豬體外發酵模型和電鏡掃描表明酶制劑可促進DDGS中纖維-淀粉-蛋白的降解

畜牧編輯

　　JAS2015 Vol. 93 No. 3, p. 1039-1051

　　豬體外發酵模型和電鏡掃描表明酶制劑可促進DDGS中纖維-淀粉-蛋白的降解

　　R.Jha, T. A. Woyengo, J. Li, M. R. Bedford, T. Vasanthan and R. T. Zijlstra

　　原文鏈接：https://www.animalsciencepublica ... abstracts/93/3/1039

　　本試驗研究了復合碳水化合物酶單獨酶解或其與蛋白酶合用對玉米DDGS和小麥DDGS豬體外消化模型的影響。三個DDGS樣品，小麥DDGS樣品1（wDDGS1），小麥DDGS樣2（wDDGS2）、玉米DDGS樣1（cDDGS），試驗開始前先經胃蛋白酶和胰蛋白酶處理進行預消化。酶解產物再加入礦物緩沖液，并在體外發酵模型，試驗為3×3因子設計，三個樣品，三個發酵模型（添加新鮮豬糞便發酵、或再增加復合碳水化合物酶、或再增加復合碳水化合物酶和蛋白酶）。測定72小時內產氣量。同時測定揮發性脂肪酸（VFA）含量。DDGS樣品和發酵酶解后的產物通過激光共聚焦顯微鏡測定其組成，并使用掃描電子顯微鏡檢查法觀察其內外結構。干物質基礎下，wDDGS1, wDDGS2, 和cDDGS分別含蛋白35.5%、43.4%和29%，淀粉2.23%、0.51%、6.40%，含可利用賴氨酸0.82%、0.80%、0.89%，含非淀粉多糖24.8、22.5、23.0%。玉米DDGS總產氣量和VFA含量高于小麥DDGS(P< 0.05)。復合碳水化合物酶可增加玉米DDGS的總產氣量和小麥DDGS1的VFA產量(P <0.05)，但是不影響小麥DDGS樣2的產氣量和VFA產量。在復合碳水化合物酶基礎上添加蛋白酶可以降低3個DDGS樣品的總產氣量和VFA產量，增加支鏈VFA的產量。激光共聚焦顯微鏡和掃描電子顯微鏡檢測結果表明DDGS主要是抗性淀粉和非淀粉復合物在生產過程中聚合而成。在體外經豬糞便發酵后，酶解DDGS的顆粒總的來說較未酶解樣品要小。總的來說玉米DDGS顆粒孔隙較小麥DDGS更多，其更容易發酵。小麥DDGS2的可發酵性低于小麥DDGS1，表明發酵的效率取決于顆粒的多孔性和DDGS的來源。蛋白酶降低復合碳水化合物的酶解效率。

　　Enzymes enhance degradation of the fiber–starch–protein matrix of distillers dried grains with solubles as revealed by a porcine in vitro fermentation model and microscopy

　　R. Jha*&#8224;, T. A. Woyengo*, J. Li*22, M. R. Bedford&#8225;, T. Vasanthan* and R. T. Zijlstra 3*

　　Website link: https://www.animalsciencepublica ... abstracts/93/3/1039

　　Effects of treating corn and wheat distillers dried grains with solubles (DDGS) with a multicarbohydrase alone or in combination with a protease on porcine in vitro fermentation characteristics and the matrix structure of the DGGS before and after the fermentation were studied. Three DDGS samples (wheat DDGS sample 1 [wDDGS1], wheat DDGS sample 2 [wDDGS2], and corn DDGS [cDDGS]) were predigested with pepsin and pancreatin. Residues were then subjected to in vitro fermentation using buffered mineral solution inoculated with fresh pig feces without or with a multicarbohydrase alone or in combination with protease in a 3 × 3 factorial arrangement. Accumulated gas production was measured for up to 72 h. Concentration of VFA was measured in fermented solutions. The matrix of native DDGS and their residues after fermentation was analyzed using confocal laser scanning microscopy and scanning electron microscopy to determine internal and external structures, respectively. On a DM basis, wDDGS1, wDDGS2, and cDDGS contained 35.5, 43.4, and 29.0% CP; 2.23, 0.51, and 6.40% starch; 0.82, 0.80, and 0.89% available Lys; and 24.8, 22.5, and 23.0% total nonstarch polysaccharides, respectively. The in vitro digestibility of DM for wDDGS1, wDDGS2, and cDDGS was 67.7, 72.1, and 59.6%, respectively. The cDDGS had greater (P < 0.05) total gas and VFA production than both wheat DDGS. The wDDGS2 had lower (P < 0.05) total gas production than wDDGS1. Multicarbohydrase increased (P < 0.05) total gas production for cDDGS and total VFA production for wDGGS1 but did not increase gas or VFA production for wDDGS2. Addition of protease with multicarbohydrase to DDGS reduced (P < 0.05) total gas and VFA productions and increased (P < 0.05) branched-chain VFA regardless of DDGS type. Confocal laser scanning microscopy and scanning electron microscopy revealed that DDGS were mainly aggregates of resistant and nonfermentable starchy and nonstarchy complexes formed during DDGS production. After in vitro fermentation with porcine fecal inoculum, particles of enzyme-treated DDGS were generally smaller than those of the untreated DDGS. In conclusion, cDDGS had a more porous matrix that was more fermentable than the wheat DDGS. The wDDGS2 was less fermentable than wDDGS1. Multicarbohydrase increased fermentability of cDDGS and wDDGS1 but not wDDGS2, indicating that its efficacy in DDGS is dependent on matrix porosity and DDGS source. Protease hindered efficacy of multicarbohydrase。由企業提供的稿件