a State Key Laboratory of Animal Nutrition , College of Animal Science and Technology, China Agricultural University , Beijing , China.
Arch Anim Nutr. 2019 Feb;73(1):30-43. doi: 10.1080/1745039X.2018.1545502. Epub 2018 Dec 4.
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 (NH-N) ( < 0.01) and improved the CP digestibility ( < 0.001). Adding TA at 16.9 g/kg DM inhibited rumen fermentation and decreased the digestibility of dietary CP ( < 0.001), DM ( < 0.05) and organic matter ( < 0.01). Increasing the dietary CP level or adding TA did not affect the relative abundances of the major bacteria and at the phylum level and and 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.
本试验旨在研究饲粮粗蛋白（CP）和单宁酸（TA）对肉牛瘤胃发酵、微生物区系和养分消化的影响。选用 8 头生长育肥牛（活重 350±25 kg），采用 2×2 交叉试验设计，设置 2 个饲粮 CP 水平[111 g/kg 干物质（DM）和 136 g/kg DM]和 2 个 TA 水平（0 和 16.9 g/kg DM）。每个试验期持续 19 d，包括 14 d 的适应期和 5 d 的采样期。采用高通量测序技术对 16S rRNA 基因进行分析，研究饲粮 CP 和 TA 对瘤胃微生物区系的影响。结果表明，饲粮 CP 和 TA 之间不存在互作效应，对瘤胃发酵和养分消化率无影响。CP 水平由 111 g/kg DM 提高到 136 g/kg DM，瘤胃氨态氮（NH-N）浓度升高（<0.01），CP 消化率提高（<0.001）。饲粮添加 16.9 g/kg DM TA 抑制瘤胃发酵，降低 CP（<0.001）、DM（<0.05）和有机物（<0.01）消化率。提高饲粮 CP 水平或添加 TA 均不影响主要细菌门（Firmicutes 和 Bacteroidetes）和属（Prevotella 和 Butyrivibrio）的相对丰度，尽管添加 TA 增加了瘤胃细菌群落的 Shannon 指数。TA 在瘤胃液中部分水解为焦儿茶酚、没食子酸和间苯二酚，TA 对瘤胃发酵和养分消化率的抑制作用可能是由于 TA 代谢物（包括焦儿茶酚、没食子酸和间苯二酚）以及与蛋白质的结合作用所致。
