College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, PR China.
Animal Nutrition Group, Wageningen University & Research, Wageningen, the Netherlands.
Animal. 2022 Aug;16(8):100595. doi: 10.1016/j.animal.2022.100595. Epub 2022 Jul 27.
We hypothesised that adding a combination of fibrolytic and amylolytic enzymes to the diet of early-lactation dairy cows would improve rumen enzyme activity and bacterial diversity, promote energy metabolism, and benefit milk production in cows. Twenty multiparous early-lactation (90 ± 5 d) Holstein cows with similar body conditions were randomly allocated to control (CON, n = 10) and experimental (EXP, n = 10) groups in a completely randomised single-factor design. The CON was fed only a basal total mixed ration diet, and the diet of the EXP was supplemented with a combination of fibrolytic and amylolytic enzymes at 70 g/cow/d (cellulase 3 500 CU/g, xylanase 2 000 XU/g, β-glucanase 17 500 GU/g, and amylase 37 000 AU/g). The experiment lasted 28 days, with 21 days for adaptation and 7 days for sampling. Enzyme addition increased the activity levels of α-amylase and xylanase, and the ammonia-N concentration (P < 0.05) tended to increase the activity of β-glucanase (P = 0.08) in rumen fluid. However, there was no significant difference in the rumen bacterial richness and diversity, phylum (richness > 0.1%) or genus (richness > 1%) composition between the CON and EXP groups (P > 0.05). A tendency of difference was found between CON and EXP (R = 0.22, P = 0.098) in principal component analysis. Ten genera showed different abundances across the CON and EXP groups (linear discriminant analysis effect size, linear discriminant analysis > 2). EXP increased the ratio of albumin to globulin and the concentrations of total cholesterol and low-density lipoprotein cholesterol (P < 0.05) and tended to increase triglycerides (P = 0.09) in blood. Milk yield, 3.5% fat-corrected milk yield and energy-corrected milk yield increased with enzyme supplementation (P < 0.05). The production levels of milk fat and lactose increased, but the percentage of solids, not fat and protein, decreased in EXP (P < 0.05). Although the DM intake was not affected, the feed efficiency tended to increase (P = 0.07) in EXP. In conclusion, dietary supplementation with a mixture of fibrolytic and amylolytic enzymes on multiparous early-lactation dairy cows increased α-amylase and xylanase activity levels in rumen fluid, enhanced milk performance and tended to improve the feed efficiency in cows.
我们假设在泌乳早期奶牛的日粮中添加纤维分解酶和淀粉分解酶的混合物将提高瘤胃酶活性和细菌多样性，促进能量代谢，并有益于奶牛产奶。将 20 头具有相似体况的初产泌乳（90±5d）荷斯坦奶牛按完全随机单因素设计随机分配到对照组（CON，n=10）和实验组（EXP，n=10）。CON 仅饲喂基础全混合日粮，EXP 日粮添加纤维分解酶和淀粉分解酶混合物 70g/头/d（纤维素酶 3500CU/g、木聚糖酶 2000XU/g、β-葡聚糖酶 17500GU/g 和淀粉酶 37000AU/g）。试验持续 28 天，适应期 21 天，采样期 7 天。添加酶增加了α-淀粉酶和木聚糖酶的活性水平，氨氮浓度（P<0.05）趋于增加β-葡聚糖酶的活性（P=0.08）。然而，CON 和 EXP 组之间的瘤胃细菌丰富度和多样性、门（丰富度>0.1%）或属（丰富度>1%）组成没有显著差异（P>0.05）。在主成分分析中，CON 和 EXP 之间存在差异的趋势（R=0.22，P=0.098）。10 个属在 CON 和 EXP 组之间表现出不同的丰度（线性判别分析效应大小，线性判别分析>2）。EXP 增加了白蛋白与球蛋白的比值以及总胆固醇和低密度脂蛋白胆固醇的浓度（P<0.05），并趋于增加甘油三酯（P=0.09）。添加酶后，产奶量、校正乳脂率和校正乳能量均增加（P<0.05）。乳脂和乳糖产量增加，但 EXP 中固形物而非脂肪和蛋白质的百分比下降（P<0.05）。尽管干物质采食量不受影响，但 EXP 中的饲料效率趋于增加（P=0.07）。总之，在多产泌乳早期奶牛日粮中添加纤维分解酶和淀粉分解酶混合物可提高瘤胃液中α-淀粉酶和木聚糖酶的活性，提高牛奶产奶量，提高奶牛饲料效率。
