Youngji Rho, Elijah Kiarie, and Cornelis (Kees) F. M. de Lange

翻譯：蔣輝 校對：上海亙泰實業(yè)集團

      玉米DDGS在日糧中的使用常常因為纖維高而受到限制。浸泡纖維降解酶（FDE）后可能會改善飼喂價值。DDGS浸泡或者不浸泡兩種商業(yè)FDE（A,B）后，我們來評估它的表觀回腸消化率（AID），標(biāo)準(zhǔn)回腸消化率（SID）和全消化道表觀消化率（ATTD）。

      將350gDDGS，纖維降解酶（對照組無添加）和1.5升水混勻，放到40攝氏度培養(yǎng)24小時，每隔40分鐘攪拌15分鐘。酶A組（純組合）給每千克DDGS提供5500U木聚糖酶，1050U的β-葡聚糖酶，而酶B（復(fù)合酶）組，每千克DDGS提供1200U木聚糖酶、150Uβ-葡聚糖酶、500U纖維素酶、5000U的蛋白酶，還有其它一些酶活性。分別在0、4、8、24小時時，取樣品測定有機酸和pH值。三份半純和的玉米淀粉日糧，浸泡DDGS作為粗蛋白的唯一來源。混合物中加入0.2%二氧化鈦作為指示劑。六頭帶有回腸插管的豬（20公斤體重）飼喂這三種日糧，采用3×3的拉丁方設(shè)計，每個日糧6個重復(fù)。豬只被飼喂2.8倍的維持能量需求，自由飲水。每個試驗期，豬只日糧調(diào)整期7天，此后連續(xù)2天收集糞便，2天收集回腸食糜（每天8小時）。

      日糧處理和食糜收集時期對pH值和乳酸濃度沒有互作（P>0.05）。隨著時間推移，乳酸和乙酸增加，pH值降低（P<0.05）。不同處理粗蛋白、NDF和粗脂肪AID，以及粗蛋白SID沒有顯著差異（P>0.05）。酶A組DDGS的NDF的ATTD比對照組低，但是粗脂肪的ATTD比對照組和酶B組高（P=0.01）。浸泡后DDGS的消化能值無明顯差異，對照組、酶A、酶B組DDGS消化能分別為4095、4039、3974kcal/kg干物質(zhì)?？傊?，在研究條件下，浸泡外源酶沒有提高纖維和能量消化率。

關(guān)鍵詞：玉米DDGS，消化率，纖維，外源酶，浸泡，豬

Nutritive value of corn distiller’s dried grains with solubles steeped without or with exogenous feed enzymes for 24 h and fed to growing pigs

Youngji Rho, Elijah Kiarie, Cornelis (Kees) F M de Lange

The use of corn distillers dried grains with solubles (DDGS) in pig dietsis limited due to high fiber concentration. Steeping with exogenous fiber-degradingenzymes (FDE) may improve their feeding value. We evaluated apparent ilealdigestibility (AID), standardized ileal digestibility (SID), and apparent totaltract digestibility (ATTD) of components and DE content in DDGS steeped withoutor with two commercial FDE (A and B). Mixture of 350 g of DDGS, FDE (none forcontrol), and 1.5 liters of water was incubated at 40 °C for 24 h with 15 minagitation every 40 min. FDE-A (pure combination) supplied 5,500 U of xylanaseand 1,050 U of β-glucanase while FDE-B (multienzyme complex) supplied 1,200 Uof xylanase, 150 U of β-glucanase, 500 U of cellulase, and 5,000 U of proteaseper kg of DDGS plus side activities. Samples were taken at time 0, 4, 8, and 24h for organic acids and pH measurements. Three semi-purified corn starch–baseddiets were formulated with steeped DDGS as the sole source of CP. The basalmixture contained 0.2% TiO2 as indigestible marker. Six ileal-cannulated pigs(20 kg BW) were fed the three diets in a replicated 3 × 3 Latin square designto give six replicates per diet. Pigs were fed at 2.8× maintenance energyrequirements and had free access to water. In each period, pigs were adjustedto diets for 7 d followed by 2 d for grab fecal and 2 d of 8 h continuous ilealdigesta collection. There were no (P > 0.05) treatment and sampling timeinteraction or treatment effects on pH and lactic concentration. Lactic andacetic acids increased, and pH decreased (P < 0.05) over time points. TheAID of CP, NDF, and crude fat and SID of CP were not different (P > 0.05)among treatments. Steeping DDGS with FDE-A had lower (P = 0.01) ATTD of NDFthan control but higher (P = 0.001) ATTD of crude fat compared with the controlor DDGS steeped with FDE-B. Values for DE content in steeped DDGS were not different(P > 0.05) and amounted to 4,095, 4,039, and 3,974 kcal/kg DM for thecontrol, FDE-A, and FDE-B, respectively. In conclusion, under conditions of thestudy, steeping DDGS with exogenous enzymes did not improve fiber and energydigestibility.