Addition of Glucomannans to Low-Protein Diets Based on Sorghum-Soybean Meal for Growing and Finishing Pigs

The growth performance of fattening pigs fed sorghum-soybean meal, low-protein diets (LPD) has been inconsistent; some times the productive variables do not change, but other times they are deteriorated. In addition, because the sorghum grain represents the main ingredient, it is likely that the diet has higher amounts of mycotoxins than standard diets or diets formulated with corn grain. So, two experiments were conducted with growing-finishing pigs to determine the effect of a mycotoxin sequestrant (MSEQ) added to standard or LPD on growth performance, carcass characteristics, and plasma urea nitrogen concentration. In the growing experiment, 40 growing (22.18 0.82 kg) barrows were used in a randomized complete block design in a factorial (2x4) arrangement: two levels of crude protein (CP: 16 and 11.5%) and four levels of micotixins sequestrant (glucomannans; 0, 0.5, 1.0, 1.5 kg t(-1)), with five replicates per treatment. Lowering CP reduced (P <= 0.05) average daily gain (ADG) and fat free lean gain (FFLG), and increased (P <= 0,05) feed:gain ratio. In the finishing experiment, 40 finishing (49.48 +/- 1.10 kg) barrows were used in a randomized complete block design in a factorial (2x4) arrangement: two levels of CP (14 and 9.5%) and four levels of micotoxins sequestrant (glucomannans; 0, 0.5, 1.0, 1.5 kg t(-1)), with five replicates per treatment. Diminishing CP reduced (P <= 0.05) ADG, average daily feed intake, and FFLG. The addition of glucomannans to low-protein diets did not affect growth performance in both experiments. It was concluded that adding glucomannans as mycotoxins sequestrant does not improve productive variables in pigs fed low-protein diets, but it produces similar carcass characteristics as in pigs fed standard diet, except the lower FFLG.