title: Protective effect of in ovo treatment with the chicken cathelicidin analog D-CATH-2 against avian pathogenic E. coli.
abstract: Increasing antibiotic resistance and ever stricter control on antibiotic use are a driving force to develop alternatives to antibiotics. One such strategy is the use of multifunctional Host Defense Peptides. Here we examined the protective effect of prophylactic treatment with the D analog of chicken cathelicidin-2 (D-CATH-2) against a respiratory E. coli infection. Chickens were treated with D-CATH-2 in ovo at day 18 of embryonic development or intramuscularly at days 1 and 4 after hatch. At 7 days of age, birds were challenged intratracheally with avian pathogenic E. coli. Protection was evaluated by recording mortality, morbidity (Mean Lesion Score) and bacterial swabs of air sacs at 7 days post-infection. In ovo D-CATH-2 treatment significantly reduced morbidity (63%) and respiratory bacterial load (>90%), while intramuscular treatment was less effective. D-CATH-2 increased the percentage of peripheral blood lymphocytes and heterophils by both administration routes. E. coli specific IgM levels were lower in in ovo treated animals compared to intramuscular D-CATH-2 treatment. In short, in ovo treatment with the Host Defense Peptide derived D-CATH-2 can partially protect chickens from E. coli infection, making this peptide an interesting starting point to develop alternatives to antibiotics for use in the poultry sector.
authors.affiliation: Division of Molecular Host Defence, Department of Infectious Diseases &Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
authors.forename: Tryntsje
authors.initials: T
authors.lastname: Cuperus
authors.affiliation: Division of Molecular Host Defence, Department of Infectious Diseases &Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
authors.forename: Albert
authors.initials: A
authors.lastname: van Dijk
authors.affiliation: Division of Poultry Health, Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
authors.forename: Mieke G R
authors.initials: MG
authors.lastname: Matthijs
authors.affiliation: Division of Molecular Host Defence, Department of Infectious Diseases &Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
authors.forename: Edwin J A
authors.initials: EJ
authors.lastname: Veldhuizen
authors.affiliation: Division of Molecular Host Defence, Department of Infectious Diseases &Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
authors.forename: Henk P
authors.initials: HP
authors.lastname: Haagsman
mesh_terms: D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology*; D002642:Chick Embryo; D002645:Chickens / Q000276:immunology / Q000382:microbiology; D004926:Escherichia coli / Q000276:immunology*; D004927:Escherichia coli Infections / Q000276:immunology / Q000517:prevention & control; D011201:Poultry Diseases / Q000276:immunology / Q000517:prevention & control; D054804:Cathelicidins
chemical_list: D023181:Antimicrobial Cationic Peptides; D054804:Cathelicidins