Apparent Ileal Digestibility of Energy, Nitrogen, and Amino Acids of Soybean Meals of Different Origin in Broilers

Abstract

The coefficient of apparent ileal digestibility (CAID) of DM, gross energy (GE), N, and amino acids (AA) of 6 soybean meal (SBM) samples were compared in 21-d-old broilers. In addition, the digestibility of DM and N of diets that contained these SBM were tested in vitro. Four of the SBM were of South American origin, had a CP content varying from 45.2 to 47.2% and a trypsin inhibitor activity (TIA) varying from 4.1 to 6.5 mg/g, and were collected from local traders. The other 2 SBM were from US origin; one was a branded product with 48.6% CP and 1.8 mg of TIA/g and the other was obtained from soybeans of US origin that were dehulled and processed in Spain (50.6% CP and 2.4 mg of TIA/g). The experimental design was completely randomized with 6 diets and 6 replicates per treatment. Chicks were fed a commercial diet from 1 to 16 d of age and then their respective experimental diets for 5 d. The diets were based on sucrose and corn starch, with the SBM tested as the only source of protein. At 21 d of age, digesta was collected from the distal ileum and the CAID of nutrients was determined using celite as an indigestible marker. Diets that included the 2 SBM with the greatest CP content had greater CAID of DM (P <or= 0.001), GE (P <or= 0.001), N (P <or= 0.01), and S AA (P <or= 0.001) than the other diets. The regression coefficient (R(2)) between in vitro and in vivo CAID was 0.76 for DM and 0.68 for N (P <or= 0.05). We conclude that DM, GE, N, and AA digestibility varies among SBM samples with the greater values for those samples with the greater CP and lesser TIA. Also, the in vitro test can be used to predict ileal digestibility of DM and N of SBM in broilers.