利用体外发酵技术研究锡林郭勒草原不同生长期牧草瘤胃内甲烷产生规律

Study on Rumen Methane Emission at Different Growing Stages in Xilinguole Grassland by In Vitro Fermentation Technology

试验研究了锡林郭勒地区典型草原夏季不同月份(7、8、9月),单一和混合牧草瘤胃体外发酵甲烷、氢气、挥发性脂肪酸生成的动态变化规律,为科学估测放牧绵羊甲烷排放及其减排策略制定奠定基础依据。体外发酵瘤胃液供体选择2只装有永久性瘤胃瘘管的湘东黑山羊。通过48h体外模拟发酵试验,测定总产气量、挥发性脂肪酸、干物质消失率和甲烷产量等指标。结果表明:在7、8、9三个月试验期间,随着牧草生长成熟,挥发性脂肪酸、干物质消失率和甲烷产量都有所下降,其中8、9两个月份混合牧草甲烷产量与7月份相比,下降显著(P<0.05)。单一牧草同月份之间差异不显著。干物质消失率表现为羊草的平均干物质消失率最高,针茅的平均干物质消失率最低,随月份增加呈现下降趋势。混合牧草的乙酸、丙酸和乙酸/丙酸比值随月份增加都呈现下降趋势,特别是9月份和7月份相比,差异显著(P<0.05)。单一牧草的乙酸、丙酸和乙酸/丙酸比值变化,随着羊草、针茅生长,下降明显。

In this study,the dynamic changes of methane,hydrogen and volatile fatty acids of rumen fermentation in vitro for single and mixed grasses in different months（7,8,and 9）in Xilinguole grassland were studied,which lay a scientific foundation for the evaluation of methane emission and reduction.Two Xiangdong black goats with permanent rumen fistula were selected to do the experiment.After 48 h＇s in vitro simulated fermentation,the total gas production,volatile fatty acids,dry matter disappearance and methane yield were measured.The results show during the three months,the three indexes were all dropped with the pasture growing,among which methane production of mixed pasture in August and September declined significantly in comparison to that of July（P〈0.05）.That of single pasture had no difference in three months.Average day matter disappearance rate was the highest for Leymus chinensis,and the lowest for Stipa spp,which dropped by the passage of time.Ratio of acetic acid,propionic acid and acetic acid/propionic acid for mixed pasture showed a decreasing trend,especially in September and July（P〈0.05）,and those for single pasture declined remarkably with the growth of Leymus chinensis and Stipa spp.