Zhou X, Zijlstra R T, Beltranena E
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada.
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada Alberta Agriculture and Rural Development, Edmonton, AB T6H 5T6, Canada
J Anim Sci. 2015 Jan;93(1):217-28. doi: 10.2527/jas.2014-7451.
Energy and nutrient digestibility of solvent-extracted canola meal (CM) is limited in pigs by its relatively high fiber content. The seed hull, which greatly contributes to the fiber content of CM, is denser than the oil-free cotyledon. By utilizing streams of air, air classification partially separates these seed components on the basis of their different sizes and densities to produce a low-fiber, light-particle fraction and a high-fiber, heavy-particle fraction. Compared with parent CM, ADF and NDF were reduced by 31.9% and 29.5% in the light-particle fraction and were enriched by 16.5% and 9.0% in the heavy-particle fraction (DM basis), respectively. Particle size was 638, 18.9, and 76.1 µm for the parent CM and light- and heavy-particle fractions, respectively. To determine the nutrient digestibility of CM and their air-classified fractions, Brassica napus and B. juncea CM and their 2 air-classified fractions were evaluated in a 2 × 3 factorial arrangement together with a basal diet and an N-free diet. The experiment was conducted as an 8 × 8 Latin square in which diets contained 40% B. napus or B. juncea CM or their air-classified fractions and 60% basal diet. Digesta data from pigs fed the N-free diet served to subtract basal endogenous AA losses. Eight ileal-cannulated barrows (32 kg initial BW) were fed the 8 diets at 2.7 times maintenance DE for eight 11-d periods. At the end of each period, feces were collected for 48 h, and ileal digesta were collected for two 12-h periods. The DE and calculated NE values and the apparent total tract digestibility (ATTD) of GE were 6.3%, 10.0%, and 7.8% greater (P < 0.001) for B. juncea CM than for B. napus CM; 6.1%, 10.8%, and 5.3% greater (P < 0.001) for the light-particle fraction than for parent CM; and 5.4%, 7.2%, and 3.8% lower (P < 0.001) for the heavy-particle fraction than for parent CM, respectively. The standardized ileal digestibilities (SID) of His, Ile, Val, Asp, and Tyr were greater (P < 0.05) for B. juncea CM than for B. napus CM. The SID of CP and AA were greater (P < 0.01) in the light-particle fraction than in the heavy-particle fraction. The SID of Trp, Glu, Pro, and Tyr were greater (P < 0.05) in the light-particle fraction than in parent CM. In conclusion, B. juncea CM had greater energy and AA digestibility than B. napus CM because of reduced fiber content. Air classification of CM increased its energy and AA digestibility in the light-particle fraction for pigs because of the reduced dietary fiber content and decreased particle size.
溶剂萃取油菜籽粕（CM）的能量和养分消化率在猪中受到其相对较高纤维含量的限制。种皮对CM的纤维含量有很大贡献，其密度比无油子叶大。通过利用气流，空气分级根据种子成分不同的大小和密度部分分离这些种子成分，以产生低纤维、轻颗粒部分和高纤维、重颗粒部分。与亲本CM相比，轻颗粒部分的酸性洗涤纤维（ADF）和中性洗涤纤维（NDF）分别降低了31.9%和29.5%，重颗粒部分则分别增加了16.5%和9.0%（以干物质计）。亲本CM以及轻、重颗粒部分的粒度分别为638、18.9和76.1 µm。为了确定CM及其空气分级部分的养分消化率，对甘蓝型油菜和芥菜型油菜CM及其2个空气分级部分与基础日粮和无氮日粮一起进行了2×3析因试验设计。试验采用8×8拉丁方设计，日粮中含有40%的甘蓝型油菜或芥菜型油菜CM或其空气分级部分以及60%的基础日粮。饲喂无氮日粮的猪的消化物数据用于减去基础内源性氨基酸损失。8头回肠造瘘公猪（初始体重32 kg）以维持能量需求的2.7倍的消化能（DE）饲喂这8种日粮，为期8个11天周期。在每个周期结束时，收集48小时的粪便，并在两个12小时时间段收集回肠消化物。与甘蓝型油菜CM相比，芥菜型油菜CM的DE、计算得出的净能（NE）值和总能的表观全肠道消化率（ATTD）分别高6.3%、10.0%和7.8%（P<0.001）；与亲本CM相比，轻颗粒部分的DE、计算得出的净能（NE）值和总能的表观全肠道消化率（ATTD）分别高6.1%、10.8%和5.3%（P<0.001）；与亲本CM相比，重颗粒部分的DE、计算得出的净能（NE）值和总能的表观全肠道消化率（ATTD）分别低5.4%、7.2%和3.8%（P<0.001）。芥菜型油菜CM的组氨酸、异亮氨酸、缬氨酸、天冬氨酸和酪氨酸的标准回肠消化率（SID）高于甘蓝型油菜CM（P<0.05）。粗蛋白（CP）和氨基酸的SID在轻颗粒部分高于重颗粒部分（P<0.01）。色氨酸、谷氨酸、脯氨酸和酪氨酸的SID在轻颗粒部分高于亲本CM（P<0.05）。总之，由于纤维含量降低，芥菜型油菜CM的能量和氨基酸消化率高于甘蓝型油菜CM。CM的空气分级提高了猪对轻颗粒部分的能量和氨基酸消化率，这是因为膳食纤维含量降低且粒度减小。
