Alison Gelinas' MSc Defence

The effects of novel Bacillus subtilis DFM (BS-9) on growth performance, indices of intestinal health, and cecal microbial composition in broiler chickens challenged with Eimeria

Examining Chair: Dr. Mike Steele

Advisor: Dr. Elijah Kiarie

Adv. Committee Member: Dr. David Huyben

Additional Graduate Member: Dr. Lee-Anne Huber

The shift from antibiotic growth promoter (AGP) use in poultry production has increased the demand for AGP alternatives to promote poultry gut health and performance. Bacillus subtilis DFM produces antimicrobial peptides (AMP) to modulate the cecal microflora and promote growth performance during enteric pathogen challenges. Therefore, the provision of BS-9 (DFM) to broiler chickens with or without (- or +) an Eimeria challenge was evaluated for effects on growth performance and intestinal health parameters (CH 3), as well as its impact on the ceca microbial composition and short-chain fatty acid (SCFA) production (CH 4). The DFM improved broiler body weight, weight gain, and intestinal surface area but did not effect the feed conversion ratio (FCR). However, birds given DFM had similar FCR to control despite the Eimeria challenge due to increased FI (CH 3). Additionally, the DFM effect on members of Firmicutes, particularly from order Clostridiales, appeared interactive, with the greatest reduction in DFM +Eimeria birds. Moreso, DFM birds had reduced members of Clostridiales and altered SCFA production. Overall, DFM mitigated the adverse effects of an Eimeria challenge suggesting potential in modulating enteric ecology in animals experiencing enteric challenges