Department of Animal and Poultry Science, College of Agriculture and Bioresources, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada.
Department of Animal and Poultry Science, College of Agriculture and Bioresources, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada.
Animal. 2022 Sep;16(9):100606. doi: 10.1016/j.animal.2022.100606. Epub 2022 Aug 12.
Whole-plant faba bean silage has a high content in indigestible fiber. Improvement of fiber digestibility of faba bean silage would benefit animal production. However, there is no study on pretreating fibrolytic enzyme in whole-plant faba bean silage-based diet for dairy cows on animal performance. The objectives of this study were to evaluate the effects of pretreating whole-plant faba bean silage-baseddiet with fibrolytic enzyme (a mixture of xylanase and cellulase; AB Vista, UK) derived from Trichoderma reesei(FETR) on lactational performance, digestibility, ruminal fermentation characteristics, and feeding behavior of dairy cows. The animal trial was conducted using eight lactating Holstein cows (BW = 710 ± 44 kg and Days in Milk (DIM) = 121 ± 17 days) with four levels of FETR (0, 0.5, 0.75, and 1.0 mL of FETR/kg DM of silage) in a replicated Latin square design. These enzyme treatments were selected based on the previous in situ and in vitro findings that showed positive responses to the whole-plant faba bean silage. The enzyme treatments were directly applied on the silage prior to mixing process. The total mixed rations contained 31% of faba bean silage, 14% of grass hay, 3.5% of straw, 30% of barley and corn grain and 21.5% of concentrate. There was no significant difference of applying FETR on nutrient intake (P > 0.05) except for CP intake, which was reduced in FETR group compared to control (P < 0.01, 4.4 vs 4.54 kg/d). There was a linear effect found in NDF digestibility when treated with FETR, where maximum improvement was achieved with 0.5 mL of FETR application. The milk fat yield, percentage of milk fat and fat-corrected milk were linearly affected by the increasing level of enzyme. The cows fed a diet supplemented with enzymes tended to have a lower milk fat. Feed efficiency linearly responded to incremental levels of FETR. There was no enzyme effect on feeding behavior and nitrogen balance and utilization. Results from this study indicated that supplementing fibrolytic enzyme on whole-plant faba bean silage diets for dairy cows improved lactational performance, intake and digestibility with 0.5 mL of FETR application. However, adding higher enzyme level resulted in negative effects on animal performance.
整株羽扇豆青贮饲料中含有大量不可消化纤维。改善羽扇豆青贮饲料的纤维消化率将有利于动物生产。然而，目前还没有研究在奶牛生产中用纤维分解酶预处理整株羽扇豆青贮饲料对动物性能的影响。本研究的目的是评估用纤维分解酶（木聚糖酶和纤维素酶的混合物；AB Vista，英国）预处理整株羽扇豆青贮饲料（来源于里氏木霉（FETR））对泌乳奶牛的泌乳性能、消化率、瘤胃发酵特性和采食量的影响。该动物试验采用 8 头泌乳荷斯坦奶牛（BW=710±44kg，泌乳天数（DIM）=121±17d）进行重复拉丁方设计，用 4 个 FETR 水平（青贮饲料干物质的 0、0.5、0.75 和 1.0ml）处理。这些酶处理是根据以前的原位和体外研究结果选择的，这些结果表明对整株羽扇豆青贮饲料有积极的反应。在混合过程之前，直接将酶处理应用于青贮饲料。全混合日粮含有 31%的羽扇豆青贮饲料、14%的干草、3.5%的秸秆、30%的大麦和玉米谷物和 21.5%的浓缩饲料。除 CP 摄入量外，应用 FETR 对养分摄入量没有显著影响（P>0.05），与对照组相比，FETR 组 CP 摄入量减少（P<0.01，4.4 比 4.54kg/d）。用 FETR 处理时，NDF 消化率呈线性变化，最大改善发生在应用 0.5ml FETR 的情况下。牛奶脂肪产量、牛奶脂肪百分比和脂肪校正奶线性受酶添加水平的影响。用酶补充饲料的奶牛牛奶脂肪含量趋于降低。饲料效率线性响应于 FETR 的递增水平。酶对采食量行为和氮平衡和利用率没有影响。本研究结果表明，在奶牛的整株羽扇豆青贮饲料日粮中添加纤维分解酶可提高泌乳性能、采食量和消化率，应用 0.5ml FETR。然而，添加更高的酶水平会对动物性能产生负面影响。
