On‐Farm Slurry Treatment With Bacterial–Enzymatic Bioactivators Reduces Air Pollution in a Pig Growing Unit

ABSTRACT Intensive pig production systems generate large volumes of slurry, which represent a major source of ammonia emissions and environmental pollute. On‐farm strategies capable of improving slurry quality and reducing gaseous emissions are therefore increasingly needed. The study aimed to evaluate the effects of bacterial–enzymatic bioactivators on ammonia emissions, slurry characteristics, and the welfare of pigs during the growing phase. A total of 980 pigs (47.14 ± 3.82 kg) were assigned to two groups: (i) a control group (CTR), without manure treatment; and (ii) a treated group (TRT), which received a multi‐component bioactivator treatment in their pen. Pigs were housed in four pens, two per group, each with an individual manure tank. Slurry samples were collected prior to each emptying event on days 21 (T1), 42 (T2), and 63 (T3). The trial lasted 63 days. The bioactivator influenced several slurry characteristics. Significant treatment × time interactions were observed for P₂O₅, K₂O, dry matter, ash, biochemical oxygen demand (BOD₅), and chemical oxygen demand (COD). In particular, Ammonia, nitrogen and pH revealed lower values in TRT slurry at T2 ( p < 0.05) and at the end of the trial, BOD₅ and COD were significantly lower in TRT slurry than in CTR slurry ( p < 0.05). Microbiota analysis confirmed that the treatment changed the slurry microbial community, with key findings including lower Shannon and InvSimpson indices at T1 ( p < 0.01) but a higher Shannon index at T2 ( p < 0.05). Beta diversity was significantly different between groups at all sampling times. Specifically, taxa such as Lactobacillus and Sphaerochaeta were enriched in the TRT group, while Clostridium sensu stricto and Christensenellaceae R‐7 group were enriched in the CTR group. In conclusion, on‐farm application of bacterial–enzymatic bioactivators improves manure quality and mitigates ammonia emissions without negatively affecting pig welfare.