Evaluation of the efficacy of chitosan nanoparticles loaded Phi KAZ14 bacteriophage in the biological control of colibacillosis in chickens

摘要

Disease inflicted by avian pathogenic Escherichia coli (APEC) causes economic losses and burden to the poultry industry worldwide. In this study, the efficacy of chitosan nanoparticles loaded Phi KAZ14 (C-Phi KAZ14 NPs) as an oral biological therapy for Colibacillosis was evaluated. C-Phi KAZ14 NPs containing 10(7) PFU/ml of Phi KAZ14 (Myoviridae; T4-like coliphage) bacteriophage were used to treat experimentally APEC-infected COBB 500 broiler chicks. C-Phi KAZ14 NPs and Phi KAZ14 bacteriophage were administered orally in a single dose. The clinical symptoms, mortality, and pathology in the infected birds were recorded and compared with those of control birds that did not receive C-Phi KAZ14 NPs or naked Phi KAZ14 bacteriophage. The results showed that C-Phi KAZ14 NP intervention decreased mortality from 58.33 to 16.7% with an increase in the protection rate from 42.00 to 83.33%. The bacterial colonization of the intestines of infected birds was significantly higher in the untreated control than in the C-Phi KAZ14 NPtreated group (2.30x10(9) +/- 0.02 and 0.79x10(3) +/- 0.10 CFU/mL, respectively) (P = 0.05). Similarly, a significant difference in the fecal shedding of Escherichia coli was observed on d 7 post challenge between the untreated control and the C-Phi KAZ14 NP-treated group (2.35x10(9) +/- 0.05 and 1.58x10(3) +/- 0.06 CFU/mL, respectively) (P = 0.05). Similar trends were observed from d 14 until d 21 when the experiment was terminated. Treatment with C-Phi KAZ14 NPs improved the body weights of the infected chicks. A difference in body weight on d 7 post challenge was observed between the untreated control and the C-Phi KAZ14 NP-treated group (140 +/- 20 g and 160 +/- 20 g, respectively). The increase was significant (P = 0.05) on d 21 between the 2 groups (240 +/- 30 g and 600 +/- 80 g, respectively). Consequently, the clinical signs and symptoms were ameliorated upon treatment with C-Phi KAZ14 NPs compared with infected untreated birds. In all, based on the results, it can be concluded that the encapsulation of bacteriophage could enhance bacteriophage therapy and is a valuable approach for controlling APEC infections in poultry.