Impact of Novel Aeration Strategies on Ammonia (NH3) and Methane (CH4) Emissions and Their Influence on Bacterial Diversity in Swine Farms

Highlights The heat pump kept temperature and humidity stable, cutting severe tail biting cases by 65.6%. The heat pump improved air quality by reducing CH4 and NH3, likely lowering tail biting through a stable environment. The heat pump device altered fecal microbiota function, enhancing NR assimilation and potentially improving air quality. ABSTRACT. Post-weaning is a crucial phase in meat pig breeding, as it involves various social, transport, and environmental stressors. Typically, ventilation and heating in post-weaning rooms are managed separately with air and radiant heaters keeping the temperature stable. However, this separation leads to conflicting air movements, resulting in the accumulation of stale air and potential failure to remove excess moisture and ammonia. This poses a challenge in maintaining temperature compliance and causes added stress for piglets. A study was conducted at the experimental farm of the Regional Chamber of Agriculture of Brittany (France), which focused on two batches of crossbred piglets with docked tails [(Large White x Landrace) x Pietrain] in post-weaning rooms. The objective was to compare the effects of heat pump and infrared radiant heating devices on gas emission, temperature and humidity, animal welfare, and gut bacterial diversity. The results showed that a heat pump system maintains stable temperature and humidity, improving compliance with heating instructions during the growth period. We observed reductions of 65.6% in severe tail biting cases and improved air quality, with lower CH 4 and NH 3 concentrations. Gut bacterial diversity increased in heat pump rooms compared to infrared ones and positively influenced nitrogen and methane metabolisms. This progressive improvement in tail biting, air quality, and microbial differentiation aligns with the Microbial Growth-Based Approach. This study highlights the importance of choosing the right type of heating system in pig weaning to enhance animal welfare without compromising production. It offers potential benefits for ecological sustainability and improved working conditions by reducing greenhouse gas emissions.