體外發(fā)酵法評估呼倫貝爾羊瘤胃對過瘤胃蛋氨酸的生物利用率及過瘤胃蛋氨酸對瘤胃微生物的影響

doi：10.3969/j.issn.1000-4440.2024.05.012

收稿日期：2023-06-13

基金項(xiàng)目：中國科學(xué)院國際伙伴計(jì)劃項(xiàng)目（161343KYSB20200015）

作者簡介：羅志斌（1999-），男，湖南婁底人，碩士研究生，從事反芻動物營養(yǎng)研究。（E-mail）1851375407@qq.com

通訊作者：焦金真，（E-mail）jjz@isa.ac.cn

摘要：" 為了探究呼倫貝爾羊瘤胃體外發(fā)酵體系對過瘤胃蛋氨酸（RPMet，由玉米淀粉和棕櫚油包被）的生物利用率及過瘤胃蛋氨酸對瘤胃微生物類群的影響，取4只裝有瘺管的雌性呼倫貝爾羊的瘤胃液進(jìn)行體外發(fā)酵試驗(yàn)，在發(fā)酵起始階段與發(fā)酵后2 h、4 h、6 h、8 h、12 h、24 h測定發(fā)酵體系中的RPMet降解率。每個發(fā)酵時間節(jié)點(diǎn)設(shè)置5個平行處理，在以上7個時間節(jié)點(diǎn)取發(fā)酵液并進(jìn)行16S rDNA測序分析。結(jié)果表明，在體外發(fā)酵體系中，RPMet在發(fā)酵后8 h的降解率小于30.0%，說明該產(chǎn)品的包被效果較好。測序結(jié)果顯示，發(fā)酵24 h后的Simpson指數(shù)顯著低于發(fā)酵12 h后的Simpson指數(shù)（Plt;0.05）。主坐標(biāo)分析（PCoA）能夠顯示物種的β-多樣性，本研究結(jié)果顯示，各時間點(diǎn)的聚類結(jié)果皆存在顯著差異（Plt;0.05）。擬桿菌門、瘤胃球菌屬、普雷沃氏菌屬菌的相對豐度在發(fā)酵后8 h內(nèi)顯著上升，發(fā)酵12 h后顯著下降（Plt;0.05）。厚壁菌門、廣古菌門、甲烷桿菌屬、解琥珀酸菌屬、顫螺菌屬菌的相對豐度在發(fā)酵后12 h內(nèi)顯著下降，之后顯著上升（Plt;0.05）。綜上所述，研究中所用的RPMet的包被效果較好，且發(fā)酵前期主要是普雷沃氏菌屬、瘤胃球菌屬微生物降解玉米淀粉包被層，而RPMet的過度降解顯著提高了甲烷桿菌屬微生物的相對豐度。

關(guān)鍵詞：" 過瘤胃蛋氨酸；綿羊；體外發(fā)酵；16S rDNA；微生物

中圖分類號：" S852.23""" 文獻(xiàn)標(biāo)識碼：" A""" 文章編號：" 1000-4440（2024）05-0874-07

Evaluation for bioavailability of rumen protected methionine and its effects on rumen microorganisms in Hulun Buir sheep by in vitro fermentation

LUO Zhibin1，2，" OU Huimin1，2，" LI Jianzhong2，" TAN Zhiliang1，" JIAO Jinzhen1

（1.Institute of Subtropical Agriculture， Chinese Academy of Sciences/Key Laboratory of Agro-ecological Processes in Subtropical Region/National Engineering Laboratory for Poultry Breeding Pollution Control and Resource Technology/Hunan Key Laboratory of Animal Nutritional Physiology and Metabolic Process， Changsha 410125， China;2.College of Life Sciences， Hunan Normal University/Hunan Provincial Key Laboratory of Animal Intestinal Function and Regulation， Changsha 410081， China）

Abstract：" The purpose of this study was to investigate the bioavailability of rumen-protected methionine （RPMet， coated with corn starch and palm oil） in the rumen in vitro fermentation system of Hulun Buir sheep and the effects of rumen-protected methionine on rumen microbial groups. The rumen fluids of four female Hulun Buir sheep with fistulas were taken for in vitro fermentation test. The degradation rate of RPMet in the fermentation system was determined at the initial stage of fermentation and 2 h， 4 h， 6 h， 8 h， 12 h and 24 h after fermentation. Five parallel treatments were set up at each fermentation time node， and the fermentation broth was taken at the above seven time nodes for 16S rDNA sequencing analysis. The results showed that the degradation rate of RPMet was less than 30.0% at 8 h after fermentation in the in vitro fermentation system， indicating that the coating effect of the product was good. The sequencing results showed that the Simpson index at 24 h after fermentation was significantly lower than that at 12 h after fermentation （Plt;0.05）. Principal coordinate analysis （PCoA） could show the β-diversity of species. The results of this study showed that there were significant differences in the clustering results at each time point （Plt;0.05）. The relative abundance of Bacteroidetes， Ruminococcus and Prevotella increased significantly within 8 h after fermentation， and decreased significantly after 12 h of fermentation （Plt;0.05）. The relative abundance of Firmicutes， Euryarchaeota， Methanobrevibacter， Succiniclasticum and Oscillibacter decreased significantly within 12 h after fermentation， and then increased significantly （Plt;0.05）. In summary， the coating effect of the RPMet product is good. The Prevotella and Ruminococcus act as main genera to degrade the coating layer of corn starch during the early fermentation period， while excessive degradation of RPMet significantly increase the abundance of Methanobrevibacter.

Key words：" rumen protected methionine;sheep;in vitro fermentation;16S rDNA；microorganism

對反芻動物而言，氨基酸是其重要的營養(yǎng)來源之一，然而在實(shí)際生產(chǎn)中，大部分氨基酸在反芻動物瘤胃中就會被微生物分解利用，只有少量到達(dá)小腸并被機(jī)體吸收利用。……