Applied Research Note: Evaluation of a Bacillus-based direct-fed microbial as a strategy to reduce hydrogen sulfide emissions from poultry excreta using a practical monitoring method

Effective implementation of noxious odor mitigation strategies requires a thorough understanding of production causes, a clear definition of harmful odor limits, and practical and effective methods to measure emissions into the environment. With the increasing demand for poultry products and consequently, intensification of production systems, there is a need for versatile odor remediation approaches. Hydrogen sulfide (H2S) is a pungent noxious gas associated with poultry farms. The presence and intensity of H2S from animal excreta is the result of the dynamic balance of its formation and reduction, under primarily anaerobic microbial fermentation conditions. Unlike other odors such as ammonia, H2S production and emission is a less researched subject. In the present study, a practical monitoring method was devised to evaluate the efficacy of a Bacillus-based microbial product as a strategy to remediate H2S emissions from poultry excreta. The evaluated excreta were preconditioned with distilled water and then incubated for 24 h under controlled temperature before odor measurement. Plastic containers were used as incubation units, and H2S diffusion tubes were used as the monitoring tool. Hydrogen sulfide emitted from the excreta of broilers fed the microbial product was reduced on average by 42.9% compared to a nonmicrobial fed group. Under the current trial conditions, H2S emitted from growing broiler chicken excreta was easily detectable and variation was low. Moreover, the method allowed dynamic and quick H2S monitoring that will further offer tools to the commercial poultry industry for evaluating the effectiveness of feeding strategies in odor remediation.