Estudo dos processos de compostagem no sistema de produção de suínos sobre cama

• Autor(a) principal: Corrêa, Érico Kunde
• Data de Publicação: 2007
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFPel - Guaiaca
• Texto Completo: http://guaiaca.ufpel.edu.br/handle/123456789/1230
• topic: Biotechnology; Veterinary; Litter; Depth; Temperature; Physical and chemical characteristics; Microbial populations; Swines; Biotecnologia; Veterinária; Cama; Profundidade; Temperatura; Características físico-químicas; Microbiota; Suíno; CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA::REPRODUCAO ANIMAL

Deep litter systems (DLS) have lower facility cost and less environmental impact than conventional swine production systems, but the animal thermal comfort may not be ideal, during warm seasons. This thesis studied the effect of the use of litters having different depths on indicators of environmental comfort, animal growth performance and physical, chemical and microbiological characteristics of the litter. Three treatments were compared: solid concrete floor (control); litter of rice husk with depth of 0.25 (L25) and 0.50 m (L50). The first liter was used in two lots and replaced by a second litter used in other two lots. The environmental conditions were determined by the relative humidity of the air (RH), atmospheric temperature (AT) and litter temperature at the center of the pen, both in the surface (TSF) and at half of the depth (THD). Feed intake, weight gain and feed conversion for the pigs raised on DLS were also estimated. Concentrations of thermophilic and mesophilic bacteria, fungi and actinomycetes were determined by the most probable number method. TSF was lowest in the control group (P < 0.05), but it did not differ between C25 and C50 (P > 0.05). TSF was higher for new than for used litters and for the first than for the second litters (P < 0.05). The highest levels of N, P and K found in the L25 indicate that its compost has greater agronomical values. The concentration of mesophilic bacteria was higher in L50 than in L25 (P < 0.05). Although no statistical comparison was performed for growth performance parameters, feed conversion was similar for pigs in the control and DLS groups, with an apparent advantage for L25. This thesis also studied the effect of the addition of inoculums, in a pilot scale, on litters similar to those used in DLS, on the parameters mentioned above. The experimental units were boxes having area equal to 1 m2., on which litter of rice husk was added at the depths of 0.25 (L25) and 0.50 m (L50). On a daily basis, 6.4 l of swine dejects were added to the boxes, which consisted of three treatments: control without inoculums (T1); inoculation of 250 g of Bacillus cereus var. tyoii with 8,4 x 107 UFC/g (T2); and inoculation of 250 g of EnziLimp with 8,4 x 107 UFC/g (T3). Concentration of mesophilic and thermophilic bacteria, fungi and actinomycetes were determined and the chemical characteristics of the litter were evaluated. The addition of inoculums allowed higher concentration of thermophilic bacteria than in the control group (P < 0.05), so it would not be recommended for DLS. There was a higher concentration of thermophilic bacteria and fungi in the first lot of L50 (P < 0.05). Increased N level had a negative association with the concentration of all the thermophilic microbial populations (P < 0.05). Therefore, L25 can be recommended as a feasible option for DLS because it is associated with reduced concentration of thermophilic microbial populations in the litter, which leads to better thermal comfort for the pigs, without negative effects for growth performance, also generating compost having high agronomical value.