Substitution of reference rations by soybean meal over metabolic balances in swines

Abstract

The objective of this study was to evaluate the reference diets and inputs of soybean meal as test ingredient on the metabolic balance in swines. Twenty four crossbred barrows with initial weight of 29.01 ± 3.64kg were used, allotted in a randomized blocks design in a 2x2 + 2 factorial scheme (two reference rations and two levels of substitution for the test food), plus two extra treatments. The methodology used was the total collection of feces, and the urine was daily filtered and collected. Blood samples were obtained from puncture in the jugular vein to evaluate the levels of plasma urea nitrogen. The digestibility and metabolizability coefficients of gross energy were determined, as the digestible and metabolizable energy values and the nitrogen balance. Variations of DCGE mean are associated with differences in the digestibility of the nutrients that make up the organic matter. The average DE values were also significant for both levels of substitution. The best result for nitrogen utilization efficiency (NUE) was obtained for the diet containing the lowest level of CP, since there was a significant interaction (P=0.01) among the factors evaluated, and the replacement with 15% of the test food had the best result. It was concluded that the substitution levels of soybean meal in references diets influenced the digestible energy for swines and test diet containing a crude protein level close to the recommendation provided an optimization in the efficiency of nitrogen utilization.