The antibiotic resistance of Avian Pathogenic E. coli is considered one of the biggest public health concerns worldwide and with the growing necessity to find unconventional approaches for formulating new forms of safe and price of effective antibiotics for monitoring the spread of resisted pathogens globally, zinc oxide (ZnO) has the prospective to influence many aspects because of their antimicrobial efficacy. Therefore, our study is intended to evaluate the in vivo antibacterial activity of the chemically synthesized PEG-6000 coated-ZnO nanoparticles in low (11.6mg/ml) and high (23mg/ml) doses alone and in combination with florfincol and streptomycin, experimentally. The obtained results showed that oral administration of a low dose of ZnO NPs (11.6 mg/ml) alone or with florfincol and streptomycin revealed mild efficacy against APEC infection, while a high dose of ZnO-NPs (23 mg/ml) whether alone or combined with florfincol and streptomycin for 3 days of treatment, gave good improvement, that was confirmed grossly, and by histopathological inspection of the liver and kidney. It could be concluded that not only do PEG-6000 Coated ZnO NPs have a powerful antibacterial effect against APEC in broilers, but they also can enhance the antibacterial activity of resisted antibiotics.

The obtained results showed that oral administration of a low dose of ZnO NPs (11.6 mg/ml) alone or with florfincol and streptomycin revealed mild efficacy against APEC infection, while a high dose of ZnO-NPs (23 mg/ml) whether alone or combined with florfincol and streptomycin for 3 days of treatment, gave good improvement, that was confirmed grossly, and by histopathological inspection of the liver and kidney.

It could be concluded that not only do PEG-6000 Coated ZnO NPs have a powerful antibacterial effect against APEC in broilers, but they also have the ability to enhance the antibacterial activity of resisted antibiotics.