# Highly Specific Polyphenolic Colloids as Alternatives to Antimicrobials in Livestock Production

## TL;DR

This study explores using polyphenolic colloids as a safe and effective alternative to antibiotics in livestock to combat antimicrobial resistance.

## Contribution

The study introduces cost-effective, stable polyphenolic colloids from wood-processing waste as potential antimicrobial substitutes.

## Key findings

- Colloidal chestnut effectively inhibited S. aureus but not E. coli.
- Colloidal pine showed weak activity against S. aureus but targeted E. coli.
- The colloids demonstrated stability and antioxidant activity suitable for real-world applications.

## Abstract

The dispersion of antibiotics in livestock farming represents a health concern worldwide, contributing to the spread of antimicrobial-resistant bacteria through animals, the environment, and humans. Phenolic compounds could be alternatives to antibiotics, once drawbacks such as their low water solubility, bioavailability, and reduced stability are overcome. Although nano- or micro-sized formulations could counter these shortcomings, they do not represent cost-effective options. In this study, three phenolic compounds, obtained from wood-processing manufacturers, were characterized, revealing suitable features such as their antioxidant activity, size, and chemical and colloidal stability for in-field applications. The minimum inhibitory concentration (MIC) of these colloidal suspensions was measured against six bacterial strains isolated from livestock. These particles showed different inhibition behaviors: Colloidal chestnut was effective against one of the most threatening antibiotic-resistant pathogens, i.e., S. aureus, but ineffective toward E. coli. Instead, colloidal pine showed a weak effect on S. aureus but specificity toward E. coli. The present proof-of-concept points at colloidal polyphenols as valuable alternatives for antimicrobial substitutes in the livestock context.