关键词: 中草药水提物; 幼龄滩羊; 瘤胃发酵; 细菌组成

Abstract: 【Objective】 The experiment was conducted to investigate the effect of Chinese herbal compound additive of Astragalus membranaceus,Licorice and Sophora alopecuroides on the ruminal fermentation parameters and bacterial composition in Tan lambs. 【Method】 A single factor design was used in the experiment，and forty 3-month-old healthy Tan lambs with similar weight were randomly divided into four groups: Control group (k0),experimental group 1 (s1),experimental group 2 (s2) and experimental group 3 (s3), with ten sheep in each group. The Tan lambs were fed with diets containing 0,0.50%,1.00% and 1.50% compound preparation of Chinese herbal aqueous extract,respectively. The pre trial period for the experiment was 10 days,and the main trial period was 60 days.The rumen fluid was collected orally to measure pH,NH₃-N and volatile fatty acids and other related rumen fermentation parameters.Subsequently,high-throughput sequencing technology was used to determine the diversity of rumen bacteria,then the correlation between the main differential bacterial genera in the rumen and ruminal fermentation parameters was analyzed by sequencing platform. 【Result】 There were no significant changes in levels of total volatile fatty acids (TVFA),propionate,isobutyrate,isovalerate,valerate,NH₃-N and pH in the rumen fluid among the groups (P＞0.05).Compared with k0 group,there were no significant changes in the proportion of acetate and butyrate in s1 and s2 groups (P＞0.05)，in s3 group，the proportion of acetate in rumen fluid was significantly increased (P＜0.05),while the proportion of butyrate was significantly reduced (P＜0.05).In s1,s2 and s3 groups,the proportions of propionate in rumen fluid were significantly reduced (P＜0.05),and the ratios of acetate to propionate were significantly increased (P＜0.05).From the analysis of rumen bacterial diversity,at the phylum level,compared with k0 group,the relative abundance of Firmicutes in s2 and s3 groups were significantly reduced (P＜0.05),the relative abundance of Spirochaetota in s2 group was significantly reduced (P＜0.05),and the relative abundance of Patescibacteria in s1,s2 and s3 groups were significantly reduced (P＜0.05).At the genus level,compared with k0 group,the relative abundance of Selenomonas in s1 group was significantly increased (P＜0.05),while the relative abundance of Treponema in s1 and s2 groups were significantly reduced (P＜0.05).Through correlation analysis,it was found that Fibrobacter was significantly positively correlated with the proportion of acetate and the ratio of acetate to propionate,negatively correlated with the proportion of propionate.Rikenellaceae RC9_gut_group was significantly positively correlated with valerate.Treponema was significantly negatively correlated with pH value (P＜0.05). 【Conclusion】 0.50% compound preparation of Chinese herbal aqueous extract was the optimal concentration for adding to the dietary of Tan lamb,which could adjust the proportion of volatile fatty acids in the rumen,and improve the diversity of rumen bacterial communities.To some extent，the relative abundance of rumen fiber degrading bacteria(such as Fibrobacter) was increased,while the relative abundance of lactic acid inhibiting bacteria (such as Selenomonas) was significantly increased,and the relative abundance of semi fiber degrading bacteria (such as Treponema) was significantly reduced.0.50% compound preparation of Chinese herbal aqueous extract was more suitable for the growth needs of Tan lambs.

Key words: Chinese herbal aqueous extract; Tan lambs; ruminal fermentation; bacterial composition