Galli Gabriela M, Levesque Crystal L, Cantarelli Vinicius S, Chaves Rhuan F, Silva Claudia C, Fascina Vitor B, Perez-Palencia Jorge Y
Department of Animal Science, South Dakota State University, Brookings, SD 57007, USA.
Department of Animal Science, Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
J Anim Sci. 2024 Jan 3;102. doi: 10.1093/jas/skae345.
This study was conducted to investigate the effect of protease inclusion level in two different ages on the apparent (AID) and standardized (SID) ileal digestibility of crude protein (CP) and amino acids (AAs) in soybean meal (SBM) fed to growing-finishing pigs. Ten cannulated pigs (21 ± 2 kg) were assigned to experimental diets in a duplicate 5 × 5 Latin square design. In phase I (23 to 30 kg-pigs, 90 ± 17 d of age), ileal digesta was collected in five periods of 7 d (5 d adaptation and 2 d ileal digesta collection). In phase II, (50 to 65 kg-pigs, 140 ± 17 d of age), ileal digesta was collected in 5 more periods of 7 d. For both phases, a corn starch-based diet was formulated with SBM as the sole source of CP and AA and containing titanium as an indigestible marker. Protease was supplemented at 0, 15,000, 30,000, and 45,000 NFP/kg of feed (0, 25, 50, and 75 g/ton of ProAct 360). A nitrogen-free diet was used to estimate basal ileal endogenous AA losses. Pigs were fed at 4% of their body weight, which was adjusted at the end of each period. Orthogonal polynomial contrasts were used to determine the linear and quadratic effects of dietary protease supplementation in each phase. In phase I, increasing levels of protease resulted in a linear increase (P < 0.10) in SID for the 7/11 indispensable AA (Except Arg, His, Met + Cys, and Trp) and the average of all dispensable AA. In phase II, the SID of Ile, Leu, Met, Met + Cys, Val, the average of all indispensable AA, and 4/7 dispensable AA were quadratically increased (P < 0.10). In most cases, supplementation with 30,000 NFP/kg of feed (50 g/ton) resulted in the greatest increase in AA digestibility. However, the linear response in phase I for some AA suggests that diets for younger pigs could be supplemented with a greater level (45,000 NFP/kg or 75 g/ton of feed). Interestingly, younger pigs had consistently increased (P < 0.10) SID of CP and 15/18 AA (Except Arg, Cys, and Ser), being ~5.6% greater for indispensable AA when compared to older pigs. In conclusion, dietary protease supplementation can increase the SID of AA in SBM in both growing and finishing periods. Pig age can potentially influence AA digestibility, possibly related to a greater ileal endogenous AA flow in younger pigs. However, this fact warrants further investigation.
本研究旨在探讨两种不同年龄阶段添加蛋白酶水平对生长育肥猪饲粮中豆粕粗蛋白（CP）和氨基酸（AA）的表观回肠消化率（AID）和标准回肠消化率（SID）的影响。选用10头安装了回肠瘘管的猪（体重21±2 kg），采用重复5×5拉丁方设计分配到各试验饲粮中。在第一阶段（体重23至30 kg的猪，90±17日龄），分5个7天周期收集回肠食糜（5天适应期和2天回肠食糜收集期）。在第二阶段（体重50至65 kg的猪，140±17日龄），再分5个7天周期收集回肠食糜。两个阶段均配制以玉米淀粉为基础的饲粮，以豆粕作为CP和AA的唯一来源，并添加钛作为不可消化标记物。蛋白酶添加量分别为0、15,000、30,000和45,000 NFP/kg饲料（即0、25、50和75 g/吨ProAct 360）。采用无氮饲粮估算基础回肠内源AA损失。按猪体重的4%饲喂，每个周期末进行调整。采用正交多项式对比分析各阶段饲粮添加蛋白酶的线性和二次效应。在第一阶段，随着蛋白酶添加水平的增加，7/11种必需AA（除精氨酸、组氨酸、蛋氨酸+半胱氨酸和色氨酸外）以及所有非必需AA的平均值的SID呈线性增加（P< 0.10）。在第二阶段，异亮氨酸、亮氨酸、蛋氨酸、蛋氨酸+半胱氨酸、缬氨酸、所有必需AA的平均值以及4/7种非必需AA的SID呈二次增加（P< 0.10）。在大多数情况下，添加30,000 NFP/kg饲料（50 g/吨）时AA消化率提高幅度最大。然而，第一阶段某些AA的线性反应表明，幼龄猪饲粮可添加更高水平（45,000 NFP/kg或75 g/吨饲料）的蛋白酶。有趣的是，幼龄猪CP和15/18种AA（除精氨酸、半胱氨酸和丝氨酸外）的SID始终较高（P< 0.10），与老龄猪相比，必需AA的SID高约5.6%。总之，饲粮添加蛋白酶可提高生长育肥期豆粕中AA的SID。猪的年龄可能会影响AA消化率，这可能与幼龄猪回肠内源AA流量较大有关。然而，这一情况有待进一步研究。
