Principal investigator: Steven Theriault

Coinvestigator: Bradley Cook

Years the work was done: 2019-2023

Overall objective: to evaluate the ability of bacteriophage (phage) to prevent or reduce necrotic enteritis (NE) disease in broiler chickens.

Outcomes:

• Six different treatment groups (27 birds per group) were used to test the effect of phage for preventing NE in broilers. The antibiotic bacitracin (BMD) is typically used for the prevention of NE, so treatments groups included a regular (50g/ton of feed) and lower dose (5g/ ton of feed) of BMD, with and without phage, a control group with neither, and phage alone.
• Broiler chickens were intentionally infected with perfringens, and monitored daily for signs of disease. Birds were assessed daily for signs of disease, and at the end of the study, necrotic enteritis lesions and bacterial presence was evaluated.
• Phage on its own was not very successful at preventing necrotic enteritis, but phage combined with the recommended dose of BMD resulted in improved lesion scores compared to BMD alone; bacteria was undetectable in both the BMD normal dose and BMD normal dose + phage groups.
• When phage was combined with the lower dose of BMD, lesion scores were improved by almost one severity score, and bacterial counts were three times lower, compared to low dose BMD without phage.
• Weight loss and feed gain were similar to one another in the treated groups, and all were better than the untreated groups.

Application: The results of this study show the ability of phages to play a role in antibiotic use reduction; a lower dose of BMD with the addition of phage was comparable to a regular dose of BMD alone with respect to lesion scores. Phage and antibiotic synergy may allow for greater antibiotic conservation.

Funding: This research was supported by Chicken Farmers of Canada and Cytophage Technologies Inc.