乌拉尔甘草茎叶粉替代混播牧草干草粉对绵羊瘤胃体外发酵特性的影响

Effects of Mixed Swards Meal Replaced by the Aerial Parts of Ural Licorice Meal on in Vitro Rumenal Fermentation Characteristics in Sheep

本试验采用体外产气法研究了不同比例乌拉尔甘草茎叶粉替代混播牧草干草粉对绵羊瘤胃体外产气和发酵特性的影响，探讨甘草茎叶饲料添加的适宜比例。乌拉尔甘草（Glycyrrhiza uralensis）茎叶粉替代混播牧草干草粉按0：100（GO）、20：80（G20）、40：60（G40）、60：40（G60）、80：20（G80）与100：0（G100）的比例组合进行体外发酵试验，分别培养2、4、8、12、24、36、48h，研究体外培养发酵48h后其对绵羊瘤胃发酵参数（产气量、体外干物质消化率、发酵液pH、挥发性脂肪酸浓度）的影响。结果表明：累积产气量及产气速率随着乌拉尔甘草茎叶粉在发酵底物中比例的增加而减少，甘草茎叶粉占60％以上的试验组与GO、G20和G40处理间差异显著（P〈0．05）；G0、G20、G40试验组间的体外干物质消化率极显著高于G60、G80、G100（P〈0．01）；随着甘草茎叶粉添加比例的增加，发酵液的总挥发性脂肪酸浓度下降而pH值上升。结果显示，本试验条件下，乌拉尔甘草茎叶替代一般牧千草的比例超过60％时，对绵羊瘤胃发酵具有一定抑制作用，按20％~40％比例添加则无负面影响。

This experiment using in vitro gas production technique was to investigate the effects of mixed swards meal replaced by the aerial parts of ural licorice （Glycyrrhiza uralensis） meal on rumen in vitro fermentation characteristics in sheep, and to obtain the optimal replacement ratio in ration. The in vitro fermentation experiment was incubated with mixed swards meal replaced by the aerial parts of ural licorice meal at ratios of 0：100 （GO）, 20：80 （G20）, 40：60 （G40）, 60：40 （G60）, 80：20 （GS0） and 100：0 （G100） for 2, 4, 8, 12, 24, 36 and 48 h, respectively, observation and assessment of rumen fermentation parameters including gas production, in vitro dry matter digestibility, pH and volatile fatty acid concentration of fermentation liquid for 48 h fermentation in sheep. The results showed that gas volume and rate of gas production were decreased with increasing levels of the aerial parts of ural licorice meal inclusion, and significantly decreased when 60% mixed swards meal replaced by the aerial parts of ural licorice meal compared with GO, G20 and G40 （P〈0.05）; the in vitro dry matter digestibility of GO, G20 and G40 was extremely higher than those of G60, G80, G100 （P〈0.01）; the pH value increased and total volatile fatty acids concentration decreased in the fermentation liquid with increasing of the aerial parts of ural licorice meal. The results indicated that when exceed 60% mixed swards meal replaced by the aerial parts of ural licorice meal was added, it had some inhibitory effects on rumen fermentation, while it had no bad affection that replacement ratio was 20%-40% in sheep under conditions in this study.