Influence of hydrolysis rate of urea on ruminal bacterial diversity level and cellulolytic bacteria abundance in vitro.
Influence of hydrolysis rate of urea on ruminal bacterial diversity level and cellulolytic bacteria abundance in vitro.
复制标题
尿素水解速率对体外瘤胃细菌多样性水平和纤维素分解菌丰度的影响
作者：
Wang P;Zhao S;Nan X;Jin D;Wang J
本试验旨在体外研究尿素水解率对瘤胃细菌多样性水平和纤维分解菌丰度的影响。为控制尿素水解速率，采用2 × 2析因设计，分别添加尿素和脲酶抑制剂乙酰异羟肟酸（AHA），尿素添加量为0或20 g/kg干物质（DM），AHA添加量为0或450 mg/kg DM。从三头中国荷斯坦奶牛收集瘤胃液，饲喂TMR，并在添加尿素和AHA后在39 °C下孵育12小时。通过化学分析测定了瘤胃发酵参数，包括氨态氮（NH3-N）和尿素氮浓度、脲酶活性和微生物粗蛋白。变性梯度凝胶电泳（DGGE）分析细菌多样性。采用定量PCR检测细菌总数和纤维素分解菌丰度。结果表明，添加AHA显著降低了尿素的氨生成速率。根据16 S DGGE图像的Shannon-Weiner指数，尿素和AHA的补充显著增加了细菌群落多样性水平。此外，根据DGGE和系统聚类分析，以尿素的氨释放速率为指标对瘤胃细菌谱进行了分离。尿素的补充降低了纤维素分解菌的丰度，如白色瘤胃球菌、R. flavefaciens，Fibrobacter succinogenes，和Butyrivibrio fibrosolvens，但抑制尿素水解AHA此外缓解了减少在早期的孵化期。总之，脲酶抑制剂诱导的氨缓释影响了瘤胃细菌多样性水平，减轻了培养12 h和F.在孵化的早期阶段。
The objective of this experiment was to evaluate the effects of urea hydrolysis rate on ruminal bacterial diversity level and cellulolytic bacteria abundance in vitro. To control urea hydrolysis rate, urea and urease inhibitor (acetohydroxamic acid, AHA) were supplemented to a 2 × 2 factorial design, with urea supplemented at 0 or 20 g/kg dry matter (DM) of substrate, and AHA equivalent to 0 or 450 mg/kg DM of substrate. Ruminal fluid was collected from three Chinese Holstein dairy cows, fed a TMR, and incubated at 39 °C for 12 h after the addition of urea and AHA. Rumen fermentation parameters, which indicated the rate of ammonia formation (including ammonia-nitrogen (NH3-N) and urea-nitrogen concentrations, urease activity, and microbial crude protein) were measured by chemical analysis. Bacterial diversity was analyzed by denaturing gradient gel electrophoresis (DGGE). Total bacteria and cellulolytic bacteria abundance was detected by quantitative PCR. Results showed that AHA addition significantly decreased the rate of ammonia formation when urea was supplemented. Urea and AHA supplementation significantly increased the bacterial community diversity level according to the Shannon–Weiner index of 16S DGGE images. Furthermore, ruminal bacterial profiles were separated by ammonia release rate when urea was supplemented, according to the DGGE and hierarchical cluster analysis. Urea supplementation reduced the abundance of cellulolytic bacteria, such as Ruminococcus albus, R. flavefaciens, Fibrobacter succinogenes, and Butyrivibrio fibrosolvens, but inhibition of urea hydrolysis by AHA addition alleviated the reductions during the early period of incubation. In conclusion, slow release of ammonia induced by urease inhibitor influenced the ruminal bacterial diversity level and lessened the inhibition of total bacteria growth at the incubation of 12 h and F. succinogenes during the early period of incubation.
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影响因子：
4.2
作者：
Denman, Stuart E.;McSweeney, Christopher S.
通讯作者：
McSweeney, Christopher S.
影响因子：
3.2
作者：
Amaya, KR;Kocherginskaya, SA;Cann, IKO
通讯作者：
Cann, IKO
影响因子：
2
作者：
Granja-Salcedo, Yury T.;Ribeiro Junior, Carlos S.;Berchielli, Telma T.
通讯作者：
Berchielli, Telma T.
影响因子：
3.5
作者：
MAKKAR, HPS;SHARMA, OP;NEGI, SS
通讯作者：
NEGI, SS
影响因子：
3.6
作者：
Makkar, HPS;Becker, K
通讯作者：
Becker, K