Efecto de la harina de soja de diferentes lotes y de la suplementación con proteasa sobre la digestibilidad ileal de los aminoácidos en pollos de engorde

Resumen

Soybean meal (SBM) is the most common protein source in poultry diets, as it has an excellent profile and high digestibility of amino acid (AA). However, SBM proximate composition may vary due to several factors, the most relevant considering protein quality evaluations and AA composition for broiler, is the thermal processing. Exogenous enzymes are a well-established technique in poultry nutrition for increasing nutrient digestibility. The purpose of this study was to investigate two batches of SBM and exogenous protease on the apparent ileal digestibility (AID) of AA for broilers. A total of 360 male broilers were allocated from 14 to 26 days of age. The animals were assigned in 4 treatments with 9 replications of 10 birds each in a completely randomized design and housed in metabolic battery cages, following a 2 × 2 factorial arrangement, with 2 different SBM batches (A and B) and 2 exogenous protease doses (0 and 50 g/ton of diet). The protease used was a commercial granulated thermostable enzyme that contains 600,000 protease units (NFP)/g. At 26 days, 6 broilers from each replication were euthanized by cervical dislocation, then eviscerated for ileal digesta removal to measure the AID concentrations of essential and non-essential AA. KOH protein solubility was determined in SBM batches. Feed and ileal content analysis of AA composition were performed by high-performance liquid chromatographic. Data were submitted to a two-way ANOVA (P<0.05), and when significant, the averages were compared by Tukey test. The values of KOH protein solubility were 85 % and 75 %, for SBM from batches A and B, respectively. AID coefficient of lysine and methionine were greater in SBM from batch A (table 1, P<0.05), whereas protease supplementation improved other AA AID coefficients (P<0.05), the same effect was reported by Liu et al. (2024) that demonstrated improvements using protease supplementation regardless the SBM. An interaction between SBM batches and protease was observed for tyrosine AID coefficient (P<0.05), where broiler fed with SBM from batch A and B supplemented with protease exhibited greater tyrosine utilization compared to non-supplemented. No interactions were observed for the remaining AA AID coefficients (P>0.05). In conclusion, SBM may impact the digestibility of lysine and methionine, whereas protease supplementation may improve AA utilization, regardless of the SBM type used.