ABSTRACT

Thirteen pea grain samples from different origins were used to examine the variation in in situ ruminal degradation of crude protein (CP) and starch as well as in vitro gas production (GP) kinetics. In vitro GP was used to estimate the digestibility of organic matter (dOM), metabolisable energy (ME) and utilisable CP at the duodenum (uCP). Protein fractions were also determined according to the Cornell Net Carbohydrate and Protein System. Degradation of CP and starch from all pea grains in the rumen was almost complete, with a high proportion of the instantly disappearing fraction. The variation in the degradation constants among pea grain variants was high, and degradation of CP and starch showed a significant initial lag phase in the rumen. The mean effective degradation (ED) calculated for a rumen outflow of k = 8%/h of CP (EDCP8) was higher than ED of starch (EDST8), averaging 77.0 and 71.5%, respectively, with low variation among variants. A correlation analysis between GP parameters and in situ degradation constants showed no clear relationship, but the rates of in vitro GP and in situ starch degradation were similar. Most of the protein in the pea grains was buffer-soluble with fast and intermediate degradation. Variation in the protein fractions among the pea grain variants was low and not suitable for predicting differences in in situ degradation characteristics. The mean in vitro uCP of pea grains was 198 g/kg dry matter (k = 8%/h) and variation was low and consistent with that of GP kinetics and in situ rumen undegradable crude protein values. The estimation of dOM and ME from 24 h GP led to very high values indicating that the existing prediction equations may not be suitable for pea grains as a single feed.

 抽象的

使用来自不同来源的 13 个豌豆粒样品来检查粗蛋白 (CP) 和淀粉的原位瘤胃降解以及体外产气 (GP) 动力学的变化。体外GP 用于估计十二指肠有机物消化率 (dOM)、代谢能 (ME) 和可用 CP (uCP)。蛋白质组分也根据康奈尔净碳水化合物和蛋白质系统测定。所有豌豆粒中的 CP 和淀粉在瘤胃中几乎完全降解，其中立即消失部分的比例很高。豌豆粒变体之间的降解常数变化很大，并且CP和淀粉的降解在瘤胃中表现出显着的初始滞后期。对于瘤胃流出量 k = 8%/h 的 CP (EDCP8) 计算的平均有效降解 (ED) 高于淀粉 (EDST8) 的 ED，平均分别为 77.0 和 71.5%，且变体之间的差异较小。 GP参数与原位降解常数之间的相关性分析显示没有明确的关系，但体外GP和原位淀粉降解速率相似。豌豆粒中的大部分蛋白质是缓冲液可溶的，具有快速和中等降解。豌豆粒变体之间蛋白质组分的变异较低，不适合预测原位降解特性的差异。豌豆粒的平均体外uCP 为 198 g/kg 干物质 (k = 8%/h)，变化较小，与 GP 动力学和原位瘤胃不可降解粗蛋白值一致。 根据 24 小时 GP 估算的 dOM 和 ME 得出非常高的值，表明现有的预测方程可能不适合作为单一饲料的豌豆粒。