中文摘要：

本试验旨在研究广藿香精油对锦江黄牛瘤胃体外发酵指标及养分降解率的影响.采用体外批次培养法,在精粗比为20∶80的基础饲粮中添加广藿香精油,添加水平分别为0、0.50％、1.00％、1.50％和2.00％.结果表明：1）与对照组相比,饲粮中添加广藿香精油体外培养24 h后,瘤胃液pH无显著变化（P＞0.05）,氨态氮浓度呈现下降趋势,总产气量、菌体蛋白和乙酸浓度、乙酸/丙酸均提高,其中1.00％组的菌体蛋白浓度比对照组提高了47.73％ （P＜0.01）.2）与对照组比较,各试验组的干物质和中性洗涤纤维降解率无显著变化（P＞0.05）,酸性洗涤纤维和粗蛋白质降解率升高,其中1.50％组酸性洗涤纤维、粗蛋白质降解率分别提高了19.23％ （P ＜0.01）、44.12％ （P ＜0.05）.结果提示,饲粮添加1.00％的广藿香精油能够稳定锦江黄牛瘤胃内环境,增加瘤胃液菌体蛋白浓度,优化发酵类型;添加1.50％的广藿香精油能够提高瘤胃中酸性洗涤纤维和粗蛋白质降解率.

英文摘要：

The objective of this study was to determine the effects of Pogostemon cablin essential oil on in vitro rumen fermentation indices and nutrient degradability of Jingjiang cattle.An in vitro batch culture method was used in the study,and a basal diet with concentrate to forage ratio of 20∶80 was supplemented with Pogostemon cablin essential oil by 0 （control group）,0.50%,1.00%,1.50% and 2.00%,respectively.The results showed as follows：1） compared with control group,rumen fluid pH was not influenced by dietary supplementation of Pogostemon cablin essential oil （P 〉 0.05）,however,the concentration of ammonia nitrogen （NH3-N） was declined,the total gas production,concentrations of acetic acid and microbial protein （MCP）,and the acetic acid/propionic acid were increased.The MCP concentration in 1.00% group was increased by 47.73% （P 〈0.01）.2） Compared with control group,no significant difference was noticed about the degradability of dry matter （DM） and neutral detergent fiber （NDF） in experimental groups （P 〉 0.05）,but the degradability of crude protein （CP） and acid detergent fiber （ADF） in rumen fluid were increased,especially in 1.50% group [CP and ADF degradability was increased by 19.23% （P 〈0.01） and 44.12% （P 〈0.05）,respectively].These results indicate that supplementation of 1.00% Pogostemon cablin essential oil can improve rumen fermentation,increase MCP concentration and optimize fermentation modes; but supplementation of 1.50% Pogostemon cablin essential oil can increase the degradability of ADF and CP in rumen of Jinjiang yellow cattle.