Effects of methoxychlor on broiler gut microbiota and liver and its residue accumulation risk to human health

Abstract

Methoxychlor as a persistent organic pollutant poses significant risks to human health and the environment. Most toxicological studies focus on high-dose exposures, which do not reflect typical chronic and low-dose human exposure, necessitating the examination of the cumulative effects of chronic exposure to persistent organic pollutants. Our study exposed broilers to different concentrations of p,p’-methoxychlor (0.01–5 mg/kg) in feed, reflecting the doses commonly used in agricultural practices. The results show that even at low doses, methoxychlor causes liver damage, metabolic disturbances, disrupts the intestinal microbiota, and leads to significant accumulation of residues, particularly in the liver. When methoxychlor contamination in the feed exceeds 0.01 mg/kg, residue levels in the broiler liver surpass the EU-established limit, and the residue levels in the broiler muscle surpass this limit when contamination exceeds 0.2 mg/kg. In addition, methoxychlor disrupts the gut microbiota, causing significant shifts in microbial composition, including a decrease in beneficial bacteria and an increase in potentially harmful taxa. The gut dysbiosis, bioaccumulation potential of methoxychlor and changes in liver metabolic indicators may be associated with the liver pathology observed in this study, warranting further investigation. The harmful consequences significantly impact broiler production, leading to food safety concerns and risks to human health. At similar exposure levels, humans may face health risks comparable to those observed in broilers. This study provides important evidence for establishing strict regulations on methoxychlor residues in food products and assessing the potential risks of low-dose and long-term exposure to methoxychlor.