Addition of Bacillus sp. inoculums in bedding for swine on a pilot scale: Effect on microbial population and bedding temperature

Thermal and microbiological characteristics of beddings for swine were compared according to their depth and of addition of inoculums. Bedding was added to boxes at 0.25 (25D) and 0.50 m (50D), with three treatments: control (no inoculums); T1, with 250 g of Bacillus cereus var. toyoii at 8.4 × 107 CFU; and T2, with 250 g of a pool of B. subtilis, Bacillus licheniformis and Bacillus polymyxa at 8.4 × 107 CFU (250 g for 25D and 500 g for 50D). Mean temperatures were 28.5 ± 3.9 at the surface and 35.2 ± 8.9 inside the beddings. The most probable number (MPN) of thermophilic bacteria was higher for T1 and T2 than for the control (P < 0.05). The MPN of thermophilic bacteria and fungi was greater for D50 than for D25 (P < 0.05). The use of 25D without inoculums is recommended due to the reduction of thermophilic microbiota.