摘要
Several feed additives have been assessed for their potential to reduce enteric methane (CH4) emissions from ruminants. It has been suggested that combination of individual dietary enteric CH4 mitigation strategies may results in larger increases compared when each individual strategy is applied alone. In this study, the aim was to determine the effects of increasing doses of active dry yeast Saccharomyces cerevisiae (ADY), surfactant, or their combination on rumen microbial fermentation and CH4 production using in vitro batch culture. For this purpose, 24 h batch cultures of ruminal fluid incubations were conducted in a complete randomized block design (repeated 3 times) that included a negative control (no additive), a positive control (monensin, 10 mg/L), ADY (15, 30, 60, 150, 600, 1200 mg/L), surfactant (0.03, 0.06, 0.12, 0.30, 0.60 and 2.00 mL/L), and 6 mixtures resulting from the combination of each level of S. cerevisiae and the surfactant. Compared with the negative control, monensin increased propionate at the expense of acetate, decreased ammonia (NH3) concentration and CH4 production (−28%). The addition of ADY at 600 and 1200 mg/L increased total gas production and total volatile fatty acid (VFA) concentration and lowered media pH. These ADY doses, did not affect propionate concentration but increased acetate concentration, CH4 production (up to 18% increase), and NH3 concentration. At the doses of 0.30, 0.60, and 2.00 mL/L, the surfactant decreased total gas production, total VFA and acetate concentrations, but increased propionate concentration. At doses ≥ 0.30 mL/L, surfactant decreased CH4 production by up to 70%. When the mixture consisted of doses of ADY ≥ 150 mg/L and surfactant ≥ 0.30 mL/L, changes in fermentation characteristics and CH4 production were similar to the doses observed when the surfactant was supplied alone at the same concentrations provided in the mixture. In conclusion, under the experimental conditions of this in vitro study, results show that surfactant has the potential to mitigate enteric CH4 emissions. However, ADY supply increased CH4 production and NH3 concentration. An increase in ruminal NH3 may increase urinary N excretion, which may result in greater ammonia and nitrous oxide emissions. No benefits can be therefore expected from combining ADY with surfactant to alter favorably rumen microbial fermentation to reduce enteric CH4 emissions. However, given the differences between in vitro and in vivo methodologies, validation of our findings in vivo is warranted.
摘要译文
已经评估了几种饲料添加剂，以减少反刍动物的肠甲烷（CH 4）排放的潜力。已经提出，单独采用单独的策略时，单个饮食中的CH 4缓解策略的组合可能会导致更大的增加。在这项研究中，目的是确定酿酒酵母（ADY），表面活性剂的剂量增加的影响，或使用体外批处理培养物对瘤胃微生物发酵和CH 4产生的组合。为此，在完整的随机块设计（重复3次）中进行了24小时的瘤胃液孵育培养物，其中包括阴性对照（无添加剂），阳性对照（Monensin，10 mg/L），ADY（15），30、60、150、600、1200 mg/l），表面活性剂（0.03、0.06、0.12、0.30、0.30、0.60和2.00 ml/l），以及6个混合物，由苏氏链球菌和表面活性剂和表面活性剂的每个水平组合产生。与阴性对照相比，Monensin以乙酸代码为代价，氨（NH 3）浓度降低和CH 4产生（-28％）。在600和1200 mg/l的ADY增加增加了气体产量和总挥发性脂肪酸（VFA）浓度，并降低了培养基pH。这些ADY剂量不影响丙酸丙酸酯的浓度，而是乙酸浓度升高，CH 4产生（增加18％）和NH 3浓度。在0.30、0.60和2.00 mL/L的剂量下，表面活性剂降低了总气体产量，总VFA和乙酸浓度，但丙酸浓度升高。在≥0.30mL/L的剂量下，表面活性剂的CH 4产量降低了70％。当混合物由ADY≥150mg/L的剂量组成，表面活性剂≥0.30mL/L时，发酵特性的变化和Ch 4产生的变化与当在混合物中提供的相同浓度下单独提供表面活性剂时观察到的剂量相似。总之，在这项体外研究的实验条件下，结果表明，表面活性剂有可能减轻肠肠体CH 4排放。但是，ADY供应增加了CH 4的产量和NH 3浓度。瘤胃NH 3的增加可能会增加尿液的排泄，这可能导致氨和一氧化二氮排放。因此，将ADY与表面活性剂结合起来可以改变有利的瘤胃微生物发酵以减少肠ch 4排放量。但是，鉴于体外和体内方法之间的差异，有必要对我们的体内发现的验证。
W.Z. Yang [c]. Effects of active dried yeast (Saccharomyces cerevisiae), a non-ionic surfactant, or their combination on gas production, rumen microbial fermentation and methane production in vitro[J]. Animal Feed Science and Technology, 2024,307: 115844