Develop technologies to reduce the use of antibiotics in food animal production in low- and middle-income countries
Why this research is being done
Pakistan is the 11th largest producer of poultry in the world. These products provide a high-quality and affordable source of protein to communities throughout the country, many of which are protein-deficient. However, Pakistani poultry production faces numerous threats, from endemic and emerging diseases to extreme weather events. Currently, antibiotics are regularly included in poultry feeds to overcome some of these challenges. Here, we aimed to develop non-antibiotic technologies that could afford producers means to control bacterial infections without contributing to the growing problem of antibiotic resistance in both veterinary and human medicine.

Data
Concentrations of Salmonella Gallinarum (log10 CFU/g of cecal content) in the ceca of birds treated with unprotected phages, encapsulated phages, or a mixture of encapsulated phages and unprotected phages on 1, 2, 4, and 7 days post challenge (dpc)
Treatment groups
Unprotected phageEncapsulated phage
Mixed phage
Control 1
Control 2
P-value
1-dpc
2-dpc
4-dpc
7-dpc
dpc = days post-challenge; Control 1 birds received Salmonella Gallinarum challenge and no phage treatment; Control 2 birds received neither bacterial challenge nor phage treatment; numbers with different superscripts (“a”, “b”, and/or “c”) are statistically different at P < 0.05. Comparisons are within dpc. The “mixed phage” treatment contained equal volumes of unprotected and encapsulated phages.
Concentration of E. coli recovered from cecal contents and lung samples of chickens in all treatment groups
E. coli concentration (log CFU/g)
Treatment groups
1
2
3
4
Cecal contents 0.0 ±0.0 |
Lungs 0.0 ±0.0 |
Cecal contents 0.0 ±0.0 |
Lungs 0.0 ±0.0 |
Cecal contents 0.2 ±0.7 |
Lungs 0.0 ±0.0 |
Group 1) unchallenged birds receiving no phage treatment (-ve control); group 2) APEC challenged birds receiving no phage treatment (+ve control); group 3) unchallenged birds receiving a mixture of unprotected and encapsulated phages; and group 4) APEC challenged birds receiving a mixture of unprotected and encapsulated phages. * = statistically significant (P < 0.05).
Results
We (Purdue University, Sargodha University [Sargodha, Pakistan], University of the Punjab [Lahore, Pakistan]) focused on utilizing bacteriophages to target bacteria associated with fowl typhoid (Salmonella Gallinarum) and colibacillosis (avian pathogenic E. coli [APEC]). Bacteriophages are viruses that are very specific to bacteria; they infect bacteria, replicate, and cause the bacterial cell to burst. The newly replicated phages can then go on to infect and destroy other bacteria. To create prototypes, we isolated bacteriophages from waste water, sewage, and poultry waste in both the US and Pakistan. We characterized these bacteriophages in terms of: 1) the ability of these bacteriophages to kill Salmonella Gallinarum and APEC isolates obtained from diseased chickens in Pakistan; 2) growth of the bacteriophages under different extreme conditions (e.g., low pH); and 3) their genetic sequences. The antibacterial efficacy of the two prototypes was then measured in live animals receiving experimental Salmonella Gallinarum or APEC infections. In both cases, the prototypes reduced colonization of the targeted bacteria by up to 99.999%. Importantly, chickens receiving the phage prototypes grew at rates equal or greater than untreated chickens and the prototypes caused no significant changes in the overall chicken microbiome. Finally, we found that chickens do not produce an appreciable antibody response to the phages, indicating that the treatment could be used multiple times during the broiler production cycle.
In collaboration with agricultural economists, we also conducted a national-level willingness-to-pay study to better guide commercialization of the prototypes. We found that Pakistanis are very accepting of the use of "viruses" to control bacterial infections in poultry and would pay a premium for products from chickens treated with bacteriophages instead of antibiotics.
Conclusions
Working with Purdue's Office of Technology Commercialization, we have submitted to full patent applications for the two prototypes (fowl typhoid and colibacillosis) and we are currently working with potential licensees to commercialize both of them. The project was chosen for a second round of funding where we will measure the efficacy of the bacteriophage prototypes in combination with other compounds (e.g., phytochemicals from agro-wastes) to prevent fowl typhoid and colibacillosis in large-scale animal trials taking place in Pakistan. At the same time, we are using behavior theory to identify barriers to adoption of the technology and how those barriers can be lowered.
Contact information
Paul Ebner pebner@purdue.edu | 765-494-4820 | Purdue ANSC Directory