Chloroxylenol disrupts Rana chensinensis tadpoles metabolic homeostasis via gut microbiota-dysregulated: A multi-omics perspective

Chloroxylenol (para‑chloro-meta-xylenol, PCMX), a widely used disinfectant with increasingly detected in aquatic systems, poses understudied risks to aquatic organisms, particularly regarding intestinal health. This study systematically evaluated the multilevel toxicity of environmentally relevant PCMX concentrations (1.43, 14.3, 143 μg/L) in Rana chensinensis tadpoles through chronic exposure from Gosner stage 26 to 38. Following chronic exposure PCMX induced morphological changes, intestinal histopathological damage and decreased the activities of intestinal digestive enzymes (α-amylase, pepsin, trypsin). 16S rRNA sequencing revealed that PCMX exposure altered the structure and composition of tadpole intestinal microbiota. Transcriptomic analysis identified disruptions in smooth muscle contraction regulators and metabolic pathways, which had a negative impact on tadpole growth and development. These multilevel disruptions collectively suggest that PCMX interferes with nutrient absorption, microbial homeostasis, and metabolic regulation, impairing tadpole gut health and ultimately disrupting normal amphibian development. This study provides novel evidence that chronic PCMX exposure at environmentally relevant concentrations compromises amphibian larval development, highlighting the need for enhanced environmental monitoring and regulatory considerations.