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

翻译：蒋辉 校对：上海亘泰实业集团

      玉米DDGS在日粮中的使用常常因为纤维高而受到限制。浸泡纤维降解酶（FDE）后可能会改善饲喂价值。DDGS浸泡或者不浸泡两种商业FDE（A,B）后，我们来评估它的表观回肠消化率（AID），标准回肠消化率（SID）和全消化道表观消化率（ATTD）。

      将350gDDGS，纤维降解酶（对照组无添加）和1.5升水混匀，放到40摄氏度培养24小时，每隔40分钟搅拌15分钟。酶A组（纯组合）给每千克DDGS提供5500U木聚糖酶，1050U的β-葡聚糖酶，而酶B（复合酶）组，每千克DDGS提供1200U木聚糖酶、150Uβ-葡聚糖酶、500U纤维素酶、5000U的蛋白酶，还有其它一些酶活性。分别在0、4、8、24小时时，取样品测定有机酸和pH值。三份半纯和的玉米淀粉日粮，浸泡DDGS作为粗蛋白的唯一来源。混合物中加入0.2%二氧化钛作为指示剂。六头带有回肠插管的猪（20公斤体重）饲喂这三种日粮，采用3×3的拉丁方设计，每个日粮6个重复。猪只被饲喂2.8倍的维持能量需求，自由饮水。每个试验期，猪只日粮调整期7天，此后连续2天收集粪便，2天收集回肠食糜（每天8小时）。

      日粮处理和食糜收集时期对pH值和乳酸浓度没有互作（P>0.05）。随着时间推移，乳酸和乙酸增加，pH值降低（P<0.05）。不同处理粗蛋白、NDF和粗脂肪AID，以及粗蛋白SID没有显著差异（P>0.05）。酶A组DDGS的NDF的ATTD比对照组低，但是粗脂肪的ATTD比对照组和酶B组高（P=0.01）。浸泡后DDGS的消化能值无明显差异，对照组、酶A、酶B组DDGS消化能分别为4095、4039、3974kcal/kg干物质。总之，在研究条件下，浸泡外源酶没有提高纤维和能量消化率。

关键词：玉米DDGS，消化率，纤维，外源酶，浸泡，猪

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.