Escherichia coli (E. coli) infections pose significant health risks to poultry and humans globally. In the face of antibiotic-resistant strains, metal oxide nanoparticles and plant extracts have emerged as promising alternatives. This study evaluated the effectiveness of copper oxide nanoparticles (CuO-NPs) and black elderberry extract (BEE) against E. coli O78 infection in specific pathogen-free chicks. The birds were divided into four groups: a negative control NC, a positive control (PC; challenged with E. coli O78), CuO-NPs treatment post-challenge, and BEE treatment post-challenge. Various parameters, including clinical signs, organ lesions, bacterial load, biochemical markers, and histopathology, were assessed. Both CuO-NPs and BEE demonstrated a reduction in clinical morbidity, organ damage, and E. coli counts compared to the PC. However, BEE exhibited slightly greater efficacy in alleviating liver and kidney dysfunction. Overall, CuO-NPs and BEE hold therapeutic potential against avian colibacillosis, likely acting through antimicrobial and immunomodulatory mechanisms. These findings underscore the potential of bio-based nanoparticles and plant extracts as safer, multi-modal alternatives to antibiotics for avian colibacillosis. Further optimization and mechanistic studies are needed to support their clinical application. |