Soybean meal (SBM) contains anti-nutritional factors (ANF) that may limit kinetics and total extent of protein digestion in pigs. This study evaluated the effects of thermomechanical and enzyme-facilitated (TE) processing on in vitro kinetics of crude protein (CP) digestion and CP and amino acid (AA) digestibility in weaned pigs. Each batch of SBM (48% CP) was divided into two parts: non-processed SBM as control vs. thermomechanical and enzyme-facilitated processed soybean meal (TES) as the experimental group. For digestion kinetics, samples (three batches of non-processed SBM vs. TES) were incubated in triplicate sequentially with pepsin at pH 3.5 for 1.5 h (stomach phase) and subsequently with pancreatin and bile extract at pH 6.8 for 0, 0.5, 1, 2, 4, or 6 h (small intestine phase). Protein was classified into CP_fast, CP_slow, and CP_resistant corresponding to CP digested within the first 0.5 h, from 0.5 to 4 h, and after 4 h plus undigested CP, respectively. Eight weaned barrows (Large White × Duroc, 9.43 ± 0.40 kg) were surgically fitted with a T-cannula at the terminal ileum. Pigs were randomly assigned to a Youden square with three diets over four periods. The three diets were an N-free diet and two diets using 40% SBM or TES as the sole source of AA with Cr₂O₃ as an indigestible marker. Each period included sequentially a 5-d adaptation, 2-d collection of feces, and 2-d collection of ileal digesta. The TE processing reduced ANF content in TES by 91% for lectin, 22% for trypsin inhibitor activity, 75% for β-conglycinin, and 62% for glycinin compared with SBM. In vitro, TE processing increased (P < 0.05) digested CP by 5.6% and enhanced the kinetics of CP digestion by tending to increase (P = 0.056) CP_fast by 25% and reducing (P < 0.05) CP_slow and CP_resistant by 48% and 11%, respectively. In pigs, TE processing increased (P < 0.05) apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of CP in TES by 2.3% and 2.1%, respectively. The TE processing increased (P < 0.05) AID and SID of all AA up to 3.3%, except for AID of Pro and SID of Pro, Gly, and Cys. The TE processing did not change reactive Lys or Lys:CP but increased (P < 0.05) SID of Lys and reactive Lys by 3%. Combined, the greater in vitro digestion kinetics matched the greater in vivo AID and SID of CP in TES and lower ANF compared with SBM. Thus, TE processing created a protein source that is digested faster and to a greater extent than SBM, thereby lowering the chance of protein fermentation.

中文翻译：

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豆粕的热机械和酶促加工增强了断奶猪的蛋白质消化以及蛋白质和氨基酸消化率的体外动力学。

豆粕（SBM）含有抗营养因子（ANF），可能会限制猪的动力学和蛋白质消化的总范围。这项研究评估了热机械和酶促（TE）处理对断奶仔猪粗蛋白（CP）消化，CP和氨基酸（AA）消化率的体外动力学的影响。每批SBM（48％CP）分为两个部分：未加工的SBM作为对照与热机械和酶促加工的大豆粉（TES）作为实验组。对于消化动力学，将样品（三批次未处理的SBM与TES）一式三份依次与胃蛋白酶在pH 3.5下孵育1.5小时（胃阶段），然后与胰酶和胆汁提取物在pH 6.8孵育0、0.5、1 ，2、4或6小时（小肠期）。蛋白质分为CP_快，CP_慢和CP_抵抗分别对应于在前0.5小时，0.5至4小时和4小时后消化的CP以及未消化的CP。八头断奶的公猪（大白×杜洛克，9.43±0.40公斤）在回肠末端用T型插管进行手术安装。在四个时期内，将猪随机分配到有三种饮食的尤登广场。三种饮食为无氮饮食，两种饮食使用40％SBM或TES作为AA的唯一来源，而Cr ₂ O ₃为难消化的标志物。每个时期依次包括5-d适应，2-d粪便收集和2-d回肠消化物收集。与SBM相比，TE加工使TES中的ANF含量对凝集素降低了91％，对胰蛋白酶抑制剂活性降低了22％，对β-伴大豆球蛋白降低了75％，对于大豆球蛋白降低了62％。体外，TE处理增加（P<0.05）5.6％消化CP，并通过倾向于增加（增强CP消化的动力学P = 0.056）CP_快25％和减少（P <0.05）CP_缓慢和CP_抗由分别为48％和11％。在猪中，TE处理使TES中CP的表观回肠消化率（AID）和标准化回肠消化率（SID）分别提高（P <0.05）2.3％和2.1％。除Pro的AID和Pro，Gly和Cys的SID外，TE加工使所有AA的AID和SID增加（P <0.05），达到3.3％。TE处理不会改变反应性Lys或Lys：CP，但会增加（P<0.05）Lys和反应性Lys的SID降低了3％。综合起来，与SBM相比，更大的体外消化动力学与TES中CP的体内AID和SID更高，而ANF更低。因此，TE加工产生的蛋白质源比SBM消化更快，消化程度更高，从而降低了蛋白质发酵的机会。