Degradation Kinetics of Carbohydrate Fractions of Ruminant Feeds Using Automated Gas Production Technique
Degradation Kinetics of Carbohydrate Fractions of Ruminant Feeds Using Automated Gas Production Technique
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DOI：
10.5713/ajas.2009.80613
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发表时间：
2009-03-01
期刊：
影响因子：
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通讯作者：
Ha, Jong K.
中科院分区：
文献类型：
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作者：
Seo, S.;Lee, Sang C.;Ha, Jong K.
目前的反刍动物饲养模型需要对饲料成分中碳水化合物部分的消化动力学进行参数化，以估计日粮中营养物质的供应量。使用自动化气体生产技术，统计明确碳水化合物（包括可溶性碳水化合物）的消化率。可以用相对简单的方法来估计。在这项研究中，通过自动气体生产系统测量和记录体外发酵过程中的气体产量，以研究各种反刍动物饲料的碳水化合物部分的降解动力学：玉米青贮饲料、稻草、玉米、大豆皮、豆粕和赖氨酸生产的细胞团（CMLP）。获得了来自饲料样品的未分馏、乙醇不溶性残留物和中性洗涤剂不溶性残留物的气体产量。使用减法方法生成基于康奈尔净碳水化合物和蛋白质系统（A、B1、B2、B3 和 C）碳水化合物方案的碳水化合物组分的气体剖面。将气体分布随时间绘制后，用具有离散滞后的单池指数方程拟合曲线，以获得可用作现代营养模型输入的动力学参数。玉米青贮饲料的分数降解率常数（Kd）分别为11.6、25.7。未分级、A、B1 和 B2 级分分别为 14.8 和 0.8%/h。这些值在统计上得到了很好的估计，通过高 t 值 (>12.9) 进行评估。稻草中碳水化合物组分的 Kd（未分级组分、A、B1 和 B2 组分）分别为 4.8、21.1、5.7 和 0.5%/h。尽管 B2 级分的 Kd 定义不明确，t 值为 4.4，但其他级分的 Kd 显示 t 值高于 21.9。在测试的饲料中，未分级玉米的 Kd 最高（18.2%/h），A 加 B1 分级的 Kd 为 18.7%/h。未分级的大豆皮、A、B1 和 B2 的 Kd 分别为 6.0、29.0、3.8 和 13.8%/h。 B2组分的Kd较大表明大豆皮中的NDF很容易降解。除 B1 分数 (5.7) 外，t 值均高于 20。对于未分级、A 和 B1 级分，豆粕的估计 Kd 分别为 9.6、24.3、5.0%/h。含有少量碳水化合物的 CMLP 发酵产生少量气体（培养 48 小时为 5.6 毫升）。总之，自动化气体生产系统对于估计明确的（t 值> 12）动力学参数和主要供应碳水化合物的各种饲料的可溶性碳水化合物部分的 Kd 是令人满意的。然而，对于某些浓缩物，尤其是粗蛋白含量高的浓缩物，应谨慎使用扣除方法，因为含氮化合物会干扰气体产生。
The current ruminant feeding models require parameterization of the digestion kinetics of carbohydrate fractions in feed ingredients to estimate the supply of nutrients from a ration. Using an automated gas production technique, statistically well-defined digestion rate of carbohydrate, including soluble carbohydrate. can be estimated in a relatively easy way. In this study, the gas production during in vitro fermentation was measured and recorded by an automated gas production system to investigate degradation kinetics of carbohydrate fractions of a wide range of ruminant feeds: corn silage, rice straw, corn, soybean hull, soybean meal, and cell mass from lysine production (CMLP). The gas production from un-fractionated, ethanol insoluble residue and neutral detergent insoluble residue of the feed samples were obtained. The gas profiles of carbohydrate fractions on the basis of the carbohydrate scheme of the Cornell Net Carbohydrate and Protein System (A, B1, B2, B3 and C) were generated using a subtraction approach. After the gas profiles were plotted with time, a curve was fitted with a single-pool exponential equation with a discrete lag to obtain kinetic parameters that can be used as inputs for modern nutritional models. The fractional degradation rate constants (Kd) of corn silage were 11.6, 25.7. 14.8 and 0.8%/h for un-fractioned, A. B1 and B2 fractions, respectively. The values were statistically well estimated, assessed by high t-value (>12.9). The Kd of carbohydrate fractions in rice straw were 4.8, 21.1, 5.7 and 0.5%/h for un-fractioned, A, B1 and B2 fractions, respectively. Although the Kd of B2 fraction was poorly defined with a t-value of 4.4, the Kd of the other fractions showed t-values higher than 21.9. The un-fractioned corn showed the highest Kd (18.2%/h) among the feeds tested, and the Kd of A plus B1 fraction was 18.7%/h. Soybean hull had a Kd of 6.0, 29.0 3.8 and 13.8%/h for un-fractioned, A, B1 and B2, respectively. The large Kd of fraction B2 indicated that NDF in soybean hull was easily degradable. The t-values were higher than 20 except for the B1 fraction (5.7). The estimated Kd of soybean meal was 9.6, 24.3, 5.0%/h for un-fractioned, A and B1 fractions, respectively. A small amount of gas (5.6 ml at 48 ho of incubation) was produced from fermentation of CMLP which contained little carbohydrate. In summary, the automated gas production system was satisfactory for the estimation of well defined (t-value >12) kinetic parameters and Kd of soluble carbohydrate fractions of various feedstuffs that supply mainly carbohydrate. The subtraction approach, however, should be applied with caution for some concentrates, especially those which contain a high level of crude protein since nitrogen-containing compounds can interfere with gas production.