By 2050, the U.S. beef industry must produce an extra 40 million tons of beef to satisfy the global demand. Such an increase in inventory will undoubtedly enhance methane (CH4) production from livestock, which should be reduced by over 20%. The addition of plant secondary metabolites, such as anacardic acid present in cashew nutshell extract (CNSE), has shown promising results in reducing CH4 yield, although its effects seemed to be diet dependent. This study evaluated the addition of CNSE to a high-grain diet (85:15 Grain: forage) on in vivo CH4 emissions, nutrients digestibility, performance, feeding behavior, and ruminal fermentation parameters of beef steers. Sixteen Angus crossbred steers [599 ± 40 kg of bodyweight (BW)] and six ruminally cannulated crossbred steers (490 ± 51 kg of BW) were utilized in a crossover design with 2 experimental periods of 56 d each, composed by 14 d of adaptation, 35 d of measurement, and 7 d of washout. Following adaptation, steers were sorted by BW, and assigned to receive no additive (CON) or CNSE at 5 g/steer/d. Data were analyzed using the MIXED procedure of SAS. Inclusion of CNSE increased (P < 0.05) propionate concentration and molar proportion (MP; mol/100 mol), tended to decrease acetate MP (P = 0.10), reduced the acetate: propionate (A:P) ratio (P = 0.05), and MP of branched chain volatile fatty acids (P < 0.01). Neither in vitro organic matter digestibility nor in vitro CH4 yield were affected by CNSE inclusion (P > 0.05). Steers receiving CNSE exhibited greater (P < 0.05) final BW, dry matter intake (DMI), and average daily gain (ADG) but lesser (P < 0.05) in vivo CH4 emission rate (g/d), yield (g/kg of DMI), and intensity (g/kg of ADG). Meal length, bunk visit duration, and apparent total tract digestibility of DM increased (P < 0.05) after CNSE addition. Considering CNSE-supplemented steers spent more time in the feedbunk and exhibited higher DMI, CH4 mitigation was unlikely associated with intake reduction. The addition of CNSE to a high-grain diet in beef steers demonstrated significant improvements in animal performance and reduced CH4 emissions, as the result of shifts in ruminal fermentation patterns, favoring propionate instead acetate concentration, leading to a reduction in the A:P ratio. CNSE shows promise as a strategy to enhance beef industry sustainability.

中文翻译：

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在高谷物育肥饲料中添加腰果壳提取物对阉牛甲烷排放、营养消化率和瘤胃发酵的影响


到 2050 年，美国牛肉行业必须额外生产 4000 万吨牛肉才能满足全球需求。这种库存的增加无疑会提高畜牧业的甲烷 （CH4） 产量，这应该减少 20% 以上。添加植物次生代谢物，例如腰果壳提取物 （CNSE） 中存在的漆树酸，在降低 CH4 产量方面显示出有希望的结果，尽管其影响似乎取决于饮食。本研究评估了在高谷物饮食（85：15 谷物：饲料）中添加 CNSE 对肉牛体内 CH4 排放、营养物质消化率、性能、摄食行为和瘤胃发酵参数的影响。16 头安格斯杂交公牛 [599 ± 40 公斤体重 （BW）] 和 6 头反刍空饲杂交公牛 （490 ± 51 公斤 BW） 用于交叉设计，有 2 个实验期，每个实验期 56 天，由 14 天适应、35 天测量和 7 天洗脱组成。适应后，按 BW 对公牛进行分类，并分配接受 5 g/steer/d 的无添加剂 （CON） 或 CNSE。使用 SAS 的 MIXED 程序分析数据。加入 CNSE 增加了 （P < 0.05） 丙酸盐浓度和摩尔比 （MP;mol/100 mol），倾向于降低乙酸盐 MP （P = 0.10），降低了乙酸盐：丙酸盐 （A：P） 比 （P = 0.05） 和支链挥发性脂肪酸的 MP （P < 0.01）。体外有机物消化率和体外 CH4 产量均不受 CNSE 包涵的影响 （P > 0.05）。接受 CNSE 的公牛表现出较高 （P < 0.05） 最终体重、干物质摄入量 （DMI） 和平均日增重 （ADG） 但较低 （P < 0.05） 体内 CH4 排放率 （g/d）、产量 （g/kg DMI） 和强度 （g/kg ADG）。 添加 CNSE 后，DM 的进餐时间、上铺时间和表观总消化率增加 （P < 0.05）。考虑到补充 CNSE 的阉牛在饲喂站中花费的时间更长并且表现出更高的 DMI，CH4 缓解不太可能与摄入量减少相关。在肉牛的高谷物饮食中添加 CNSE 表明，由于瘤胃发酵模式的变化，有利于丙酸盐而不是乙酸盐浓度，导致 A：P 比率降低，因此在牛肉阉牛的高谷物饮食中添加 CNSE 表明动物生产性能显著改善并减少了 CH4 排放。CNSE 有望成为提高牛肉行业可持续性的战略。