摘要
The objectives of the trial were to study the effects of dietary crude protein (CP) and tannic acid (TA) on rumen fermentation, microbiota and nutrient digestion in beef cattle. Eight growing beef cattle (live weight 350 ± 25 kg) were allocated in a 2 × 2 crossover design using two levels of dietary CP [111 g/kg dry matter (DM) and 136 g/kg DM] and two levels of TA (0 and 16.9 g/kg DM) as experimental treatments. Each experimental period lasted 19 d, consisting of 14-d adaptation and 5-d sampling. The impacts of dietary CP and TA on ruminal microbiota were analysed using high-throughput sequencing of 16S rRNA gene. Results indicated that no interactions between dietary CP and TA were found on rumen fermentation and nutrient digestibility. Increasing dietary CP level from 111 to 136 g/kg DM increased the ruminal concentrations of ammonia nitrogen (NH3-N) (p < 0.01) and improved the CP digestibility (p < 0.001). Adding TA at 16.9 g/kg DM inhibited rumen fermentation and decreased the digestibility of dietary CP (p < 0.001), DM (p < 0.05) and organic matter (p < 0.01). Increasing the dietary CP level or adding TA did not affect the relative abundances of the major bacteria Firmicutes and Proteobacteria at the phylum level and Prevotella_1 and Christensenellaceae_R-7_group at the genus level, even though adding TA increased the Shannon index of the ruminal bacterial community. TA was partly hydrolysed to pyrogallol, gallic acid and resorcinol in rumen fluid and the inhibitory effects of TA on rumen fermentation and nutrient digestibility could have been resulted from the TA metabolites including pyrogallol, gallic acid and resorcinol as well as the protein-binding effect.
摘要译文
该试验的目的是研究日粮粗蛋白（CP）和单宁酸（TA）对肉牛瘤胃发酵，微生物群和营养物质消化的影响。使用两种水平的日粮CP [111 g / kg干物质（DM）和136 g / kg DM]和两种水平的TA（2），以2×2交叉设计分配8头生长肉牛（活重350±25 kg） 0和16.9g / kg DM）作为实验处理。每个实验期持续19天，包括14天适应和5天采样。利用16S rRNA基因的高通量测序分析了日粮CP和TA对瘤胃微生物群的影响。结果表明，日粮CP和TA之间没有发现瘤胃发酵和养分消化率的相互作用。将日粮CP水平从111增加至136 g / kg DM可增加瘤胃氨氮（NH 3 -N）浓度（p <0.01）并提高CP消化率（p <0.001）。以16.9g / kg DM添加TA抑制瘤胃发酵并降低日粮CP（p <0.001），DM（p <0.05）和有机物质（p <0.01）的消化率。增加日粮CP水平或添加TA不会影响门级主要细菌厚壁菌门和变形杆菌以及属级别的Prevotella_1和Christensenellaceae_R-7_group的相对丰度，即使添加TA也会增加瘤胃细菌群落的香农指数。 TA在瘤胃液中部分水解为邻苯三酚，没食子酸和间苯二酚，TA对瘤胃发酵和营养物质消化的抑制作用可能是由于邻苯三酚，没食子酸和间苯二酚等TA代谢产物以及蛋白结合作用所致。
Ke Zhou[1];Yu Bao[1];Guangyong Zhao[2]. Effects of dietary crude protein and tannic acid on rumen fermentation, rumen microbiota and nutrient digestion in beef cattle[J]. Archives of Animal Nutrition, 2019,73(1): 30-43