PDF(Pubmed)
Abstract：
The inclusion of fibrolytic enzymes in the diet is believed to have positive effects on animal production. Hence, the objective of this study was to investigate the impact of supplementing diets with a commercial fibrolytic enzyme preparation (Vistamax; mixture of xylanase and cellulase) derived from Trichoderma reesei on lactational performance, digestibility, and plasma nutrient levels in high-producing dairy cows. Two dietary energy levels were considered: a normal energy diet (metabolizable energy = 2.68 Mcal/kg) and a slightly lower energy diet (metabolizable energy = 2.55 Mcal/kg). A total of 120 lactating Holstein cows (parity = 2; Days in Milk = 113 ± 23) were randomly assigned to four treatment groups using a 2 * 2 factorial arrangement. The dietary treatments consisted of: (1) normal energy diet without enzyme supplementation (NL); (2) normal energy diet with enzyme supplementation (NLE); (3) slightly lower energy diet without enzyme supplementation (SL); and (4) slightly lower energy diet with enzyme supplementation (SLE). The amount of enzyme added to the diets was determined based on previous in vitro studies and supplier recommendations. The enzyme and premix were mixed prior to the preparation of the total mixed ration, and the trial lasted for a duration of 42 days. The results indicated that the application of the fibrolytic enzyme did not have a significant effect on dry matter intake (DMI), but it did enhance the digestibility of dry matter (DM), neutral detergent fiber (NDF), potentially digestible NDF (pdNDF), organic matter (OM), milk production, milk urea nitrogen (MUN), and blood urea nitrogen (BUN). On the other hand, the slightly lower energy diet resulted in a decrease in DMI, milk production, milk protein yield, plasma free amino acids (FAA), and an increase in plasma B-hydroxybutyrate (BHBA). In conclusion, the inclusion of the fibrolytic enzyme in the diets of dairy cows led to improvements in the digestibility of DM, NDF, pdNDF, OM, milk production, and feed efficiency. Furthermore, the application of the enzyme to the slightly lower energy diet resulted in milk production levels comparable to those observed in cows fed the untreated normal energy diet.
摘要：
据信在饮食中包含纤维裂解酶对动物生产具有积极影响。因此，这项研究的目的是调查的影响补充饮食与商业纤维酶制剂（Vistamax;木聚糖酶和纤维素酶的混合物）从里氏木霉的泌乳性能，消化率，和高产奶牛的血浆营养水平。考虑了两种饮食能量水平：正常能量饮食（代谢能=2.68Mcal/kg）和略低能量饮食（代谢能=2.55Mcal/kg）。使用2*2阶乘排列将总共120头泌乳荷斯坦奶牛（胎次=2；牛奶中的天数=113±23）随机分配到四个处理组。饮食处理包括：（1）不补充酶的正常能量饮食（NL）；（2）补充酶的正常能量饮食（NLE）；（3）不补充酶的能量略低的饮食（SL）；（4）补充酶的能量略低的饮食（SLE）。添加到饮食中的酶的量基于先前的体外研究和供应商的建议来确定。在制备总混合日粮之前，将酶和预混物混合。试验持续了42天。结果表明，纤维水解酶的应用对干物质摄入量（drymatteradvance)没有显著影响，但它确实提高了干物质(DM)的消化率，中性洗涤剂纤维（NDF），潜在可消化的NDF(pdNDF)，有机质(OM)，牛奶生产,牛奶尿素氮（MUN），和血尿素氮（BUN）。另一方面,略低能量的饮食导致了STI的减少，牛奶生产,牛奶蛋白质产量，血浆游离氨基酸（FAA），和血浆B-羟基丁酸酯(BHBA)的增加。总之,在奶牛日粮中加入纤维分解酶可以改善DM的消化率，NDF,pdNDF,OM,牛奶生产,和饲料效率。此外，将酶应用于略低能量的饮食导致产奶水平与在饲喂未经处理的正常能量饮食的奶牛中观察到的产奶水平相当。
