Poultry by-product feeding as a vector for antibiotic residues and microbiota shifts in yellow catfish ( <i>Pelteobagrus fulvidraco</i> ) aquaculture

Poultry by-products (PBPs) are increasingly used in aquacultural environments and have emerged as a potential source of veterinary antibiotics and pathogens; however, the ecological risks remain unclear. This study investigated tissue-specific accumulation of 34 antibiotics and microbial risks in yellow catfish (<i>Pelteobagrus fulvidraco</i>) following exposure to PBPs. Among the 11 tissues analyzed, the data suggest that over 93% of antibiotic residues may be derived from PBPs, with concentrations ranging from 1.21 to 354.31 ng g^-1, with the highest concentrations observed in bile, kidney, and liver. Bioaccumulation of tilmicosin, enrofloxacin, and florfenicol occurred <i>via</i> both dietary intake and dermal exposure, with log bioaccumulation factor (BAF) values of up to 3.79 for bile. High-throughput 16S rRNA sequencing revealed the consistent occurrence of <i>Acinetobacter</i> and <i>Mycobacterium</i> across fish tissues, feed, and water, with 40% of dominant taxa identified as known or suspected cross-species potentially pathogenic genera. A significant reduction in skin microbiota diversity further indicates a possible risk of exposure-induced dysbiosis. These findings highlight PBPs as vectors of both antibiotic residues and microbial disturbance, underscoring the need for targeted control of PBP-derived risks to safeguard freshwater ecosystem health.