Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE 68503.
Department of Animal Sciences, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH 44691.
J Dairy Sci. 2024 Aug;107(8):5699-5708. doi: 10.3168/jds.2023-24318. Epub 2024 Apr 11.
Lignin is a polyphenolic polymer that is an important factor in limiting fiber digestibility by ruminants. The objective of the current study was to evaluate lignin's effects on whole animal energy utilization in diets similar in NDF content. A low-lignin (LoLig) diet was formulated to contain 32.5% NDF (DM basis) and 9.59% lignin (NDF basis) and the high-lignin (HiLig) diet was formulated to contain 31.0% NDF (DM basis) and 13.3% lignin (NDF basis). These diets were randomly assigned and fed to 12 late-lactation (mean ± SD; 214 ± 14.9 DIM) multiparous Jersey cows (mean ± SD; 435 ± 13.9 kg) in a 2-period crossover design. Cows fed the LoLig treatment consumed more DM than cows on the HiLig diet (mean ± SD; 19.9 vs. 18.7 ± 0.645 kg/d) and the LoLig diet was concurrently of a greater gross energy concentration (mean ± SEM; 4.27 vs. 4.23 ± 0.03 Mcal/kg). As expected, increasing the concentration of lignin resulted in a reduction in total-tract NDF digestibility (45.5% vs. 40.4% ± 0.742%). Increasing lignin also resulted in a reduction in the digestibility of starch (97.7 vs. 96.3 ± 0.420) and CP (65.0 vs. 60.0 ± 0.829). Lignin also decreased the concentration of digestible energy (2.83 vs. 2.63 ± 0.04 Mcal/kg) and ME (2.52 vs. 2.36 ± 0.05 Mcal/kg), but the concentration of NE was similar (1.81 vs. 1.75 ± 0.06 Mcal/kg). Increasing the concentration of lignin also reduced yields of ECM (33.7 vs. 30.0 ± 0.838 kg/d), milk protein (1.00 vs. 0.843 ± 0.027 kg/d), and milk fat (1.30 vs. 1.19 ± 0.058 kg/d). Decreasing the dietary lignin concentration did not affect daily methane emissions, averaging 391 ± 29.6 L/d. Results of this study indicate that feeding a diet greater in lignin decreases the digestibility of nutrients and provides less energy for production responses and that energy supplied from digestible NDF may be less than predicted by some nutrition models.
木质素是一种多酚聚合物，是反刍动物纤维消化的重要限制因素。本研究的目的是评估木质素对类似中性洗涤纤维（NDF）含量日粮中动物整体能量利用的影响。设计了低木质素（LoLig）日粮，其 NDF（干物质基础）含量为 32.5%，木质素（NDF 基础）含量为 9.59%；高木质素（HiLig）日粮，其 NDF（干物质基础）含量为 31.0%，木质素（NDF 基础）含量为 13.3%。这两种日粮以随机方式分配给 12 头泌乳后期（平均±标准差；214±14.9 DIM）的荷斯坦奶牛（平均±标准差；435±13.9kg），采用 2 期交叉设计进行饲喂。与 HiLig 日粮相比，饲喂 LoLig 日粮的奶牛采食量更高（平均±标准差；19.9 比 18.7±0.645kg/d），且 LoLig 日粮的总能浓度更高（平均±SEM；4.27 比 4.23±0.03Mcal/kg）。正如预期的那样，木质素浓度的增加导致了总肠道 NDF 消化率的降低（45.5%比 40.4%±0.742%）。木质素浓度的增加还降低了淀粉（97.7%比 96.3%±0.420%）和 CP（65.0%比 60.0%±0.829%）的消化率。木质素还降低了可消化能量（2.83 比 2.63±0.04Mcal/kg）和 ME（2.52 比 2.36±0.05Mcal/kg）的浓度，但净能的浓度相似（1.81 比 1.75±0.06Mcal/kg）。木质素浓度的增加还降低了 ECM（33.7 比 30.0±0.838kg/d）、乳蛋白（1.00 比 0.843±0.027kg/d）和乳脂（1.30 比 1.19±0.058kg/d）的产量。降低日粮木质素浓度不会影响每日甲烷排放量，平均为 391±29.6L/d。本研究结果表明，饲喂富含木质素的日粮会降低养分的消化率，为生产反应提供的能量减少，且可消化 NDF 提供的能量可能低于某些营养模型的预测。
