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 × 10(7) CFU; and T2, with 250 g of a pool of B. subtilis, Bacillus licheniformis and Bacillus polymyxa at 8.4 × 10(7) 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.

Chemical and microbiological characteristics of rice husk bedding having distinct depths and used for growing-finishing swine.

This study compared the effects of different bedding depths on the chemical and microbiological characteristics of the bedding material used to raise pigs during growing and finishing. The experiment was conducted in two pens housing 5 pigs from 60 to 145 days of age, with rice husk beddings 0.50 or 0.25 m deep. Four lots of pigs (replicates) were raised over time in each bedding depth: each bedding was used by two consecutive lots. Bedding samples were collected quarterly to determine the most probable number (MPN) of thermophilic and mesophilic bacteria, fungi and actinomycetes. Contents of N, P, K, C, organic, mineral and dry matter, C:N ratio and pH were also determined. The MPN of thermophilic bacteria was higher for the 0.50 m than for the 0.25 m bedding (p<0.05). The compost of 0.25 m deep bedding had a higher N, P and K content than that from the 0.50 m bedding (p<0.05). Thus, the use of the 0.25 m deep bedding would be recommended due to its greater agronomical value in comparison with the deeper bedding.