms from host physiology to microecology.