Lactiplantibacillus plantarum YZ2 Immersion Reduces Chloramphenicol Residues in Common Carp (Cyprinus carpio)

The antibiotic toxicity and risks associated with their residues pose a serious threat to food safety.

The aim of this study is to investigate the mechanism by which probiotic immersion reduces antibiotic residues in common carp.

A chloramphenicol (CAP) enrichment model was established in common carp (Cyprinus carpio), followed by screening for CAP-depleting strains from 6 candidate Lactobacillus strains. A total of 270 Carp (50.01 ± 1.12 g) were then immersed with screened strains for 14 d. CAP residues in tissues and water were monitored using high-performance liquid chromatography. Hepatic Phase I/II enzymes, ATP-binding cassette (ABC) transporters, antioxidant enzymes, and cytokines were analyzed via enzyme-linked immunosorbent assay and reverse transcription quantitative real-time polymerase chain reaction. The involvement of the nuclear factor erythroid 2-related factor 2 (NRF2) signaling pathway in CAP elimination and flesh quality improvement was further validated using the NRF2 activator sulforaphane and the inhibitor VVD-130037. Data were subjected to one-way analysis of variance or Student t test to determine statistical significance.

Natural recovery failed to clear CAP residues within 14 d. In contrast, Lactiplantibacillus plantarum YZ2 immersion significantly accelerated CAP elimination, reducing hepatic and muscular residues by 42% and 38% at day 7, respectively (P < 0.05). Mechanistically, YZ2 likely activated the hepatic NRF2 signaling pathway, which coordinately upregulated Phase I/II enzymes (e.g., cytochrome P450 3A-like, UDP-glucuronosyltransferase-family) and ABC transporters (e.g., abcb3, abcb4), enhancing systemic excretion. Pharmacological activation of NRF2 mimicked YZ2's effects, reducing residues (P < 0.01) and mitigating oxidative stress (total antioxidant capacity increased by 35%, P < 0.05), whereas NRF2 inhibition abrogated these protective benefits. Furthermore, YZ2 enhanced flesh quality by upregulating myogenic regulatory factors (myf5, myod1, myog) and collagen genes (col1a1a, col1a2) (P < 0.05), leading to a 22% increase in myofiber density.

These findings demonstrate that L. plantarum YZ2 facilitates antibiotic depletion and improves muscle quality through an NRF2-mediated hepatic biotransformation and tissue-specific clearance.