Microplastics induce liver inflammation in cattle through the rumen microbiota-gut-liver axis

Area of Science:

• Veterinary Medicine
• Environmental Science
• Toxicology

Background:

• Microplastic (MP) pollution is prevalent in livestock environments, impacting animal health and potentially entering the food chain.
• Polyethylene (PE) MPs are common in ruminant feed, but their specific effects on cattle remain understudied.
• MP exposure can compromise the gastrointestinal barrier, alter gut microbiota, and cause organ damage.

Purpose of the Study:

• To investigate the toxic effects of MP exposure in cattle, focusing on the rumen microbiota-gut-liver axis.
• To elucidate the mechanisms by which MP induce toxicity in calves.
• To assess the impact of MP on cattle growth, liver health, and systemic inflammation.

Main Methods:

• Utilized calves as an animal model to study MP exposure effects.
• Analyzed weight gain, liver development, and histopathology.
• Performed blood analysis for lipopolysaccharide (LPS) and inflammatory markers.
• Assessed rumen, jejunum, and colon barrier integrity.
• Conducted rumen fluid metabolomics and liver transcriptomics.

Main Results:

• MP exposure impaired weight gain and liver development, with the liver identified as the primary target organ.
• MP disrupted rumen microbiota, damaged intestinal barrier integrity, and increased LPS levels, triggering systemic inflammation.
• MP altered lipid homeostasis and nutrient composition in muscle tissue, promoting LPS deposition.
• The TLR4/MyD88/NF-κB signaling pathway was identified as central to MP-induced liver inflammatory injury.

Conclusions:

• Microplastics impair liver function in cattle by disrupting the rumen microbiota-gut-liver axis.
• Perturbation of rumen flora and intestinal barriers leads to LPS translocation and subsequent liver damage.
• MP pollution poses a significant risk to cattle health and potentially the food chain.