Neem-extract stabilized ZnO nanoparticles effectively treat avian pathogenic E. coli colibacillosis in broilers

The poultry industry faces significant challenges from colibacillosis, an infectious disease caused by avian pathogenic Escherichia coli. Widespread antibiotic use to combat this has fueled a global crisis of antimicrobial resistance, rendering many conventional treatments ineffective. This necessitates the urgent development of novel, non-antibiotic therapeutic strategies. Zinc oxide nanoparticles (ZnO-NPs) offer a promising alternative due to their inherent antimicrobial properties, and stabilization with natural extracts like neem can enhance their efficacy and biocompatibility.

Researchers evaluated neem-extract stabilized ZnO-NPs in 100 one-day-old Cobb broiler chicks, randomly assigned to five groups (n=20). All groups except the negative control were intraperitoneally challenged with avian pathogenic E. coli (3 × 10^8 CFU/0.25 ml) at 10 days of age. Group G3 received colistin sulphate (1 g/5L drinking water), while Groups G4 and G5 were orally treated with 50 mg kg-1 and 70 mg kg-1 of neem-extract stabilized ZnO-NPs, respectively, over five days. Primary endpoints included agar-well diffusion assay for antibacterial activity, growth performance, mortality, serum biochemistry, and histopathology.

Neem-extract stabilized ZnO-NPs demonstrated excellent in vitro antibacterial properties against avian pathogenic E. coli, with inhibition zones comparable to those achieved by colistin sulphate. In the in vivo broiler model, treated groups showed significantly better body weight gain and reduced mortality compared to the untreated infected group (p< 0.001). Biomarkers for liver and kidney function were also normalized after treatment, indicating improved hepatic and renal health. Histopathological examination revealed significant recovery of liver and kidney tissues, alongside a decrease in congestion and leukocytic infiltration, particularly pronounced in the 70 mg kg-1 ZnO-NP treatment group. This suggests a robust organ-protective effect.

The ZnO nanoparticles stabilized with neem extracts exhibited strong antibacterial and organ-protective effects against avian pathogenic E. coli infection in broilers, proving as effective as colistin sulphate.