Bach A, Ruiz Moreno M, Thrune M, Stern M D
Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain.
J Anim Sci. 2008 Jun;86(6):1364-71. doi: 10.2527/jas.2007-0736. Epub 2008 Mar 14.
Eight dual-flow continuous culture fermenters (1.03 +/- 0.05 L) were used to assess differences in microbial degradation of the soluble CP fraction of canola meal (CMSCP), soybean meal (SBMSCP), and fish meal (FMSCP) using a completely randomized design with two 9-d experimental periods and a solution of tryptone as a control treatment (control). All fermenters received the same basal diet (58% ground corn, 40% canary grass hay, 0.4% vitamin-mineral premix, 1% CaCO(3), 0.6% salt on a DM basis) in 8 equal portions daily. During sampling on the last 3 d of each period, 90-mL doses containing soluble CP were infused into the fermenters 30 min after the beginning of the first and last feedings of the day. The total amount of soluble CP supplied by the infusions of FMSCP, CMSCP, and SBMSCP was 3.2 g/d, representing 24% of the daily dietary CP intake. Infusion of FMSCP resulted in the greatest (P < 0.05) NH(3)-N concentration (4.6 +/- 0.40 mg/dL) compared with the other treatments (0.5 +/- 0.40 mg/dL). Microbial N flow (g/d) from the fermenters was also greatest (P < 0.05) with FMSCP (1.42 +/- 0.062) compared with the other soluble CP fractions (1.08 +/- 0.062). The efficiency of microbial protein synthesis tended to be lowest with the control diet, and the efficiency of N utilization was lowest with FMSCP treatment. These results indicate that N was limiting microbial growth in the control diet, and there was more rumen-available N with the FMSCP diet compared with the other dietary treatments. The extent of degradation of the soluble CP fraction from fish meal, soybean meal, and canola meal was determined to be 99, 30, and 37% of soluble CP, respectively. These results indicate that the soluble CP fraction is not 100% degraded in all feeds and that assuming a high degradation extent of the soluble CP fraction from soybean meal and canola meal may result in an underestimation of the supply of undegradable protein from these protein sources.
使用八个双流连续培养发酵罐（1.03±0.05升），采用完全随机设计，设置两个9天的试验期，并以胰蛋白胨溶液作为对照处理（对照），来评估油菜籽粕（CMSCP）、大豆粕（SBMSCP）和鱼粉（FMSCP）中可溶性粗蛋白部分的微生物降解差异。所有发酵罐每天分8等份接受相同的基础日粮（以干物质计，58%玉米粉、40%金丝雀草干草、0.4%维生素-矿物质预混料、1%碳酸钙、0.6%盐）。在每个时期的最后3天采样期间，每天第一次和最后一次喂食开始30分钟后，将含有可溶性粗蛋白的90毫升剂量注入发酵罐。FMSCP、CMSCP和SBMSCP注入的可溶性粗蛋白总量为3.2克/天，占日粮粗蛋白每日摄入量的24%。与其他处理（0.5±0.40毫克/分升）相比，注入FMSCP导致的氨氮浓度最高（P<0.05）（4.6±0.40毫克/分升）。与其他可溶性粗蛋白部分（1.08±0.062）相比，FMSCP处理时从发酵罐流出的微生物氮流量（克/天）也最高（P<0.05）（1.42±0.062）。对照日粮的微生物蛋白质合成效率往往最低，FMSCP处理的氮利用率最低。这些结果表明，氮限制了对照日粮中的微生物生长，与其他日粮处理相比，FMSCP日粮中瘤胃可利用氮更多。已确定鱼粉、大豆粕和油菜籽粕中可溶性粗蛋白部分的降解程度分别为可溶性粗蛋白的99%、30%和37%。这些结果表明，并非所有饲料中的可溶性粗蛋白部分都能100%降解，假设大豆粕和油菜籽粕中可溶性粗蛋白部分的降解程度较高，可能会低估这些蛋白质来源中不可降解蛋白质的供应量。
