Willow (Salix spp): The potential of a tannin-rich tree fodder to reduce ammonia emissions and improve productivity of dairy cattle

柳树（Salix spp）：富含单宁的树饲料在减少氨排放和提高奶牛生产力方面的潜力

• 批准号: 2643190
• 金额: --
• 依托单位: Queen's University Belfast
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2643190
• 关键词: Willow; Salix; spp; potential; tannin

As the global demand for animal products is rising, these should be produced with less environmental impact. Climate-induced shifts increase feed costs due to increased need for resources (land and water). However, protein is poorly utilized by ruminant livestock and 20-35% of ingested N is excreted via urine and faeces. Therefore, alternative feeds associated with reduce competition for land and constitute industry by-products, are required. Willow (Salix sp.) fodder is used in biofuel production but leaves and branches, up to 18mm diameter, are considered as waste. Willow fodder tree has a high protein content (well above from that required for livestock maintenance) and contains condensed tannins (CT) which bind to proteins, reduce their ruminal degradation and shift N excretion from urine to faeces (environmentally friendly N form). Although willows fodder shows good potential in animal nutrition, data on its nutritive value are scarce. The aim of this project is to evaluate the nutritive value of willow and assess its potential to improve N use efficiency in dairy cows; by also assessing its impact on milk quality. This will be achieved via the following studies: 1. In vitro assessment of the effects of willow CT on rumen digestive capacity. Different willow varieties will be screened using the ANKOM Gas Production System. Measurements include: gas production/composition, fermentation of end products (VFA/ammonia) (QUB), biochemical profile (QUB), and CT quantification and profiling (URE). 2. Optimization of the ensiling process. Two willow varieties with the most potent ammonia inhibitory properties (study 1) will be selected. Raw material will be harvested in two seasons and willow silage (WS), with or without inoculum, will be prepared and stored for 3 months. The most efficient ensiling method will be used for the production of fodder for the animal trials (QUB). 3. Assessment of the effect of WS inclusion in the diet of dairy cow and ammonia emissions. A dairy cow trial will be contacted at AFBI, including the following assessments: (1) Determination of optimum replacement rates of grass silage. The inclusion rates of 2 WSs will be gradually increased with an interval of 7 days until a maximum inclusion rate is determined. (2) Quantifying the effect of WS inclusion on feed intake, milk production, nutrient digestibility, energy/N utilisation efficiency and CH4 emissions. Twelve lactating dairy cows, in a 3(diets)*3 (periods) Latin-Squared design, will be blocked into 4 groups of 3 cows based on live weight, body condition score, parity, lactation stage and milk production. Cows will be randomly allocated, within each group, into 3 diets: control (no WS) and 2 diets (50% and 100% of the maximum level). Each period will include a feeding phase of 19 days in cubicle accommodation, followed by a 9-day digestibility/chamber measurements (6-day period in individual metabolism units plus a 3-day period in indirect open-circuit respiration chambers). Feed intake and faecal/urine outputs will be measured in the final 8 days, while gaseous exchange will be measured on the final 2 days in chambers. (3) Measurement of ammonia emission rate from slurry. A sub-sample of faeces/urine collected during the digestibility/measurement phase will be placed in respiration calorimeter chambers for 2 days to measure ammonia in two different temperatures (5, 200C; to simulate winter and summer temperatures). 4. Reveal how rumen microbes influence metabolic pathways related to N use efficiency and milk quality. Basic milk composition analysis (QUB), FA profiling (URE), metagenomics (QUB) and 500MHz NMR-based metabolomics techniques (URE) using samples from the animal trial will be used to identify rumen microbes, their genes, and relevant metabolic pathways, which promote N use efficiency and milk quality.

随着全球对动物产品的需求正在上升，它们应以较小的环境影响产生。气候引起的转变增加了由于对资源（土地和水的需求增加）而导致的饲料成本。然而，蛋白质被反刍动物牲畜的使用不足，而20-35％的摄入的n被尿液和粪便排泄。因此，需要与减少土地竞争并构成行业副产品相关的替代提要。柳树（Salix sp。）饲料用于生物燃料生产中，但直径高达18mm的叶子和树枝被认为是废物。柳树饲料树具有较高的蛋白质含量（远高于牲畜维持所需的蛋白质），并包含凝结的单宁（CT），它们与蛋白质结合，减少其瘤胃降解并将n从尿液转移到粪便（环境友好的N形式）。尽管柳树饲料在动物营养方面具有良好的潜力，但其营养价值的数据很少。该项目的目的是评估柳树的营养价值，并评估其提高奶牛使用n使用效率的潜力；通过评估其对牛奶质量的影响。这将通过以下研究来实现：1。在体外评估柳树CT对瘤胃消化能力的影响。将使用Ankom气体生产系统筛选不同的柳树品种。测量包括：气体产生/组成，最终产物的发酵（VFA/氨）（QUB），生化剖面（QUB）以及CT量化和分析（URE）。 2。隔离过程的优化。将选择两个具有最有效氨抑制特性的柳树品种（研究1）。原材料将在两个季节中收获，并在有或没有接种物的情况下收获柳树青贮饲料（WS），并将准备3个月。最有效的累积方法将用于生产动物试验（QUB）的饲料。 3。评估WS包含在乳制牛和氨排放饮食中的影响。将在AFBI进行乳制牛试验，包括以下评估：（1）确定最佳的草药替代率。 2 WS的纳入率将逐渐增加，间隔为7天，直到确定最大纳入率。 （2）量化WS包含对饲料摄入量，牛奶产生，营养消化率，能量/N利用率效率和CH4排放的影响。在3（饮食）*3（时期）拉丁方格设计中，十二头乳制奶牛将根据活体重，身体状况评分，奇偶校验，哺乳期和牛奶的产量而被阻塞为4组3奶牛。牛将在每组中随机分配为3种饮食：对照（无WS）和2种饮食（最大水平的50％和100％）。每个时期将包括在隔间住宿中的19天的喂养阶段，然后进行9天的消化率/腔室测量（单个新陈代谢单位为6天，以及间接开路呼吸室的3天期间）。饲料摄入量和粪便/尿液输出将在最后8天内测量，而在腔室的最后2天将测量气态交换。 （3）测量浆液中氨发射速率。在消化率/测量阶段收集的粪便/尿液的子样本将在呼吸量热室中放置2天，以在两个不同温度（5、200C；模拟冬季和夏季温度）中测量氨。 4。揭示瘤胃微生物如何影响与N使用效率和牛奶质量有关的代谢途径。基本牛奶成分分析（QUB），FA分析（URE），宏基因组学（QUB）和500MHz NMR基于NMR的代谢组学技术（URE）使用动物试验中的样品将用于识别瘤胃微生物，其基因和相关的代谢途径，从而促进N使用效率和牛奶质量。