Submitted to: Poultry Science
Publication Type: Abstract Only
Publication Acceptance Date: June 1, 2007
Publication Date: July 1, 2007
Citation: Huff, W.E., Huff, G.R., Rath, N.C., Donoghue, A.M. 2007. Immune interference with bacteriophage efficacy to treat colibacillosis in broiler chickens [abstract]. Poultry Science. 86(1):565. Technical Abstract: Bacteriophage are viruses that kill bacteria, and may provide a natural and safe alternative to antibiotics. Colibacillosis is an important poultry disease caused by Escherichia coli. Previous work has indicated that bacteriophage could be used to both prevent and treat colibacillosis. However, bacteriophage may illicit an immune response in poultry, which could limit their effectiveness to treat bacterial diseases. The experimental design to investigate this possibility consisted of 5 treatments with 3 replicate floor pens of 20 birds per pen. The treatments were control, birds administered bacteriophage at 10 and 17 d of age, birds challenged with E. coli at 17 d of age, birds challenged with E. coli and administered bacteriophage at 17 d of age, and birds administered bacteriophage at 10 and 17 d of age and challenged with E. coli at 17 d of age. Five extra birds were placed in the pens of the control and only administered bacteriophage treatments. These extra birds were bled and euthanizied at 17 d of age and serum collected for viral neutralization assay development. All remaining birds were necropsied at 31 d of age. Bacteriophage were administered into the thigh muscle providing 6.7 X 10**8 pfu. The birds were challenged with an airsac inoculation of E. coli delivering 1 X 10**6 cfu per bird. Mortality was significantly reduced by bacteriophage from 55% in the E. coli treatment to 8% in the bacteriophage treated birds, and reduced, but not significantly, to 33% in the birds that were administered bacteriophage 7 d prior to the E. coli challenge, and consequently treated with bacteriophage. Bacteriophage neutralization assays suggest that the activity of bacteriophage was compromised by the bird’s immune response to the bacteriophage. Although bacteriophage can be developed as an alternative to antibiotics for specific applications, bacteriophage efficacy to treat bacterial diseases may be affected by repeated intramuscular administration of bacteriophage due to immune interference.